Table 8. Characteristicsof the First Pulse of the Experiments inthe 300-m-dim Cylinder. .
Time to Solution Rateof Minimum Peak of Height at Volume at Reactivity Doubling Inverse Specific Energy Experiment Pulsea Peak Power Peak Power Addition Time Period in Pulse Number set cm (liter) (dollars/set) set see-' (10'" fissions/cm3) CRAC 01 232 329 226 o.oo341 2.9 0.24 1.2 CRAC02 72 255 173 -- 0.18 3*9 1.0 CRAC03 427 274 186 o.oo141 0.138 0.93 CRAC04 197 331 225 0.00391 3':; 0.216 1.0 CRAC05 21.6 82.2 56.0 0.0667 0.060 11.6 l-1 CRACOG 22.8 82.4 56.2 0.0740 0.050 13*9 1.2 CRAC07 3.9 29-7 20.5 0.786 0.00157 442 .2.0 cruw 08 29.3 20.3 0.746 0.00069 1004 4.0 CRAC09 24' 47.1 32-3 0.247 0.015 46 1.4 CRAC 10 6.6 44 .o 30.2 0.0772 0.0176 39.4 1.4 CRAC il -a -- -- mm CRAC 12 ii; iii.3 ;;.8 0.0156 o-275 2.52 1.2 CRAC13 7*5 53.3 36.5 0.157 0.012 T-7 1.4 CRAC14 12.0 4 5.4 31*1 0.0992 0.049 14.1 l-3 CRAC15 4.0 43.6 29-9 o-253 0.033 20.8 1.2 CRAC 16 11.2 44.1 3o*3 0.0755 0.242 2.86 l-2 CRAC17 11-7 44.3 30.4 0.0820 0.177 3.92 1.2 CRAC18 43.8 43.8 30*1 0.0168 0.2 l-33 1.2 cw 19 16.2 44.9 30.8 0.0870 0.036 19.2 1.1 $g CRAC20.1 2.2 28.4 19-i 0.674 0.0061 114 1.0 $ CRACCRAC!20.320.2 2.2 28.4 19.7 0.684 0.0063 ll0 1.1 2.4 28.6 19.8 0.691 0.0066 lo5 1.0 CRAC20.4 3*4 29.2 20.2 0.685 0.00118 587 2.9 CRAC 20.5 2-5 28.5 19.7 0.616 0.00~ I20 1.1 CRAC!21 17.0 45.4 31* 1 o.o833 0.032 21.6 1.0 CRAC 22 4.6 28.9 20.0 0.501 0.00147 471 2.1 CRAC 23 4.6 39.6 27.2 0.310 o.oog.3 I20 1.6 cwic 24 -- -- me es -- CRAC25 ii.0 22.2 0.871 0.00153 4;; l-7 CRAC 26 78.: 33.6 23.1 0.638 0.0027 252 l-7 CRAC27 I+:7 41.3 28.4 o-315 0.032 56 1.2 CRAC28 8.8 42.3 29.1 0.226 0.011 63 l-3 CRAC 29 44. 9 30.0 0.0808 0.032 21.7 1.1 V /- Report SRSC no 223- September 1994
SILENE Reactor
Results of selected typical experiment
Francis BARBRY
CEA INSTITUT DE PROTECTION ET DE SURETE NUCLEAIRE DEPARTEMENT DE RECHERCHES EN SECURITE SERVICE DE RECHERCHES EN SUKETE ET CRITICITE Crntrr d’Etudo dr VALDUC - SRSC - 21 120 Is-sur-Tillv - Francr - P 80 23 40 00 SILENE
SUMMARY OF REFERENCE DATA AND LIST OF
THE MOST REPRESENTATIVE EXPERIMENTS
SUMMARY
This document recapitulates the most representative experimental results found on the Silene reactor in a configuration without shielding in studies on solution criticality accidents. Most of this data is relative to the nominal operating concentration of the reactor, i.e. 71 g/l, but in the appendix we have also included the results of a test series at 220 g/l as well as the results of the reactor calibration campaign.
This set of reference data can of course be used by the ‘operator, but was initially compiled for validating computing models of accidental criticality excursions.
Two documents reviewing the lessons learned from the SILENE experiments are given in appendix.
I1 y a eu quelques erreurs de pages entre le franqais et l’anglais lors d’un ler tirage du rapport. Pour kviter un gaspillage ces exemplaires ont CtC conservks pour la diffusion interne SRSC, les documents partis h l’extkrieur ayant CtC rectifiks. Les pages inverskes concernent les tableaux, symboles, .. . (pages entre le texte principal et les figures illustrant les expkiences SILENE) 2
CONTENTS
1 - GENERAL INFORMATION AND SILENE OPERATING PRINCIPLE
2 - THE REACTOR CORE AND ITS VARIOUS MODES OF OPERATION 2 - 1 - Description of the core 2 - 2 - The cell 2 - 3 - The fissile solution at nominal operating concentration 2 - 4 - Control rods and the corresponding control devices 2 - 5 -Operating modes
‘. 3 - REACTOR DIAGNOSIS 3 - 1 - Total number of fissions 3 - 2 - Monitoring power and radiation emission rate 3 - 3 - Routine diagnosis ‘. 3 - 4 - TempCrature and pressure measurements 3 - 5 - Measuring the fissile solution level
4 - NEUTRON DATA USED FOR REACTIVITY CALCULATION WITH THE DE 71 g.l-1 CONCENTRATION 4 - 1 - Neutron data 4 - 2 - Reactivity calculations
5 - RESULTS OBTAINED WITH THE DE 71 g.l-1 CONCENTRATION
APPENDIX 1 - Results obtained on SILENE reactor with a uranium concentration of 220 g.1’l
APPENDIX 2 - Results of the SILENE reactor calibration campaign
APPENDIX 3 - A review ofthe SILENE criticality excursions experiments 3
l- GENERAL INFORMATION AND SILRNR OPERATING PRINCIPLE
Silene is a homogeneous experimental reactor using a fissile solu- tion of uranyl nitrate (U enriched in 235U at 92.7%) as fuel.
The core is in the form of a small annular tank located in the middle of a large concrete room referred to as a "cell". The fissile solution required for operation of the reactor is prepared in a labora- tory located in the cell basement (ref:' 1 t&3).;
The general operating principle of the reactor is as follows:
- The'fissile solution, previously adjusted to the Silene operation concentration in a special large capacity tank, is pumped into the core up to predetermined supercritical level. During this phase, a control rod is present in the core to avoid divergence.
- The "divergence" power excursion is then produced by removing the rod from the core using a procedure which depends on the operating mode selected for the planned experiment.
- When the experiment has been completed, the fissile solution con- taining the radioactive fission products is dumped into a special tank located in a shielded room, allowing rapid access into the cell.
A ventilation circuit blows continuously through the upper part of the core to dilute radiolysis gases formed. After the time necessary for their radioactive decay, these gases are removed through ad hoc filtration systems. 4
2 - THE REACTOR CORE AND ITS VARIOUS MODES OF OPERATION
2.1 - DescriDtion of the core
The Silene core is in the form of a 1 m high, 360 mm diameter stainless steel core with a 70 mm diameter internal channel (Figure 3
- Main dimensions
External cylinder 360/368 mm Internal channel 70/76 mm Tank bottom thickness 36 mm Cover thickness 30 mm
- Composition of the stainless steel used (grade ZZ-CN 18.10)
Isotope Number of atoms x 10mz4 cm-?
Carbon 1.200 10“ Silicon 1.709 10-3 Chromium 1.661 10-z Iron 5.922 10-s Nickel 8.178 10-j
2.2 - me cell
The core is located in a concrete room with dimensions of 19 x 12 x 10 m and walls 1.5 m thick (Figure $).
The concrete composition is as follows:
EIIotope 1 Number of atoms x 10mz4 cm-j
Hydrogen 1.035 10-z Boron-10 1.602 1O-6 .' Oxygen 4.347 10-a Aluminum 1.563 10-j Silicon 1.417 10-Z Calcium 6.424 1O-3 Iron 7.621 10" 5
2.3 - The fissile solution at nominal 0Deratine concentration
The fissile solution used is uranyl nitrate, which, at the nominal
cOncentrati0n Of 71 g.l-1 chosen for reactor operation, has the following mean properties:
Density 1.161 g.cmS3 Total U concentration 71 g.1-1 Acidity H+ 2N 235U enrichment 92.7%
giving the following composition :
I Isotope I Number of atoms x 10mzc cmS3 Hydrogen 6.258 1O-2 Nitrogen 1.569 10-j Oxygen 3.576 1O-2 Uranium-234 1.060 1O-6 Uranium-235 1.686 10-4 Uranium-236 4.350 lo-' Uranium-238 1.170 10-s
This is a mean composition used as reference in the calculations, since it is obvious that the value of these parameters must have varied during the experiments, reprocessing and various adjustments.
The reactor calibration experiments (Ref.3) were carried out at various concentrations. A series of specific experiments was performed at a concentration of about 200 g.l-'. However, the mean nominal con- centration during reactor operation is 71 g.l-'.
2.4 - Control rods and the corresDondine control devices
Divergence in accordance with the selected procedure is initiated by rapidly or slowly displacing a rod at a predetermined speed within the central core channel. The rods are annular, allowing for the possibility I of adding test capsules in the central channel which then act as an irradiation channel. 6
There are several types of rods, wrongly called control rods, but which are actually reactivity insertion rods. The two most commonly used are made of cadmium and boron carbide. A special rod was designed for "boiling" type experiments which require reactivities of up to 5800 pcm (7.3 $1.
The reactivity values of these rods for the 71 g.l-' concentration are as follows:
Cadmium rod Akp < 3220 pcm (4.1 $) B,C rod Akp < 4560 pcm (5.8 $) Special "boiling" rod Akp < 5800 pcm (7.3 $>
Only the "Cadmium" rod was calibrated with precision (Ref. 4) since it was the only rod authorized for high reactivity insertions ("free evolution" mode).
Figures 5 show the rate of reactivity insertion with the ,C.. rod and the "critical' position of the rod respectively, for different heights of the fissile solution within the core.
There are two types of control mechanisms for removing the rod from the core:
. a mechanical device allowing rod displacements I 20 cm.s-';
. a pneumatic device which can eject the rod at about 1.5 m.s-I.
It should be understood that when constructed, Silene had a single mechanical device operating as follows :
- in "pulse" ejection, of the rod at 20 cm.s" - in "free evolution" rod output at 2 cm.s-' - in "steady state" rod displacements at-2 mm.s-'
Due to the fact that a significant percentage of “pdSeS” resulted in premature initiation of the chain reaction and therefore did not allow 7
pure reactivity "steps", it was decided two years later that a pneumatic device would be added to allow faster rod ejections to avoid any initiation of divergence before the rod was totally removed from the core. Since this period, no "pulses" have "failed".
2.5 - Operating modes
Depending on the reactivity present within the core, the rod ejec- tion speed, and the presence or absence of an auxiliary neutron source, Silene can operate in 'one of three different modes called "PULSEn, "FREE EVOLUTION" and "STEADY STATE".
- Operation in "Pulse" mode is obtained by ejection of the rod at high speed (0.2 or approx. 2 m.s"> with or without the presence of an . . auxiliary neutron source, allowing it to obtain a very high power peak in a short time (up to 1000 megawatts in a few milliseconds). This is there- fore a fast transient. The reactivity in this mode of operation is limited to 2400 pcm due to a pressure wave generated in the liquid (value limited to 8 bars absolute pressure in the Silene configuration).
. - "Free evolution" operation takes place by removal of the rod at low speed (< 2 cm-s-') in the presence of an auxiliary neutron source'. The reactivity engaged under normal operation cannot exceed 4000 pcm, but under exceptional circumstances can be increased to 5800 pcm if it is required to bring the fissile solution to boiling state.
- "Steady state" operation is obtained by having the rod controlled by a control sequence. Rod displacements take place very slowly (about
1 Reminder of the role of the external neutron source: When the presence of an external neutron source is indicated in the specifications of the experiment, this refers to a 100 mCi Am-Be source iocated at the bottom of the core tank (Figure a). Its role is to gener- ate a deterministic initiation of the chain reaction by increasing the initial neutron population in the system (Ref. 5). It is obvious that to obtain a high reactivity "step", it is better to operate without an external neutron source and with the highest possible rod ejection speed so that all reactivity is inserted before the first persistent neutron chain is initiated. 8
2 mm.s-l) in the presence of an auxiliary neutron source. In this mode of operation, Silene is brought to a predetermined stable power level.
