Long-Term Heat Load Calculation Methodology for Spent Nuclear Fuel

Home , Decay heat

KAERI/TR-3031/2005

2005. 7

KOREA ATOMIC ENERGY RESEARCH INSTITUTE KAERI/TR-3031/2005

제 출 문

한국원자력연구소장 귀하

본 보고서를 2005 년도 “건식 재가공 핵연료 노심특성 평가 기술 개발”과제의 기술 보고서로 제출합니다.

제목: Long-Term Heat Load Calculation Methodology for Spent Nuclear Fuel

2005. 7

과제명: 건식 재가공 핵연료 노심특성 평가 기술 개발 주저자: 정 창 준 공저자:

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ABSTRACT

Application of the methodology to the Korean fuel cycle scenarios which include both PWR and CANDU spent fuels is also presented. From the calculation results, it is known that the actinides dominate the long-term heat load, especially Pu and Am isotopes. For the Korean fuel cycle scenario, the PWR spent fuel long-term heat until 1500 yrs with a 5-yr cooling time is estimated to be 9600 MW-yr. The long-term heat of the CANDU reactor spent fuel is much smaller compared with that of the PWR.

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CONTENTS

ABSTRACT...... 2

1. Introduction...... 6

2. Heat Load Calculation Methodology...... 8

3. Application to Korean Nuclear Fuel Cycle...... 10

3.1 Korean Fuel Cycle Scenario ...... 10

3.2 Heat Load Calculation Calculations ...... 10 3.2.1 PWR Spent Fuel...... 11 3.2.2 CANDU Spent fuel...... 11

4. Summary...... 13

References...... 14

APPENDIX...... 27

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LIST OF TABLES

Table I Long Term Decay Heat Integrated Parameter for Key Isotopes...... 15 Table II Half life and decay constant of each isotope ...... 16 Table III Example Long-term Decay Heat Factors (GW-yr/g)...... 17 Table IV Accumulation of spent fuel with time in the Korean fuel cycle scenario...... 18 Table V PWR spent fuel isotope inventories with time after discharge (g/tIHM) ...... 19 Table VI CANDU spent fuel isotope inventories with time after discharge (g/tIHM)...... 20

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LIST OF FIGURES

Fig. 1 Long-term heat load of 1-ton of PWR spent fuel...... 21 Fig. 2 Comparison of heat load contribution of main isotopes (PWR, 5-yr cooling) ...... 21 Fig. 3 Comparison of heat load contribution of main isotopes (PWR, 10-yr cooling) ...... 22 Fig. 4 Comparison of heat load contribution of main isotopes (PWR, 20-yr cooling) ...... 22 Fig. 5 Comparison of total heat load for cooling times (PWR)...... 23 Fig. 6 Total heat load at the year of 3500 (10-yr cooling, PWR)...... 23 Fig. 7 Long-term heat load of 1-ton of CANDU spent fuel...... 24 Fig. 8 Comparison of heat load contribution of main isotopes (CANDU, 5-yr cooling)...... 24 Fig. 9 Comparison of heat load contribution of main isotopes (CANDU, 10-yr cooling)...... 25 Fig. 10 Comparison of heat load contribution of main isotopes (CANDU, 20-yr cooling)...... 25 Fig. 11 Comparison of total heat load for cooling times (CANDU)...... 26 Fig. 12 Total heat load at the year of 3500 for cooling times (10-yr cooling, CANDU) ...... 26

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1. Introduction

The purpose of this report is to provide a general methodology for calculations of the short-term and long-term integrated decay heat factors that can be implemented in fuel cycle system dynamics codes such as DYMOND [1] and DANESS [2]. The short-term decay heat at shutdown of repository active cooling and integrated long-term decay heat determine the amount of waste that can be emplaced into the repository [3]. In the case of Yucca Mountain (YM) repository, there are limits on the temperatures at the surface of the tunnels (drifts) where the waste will be placed or the temperature midway between those tunnels. Given a certain type of waste, the amount of waste that can be placed per unit of the tunnel length is determined by either one of those decay heat factors. Thus, how much waste we can place in those tunnels, i.e., the repository capacity depends on those factors.

Current version of the DYMOND code quantifies the waste long-term integrated decay heat that can affect YM capacity as follows. The cumulative amount of heat generated by spent fuel and/or high-level waste (HLW) between about 100 years and 1500 years after the spent fuel had been discharged from the reactor are quantified by integrating over the individual isotope decay heat over that period. Table I shows the decay heat integral for the different isotopes that are responsible for the majority of the long-term decay heat per unit mass. . The DYMOND code tracks the amounts of those isotopes (that are destined to repository) at each point in time and multiples the mass of each isotope by the corresponding factor, to determine the integrated long term decay heat associate with that isotope. The total amount of integrated decay heat is used to compare the repository heat-load for the different scenarios.