The performances of Silene in the three operating modes described above are illustrated and specified in Figure No. 6.
3 - RKACTOR DIAGNOSTICS
3.1 - Total number of fissions
The main objective of an experimental reactor is to have the closest possible control over the total released energy; in our case, this means determining the total number of fissions during the experiment.
Two methods can be used for this purpose, namely gamma ,spectrometry on the fission products formed, and thermal balance.
- Spectrometry
The total number of fissions carried out during an experiment can be determined by taking a sample of the fissile solution after the experiment and analyzing judiciously selected fission products by gamma spectrometry. In the case of Silene, the fission products used are generally as follows:
Radionuclide Energy KeV Period X emission Fission yield
"TC 140.52 66.02 h 89.4 X 6.16 x
132Te 228 78.8 h 90 x 4.26 X
lb3Ce 293.1 33 h 46 X 5.91 %
lo3Ru 497.1 39.35 dy 89.7 x 3 x
g5Zr 756.7 65.2 dy 54 % 6.2 % ', gsMO 739.4 66.02 h 11.82 x 6.16 % 9
Applied strictly, this method provides an accuracy of 5X, taking into account all statistical errors as well as errors due to the data libraries used.
- Thermal balance
It was observed on Silene that during short duration experiments (<2 minutes), the system was significantly adiabatic due to extremely low thermal exchange coefficients with the environment. Heating the fissile solution can therefore be used as a method of diagnosis provided that the temperature of the solution is uniform, in other words if there is enough mixing by radiolysis gases, and also provided that the thermal charac- teristics of the solution are well known.
In the case of uranyl nitrate solutions, we can establish the thermal balance by using the following relationship determined from experiments carried out in the Valduc laboratory:
CP - 0.0008154 x Cu - 0.06 H + t
At a concentration of 71 g.l", C, is approximately 0.82 Cal.g-l "C-l.
3.2 - Honitorine Dower and radiation emission rate
In order to monitor the evolution of reactor power, different types of detectors were used (fission chambers, scintillators, ionization cham- bers) which were power-calibrated based on a comparison between their signal and the number of fissions resulting from the previous diagnosis.
Certain precautions must be taken, however, to avoid errors due to:
- the time-of-flight of neutrons if measuring in thermal neutrons, 10
- radiation diffused by the concrete walls which, in particular, could significantly distort monitoring of the sudden power drop after the first peak.
On Silene, special collimated detectors placed behind shields were designed to overcome these difficulties.
Dose-calibrated detectors were used for measuring neutron and gamma radiation dose rates (kerma rads for the neutron radiation and tissue rads for the gamma radiation).
3.3 - Routine diaenosis
Since gamma spectrometry is long and complicated, routine diagnosis of the reactor is performed using:
1. Activation detectors (S, Au, Cu. 'Mg) calibrated during calibra- tion experiments,
2. Detectors to monitor the power of the reactor, whose information is sent to a data acquisition and processing system.
3.4 - Temoerature and pressure measurements
Aside from the nuclear detectors mentioned above, the only nuclear instruments installed permanently on the reactor are two thermocouples (chromel-alumel) placed in the fissile solution at 20 and 30 cm from the bottom of the tank, and a pressure sensor (CEC BELL tight-wire type sensor) placed on the bottom of the core tank in the sole aim,of ensuring that the pressure wave generated at the first power peak does not exceed 8 bars, the maximum limit allowed under the safety conditions of this facility.
Specific pressure measurements were also taken inside the fissile solution (Ref. 6 I. , 11
3.5 - Measuring the fissile solution level ' .
Two independent devices are used to measure the height of the fissile solution pumped into the core tank.
The first device is based on an "electromagnetic" principle and consists of making an electrical contact on the surface of the liquid. The corresponding assembly is thus installed on the upper part of the core.
There is another device at the bottom of the core tank that measures the level ultrasonically, consisting of two detectors immersed in the
solution. The first detector sends a signal to the surface of the liquid and processes the information through the second detector referred to as the "reference" detector. The reference detector sends a signal to a fixed reference surface, making it possible to account for variations in wave velocity as a function of the density and temperature of the fissile solution.
4 - B FOR REACTIVITY CALCULATION WI!l.'H 71 n.&" CONCENTRATION
4.1 - a data
In orbr to obtain the reactivity values that appear in the result tables. w USO~ the following neutron data determined by CEA computing coder (Apo;io, Rorot).
. Llfatlw of prompt neutrons at 71 g/l j - 36 ps . Delay.6 rmutrona
CuaL’I 1 1 I 2 3 4 5 6
cl 1 28 1.24 1.26 1.23 1.26 1.20 di 0 O?l 0.139 0.126 0.252 0.074 0.026 Ai a 0 ortc. 0.0305 0.111 0.301 1.13 3.0
ci reprorentr the efficiency of each group of delayed neutrons.
6
B l ff - I: cl x 4, - 794 pcm i-1 12
4.2 - Reactivity calculations ..
In the result tables, a distinction is made between two reactivity values Ak.
Ak, is defined as the reactivity present at the time of the first peak, corresponding to application of the Nordheim formula starting from the minimum period measured in the rise of the first peak.
l/T. 1 i-6 Ci pi p(pcm> - m. 1 + 1 /T, iI1 1 + 'Ai T .
Ak,, is defined as the total potential reactivity to be introduced in the core. In the case of a reactivity "step", implying an experiment where total reactivity is reached even before the first peak occurs, then A'b'%'
In the case of a reactivity ramp occurring in the presence of -an l xtenul neutron source (this is often the case in "free evolution" l xperlnnts) , then total reactivity is not reached in the core at the tlw tha first peak occurs, and Ilk, f Ak,.
For pure reactivity steps, an experimental relationship was estab- ll~hod betwen AkP and AH (height of the additional solution above the blqod crltlcal height).
For high reactivity levels (in "boiling" type experiments), which ore not 6Alouod in the "Pulse" mode in order to avoid steps that are too rbnr)t. cZn reactivity could only be calculated. Figure 8 illustrates t!n m evolution of keLf as a function of the height of the l oluttom TVW 'fit" below represents this variation of keti on the Silene rou tar
K~ff~O.68276 + 1.194 10-2xH - 9.905 1O-5xH2 13
I, RESULTS OBTAINED WITH THE 71 n.l-' CONCENTRATION 5
- Presentation of results
The most representative results of the Silene experiments are given in the form of:
- tables summarizing the main characteristics, the meaning of the symbols used being given beforehand,
- graphs illustrating the evolution in time, in experiments on the following parameters: . power, energy . temperature of the fissile solution . pressure at the first power peak . neutron and gamma dose rate (in general at 4 m from the source center).
To simplify presentation, however, the experiments have been classified into different catagories:
l- experiments with slow kinetics: referring to all experiments carried out with a reactivity insertion of less than B (p being the prompt critical state = 794 pcm) p/v-l 7 /&- ,d& /I DOW)' R PC =
2 - experiments at the prompt critical state (p + @)
3 and 4 - experiments with fast kinetics corresponding to reactivity steps (P >> B and Ak, 0 Ak,) with and without external neutron source.
5 - experiments corresponding to reactivity ramps: referring to all experiments carried out in the "free evolution" mode.
6- "boiling" experiments. These are the experiments 'carried out in the "free evolution" mode but using a special reactivity rod allowing the insertion of more than 7 $ of reactivity, thus bringing the reactor fissile solution to a boiling state. 14
7. Enfin now avons isole une demiere categoric d’expdriences pour leur interet sur le plan de la qualification des modeles de calcul : il s’agit dune serie d’expiriences realisees a une reactivid constante (Akp = 2350 pcm) mais avec des vitesses d’introduction de reactivid differentes obtenues en jouant sur la vitesse dejection de la barre cadmium.
II est a noter qu’un dossier complet sur chaque experience est archive a Vaiduc et qu’il est possible d’y trouver des informations plus detaillees telles que le listing de Evolution du nombre total de fissions en fonction du temps ou la position precise de la barre au moment du ler pit de puissance.
Une synthtse des resultats de SILENE est don&e dans les references 7 et 8. R,jf.1 Brochure SILENE: document CEMPSN
Ref.2 F.BARBRY, “‘Fuel solution Criticality Accident studies with the SILENE reactor : . Phenomenology, consequences and simulated intervention” International Seminar on Criticality studies programs and needs. DIJON (France) SEPT - 1983
Ref. 3 F. BARBRY, “Compte rendu des essaisd ’etalonnagedu reacteur SILENE”
Rapport CEAKEESNC no 124, 1975
Ref. 4 F. .BARBRY, Etalonnage de la barre cadmium du reacteur SILENE
Note technique SRSC no 92.11, Sept. 1992
Ref. 5 G. HANSEN, “Assembly of fissionable material in the presence of a weak neutron source”, NSE 8-709-719,196O
Ref. 6 F. BARBRY, J.P. ROZAM, “Formation of radiolysis gas and the appearanceof a pressure increase during a criticality excursion in a fissile solution” Trans. Am. Nucl. Sot., 59, 181, (1989)
Ref. 7 F. BARBRY, “A review of the SILENE criticality excursion experiments”. Topical meeting on Physics and Methods in Criticality Safety, 34,40, Sept 993, NASHVILLE, TN
Ref. 8 F. BARBRY, “Dosimetry of neutron and gamma radiation in the CR4C ans SILENE criticality accident study program
Rapport SRSC no 205, 1991 Liste des tableaux de rhultats des expkiences SILENE
Tableau 1 EipCriences B cinitique lente Ak CC j3
Tableau 2 Expiriences en mode “SALVE” Ak >> p
Tableau 3 Experiences en mode “LIBRE EVOLUTION”
Tableau 4 Expirienes du type “Ebullition”
Annexe I R~sultats des expiriences B la concentration de solution de 220 g.l-1
Annexe II Rt%ultats des expiriences de la campagne d’Ctalonnagedu premier “coeur” de SILENE Vue generale de I’installation Fig. 1
Fig. 2 Schema de principe de fonctionnement
Fig. 3 Schema de coeur
Fig. 4 Cellule
Fig. 5 Etalonnage de la barre cadmium
Fig. 6 Performances de SILENE darts les differents modes de fonctionnement ,.
Fig. 7 Evolution du Keren fonction de la hauteur de solution fissile
Fig. 8 Relation entre la puissance specifique maximale au 1er pit EN et l’inverse de la periode o
+ Catalogue des resultats des experiences
I i L- -
L I- z 0 W 5 s a W d) a
W
‘I W I
ROOM
I /’ \ /’ i \ “U. /
\ 7m7i /’ /
I I
T REACTOR ROOM
Fig:4 - SILENE Reactor diagram building A Fissile solution. critical height (cm.)
46 1-m
SILENE 7121 G.L-1 : 45 4 Unshielded configuration
38i --
37
I ‘ I I I 8 36-10 4 0I 10I 201 30I 40I 50I 60I 70I ' Rod position (cm.)
figis Fissile solution critical height as a function of Cd rod position. PEAK POWER ( 3,3.1 Olg fissi0ns.s’: (1000 Mkgawatts) . ENERGY $ 2.10 I7 fissions. DOUBLIKG TIME &1,5ms . time (set) PEAK WIDTH . 290 >/6ms
A Power 1 st PEAK POWER .L FREE EVOLUTION < 2.10 17 fissions.s-1 1st PEAK ENERGY ( 5.10 ‘6 fissions. TOTAL ENERGY g 5.1017 fissions. DOUBLING TIME ) 23 ms
0 1 2
4 Power .- 1 /I 00 WATT < Puissance c 10 kwatts STEADY &ATE DURATION Plusieurs heures
TOTAL ENERGY 4 5.1017 fissions ::I, 0 1 2 3 4
Fitj 6 _ SILENE OPERATING MODES ..A...... - ...... I ...... -...... I- .. . . . i... rn.“...“..
. . .I.._” ...... “_._ . . . . . “...I ...... - ...... ir :
i
..^.. ““““-“-+ i. -.-.....“* ..A -..., ...... -. ....
-
s * ...... -...... -.... g....:tn$*:..- ...... ;...... +....wW...... “.“. .A ...... “- ...... $23;: 1 I Y I . I J
I 1 I I+#” 11 I I I ! I II
tii iii
i i iiilii i i i i i i itjtji ‘&,-“6”t i i iiiiii i i iiijji
t ii iiiiitii ii iit
f i i I i i i.i.iii i i i i ittlii i i I
t ii iiinrlr
t ii ii
Figure 8 - Relation Bcetwen the Specific Power and the Reciprocal Period SILENE
Unshielded configuration
CUt z 71 g.l-’
List of reference experiments cut Total uranium concentration(in g.l-*) (93 % en 235U enriched uranium) ’
H f Final height of solution (cm) vf Final volume (in liters) AH Solution addition beyond critical height
Nf Total number of fissions
&P Total potential reactivity addition in the core Akeffl Effective reactivity presentat the first peak A0 Mean rise in temperature of the fissile solution at the end of the experiment (in “C),Oi designatingthe initial temperatureand Of the temperaturereached at the equilibrium stagete
Doubling time of power rise (in s)
Reciprocal of period (in s’*)
Maximum power at the top of the ftrst peak (in fissions/s)
Energy integratedup to the maximum power of the 1St peak
Dynamic pressurewave on the core tank bottom during the first peak (relative value in bars)
Energy integratedup to the botton of the first peak (in fissions)
Energy integratedduring the 1stpeak (in fissions)
Time when equilibrim of solution temperatureis reached
Energy integratedup to teq
Duration : duration of the experiment
Neutron source : oui = yes no = non indicatesthe presenceof an external neutronsource(100 mCi Am-be) I-.-. --- . . __., -. . *. .Ir__
ENERGY E POWER i (fissions) and (fissions . s -’ ) Ee Nf Energy E, ______+ __------e--c I I I I I I I I I I I I I I I I I I I I I I I I I I . 1 I ! t 1 t1 t2 te TIME TYPICAL. CRITICALITY EXCURSION IN SOLlJTlON Table -l-
SILENE
SLOW KINETICS EXPERIMENTS Ak,, 5 p
28 0.035 14400
59 0.074 16200
70 0.088 2880
111 0.14 16200
333 0.42 14400
390 0.49 780
405 0.51 I loo 682 0.98 62
700 0.88 170
769 0.97 265 779 0.98 380
. .
p -... -- __.-.- _.--_ -..... _. . . . - . . ..----.------.-..----.-. -. - . --_---- -. --. ---- .-_-----.---c..-..I --..I -*--- “---“-p,\,;, _,_-. -
SlLENE
“FREE EVOLUTIONMODEEXPERIMENTS”
1” PEAK / NUMBER c *c %un */ m Ep, E %gll cm Ep2 Mbar til~c~f +s *e9, e4Jlrsi*nr I/ LEI-362 69.9 37.57 46.0 42.17 40.90 0.136 5.1 2.0 10’6 9.6 IO’= 4.1 1O’Q 4.4 10’0 766 0.95 300 2.9 1077-l
LE2-362 69.9 37.57 46.0 42.17 40.90 0.0245 28.3 1.8 10” 1.2 10’6 4.5 10’6 4.7 10’6 890 1.12 160 2.6v
LEI-31 I 70.5 37.27 60.0 43.21 42.00 0.38 1.8 1.3 IO’0 2.0 10’6 3.7 10’6 4.6 lOI 693 0.87 600 4.0 IO”
LEl-258 70.5 37.74 60.0 43.14 42.43 0.0239 29.0 1.8 10” 1.1 10’6 4.2 10’6 4.6 lOI 893 I.12 I50 3.0 IO’7
LEI-273 70.7 37.54 62.0 43.74 42.43 0.025 27.7 1.7 10” 1.1 10’6 4.4 10’6 4.6 lOI 890 1.12 140 3.0 IO”
TEMPERATURE TOTAL REAcrMTY NUMBER DURATION N 5 oc Aooc,., dkppc* tips fjwotls pg::s PARTICULARllY CATEGORY
52 2350 2.96 700 3.1 10” OUI vitcsse sortie barre Cd 2 mm/s 5.7
50 2350 2.96 210 2.8 10” OUI vitesse sortie barre Cd 9.5 mm/s 5.7
63.4 2770 3.50 660 4.0 10” OUI vitesse sortie barre Cd 2.7 mm/s 5
LEI-258 20.2 . 62.9 2720 3.42 500 3.9 10” our vitesse sortie barre Cd 1 cm/s 5
LEI-273 21 .63 2820 3.55 1300 4.6 10” OUI Exercice Intervention/Phasepost-accidentelle + redemarrage 5 /!‘0@& SILENE . Table -4-
"BOILMC"TYPEEXPERIMENTS
1st PEAK
C H Mmm H/ NUMBER “g/l ‘cm cm “/I T2s @s-I iLena ,-I +.s*i*tls EP,m* EP2mm qj,, Ml- dk$
LEl-175 71.4 36.79 90 45.79 44.41 0.015 46 4.2 10’7 1.7 10’7 4.2 10’6 960 1.21
LEl-176 69.8 38.07 114.9 49.56 48.07 0.016 43 4.5 10’7 1.8 10’6 3.7 10’6 5.1 10’6 950 1.20
LE2-176 69.8 38.07 139.9 52.06 50.49 0.018 38 4.1 10’7 1.7 10’6 3.7 10’6 5.6 10’6 930 1.17
LE2-343 70.6 37.1 140 51.1 49.57 0.016 42.5 3.8 10’7 1.6 10’6 3.2 10’6 5.1 10’6 950 1.20 LEI-281 70.9 37.42 170 54.42 52.79 0.017 41 4.2 10’7 1.7 10’6 3.8 10’6 5.4 10’6 940 1.18
I TEMPERATUREI TOTAL I I I I I SILENE
SL.OW KINETICS CX?ERIMLNTS Akp S p
fu@ Ca&lr .. @gi3-
@lx 71.3 - @s x5 flI4 71.3 @jiji 715 fl4 71.3 cs’ij& 70.8
3% 70.9
-s-MO 70.8 31-25~ 70.5
TEM?UtAIURfI Total RCdiVitJ+ I I E DUUTIP( “,- ,.‘io.‘iook cmuaw man LY I Y-. *I- 1Ae.m a. I ui,- --- - ‘C -LB ‘la ‘S
.‘J3-229 14ooo 3.1 IO’S 20 1 2a 0.035 14400 3.1 10’5 OU’ I
2.5 70 0.088 2880 12 10’6 OU’ 1 i
I I wi 1 \ 1 \ \ .\
- SILENE 71 g/l~configuration sans &ran. Evolution de la puissance B, de l'inergie E et de,la temperature solution. .
+ 1 i
. - SILENE 71 g/l cotiiguration sans &ran. Dkbits de dose neutrons et gasma B 4 m de l'axe du rkacteur; .
: - SILENE 71 g/l configuration sans &ran. Debits de dose dreutrons et gamma;? 4 m de l'axe du riacteur. i
- STLENE71 g/l configuration sans &ran. Evolution de la,puissance i, de l'bnergie E et de la tempkrature solution - SfLLltE 71 g/l configuration sans &ran. . D&bits de dose neutrons et gamua i 4 m de l’axe du rbacteur. i ! I I I I
I
I I I
I
I
1
!
I
I i I . I I I I I I I I I 4 \
- SILENE 71 g/l configuration sans t&ran. Evolution de la puissance 8, de l'hergie E et de la tempkrature Solution . .
i
- SILENE 71 g/l configuration sans fkran. D&bits de dose neutrons et gamna B 4 m de l'axe du riacteur. I Q_. 1.
- SILENE 71 g/l configuration sans &ran. Evolution de la puissance k, de l'hergie E et de la temperature solution. c
I _ I . \ I .. I I I I I ! I I I . I I I i
- SILENE 71 g/l configuration saps &ran. Evolution de la puissance &, de l'hergie E et de la tempdrature solution.
. - SILENE 71 g/l configuration sans &ran. D&bits de dose neutrons et gamna a 4 m de l’axe du riacteur. . , ------. ------._ Puisronc, i( ro/c) _,_. -.- - -.- _._-_-.-.-.- Fnrrp E ( fir I .- - - .-- _ _ E
i i SILENE LE3.214 - SILENE 71 g/l configuration sans &ran. Debits de dose neutrons et ganmrah 4 m de l’axe du riacteur. b J. I
I -7‘
I
I i
Puisrmoe, Cnergie et tempirature SILENE Sl 300
Tempkoturc (‘Cl
si
Tempdrature solution
J--r------
:& , 0.0000 ! I I 1 1 I I I 1 200.b000 ’ 1 8 1 I ., I CRPSf Xi: 100.0000 300.0000 40
Puissance, dnergie et tumpdrature (d&ail ler pie) ._ .-- - 8 --.- . .-..-- _-___ -. .
I :
/
Puisrance, inergie l t tempirature 16 10 -
lolS r
10" r
to" 7
fern hurt I l c 1
12 6E IO y
SO
IO" -
Temphrature solution IO’O
t IO9
10 t WlPS SEC 10:0000 1S.GOOO 20.3000 z; oc Puissance, dnergie et temp6rature ----..-_ PUICSANCC tFISS1ONS/SCC.) TEnPtRATURC c-c, IS SILENE Sl .258 100
17 SO
IS EO
IS 70
14 60
1J 50
I2 TCttPCRAlURC 40
I1 30
10 20
a’ 10
8 0
TEHP6 (SEC. 1 SILENE EVOLUTION DE LA PUISSANCE. DE L’ENERGIE ET OF -,-Fb’“E,? l --UT- 17. -..- _- LA A - cc t- fWCR61f~fISSlOYS) PUISSANCC[FIS./SEt. 1 ( SILENE 9.2581
9 9
8
7 76
E 60
IE 5 SO
4 40
3 30
2 20
Ir IO
0 -I
,
, L
w c I- J 1 c ” ” a , I w 2 L
J
W 0
W u z < v, In m 3 a i < J
W 01
Z Ok l-t, I- > -I 0 > W I W Z W J
2; I Nw6r.n C Hew AP Ah . *@iI rn#Ull p PI EP, bor ‘KJI %
SZ-258 70.5 37.74 21.0 39.84 38.6 0.010 4.5 lo'6 4.7 10'6 1046 1.32 _
S3-258 70.5 37.74 28.1 40.55 39.3 0.0038 8.1 10ls 8.4 10'6 I 1458 1.84
Sl-362 69.9 37.57 46.0 42.17 40.9 0.00391 8.5 lOI 8.5 10'6 I .05 1420 1.79
S4-258 70.5 37.74 32.0 40.94 39.7 0.0028 I.0 IO" I.0 10’7 1.9 1696 2.14 s3-300 70.8 37.36 36.0 40.96 39.7 0.00243 I.0 10'7 1.010’7 2.55 1832 2.31
S2-259 70.5 37.38 40.0 41.38 40.1 0.00198 1.3 10’7 1.3 10’7 3.7 2068 2.6
S4-259 70.5 37.38 44.0 41.78 40.5 0.00192 1.3 IO" 1.3 10’7 4.4 2108 2.65
S3-259 70.5. 37.38 44.0 41.78 40.5 0.00171 1.4 10" 1.4 10’7 4.8 2269 2.86
S4-346 70.9 36.81 46.0 41.41 40.2 0.00162 1.5 IO" 1.5 10’7 5.6 2350 2.96
51-346 70.9 36.82 46.0 41.42 40.2 0.00162 1.5 IO" 1.5 10’7 5.6 2350 2.96
T~MTfRAlURf TOTAL RfXCl’MTY ADD’T’DN
HUDllER Ah Dunmow N, SOURCE ‘q, “q- %, *e**, uPpu OUeCllVI6 CAWOY ‘s *bJu
SZ-258 50 8.8 10'6 20.4 28.3 1046 1.32 11220 1.510'7 IlOll C~~ipuotrrrrtr(rdehbawIt-7mh 3
S3-258 90 1.42 10" 20.4 35.7 1458 1.84 420 1.9 10’7 lmn ciatcigw 3
N-362 160 2.6 10" 20 50 2350 2.96 210 2.8 10'7 Olli Ww6vsculloccd~hcd:20cm.s-' 4.7
S4-258 90 I.7 10'7 20.5 40.2 1696 2.14 420 2.3 10'7 non '3' 3
s3-300 . 80 1.8 10'7 22.3 39.9 1832 2.31 I20 2.1 10'7 non CindligW 3
S2-259 90 2.1 10'7 20.6 47.4 2068 2.6 420 2.7 10'7 mm CMiqw 3
S4-259 90 2.2 IO'7 20.8 50.9 2108 2.65 10920 2.9 10'7 Olli CinCtigue+~ntrdedelabml;I-7mh 4 S3-259 70 2.1 IO" 20.7 51.1 2269 2.86 420 2.910'7 non Cidique 3 S4-346 180 2.9 10'7 21.5 53 2350 2.96 180 2.9 10'7 non Ejcch~ hm Cd npidr 1.) m.s” 3.7 / 51-346 180 2.9 10'7 21 53 2350 2.96 180 2.9 IO" oui EMon bun Cd npidc I.5 m.rl 4.7 < J
W 0
z 0 c( I- > J 0 > W
W z W -I t-( ul n I.. . \ L(ILI.,‘II IS. I i PuISSAnCE~fIS./3cc.l ! El9 c I SILENE S2-258
i El3
.
j El7 .