However, the above factors are based on integrated decay heat between about 100 years and 1500 years after the spent fuel had been discharged from the reactor. Although this period of time corresponds to LWR SF that will be emplaced in YM, it might be different for other type of SF which will be implaced in different repository. For example, a type of fuel or a repository where it is important to consider integrated decay heat between 100 years and 1000 years after discharge leads to an Am 241 factor that is about 15% smaller than the factor in Table 1. This difference in the integrated decay heat factors can be important in certain cases. For example, it can be important for comparing different scenarios that uses different types of fuel, different types of repositories, or

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different shut down times of the repository active cooling.

This work describes a simple methodology for estimating the integrated decay heat integrals for the different isotopes of interest over flexible periods of time, which can be easily implemented in system dynamics codes. Application of the methodology to the Korean fuel cycle scenarios, that include both PWR and CANDU spent fuel is also presented.

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2. Heat Load Calculation Methodology

The heat load factors are calculated by the following equation;

HL = M t1 ⋅ HLF where HL = Heat load [w-yr],

Mt1 = Isotope inventory at specific time t1 [g], HLF = integrated heat load factor [w-yr/g].

The HLF can be calculated by

HLF = DH i ⋅ DHFi + DH id ⋅ DHFid

where DHi = decay heat of isotope i [W/g],

DHFi = decay heat factor of isotope i [yr],

DHid = decay heat of daughter of isotope i [W/g],

DHFid = decay heat factor of daughter of isotope i [yr]

The DHFi and DHFid can be calculated by

t t 1  − 1 − 2  DHF = e λi − e λi  i λ i  

λd DHFid = [DHFi − DHFd ] λd − λi

where λ i = decay constant of isotope i [1/yr],

λ d = decay constant of daughter of isotope i [1/yr],

t1 = starting time of integration [yr],

t2 = termination time of integration [yr].

The basic data, such as half-life and decay constant are shown in Table 2. The above equation is

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easily implemented in system codes, where the data in Tables 2 are stored into the ITHINK arrays, and the times t1 and t2 are inputs, which are provided by the user to determine the period over which the integrated decay heat is calculated. Table 3 shows example results for heat load factors estimates for different periods of times and different isotopes of interest. As mentioned before, the key isotopes in this table are Pu isotopes and Am241, because of their large integrated decay heat factors, and its relatively large compositional fractions compared to other isotopes. Some of the fission products isotopes such as Sr 90, have large factors, however, its effect is limited to short term, because of its short half-life.

Once the factor for each tracked isotope is calculated within the system dynamics code, the factor is used as a multiplier to the isotope inventory tracked by the code, to calculate the contribution of the isotope to the long-term repository heat load. The total long-term repository heat-load indicator is calculated as the sum of contributions from the different isotopes. The next section applies the methodology to Korean fuel cycle that has both LWR and CANDU reactors.

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3. Application to Korean Nuclear Fuel Cycle

3.1 Korean Fuel Cycle Scenario

The fuel cycle model considers both the PWR and pressurized heavy water reactor (PHWR), which are currently operating in Korea. Based on the nuclear power plant construction plan, where the nuclear power is expected to grow from 13.716 GWe in 2000 to 27.32 GWe in 2015. From 2016 to 2100, the growth rate was assumed to be 0%. In 2000, there were 12 PWRs and 4 PHWRs in Korea, but there will be no more construction of PHWRs after 2000. The reactor life time was assumed to be 40 yrs for both the PWR and PHWR. As given in Table 4, the SF inventory, increases with time and the total PWR SF will be ~54 kt in the year 2100. Beyond 2049, the CANDU SF remains constant at ~17 Kt, since the CANDU reactor is not constructed after 2040. The detailed results arte described in Ref. 4.

Tables 5 and 6 show the composition of PWR and CANDU spent fuel at different times after discharge, which are calculated by ORIGEN-ARP [5]. Those compositions are used in the DYMOND code, and are used to estimate the isotopic inventory at any point in time for the heat load calculations. For the PWR spent fuel, the composition and decay heat data were evaluated for typical high-burnup PWR assemblies. The high burnup assembly has an initial enrichment of 4.5% U-235 and a discharge burnup of 55,000 MWD/MT. For the CANDU spent fuel, the composition and decay heat data are generated for a fuel bundle which has an initial enrichment of 0.711% U- 235 and a discharge burnup of 7,500 MWD/MT.

3.2 Heat Load Calculation Calculations

So far, a specific repository type have not been chosen to dispose of the spent fuel in Korea. Thus, it is important to perform the calculations for a range of periods for the integrated decay-heat integral. The long-term heat load is calculated for the following isotopes of interest (although not all isotopes contribute significantly to heat load) important isotopes; - Uranium: U-232, U-234, U-235, U-236 and U-238. - Neptinium and Plutonium: Np-237, Pu-238, Pu-239, Pu-240, Pu-241 and Pu-242. - Americium: Am-241, Am-242m, Am-242 and Am-243.

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- Curium: Cm-242, Cm-243, Cm-244, Cm-245 and Cm-246. - Fission products: C-14, Sr-90, Zr-93, Tc-99, I-129, Cs-135 and Cs-137.