El3
I EIS i El4
El3 I
I El2 I I I I 1. 2. 2. 3. 3. SILENE-EVOLUTION DE LA PU'ISSANCE ET fE L ENERGIE.TE"PS 'SEC'1 ~RcR3IE(r1SSIOWsl pU1SsARcc(fIS. ISCC. I -. 1 SILENE S2-258 [
SO
80
IO
6 60
S so
4 40
fCRPCRATURE
3 30
r
2 24
PRCSSIOW 1 10
E*I. I I I 0 I. 2. 2. 3. SILENE-EV.OLUTION DE LA PUISSANCE,DE L ENERGIE~DEr'nP~'S~C'l I , --,,nrw.- ,------__ _ _ ~ERPCRATIJR~C*C] 1 SILENE S2-258 10
9
...... 7 l . l . 4
......
6 ia
0
0
I . c *.** ..** ,*
/ TEflPERATURC ..* . . . . . e . . . ..**' ...... - . ..-•* !O . /
/, i
. . . . PRESSIOM ...... - .-..*...... I ...... 0
2 / I 1.3 I . 1.4 1.5 I SILENE EVOLUTION DE LA PUISSANCE, DE L'ENERGIE TEnPS'SCc'l T!y 1 > TTupT1J- IC' -- 7.- ! ,5.!7"' Tr,r Pm-sJ--7 .7-c ,7--\ . . - I I I I u
-t- ‘; --.I- ‘t m ma u w, 00
- m ul N I PI ul
w z w J r( ul L - 6~ctFlSSl6~S) )~$CC(FIS. /stc. I . 1 SlLENE S3-258 1 PRCSSION(OAR!
90
70
SO
44
30
20
Cl3 10
Cll 1 1 1 I I I I I 1 0 .F1.2 1.4 1.6 1.0 2.0 2.2 2.4 2.6 2.a rc SILENE-EVOLUTION Of LA PUISSANCE ,DE L ENERGIESDE L-/!ps(scc.l h:I cl-141 I-III Ol-ArTill TrbjOrDATI1Qr iT nr'l A ODTCC~ llhl 1 SILENE S3-258 1
9
.* -. : ...... 9 . .I .
” I 6
Cl6
*l-’.* ” .*.* 44 . t .* .* .* : : : .: . : I / . 30 . : .* .- _*- .- I .-• 20 . . . I . * . . .* . 2. : ..- .- .- -.- -.- .- .-pa =.PRESSION : IO . .= -. .* *. .* %. 0 -..-.. .a
El2 ’ I , I I I I 1.32 I.341 1.31 1.31. 1.42 I.445 1.47 1.49s SILENf-EVOLUTION DE LA PUISSANCE DE L'ENERGIE TE”PS~SCC.1 r- . r-.*-&e.* -- -- _- . ^---r:-, -em,. - ^_.^_ - _
I
i i i i i ._.. Puiuonce i ( fb.I”) . ._Energ;e E ( fiss;ons) SILENE Sl 362 d9. .-...._._:.i
-.-_ Tempiroturc II4 (‘Cl 17
-.- - _.-.-.-.-.-.-.-. b--l.-Z.-- _ -.-.A.-.-.-. -.v.-.- .-_ OEPLACENI l-l-- BARRE(cM
---..-___ .----__ W-WERATURE --.._ -1-..141.
I
500 I i i i i : i i w’ / W Z W J ii .A I. v I\( w ” u u u ” u u J ;. u if.AL fl’ I”“’ ’ ’ ’ I”“” ’ ’ 1”“’ ’ ’ ’ I”“” ’ ’ I”“” ’ ’ F’ ’ Y I”“9 ’ I”“’ ’ ’ ’ I -“.RQILlt IL., P~~sSAncr~r1S./Scc.l TENPERATURE~ c) z 1 SILENE S4-258 PRESSION(SAR’
ENCRIIE
I El1 i I I I I I I I I 1.6 1.7 I I I I I I 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.6 2.9 3.1 SILENE-EVOLUTION DE LA PUISSANCEsDE L TEtiPERFTU'RE: ET oe r_~ PRESS?ON AIJ St-TN nlJ iSIONS 'fS./SCC . I TERPERATURE~' Cl 100 SILENE S4-258 PRESSION(SARS~
1 90
60
70 . ..*- E l2 .’ . / .’ . : . : 60 : . .. . / : . l : . f
:
: .
: SO / : . . . . .
’ IO
PRESSION 30 w/
4. l l .
-.-.- 20
..__i ’ -.-.-.-.-.-.-.-.- .- 10
I t 0 I 0 1.7s 1.77 1.19 1.81 5 SILENE-EVOLUTION !lE LE. PUISSANCE, !lE L'ENERGIE; 'JETEIPStSEC*) r-ri,, n:, nr I PTr:l.T I A TCHDTDdT;tDT r-T nr I A 0igr"~'nr, ,:I SILENE s3 300 . ‘W
I W I 2 I
.w \- 1% .-.-.--.-.-. -.-.- -..-_ ;g _ . _-.- : . I _ - 1 _I : n I c =d %A. ;;' =$ ,! : 8 'A;;,';, I, =f: ,'di ,!,, 1 =$i:;' -4 , -2
Pig. 6 Puissance, inergie at tempirature (&hells dilatde) P&nce i’( r;r.s-3 SILENE S3-300 Encrqic E (T;s)
a
‘C
I. .--. L.-.-:-. -B.-.--B.-.- .-.-. -
-.. 11 I I I I I 1 , I , I , , I W7PS SEC o LJ1.2000 1.“300 ' 1.3000 1.3300 2.2000 Fig. 7 Puissance, dnergie et temperature (detail ler pit) I
m III N I N ul
,I W Inul NI ulN W Z W J rr Iul 00 ILENE S2-259 PRCSSlON(BARS
- 90
90
ENCREIC
70
SO
50
4 40
3 30
2 20
A PRtSSlON i I\ J-- 10
I I I I I I I I 0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.9 1.9 SILENE-EVOLUWN DE LA PUISSANCE DE L ENERGIEJIE LA PRI?!!!%~.) XNPERATURE[ ~1
1 SILENE S2-259 1 1 PRCSSION(BAR91
PUISSANCE
’ 1
...... ENCRGIE ...... ’ . : . . . : . . .
El
I....*. . . .* . . . : . . PRESSION .*.* .. .* . .- . .* . .’ . . ’ b’
4
---. ..I... El@ 1.19 i.a8 I.11 1.22 1.23 1.24 - 0 i ‘-- -I- ’ I ’ ’ 1.25I 1.26’ I-27’ 1.20’ 1.29 SILENE-EVOLUTION DE LA PUISSANCC Of L ENERGIEstIE LA PR['!~J#$') I. ET Of [A T~IIP~RATIIRF AII ST?N I-!II nrArTrItRrlr9 DT~ nrTdrl7 SILENE S4-259 -l
-
- CNCROIE ._____ ----.---. -.--.- _.--- .w----
-
-4 ..; E 0 0 23 SO 7s 100 12s I50 17s 200 223 2so 275 ,; I 1E‘HPS (SEC. I :i SILENE- EVOLUT I ON DE LA PUISSANCE.DE L ENERGIE ET DE LA 1 TEMPERATURE AU SE 1.N DU REACTEURCJUSQU A L ETAT D EQUILIBRE3 . . .
PUIESANCCCFlS./SEC.l OtElT NCR/H) I SILENE S4-2591
Cl0
e 0 c u L - I
TEMPS CSEC. 1 SILENE -EVOLUTION OE LA PUISSANCE AU SEIN DU REACTEUR ET DEBITS DE DOSES N ET G A 4M DU REACTEUR.CJUSQU A L ETAT 0 EQUILIBREJ .- --.. -.-.._-__ --__
J I I N u PUISSANCCtf IS./SCC. I i21 1 SILENE S4-259 j
El6
EIS
...... El4
.
El3
El2 .
El1
! . . l- . 1 El0 IT . E .
-. i ‘. *. . . E 9 -... --.._. -.“-.... ._...... -._.-..._..._ . . ..O,., ..-.....s..,
I I I I E 6 i.15 I.il I. i9 1.21 1.13 TERPS'SEC. 1 SILEYE-EVOLU!TOY 'lf LA P'JISSPVCE 3E: L EYi9GIE +T- I I --,),-,--,,- .------. -nrr?.-..,rT-r ..-- T --+. _ --,. . J
w 0
l- W
w
z u” W’ ZW Wt-
Ai
WC 13 ul .’ n WO w u I ZZ m <- m f.nw fflm W Z Y3 W rL( J
E 5;
W+
OZ ZW OQ tw= kW >+ J 0 > W. I W Z w J ” ul . ENCRQIEt~ISElONCl PUlSSANCECFIC./SEC.l TCHPERATlJRE( Cl I SILENE S&259(
Cl I
‘9.
Cl0
TEMPS [SEC. J SILENE-EVOLUTION DE LA PUISSANCEsDE L ENERGIE Ei DE LA TEMPERATURE’ AU SEIN DU REACTEURCJUSQU A ETAT D EQUILIBRE3 ._ _. .._...__-. -- ._._. __ _ -_ ---. .- .._ -- ______.___ --. _..-. . - .----...- --.-_ . - -.... _ -..- --.- _. ___-.- _ .-1-_ . -. - W zo D 0 D l-l .I- 3 J 0 > w , D I b-J w ,Z W J
;; . EYERC1EffISSlONSl . ; PuISSARCCtfIS./sEc.l t SILENE S3-2
El0 0
El7
El6 6 66
u
El5 4
Cl4 4
El3 3
El2 2
El1 PRfSSlON -1
El0 1.3’ i.4I 1.5I I I 1 I I I 1.6 1.7 1.e 1.9 2.4 2.1 S ILENE-EVOLUTION DE LA P!JISSANCE,DE L EN[RG]Er~E Lr~"PS'SEC~l 1 SILENE S3-259 1
: ...... ENCRElC . . ..*-- p..-. . ..* . : . : l . - ...... : ...... -...... * . . . . .* . . : ......
ILENE-EVOLUTION OE LA PU ISSANCE ET DE L ENERGIErC'PS 'SEC" i ” 1 I IlllllP-Y I I llllll1%Il IIIIIIb I I llllllFs=I I IIllllf%lI llllllf”;l ( llllllP I I Illw4 ) Illlllr~r (1; 2?P4 jj ’ ‘.;:1 .-, mm.1 TU.S.’.Y 975 ‘. -,” 4 I
. b. c
I . i SILENE S'l 346
Presston ( ban)
P
2 ->0- -- .__-
1
II I 1 L 1 1.0000 1 I I I I I 1 I I I TEllPS SEC 1.2soo 1.5000 I I I l.TJOO 2. -,-.- SILENE Sl 346 -.-19 L-
Tern .I c., -
c
so
IO
I I I I I I I I I TEllW SEC 1.2500 I I I I I 1.5000 1.'1500 2.000130 . : . .. . . ,
. l l . . l ...... l . . . . l . . . . l Ttmptrolure . . (‘Cl . T I . . .-*----- . 90 l ./’ l Prcssio n . . (bOrSl I . .A . * . / I l 8’ . e .*** . . / l . . . /
60
--
IIIo !! I ,I,,, 1; ,,,,,(,,, TEtlPS St 1.1300 1.1505 1.1630 1.1'155 P.. i i J t
i T i i i
x -x. B
l-3 -::. E:
x -8. s
x -::. 6
-- ‘WW u u- E -m \ 2; .L! a3.s h Ln .I n n 0 -0 =0 -0 ‘0 -0 -0 ‘0 -0, 0 0 0 F u\ m
/
SILENE LE2,362
t&once i (t;s.x set:‘) Energ;o E (fissions) . Temperature (‘Cl I i E ______.._ ___- ______.___ -_ ._.. __ _ _ 3(1 lOI t _____------I -: c I
A A . 7c
i,
.r 60 w
so
4'
JI SILENE LE2,35;2
'1 Puissance E (Tic.r accr 1
lb Energie E ( fissions 1 IO : . Temprrotur (‘Cl -.-- _- _ __..__- --- .-- ..-- _c__._-- __ __.____- - -- # E ___-- DcplacemenL ,--- /------barrc(cm)
71
x
SC
10
rlPS SEC -0 -. --_ 0-c -. . I Oibkr i 4m. ( SILENE LE2a 362 la! :- ._._ .__I. _ -_._c -me-_.. --.-- - - -1: --.-_. -.-- - -- .- .- .--2-c. -_ - -_ IS .___e --z1 -.-_ - 14 z-- -_- - - -.- = - --..- - - I? -_ z - .. - .-__ n I I , 1 , , , , , , , , , , , i I I I , ,TEWS, SEC Ill02 1 0.0000 2s.oooo s0.0000 ~s.0000 ‘100.0000 LEZo362
P&son c c i ( Iis. s-‘) TempfLo,hre Energ;! E (fissions) T -a.’ ’ ’ ‘-.*.- ...... *...... ,*... , . * . .I.,. . . , . , h In m a3 e 2 0 0 -0 -s -9 0 r, . :- ..: r
n, .I ,.; . . -1 F&onto (h’ms x set ) ’ .-_&____. Entrgic ( rlrsfona 1 .-._-__ _--_- SILENE LE10311 IO!? --
IS E____ IIL- -
14
--
13 _.._ -TZ - -- -k +--- I-.- I..--
6' * . - .-.__.- _
Debits de dose neutron et gamma& 4 m.
Mbits de dose neutron et gamma1 4 m. c -0 .
n n .
I
m Lo N I
z J w Z Id J G; -
n
L w 0 <2 W Z W J ct ul - 2 . 2 c TCAPERATL. 1 SILENE Lfl-258 1
- 10
-- 30
- ‘0
PUlSSAlCE
60
so
10
TEMPERATURI 30
,
20
10
1 0 17.5 n.s 31.5 33.5 35.5 37.5 SILENC-EVOLUTION of LA wssANcfdf L f~fRG]f ET diYScC~ frbjtirQATllDr All Crlkl Ill, Dl-bf-TrllD~lrD DTI-1 SILENE LEl-258
Elf
60
. . ClS . . l ..*, SO . : . . : . . . : . : . . : : . . 2 40 . El4 . 2 3 . . .- 30 l * I . . 4 El3 ;.* TEflPERATlIRE
20
El2 r IO t
I I I I I I El1 I 0 27.1 27.9 28.1 26.3 26.5 28.7 28.9 29.1 SILENE-EVOLUTION DE LA PUISSANCEsDE L ENERGIE ET DET~X'SCC'i TTMP~RATIIO!F All SrThl I-III Dt-4TTT1IDfl!FD DTP nrTATt 1 a w b E w
io
- c OI a * u ” 2: Yb - 0
SILENE - Puissance, debits de dose neutrons et gamma 3 4 m du rCacteur. 0 w u) \ nb? . m UI i ..Y . .-- -. SILENE LEI 273 --_ i D&l- de dor .-._ n cl 6 4m .-.__ d .- (rodx h-‘1 ti -._-._ -.._._ I&-_-.--- -_- --- c------.------. -- __---- .-._--. -.-.-.---.-_. -.._ --- "BOILMC"TYPEEXPERIMENTS .
1stPEAK 1 c ii %un NUMBER utgll ‘cm Hfcm “fl
LEl-175 71.4 36.79 90 45.79 44.41 960 1.21
LEl-176 69.8 38.07 114.9 49.56 48.07 950 1.20
. LE2-176 69.8 38.07 139.9 52.06 50.49 930 1.17
LE2-343 70.6 37.1 140 51.1 49.57 950 1.20 LEl-281 70.9 37.42 170 54.42 52.79 940 1.18
l--LzhMTIrl UTURETOTAL SOURCE CATECORI
LEl-175 19.6 4000 5.0 540 5.4 1017 OUI
LEl-176 18.8 4100 5.2 720 6.9 1017 OUI 5.6
LE2-176 18.8 4800 6.0 900 7.4 10’7 OUI 5.6 LE2-343 22.4 5100 6.4 700 8.7 1017 OUI 5.6 LEl-281 21 5700 7.2 600 8.6 1017 OUI 5.6 CI. ..---...... - .‘. .- --Ii. Ii. .. SLENE- . Fig: 1 Jxpikience du type 8 Ebullition’ Evolution de la puissance (toute l’exp&ieice) .b_’ ).’ .- WlY-.- ._‘_ .:_ _-.-a .I - I SILENE -’ Fig: 2 -Exp&ience du type @ Ebullition” Evolution de la puissance (p&ierS pies) II II 1 I I I I I I II I I I. I I 1 2 1 i %d I I , I
SILENE Fig: 3 ,,Exp&ience du type @ Ebullition” Evolution de la puissance ;yx&: --Je-; J_:m;::I li;i:: ,.j I, y,.::: : : I =-T-l _. SILENE .. Fig: 4 -Expbrience du type o Ebullition” Debits d’exposition 86 f’m et 4m de I’axe du rhacteur (toute I’exp&ience) I I I I -__ I . . SILENE Fig: 5 ,Exptkience du type m Ebullitiorf Evolution de la puiss&e , (premiers pi4 EI-L OJ vJ
0t
I- H .--
-m-.-m .e--.-. DZ.zZ _ ---... _ . _. SILENE . Fig:’ 6 -Exp&ience du type ’ Ebullition” Evolution de la temphture au sein du rhacteur !I, j . . . . . j ,!:‘; ,:,,,
lliii Ii ! lil:, :. I;.. -
SILENE , Fig: 7 &xperience du type m Ebulhtion” Evolution de la puissance
(toute ~'~xn&imwo) I ! l!l!iI ’ ’ 2 llilli I I I li!li!! I 1 I I’1:;j: j ; I. ‘,
I. ti!( : :!I;“’‘ I! , i;!‘;; ; ! .11.!1! ; .:;!:;! ; :;,j: : / !
SILENE Fig: 8 -E&rience du type u Ebuliitior? Evolution de la puissance
bremiers nips) . SCLENE a
Fig: 9 ,Exp&ience du type l Ebullition’ Evolution de la puissance , SILENE Fig: lo -Exp&ience du type ’ .Ebullition” D&bits d’exposition )f 6 Im et 4m de I’axe du rkacteur /+ n,r+n l’n.*- L-r--- -’ SILENE , Fig: II -Exp&ience du type ’ Ebullition’ Debits &exposition x6 urn et 4m de I’axe cfu reacteur - - A (premiers pits) I I
SfLENE Fig: 12 -Exp&ence du type ’ Ebullition” Evolution de la temperature au sein du rhacteur SlL&
Fig: 1.1,Exp&ience du type l Ebuliition” Evolution de la puissance ’ (to&e i’expkrience) :;, ; ,I’:,:: I’ ,.. 1 I j:!i:. / I .i;‘, : !! ,il: ; :/I I VI i:’ :: :;jf!! j ij!i!l]i 1:::. :. ii,.: 1 ,:, , . I j!j, ;/:i, , I :.; 1 I
SILENE Fig: 14 ,Exp;?rience du type n Ebullition” Evolution de la puissance / ,,,-:-.. . \ I I II I I I I I I t t I I I I i -+ i I , 1 # ! ! I I I ; c
I I I I I I I II I I I I I I I I I I I I I I
Fig: 15 ,Exp&ience du type n Ebullition” Evolution de la puissance - - - ocf -I -
.-. . .. -. _ .-._... - --.-- -. I I . __ - ._ -3 -.. -.. - . _. - _ ._- -. .- . _ . ._ __. -.- _- _--- -._ -_._ = -. _ -. ZZ - -:2.2.. -. -2 -_ - - L: - .__-- .- . -.- -.-;I;2 - - . _. - -- _--I - .. _- _. - _ -. --._- . . -.. E 1 .-_- :L.Z. .:z -= - -‘ I. -.. -; A ;: . _ -..- 5 L h lFw-v -- .- -. _. ___ .- - ..-__ __. I”Tpjj F! fr _.- ..._ ..:: _.-. - -. ..- ._. z.: 2--- = - -- -...
hd IM . Q -. ..-I.--.. & - I I-- I I. .._ I .I . .. -. _~ .-T -. _-- _-:. . -.-1: :I _-.. _..---_ ____. ._- :1-. .- _ & ii - -.. -. .--.. ..- . _ .-T’ -:. _-.. __ _ ..___‘_ ::: - - - A -.. - I I I I I I I 1 I l-4 ..- . . -. _.._. .- .._. ._ . -. . -._ _ ._. ._._.. . . . _. .-.- _. . - _. :l ..:- -. . .~ _ -1.: . . :2 Y..- T; - ..A - ” -_ ..-..------t-. 1-.+-.+--I -._. ._ ._ . --I” 1I- -._ _. .Ijzj .-..-~-.-tl.-. _-. . -- ._ . . __ --- .- ._ . . : --..-.. -...-.-- -. __ ._.-.- _-..._..__, .:I.... 1 L -- -_ A -.. .:- :. . id+- i- -_.- .__. _. 1.. .-. :_ :. .-.. :: ‘. -- _ :: ._. I...__--._l.-- -..: I.._ L. .., :. _ ::.: SILENE Fig: 17 -Exp&ience du. type * Ebullition’ Debits &exposition x6 fm et 4m de I’axe du rdacteur (premiers pits) . -- ,--i-~- .--. - y-T-?. . ..-. y _._ . SILENE - .. Fig: 18 -Ex&ence du type 8 Ebullition” Evolution de la temphrature au sein du rhacteur
*
, - -- -. - --
- 2 g- ‘%f-’ B- I=
i :
-- ‘;; I in $ .z .-= - ‘C ’ ‘W - ’ I In n N 0 -I t*a I I I $llllllt I ‘,llllllclI c I I dlllllI I I dIllIllI I (-GM/lI 1 $ llll/lI I $11J/I 1Ql -4 -. ..-. I?&SO* Cti ( fir.s-3 _. Energio ( fissions I _ SELENE LE2 343 xiIS -.
Tompikatur - . PC 1 -.L. --_-...-_ -_-.. . llf .- 19’6 ---.--.I ----. 15 10A-_ --
-. -
--
-- Xl. II 1 ! 1 21.0000 I I I I 1 I t I I I 1 I I I ,fE"pS SEC ? 22.0000 23.0000 24.0000 25.0000 . .
. P&n ce E ( fis . I-‘) 1-t -‘Ekerg;P’ ( fissions ). SILENE LE2 34: t--’ -. -_- - 19
kii Tempbato (T 1 18 i 120 T
I I I I I I I I 1 I I I I TEnPS SEC - 21.3000 21.4000 2l.SOOO 21.6000 L- hkonco 6 (fis.x rec.-l) 25 .-.-= ---- .-
‘.----14-1 __
- - --
------II := -
!
.-
10 ’ I I I I I I ! I t I I I I I I TEFlPS SEr 20.0000 I 20.0000 &ooo 22.0000 23.0000 2. t 1
APPENDIX 1
RESULTS OBTAINED ON SILENE REACTORWITH A URANIUM CONCENTRATIONOF 220 n.l-'
1 - Preamble
A series of experiments was carried out in 1981 and 1982 using a uranium concentration of 220 g.l-' on the Silene reactor within the framework of studies on solution criticality accidents, in order to acquire experimental data in the following areas:
1. Maximum release of gaseous fission products when concentrated uranium solutions are in the boiling state.
2. Neutron and gamma radiation dosimetry associated with this type of configuration (concentrated medium, geometry different from an orthogonal cylinder).
3. Characterization of the. power level of the boiling "steps".
The results presented here cover mainly kinetics (the effect in terms of reactivity of 1 millimeter of solution, period and power of the first peak), since the rest of the information was summarized previously in other documents.
2 - Presentation of results
Because the experiments were carried out on tank no. 1 at Silene during general calibration of the reactor (Ref. 1 and 2), and more recently on core no. 2 using a slightly different configuration (dif- ferent thickness in the tank bottom and different fissile solution acidity), it is quite normal that certlfp differences will appear in critical characteristics of Silene with the 220 g-1" concentration.
The results are presented in the following manner : 1. Neutron calculations,
2. Critical characteristics and effects of one millimeter,
3. Kinetic experiments on core no. 2,
4. Dosimetry.
3 - Neutron calculations
These calculations were made by the DAS/SEC at the time of the first calibration of Silene using the Horet code.
- Characterisics of the fissile solution:
-l 23sU enrichment - 92.7% cU - 220 g.1 Acidity - 2.84 M NO, - - 4.71 M Density - 1.386
i In terms of number of atoms per cm3, this gives:
Number of 235U atoms 5.253 10zo Number of 238U atoms 3.821 10" Number of H atoms 5.802 1O22 Number of N atoms 2.838 1021 Number of 0 atoms 3.780 1O22 f 3
Calculation of kaff (Moret results)
Solution height 20 22 22.4 24 26.4 30 36.4 40
k .fC 0.931 0.961 0.965 0.999 1.025 1.065 0.110 1.127
The evolution of kafF as a function of the solution height is illustrated in figure 1.
Lifetime of prompt neutrons 1L- 12.5 ps for H - 24 cm.
Taking into account the fact that the fissile solution heights used for the kinetic experiments were higher, let A- 13 ps for the Nordheim calculations.
- Characteristics of delayed neutrons:
GROUP 1 2 3 4 5 6
;: x 0.0211.38 0.1391.33 0.1261.35 0.2521.34 0.0741.35 0.0261.20
xi s-l 0.0124 0.0305 0.111 0.301 1.13 3.00
6
B*if - B f, x pi - 853 pcm i-1
Graph no. 2 illustrates the Nordheim relationship between reactivity and doubling time T, for the Silene configuration at 220 g.l-'. 4 - Critical characteristics and eff.acts on, reactivity of one millimeter of solution
Core No. 1: fissile solut :on C - 220 g.1" I3 - 2.84 H d - 1.3860 fissile solution height H, - 25.00 cm (core tank bottom thickness 20 mm)
Effect of one millimeter E
Experiment I AH I No. T2 S p.c.m. $ 1 pcm/mm I S/mm I
D4 - 01 45.6 116 0.136 136. 0.158
D5 - 01 15.7 228 0.267 136 0.159
D6 - 01 6.7 347 0.406 137 0.160 t D7 - 01 3.75 3.19 435 0.509 136 0.160
Core No. 2:
Fissile solution Cu - 217.9 g.l-' lPt - 2.84 M d - 1.3562 core bottom thickness - 36 mm critical height H, - 23.27 cm 5
Effects of one millimeter Be~
I AP Be Experiment I AH AH No. T2 S mm p.c.m.
Dl - 115 31.1 0.97 151 0.182
D2 - 195 9.3 2.0 298 0.175
D3 - 195 3.9 2.91 430 0.173
Dl - 200 39.7 0.85 127 0.175
D2 - 200 13.9 1.67 243 0.285 146 0.171
D3 - 200 6.5 2.41 350 0.410 145 0.170
D4 - 200 3.36 3.09 454 0.532 147 0.172
5. Results of kinetic exDeriments
These results are recorded in Table 1 and illustrated on graphs 3 to 35.
The notations used are the following:
Ut : Total uranium concentration (in g.l-') (92.7 X f35U enriched uranium) Hc : Delayed critical height (in cm) v, : Critical volume (in liters) 4 : Critical mass in U, (in kg)
Hf : Final fissile solution height (in cm)
Vf : Final volume (in liters) 6
AH : Excess solution introduced above H,, i.e. H, - H, (in run)
Nf : Total number of fissions Ah : Total potential reactivity inserted in the core Ak eff, ' Effective reactivity present at the first peak 1 : Mean rise in temperature of the fissile solution at.the end of the experiment (in 'C), 8, designating the initial temperature and 8, the temperature reached at the equilibrium state t,
T2 : Doubling time of power rise (in s) T. : Period of divergence (in s) w : Reciprocal of period (in 8-l) E : Maximum power at the top of the first peak (in fissions/s) t1 .* Time corresponding to the first peak AP : Dynamic pressure wave on the core tank bottom during the first peak (relative value)
EPl : Energy integrated up to the bottom of the first peak (in fissions)
EP2 : Total energy integrated during the first peak (including residual power) t .q : Time required for the system to reach temperature equilibrium teq El q : Energy integrated at time (in fissions).
Calibration of reactor energy is obtained by gamma spectrometric analysis of the fissile solution. This radiation-chemical data was obtained in experiments Dl-12, D4-195, and LE1.201. SILENE
EXPERlMENTSREWJLTSAT 22Og.r’
1”PE
NUMBER Hfcn “f, EP,
D4-195 218 23.25 2.4 23.59 22.88 6.5 0.107 5.5 IO14 2.3 1016 4.2 lo 16 OUI Sl-196 218 23.28 5.6 23.84 23.13 0.30 2.31 8.2 1015 2.0 1016 2.5 1016 762 0.893 1 I I 8.1 1016 NON S2-196 218 23.28 7.7 24.05 23.33 0.0043 I61 1.0 1018 3.1 1016 3.4 1016 1069 1.25 I.1 IO17 NON Sl-197 218 23.28 8.4 24.12 23.40 0.0024 289 2.9 1018 4.1 1016 1.2 IO17 NON SI-198 218 23.28 9.5 24.23 23.51 0.00171 405 6.6 1018 5.4 1016 1.2 IO17 NON LE l-199 218 . 23.25 15.0 24.75 24.01 0.018 38.5 3.5 IO17 2.8 1016 2.2 IO17 OUI LE I-201 218 23.25 19.1 25.16 24.40 0.010 69.3 3.0 IO17 2.6 1016 2.5 IO17 OUI LE l-207 218 23.13 26.8 25.81 25.04 3.8 IO17 OUI LE 2-207 221 23.13 27.2 25.85 25.07 0.010 69.3 2.7 IO17 3.0 1016 3.5 IO17 OUI LE l-208 221 23.20 27.0 25.90 25.12 0.010 69.3 3.0 IO17 3.2 1016 3.5 IO17 OUI I I I I .- : ” &ff.-.-j-- ..-i I__ -;. - I : I : I I I I I I ; I : I : 1 ; : I : 1 : 1 : 1 I... .-j-j---’ .-‘-.+ -“‘;- -_-- ;-- - -. -.- : -.j-+---! _.__._ ._ :! f: I / :. I : ; I
1 ’ ..:‘I., ’ ” 1’: j,iT.i i 1. I- I ..I. :... I. I ...... - .. , . : i ...... I .’ , .I: : ...... ,,_ 8 ... .::-; : ...... :. .. : ..I.::...... & ! ....‘. .:- ... t : .. : ii; :ii.;:::i :j: .I;. 1 .:.: i ..:... .: ..j .... !.: ..... I : ...... :.:: .: I I- I I .. I. . ..1.../ I .. II ...... ,...a. 1 ..i. 1. .1... 11 ~~:~~l~~:+:.:(.; :’ “I ::.j ::I... I..:: .f .} /...... , .,.. ,: . . . . I i ,~/::~/;~:.1:.‘~/ 1: ’ .:., j ::: ::.” .” : i.:.i :i:iii. . . ‘.. . ‘.: ..: ,_::_ .:‘i’.. -::i’- _ ..i..:. :.::. ;:,.: ‘:“_ . .:..:: + . ..: ._.._. .‘ I:: : 1. ::... i
iili:::~il.liiir:l:.i.i:i:ll,:..’ :,.. I.:.:i ..,: ,.,I:;.:- i ...... ___,_... .
s SILENEs -1
Concentration 210 g.1 Variation du keff en fonction de lo houtour dP solution Rbltots MORET i ! .--_ - j:: ( ’ _-._- .- 2 rye--... .-.-- -’ ; :I _---_-_ -- -.A----.-.‘ -.-- .-. __------
i I ! I 1 I - ‘., . ; 9 .-..__--_ \I \ + i, : :\, ; i I’
. . .:. i .f . L - .; . . -. _ _ : : : : .- ! ‘.- .i _ : .: .i : t , : ! j
1 I i i ( I,,f 1.1 .I ( < , , .-, 200 un 600 boo 1000 I200 1400 1600 lb00 2wo 2200 2440 26ca 2
Fig: 2 Relation entre le temps de doublement T2 et. Ia reactivite’ A k i . I I I i
r’ t / : *’ t ,’ I I k / / ,’ Ic I, ,,: I !
N 1 I I Q *Q '$2 & D 'Q =Q Q B s
SILENE Fig: 3 - Expbrience du type ‘Divergence’ Evolution de la puissance L
I I I 1
StLENE Fig3 - Exphrience du type ‘Divergence’ Evolution de la tempkatute au sein du hacteur , I, I,,., ---y ---
! I fI (t t r
SILENE Fig: s - Expitrience du type ‘Divergence’ D6bit d ‘exposition f i lm et 4m . de I’axe du rdacteur
f ‘ I ,’ i I I I I i- ! ) I
I i / . i
SliENE Fig: 7 - Exphrience du type ‘Salve’ Evolution de la puissance (tout0 i’exp6rienceY
. z Puksonco i - fiuiona/ sec.
10" I a -.w jSILE!'dE Sl 196 j ri .- --. -- (Concrntr8tlan U total : 2 I8g/l) 1' lOI I .-, . i \ E
,! I lOIS i ’ \ i \ ,i i I t 10” I LE
i ) I 10"
10IZ
lo"
10 'O
log
SILENE Fig: 8 -Ewkfmce du type ‘Salve’ Evolution de la puissance (premier pit) I I ! I I i I I I I I ! I , I I I i
SiiENE Fig: 9 - Exphrience du type ‘Salve’ Evolution de la tempkrature au sein du rbacteur Q m 0 N S 8 s 72 .% "a h "P S b SILENE Fig: IO - Expkience du type ‘Salve’ D&bit d’exposition $ 6 lm de I ‘axe du tkacteur (toute I’exp&ience)’ I I .I I I lo15 I j ; I I &ILENE Sl 2% 1 j I i (Concomtt8tion U tot81 t 2 I Bg/l> log k i ! i -I loa _ 3 f3
10’ .
10E d 1 4 lo5 L L , I lo4 _ I j
i 1 10' L I 3
: i j I m2 I 5 = ;’ E t i
9 !- I I I 10' , I I I I I I I I : I ,mS SEC ( a.aood a 2s*0000 s0.0000 73.0000 100.3 SKENE Fig: 11 ,Exp6rience du type ‘Salve’ D&it d’exposition f d VTl de 1‘ axe du rhacteur (premier pid L
SILENE
Fig: 12 L Exphrience du type ‘Salve’ Evolution de la puissance (toute I’exptSrience)’ i 4
(Concrntr8tior U tot81 : 2 I8g/l)
I L ! - c j I I I\ r I , I I I / 1 L I ,ms. SEC\ lo r.bak 2.0000 3.0000 000 s.oc SLENE ‘* ’ Fig93 - Expbrience du type ‘Salve’ Evolution de la puissance (premier picl 5 ,u I
j
i i T
: 1 / I i 1 I i I L I -T- ’ 1
SlLENE Fig: 14 - Exphiience du type ‘Salve’ Evolution de la tempkrature au sein du rbacteur .
.
I
+
f
I I - !_ ‘5 I,,, 1 b‘. , - - .,’
b *Q “Q b SILENE Fig: 1s - Exphrience du type ‘Salve’ D6bit d’exposition )f 6 lm de I’axe du t6acteur (toute I ‘exphrience) IO'*
(Concrntrrtion Uu tot81 : 2189/l)2 189/l) log
108
10 7
lo6
lo5
104
lo3
lo2
ml?3 SEC , 1 I I 8 I 1 I , I I I I I I I I I lo' q;.oooo 2.0000 _. &WOO 4.0000 5.oc SCENE Fig: 16 ,Exp&ience du type ‘Salve’ D&bit d’exposition f ir lm de I’axe du tkacteur (premier pit) I r I
a
SILENE Fig: 17 -Exphrieke du type ‘Salve’ Evolution de la puissance (toute l’exphrience)’ 102o
1d9
loa
17 10
1o16
dS
10U
IOU
f 1 f r XJlPS SEC ,o" , I I I I L I l.pa 2.1000 L 2.6 0 3.1000 3.60
SliENE . Fig: 18 -Expbrience du type ‘Salve’ Evolution de la puissance (premier pit) SILENE Sl.197 Puissance E. ( fir , WC” 1 cCoroo~trrtlor u tot81 I 2189/l) _- .
Prtssion tl : bon)
# Tempcrotw (“2)
. FiG :‘I9 _ &NE, ( * ’ 8s”’ j Evolution de lo puissance , de 10 tempera turs , de lo pression ou s&n du rtoctcur SliENE S1.19
Puiuonct 6 ( hs. .sec-‘1 . Ttmpero;. i%) i 17 i ...... - ...... e k . . l . . . *.a.*. l l * ...... **:. l .*.*.. .***. c ,# : , I 1 I I t , I I 1 I I ,TEM,PSGecl , : oi 1.7900 . t.aiso 1.7400 1.7690_ --' - fIG:20,SlLENE-( z’h” ) Evo!u$on de lo puissance , de lo tempkaturr , de lo pc ruton QU rein du rcoctcur tdetoii I I I I I A f T / I - - - .i - No 9 SlLENE Fig: 21 - Exphrience du type ‘Salve’ Evolution de la temphrature au sein du tdacteur Y ri I 4 f I $ I .$ L 1 I I i I 1 I . r I 1i I SILENE Fig: 22 - Exphrience du type ‘Salve’ D&it d’exposition f h fm de 1‘ axe du rtjacteur (toute I ‘exphtience)’ Dibit d-exposition jf(R.h,fj I (Concrrtr8tion u tot81 : 2 I8g/l) SILENE Fig: 23 - Exp/rrien& du type ‘Salve’ D&bit d’exposition f & im de I’axe du cdacteur (premier pit) IP3asan cc E ( flS s-y SILENE Sl 1% iII ’ , 4 cCooorotr8tloo u total I 2 I eg/t> :. j ?ressiol I i bon 18 ----.... -. 4---.-_ Ter -$tur -.-- “1 _I. 90 ---. L. I Ternpkturr SE I I ./ 2( 1c FlG:Z-SILENE-( 2*81/l) ) Evolution de lo p&once , de lo temphoture , de !o prcwion au sin 6u re6cteur I ! i I I / I SILENE Fig: 2s - Exphrience du type ‘Salve’ Evolution de la puissance (toute I’exphrience)‘ SLENE Fig= 28 - Exphrience du type “Salve’. Debit d’exposition f 6 1 m de I ‘axe du rkacteur (toute l’exp&enceY c I I I I I 4 c I .= r Dibit d’oxporition (R.h,1) $ I ; I F I I i IO j 10 E = F 1 I SUNE S? ?9t! i E -! I CConcrntrrtion U total : 2 I8g/l) 1O9 -. - 2 I = t - i I _ 10 ' 2 \oooa ' i i I t I TIPS,SEC . . 2.7sao 3.0000 3.2soo -._ 22 SILENE Fig: 29 -Exphience du hype ‘Salve’ D&bit d’ expositjon f h lm de i’axe du riacteur (premier pit) .._ . I _. __ -- - .- __.- .._.------I F@:m-Exp&ience du type ’ Libre Evolution” , Evolution de la puissance (toute !‘exp6rience)‘ I 1 1 1 / I b E 2 . = F Puissance E , - E ( fissions/ IoC) I I I ,o 201 ,I = ! ipEi\lE LE! ~93) ’ f F I ccommtr~tion u total : 2 I 8g/l) = 1 ,: i I 4 = L I I I , TIPS SEC Q ‘i? :m 26.0000 31.0000 -.-- 36.0000 ‘Lb SkEI’iE Figs’l -ExpCtrience du type ’ LIbre Evolution’ . Evolution de la puissance (premier pit) i 1 i I i \ i \ : ! , I I ; ; i : I i , : I NON 1 i,OICl NON 1 ~1011'1 I , NOI L 1 - A table of results from all supercritical tests. 2 - Critical characteristics of the core (result .tahle..+nd graph). $- The vartation,of the effect pruduced on-reactivity ~by one~~~illimeter _ ' '-of &lution abve the critical h&h% ~&a&'tab~e.,%xdgraph).. ! .I -.to I i c I j L ! . c I i / ! I f ? 1 - --.- ‘W 1% .-. c i !- p -- WI .j _- ! - I P ._.:-:< I :- * f -: - 0 : i t j ! . t i ; = - DobIt d-exposition $ (Ft.h,1) i i- h--, -1-,,c - -/J -;?A r de’-.- !_ ,;- L:y - (Concrntrrtion U tot81 : 2 I8g/l) log r ._. r = E lo8 1 E Z 10' = / I E 1 ‘ErC+SSE,: 1o’ .cooc 2L.3OCO 2o.r;coo 3L.21 -- - SltENE Fig39Exphience du type ’ Libre Evolution” ’ D&bit d’ exposition $ h lm de 1‘ axe’ du rdacteur (premier .pic) P s h Q ‘b ‘s 8 5 “Q b *a “Q -a SliENE Figsa -Exp&ience du type 8 Libte Evolution’ Debit d’exposition f 6 lm de I ‘axe du rkacteur (toute I ‘exphrience)’ SILENE Fig270Expjtrience du type ’ Libre Evolution” Evolution de la temphrature au sein du rbacteur t : d9 cConcontrrtioa u total : 2 I8g/l) ldb 10” 1olC lOIS 10" 10 I3 lOi lo 11 1I I / f I , ,y!PS SECi -- lL.OOOO- -.. 19.op00 2L.0000 ~20.0000 3L.OOOf Fig%-Expbrience du type mLIbte Evolution’ &!olution de la puissance (premier piC1 SliENE Fig:%-Expbrience du type ’ Libte Evolution’ Evolution de la puissance (toute I’exp&ienceY SlLENE Fig:WExp&rience du type ’ Libre Evolution’ 2’ Debit d’exposition f h 1m de I’axe du idacteur (premier pit) ------ -0 ,- _. f:L .-__ - .- -.-- f Icnpiroturr I'C) 9( _ __ _- - el ..- 7 - --. _.-_ - ---- .6 _. - - ---.---. .- -..-- -- SILENE 1. I. ‘lb. Fig:wExphrienc6 du type ’ Llbre Evolution” Evolution de la temperature au sein du r6aCteUr I I ..L_ I ..A___. , 1._. ,. I , _L. , ._, I A.-1. J I L 1 1 IOO.OOOO ,50.4h0 20-0.d000’ 2w.oooo’ JO.o,,,,” 0’ - .I. APPENDIX HI RAPPORT SRSC 93.220 - Dkembre 1993 A REVIEW OF THE SILENE CRITICALITY EXCURSIONS EXPERIMENTS Francis Y. BARBRY CEA INSTITUT DE PROTECTION ET DE SURETE NUCLEAIRE DEPARTEMENT DE RECHERCHES EN SECURIT’ SCKVICE DE KECHEKCHES EN SUKETE ET CKITICIl C,~lll I I (I L-:llld< x dc. VAI.I~UC shlx 21120 I. ~llr.‘l‘lll, l:r‘lrll C’ P HO 23 -In , F’- A REVIEW OF THE SILENE CRITICALIn EXCURSIONS EXPERIMENTS Francis Y. Barbry Institut de Protection et de SQrctCNuclCaire CEA Valduc, 21120 Is-sur-Tille France 80 23 50 20 ABSTRACT More than one thousand experiments reproducing criticality The general operating principle of the reactor is as follows : excursions in aqueous solutions of uranium highed enriched in 235U have been conducted to date at VALDUC in the SILENE The fissilc solution, previously adjusred to SILENE facility by the French Institute for Nuclear Safety and Protection operation concentration in a special large capaciy tank, is (IPSN). This document summarizes results of selected pumped into the core up to a predetcmrined supercritical experiments with reactivity insertions ranging from 4 cents up level. During this phase,a control rod is present in the core to 7 S. Valuable results relating to the first peak characteristics so as to avoid divergence. and integrated fissions yields provide reference data for evaluating and improving analytical models describing The “divergence” power excursion is then produced by criticality excursions. In addition acquired knowledge is given withdrawing the rod from the core according to a concerning pressure increase, radiolytic gas formation and the procedure that dependson the selected operating mode for general behaviour expected in the accidental situations which each experiment. may occur in fuel cycle installations. The lessons drawn f?om those experiments concerning criticality accidents studies are When the experiment has been completed, the fissile given in this paper. solution containing the radioactive fission products is dumped into a tank located in a shielded room so as to allow quick accessto the cell. 1. INTRODUCTION It is generally assumed that criticality accidents are most likely to occur during the processing of fissile solutions. So as to be able to cope with such an eventuality, the CEA has been engaged since 1967 in an important proeramme of criticality acctdent studies] using the CRAC facilit$ to begin with and at presem since 1973 the SILENE reacror3. The general objecrivc of the work undertaken at VALDUC is to study the phenomenology as well as the radiological consequences of an nccidentai crmcxlity escurslon so as to acquire. on the one hand. indlsptnsable kno\\ledge for crltjcality safer): assessment 2nd. on rhe orher hand. 10 be m a position to define a protection and inrerventlon polic!, II. DESCRIPTIOS OF THE SILENE FACILITY SILESE 1s a homogeneous experimental reactor using a tissile solution of uran>l nnrate (U enriched in23jU a1 93 %) as fuel. The core 1s In the form of a small annular tank (36 cm dlarneter) located In rhe mlddle of a large concrete room referred IO as rhe “cell” The fissile solution required for reactor operatrou oi the reactor IS prepared in a laboraror\, located In the 7 cell basement-’ A ventilation circuit blows continuously through the upper The first feedbacks to occur are due to the thermal expansion part of the core so as to dilute the radiolysis gases that are of the system and to the neutronic temperature effect. To these formed. After the period required for their radioactive decay, initial mechanisms arresting the chain reaction is added a these gasesare removed through ad hoc filtration systems. second phenomena specific to solutions, the formation of radiolytic gas due to the decomposition of water along the SILENE is designed to operate in three different modes length of the trajectories of the fission fragments. This second depending on core reactivity, the control rod withdrawal rate mechanism, due to voiding, supplements the first feedback and the presenceor absenceof an auxiliary neutron source. reactivities which reduces the power level considerably,. However, the tndiolytic gas bubbles migrate towards the surface . “PULSE” operation is obtained by the rapid removal of the of the liquid, the accompanying reverse reactivity disappears control rod (at a rate of 0.2 or 2 m.sec-1) with or without and the power excursion starts again. It is this process of the an additional source in order to obtain a very high power appearanceof gas, then the release out of the solution which 1s peak in a very short time (up to 1000 megawatts in a few the origin of the power oscillations observed in the evolution of milliseconds). With fast transients of this kind the power. The essential difference which should be emphastzed reactivity is limited to 3.0 S. between the feedback mechanisms lies in the effect of the votd formed by the radiolytic gas bubbles being a transitory effect, “FREE EVOLUTION” is achieved by slowly removing the whilst the effect of the temperature, consequent on heating of control rod at speedslower than 2 cm.sec-l with a neutron the fissile solution, is permanent on the time scales bemg source. Reactivity cannot exceed 4 S in normal operation considered. but may reach 7 S for solution “boiling” experiments. This mode simulates an accidental criticality excursion allowed In certain cases the energy generated is suficient to either to evolve freely. bring the system to boiling, or produce a large pressure pulse resulting in significant equipment damage or solution dispersal. . “STEADY-STATE” operation involves automatic control of the rod position, with very slow displacement rates (appmx 2 mm.sec-1) in order to maintain the reactor at a predetermined stable power level. III. RESULTS A. General behaviour of a criticality excunion in a solution In general terms the development of an accidental criticality excursion in a solution is governed by the following principal parameters : . the reactivity addition Figure 1 - Typical Criticality excursion . the initial neutrons source . the effects due to the temperature, i.e. B. Results obtained at the 71 g.l-l Concentration the nuclear temperature effect the expansion effect which brings about density variation of The most representative results of the SILENE the medium as well as a “buckling” variation . experiments in the unshielded configuration are reviewed in the effects due to void ; this void arises in the first instance table 1. The experiments have been classified into different from the formation of bubbles of radiolytic gas, but void categories : also occurs if boiling of the solution develops. category I : reactivity steps below prompt criticality (p < S) Once delayed critical is exceeded,a divergent chain reaction category 2 : reactivity steps near prompt criticality (p tf 0) may be established leading to an exponential evolution of the category 3 : reactor “pulse” operation with large reactivity power. This power excursion, whose kinetics is dependent on input (p >> p) the reactivity input, is accompanied by the release of energy category 4 : the same aa category 3 but with presence of an which is manifested mainly in thermal form. The heating of external additional neutron source the fissile material results, on the ncutronic side, in the category 5 : reactivity ramps below solution boiling appearanceof feedback mechanisms. These feedback reactions category 6 : large, reactivity tamps (p >> 4 S) leading the overcome the current reactivity. The result is the appearanceof solution to boiling a first power peak ; Figure I is a sketch of the result of a typical category 7 : series of experiments performed with the same total potential reactivity but in various initial conditions transient. -. i The effective reactivity at the first peakbkl is calculated Lifetime of prompt neutrons at 71 g/l I = 36~s by the inhour equation and appropriate values of neutron lifettme and pen, The total potential reactivity Akp is calculated GROUP 1 2 3 4 !j 6 by the Monte Carlo MORET code. The relation used between ci I .28 1.24 1.26 1.23 1.26 1.20 the K value and the solution height for the SILENE 71 g.l- Pi 0.021 0.139 0.126 0.252 0.074 0.026 lsolution concentration is Ii 0.0124 0.0305 0.111 0.301 1.13 3.0 Keff= 0.68276 + 1.194 IV2 x H - 9.905 lW5 xH2 Pa =$&,xP,=794pcm (pcm = lO-5) . Neutronics data and symbols used - --s Ch~nctcristia Re¶ulla cut - ?l.gl-1 Bc=37cm s lacpuk Fld ““.- vr Akps z - 72 &I . A ti& Npk ~0 ~ NF I # I s.,.f#-1 L anioN c=sm UJ-l-n 36.1 0.015 P ‘4% 23S 0.01s I.4 10’2 1.1 IO’S - - I 1.1 IO’S I Ul-a14 M.9 0.14 F 8ow 44 0.14 43 IO” LO 10’6 - . 4 2.4 10’6. I Ltl-an S6.6 0.42 F 14400 6.2 0.42 1.1 IO’4 1.9 10’6 - . II 7.110’6* I s1-m 17.0 031 P 1106 3.1 O.Sl 1.3 IO’S 2.2 10’6 . . 14 6.S 10’6 I SZJOQ 17.7 0.07 m 260 0.1) 0.W 1.7 10’6 1.1 10’6 4.2 10’6 - 22 I.1 IO’7 2 sz-2s 11.7 1.32 mo SW 0.010 1.22 7.1 10’7 1.110’6 4.110’6 . n 1.S 1017 3 R-w 19.3 I34 w 420 0.00% 134 4.0 IO” s.4 10’6 8.1 10’6 0.05 36 I.9 10’7 Y u1461 40.9 1.0 P 210 0.021 1.12 I.~ 1017 1~10’6 4.~1016 . $0 2.1 1017 S7 ,-) oamwes.- LEI-273 42.4 3.6 P 1300 O.U23 1.12 1.7 IO’7 1.110’6 4.4 1016 - 61 461017. 5 (-) lmwwti Uf-IN s0.J 6.0 *P wo 0.018 1.17 4.1 1017 1.7 10’6 3.7 10’6 - bilia# 7.4 IO” 6 (&le) ~*llli’ txi-ni Sl.1 7.2 P 600 0.017 I.11 4.2 1017 1.7 10’6 3.11oJ6i - b∈ 1.6 101’ 6 (-MC) -.ltl a-’ -_ --~ Table I - SILENE data ci represents the efficiency of each group of delayed )cp Energy integrated up to the botton of the first peak (in neutrons I cut Total uranium concentration (in g.l-1) (93 % 23~~ fissions) enriched uranium) i Total energy integrated up to the maximum of the peak Hc Delayed critical height (in cm) power “f Final volume (in liters) N f Total number of fissions The figures 2 to 5 illustrate the evolution of the power. Ah’ Total potential reactivity addition in the core energy and temperature during the experiments. Several tycal Ak,, Effective reactivity present at the first peak excursions have been reproduced, namely : Figure 2 - A fast transient (S4-346) produced by a 3 S A0 Mean rise in temperature of the fissile solution at the reactivity step and two intermediate transients (LEZ-362 and end of the experiment (in “C), 0i designating the initial LEI-362) resulting of reactivity ramps (0.17 and 0.035 S s- temperature and 0f the temperature reached at the I), all three experiments performed with exactly the same equilibrium state te total reactivity excess. T2 Doubling time of power rise (in s) Figure 3 - A very slow transient (LEZ-229 produced by a 0 Reciprocal of period (in s-l) small reactivity addition (0.42 S) but showing that. even m i Maximum power at the top of the first peak (in this case,a restarting must be expected. fissions/s) Figure 4 - An experiment (LEl-281) with a very large excess AP Dynamic pressurewave on the core tank bottom during of reactivity (Ak z 7.2 S) leading the solution to boiling. the first peak (relative value in bars) . Figure 5 - Fast Transient 1s’ peak --- E _s- --,3--e-,--- Be=-’ ---+-- )-@-#-4 Energy Power SILENE 71g.+ A kp=3$ Volume=401 Nf =3 lo 17fissions Figure 2 - Experiments Performed at the Same 3 S Total Reactivity TEMPERATURE ‘C v-94.41 100 SO 40 1 I 70 d’r ,I 40 40 ld 40 SO 18 f tomponturo 10 18 IO 0 Figure 3 - Slow Kinetics Excursion with Power Restarting lo’% POWER (ndms..-t) TEMPEFXVRE ‘C .------G-m 200 400 400 Figure 4 - Large Reactivity Insertion with Solution Boiling -____. SILENESL 346 We can also mention other valuable information : Relation between Nf, V, Akp t For one configuration, namely a certain diameter o of the vessel. it is possible to approximately relate the total specific fission yield during the chain of pulses to the potenttal reactivity Akp (except if boiling). The total number of fissions in the excursion normalized to the total volume of solution (hence to its heat capacity) fits an expression : N, (yield) i k.Akk, total volume V k dependson the diameter of the vessel with k # 3.4 I012 fissions.(p.c.m)-i . 1-l for SILENE Relation between % and t (ref.4) From another standpoint, and this may useful for the accident estimation, it is possible using the maxtmum .‘mc , ur t ‘22 1.24 1.26 1.28 1.30 energiesmeasured during CRAC and SILENE excursions up Figure 5 - Fast Transient In Peak to 7 4 reactivity insertion, to tit an empirical correlatton N between the specific total number of fissions -$ (t) and the time as follows : Nl - t - V - 3.55 lo-” +6.38 10-l’ x t I”. KNOWLEDGE ACQUIRED with t in secondsand V volume in liters The lesson we have learnt here takes into consideration the . Relation between the first peak power E and cc(fig 6) overall results acquired during the CRAC and SILENE experiments, namely the 72 experiments conducted in the . For fast transients (p > l3) the maximum specific peak- CRAC facility with a reactivity ins&on obtained through continuous pumping of the solution into 30and 80 cm diameter power EN is varying with the reciprocal period o as the cylindrical tanks and several hundred excursions performed following relation with SILENT. . -E = cte xe, I,8 The range of the parameter and result variations were as V follows : Radiolytic gas formation uranium concentrations between 20 and 340 g x 1-l (homogeneousconfigurations only) The volume of radiolysis gas formed is propomonal to the volume of fissile solution up to 250 liters number of fissions5 teaching approximatelv 1.I x IO -13 total potential reactivity input ranging up to IO S cm3Hission (i.e. 110 liters of gas for 10lg fissions). The reactivity ramps.and “steps” reaching 2 S x s-l and 3 % threshold for the formation of radioiysis bubbles is estimated respectively at 1.5 x 10 l5 fissions per liter of tissile solution. . presenceor not of an additional neutron start-up source heating of the solution up to boiling Pressureincrease during the 1stpeak Our observations were : No significant overpressurewas observed for doubling times . maximum power observed I 1020 fissions x s-l T2 greater than 10 ms but for very fast transients the energy maximum total number of tissions I 5 x IO’* fissions generated and gas formed within the liquid may cause . doubling time ranging from a few hundred u.sto a few material ejection and some mechanical damage to the vessel minutes (i.e. CRAC 44). Dosimetry A list of dosimetric measurements have been established6. It should be kept m mind that for different configurations the number of fissions is not proportional to the dose. The maximum value observed was 5.8 x IO2 Gy at I m from the CRAC source for IO’ 8 fissions. Solution boiling The fissi’e solution is brought to its boiling point for a released energy level of about 0.33 MJ per liter (I 1.I. IO 16 fissions/l) and the boiling pseudo-plateau level depends on the excessof reactivity. Startup neutron source influence The presence of an initial neutron source (external or intrmsic) strongly influence the behaviour of the excursion by the tendency to significantly delay the initiation of the burst when the source decreases.It results in a larger burst height because of a strong reactivity step in place of moderated reactivity ramps. It could be to recommanded to provide a neutron background in some processingoperations when the internal source is weak to limit, in the case of an Figure 6 - Relation Beetwen the Specific Power and the excursion, the size of the first peak and to maintain the Reciprocal Period resulting pressurebelow the level that would othervise result in significant equipment damage or solution dispersal. REFERENCES Post accident situation I. F. BARBRY, “Review of Studies on Criticality Accidents Undertaken at CEANALDUC” Trans. Am. Nucl. Sot., 63.225. Experiments carried out without solution dumping (See table (‘991) I and Fig 3) show that in most casesof accidental situations 2. P. LECORCHE, R.SEALE, “A review of the experiments the power excursion is likely to restart after a delay performed to determine the radiological consequencesof a depending on heat transfers with the environment, unless criticality accident” Y - CDC 12 - Union Carbide Corporation - some means of intervention has been prepared so as to stop VC 46 - November 1973 the accident process. 3. F. BARBRY, “Fuel solution Criticality Accident studies Criticali? accident detection systems, if designed for that with the SILENE reactor : Phenomenology, consequencesand purpose and this is the case for the French sysrem, may be simulated intervention” International Seminar on Crltlcalib helpful in this kind of situation for providing information on studies programs and needs.DIJOK (France) SEPT - 1983 the evalution of the post-accident phase and contribute to 4. F. BARBRY, “Model to estimate the maximum fission decision making, for example in the event of intervention. yield in accidental solution excursions” Trans. Am. Nucl. Sot., 55,413. (1987) 5. F. BARBRY, J.P.ROZAM, “Formation of radiolysis gas V. CONCLUSION and the appearanceof a pressureincrease during a criticality excursion in a iissile solution” Trans. Am. Nucl. Sot., 59, 181, The CRAC and SILENE criticality accident study (1989) programmes have .provided a wealth of information on all the 6. F.BARBRY, “Exposure Risks and Possibilities of aspects of criticality excursions in aqueous fissile media : Intervention and Diagnosis in Criticality Accidents” physics, dosimetry, detection, post-accidentsituation. International Conference on Nuclear Criticality Safety. Sept-91 The practical lessons thus drawn will be helpful for OXFORD (G.B.) evaluating and coping with the consequencesof such an event. 7. J. MATHER, A.M. BICKLEY, A. PRESCOTT, F. The accurate SILENE results will allow improvement of BARBRY, P. FOUILLAUD, J.P. ROZAM, “Validation of the excursion modeling and new calculation code development ‘v8 CRITEX Code” International Conference on Nuclear Criticality The overall work will undoubtedly contribute to a better Safety, Sept. 91 OXFORD (G.B.) knowledge of the phenomena that may be encountered in 8. David L. HETRICK. “Computer Simulation of accident situations and to the elaboration of a nuclear hypothetical Criticality Accidents in aqueoustissiie solutions” installation safety policy. Trans. Am. NucI. Sac., 63,226. (1991). --