The heat loads are calculated for the cooling time of 5yr, 10yr and 20yr. It is assumed that the spent fuel will be disposed of in the repository after the cooling period and there is no active cooling of the repository beyond that period. The heat load of each isotope is calculated and the total heat load is compared for various cooling time. The long-term heat load is assessed for 1500 yrs. The detailed heat loads of each isotope are presented in appendix.

3.2.1 PWR Spent Fuel

Fig.1 shows the long-term heat load for 1 ton of the spent fuel after disposal in the repository. There is not much difference in heat load between 5yr and 10 yr cooling time. For 20-yr cooling time, the heat load is ~40% lower than 5-yr cooling case. For all the cases, the long-term heat loads decrease after 500 yr after disposal, and eventually go to the same heat level.

In order to investigate the long term heat load for the Korean nuclear fuel cycle scenario, the long term heat loads were calculated for the annual spent fuel production from 2000 to 2100. As shown in Figs. 2 – 4, the actinides dominate mainly the heat load. As the cooling time increases, the effect of Am-241 increases. Fig.5 compares the total long-term heat load for different cooling times. For the cooling times of 5yr, 10yr and 20yr, the total heat loads are ~9600 MW-yr, ~9000 MW-yr and ~8300 MW-yr, respectively.

The long-term heat load at the year of 3500 (cooling time is 10yr) is shown in Fig. 6. From this result, the total long-term heat at the year of 3500 is ~9000 MW-yr.

3.2.2 CANDU Spent fuel

The long-term heat loads for 1 ton of the spent fuel after disposal in the repository are shown in Fig. 7. From the results, it is known that the trends of the long-term heat are similar to those of the PWR spent fuel except their magnitudes. The heat loads are constant after 2050 since the CANDU spent fuel is not produced after 2040, which is indicated in Table 4. The values of the long-term heat loads are ~1/10 of those of the PWR, however, per unit of energy generated from the spent fuel this ratio

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is about 1/7.

Like the PWR spent fuel, in case of long-term case of the CANDU spent fuel, the actinides dominate mainly the heat load, which is shown in Figs. 8 – 10. As compared in Fig. 11, the total heat loads of cooling times of 5-yr, 10yr and 20yr are ~690MW-yr, ~650MW and ~600MW, respectively, which are much smaller compared with those of the PWR.

The long-term heat load at the year of 3500 is shown in Fig. 12. From this result, the total long-term heat at the year of 3500 is ~650MW.

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4. Summary

From the PWR results - The actinides dominate the long-term heat load, especially Pu and Am isotopes. - For the Korean fuel cycle scenario, the long-term heat of 5-yr cooling time is 9600 MW-yr. The long-term heats of 10yr and 20yr cooling times are reduced by ~6% and ~14%, respectively, compared with 5yr cooling case. - The long-term heat load at the year of 3500 with 10-yr cooling time is ~9000MW-yr.

From the CANDU results - The long-term heats of the CANDU reactor spent fuel are much smaller compared with those of the PWR. - The total long-term heats for 5yr, 10yr and 20yr cooling times are 690 MW-yr, 650 MW-yr and 600 MW-yr, respectively. - The long-term heat load at the year of 3500 with 10-yr cooling time is ~650 MW-yr.

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References

1. J.H. Park, C.J. Jeong and H.B. Choi, “Implementation of a Dry Fuel Cycle Model into the DYMOND Code,” J. of Korean Nuclear Society, Vol. 36, pp175-183, 2004. 2. L. Van Den Durpel, A. Yacout, D. Wade and H. Khalil, “DANESS, Dynamic Analysis of Nuclear System Strategies,” Global 2003, New Orleans, November 16-20. 3. R. Wigeland, T. Bauer, T. Fanning, E. Morris, “Repository Impact of LWR MOX and Fast Reactor Recycling Options,” ANS Winter Meeting / Global 2003, New Orleans, November 16-20. 4. C.J. Jeong, “Dynamic Anbalysis of Korean Nuclear Fuel Cycle with Fast Reactor System,” KAERI/TR-2859/200R, KAERI, December 2004. 5. J.C. Gauld, S.M. Bowman, J.E. Horwedel, and L.C. Leal, “ORIGEN-ARP: Automatic Rapid Processing for Spent Fuel Depletion, Decay, and Source Term Analysis,” NUREG/CR-0200 (Rev.7), Vol. I, Section D1, ORNL/NUREG/CSD-2/VI/R7. ORNL, May 2004.

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Table I Long Term Decay Heat Integrated Parameter for Key Isotopes

Isotope Decay Heat Integral (GWy/g) Pu-238 33.18 Pu-239 2.61 Pu-240 8.97 Pu-241 56.3 Am-241 54.42

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Table II Half life and decay constant of each isotope

-1 Isotope T 1/2 (yr) λ (yr ) U232 2.207E+01 7.084E-01 U233 9.633E-03 2.805E-04 U234 6.217E-03 1.790E-04 U235 2.161E-06 5.992E-08 U236 6.468E-05 1.754E-06 U238 3.361E-07 8.510E-09 NP237 7.047E-04 2.075E-05 PU238 1.712E+01 5.675E-01 PU239 6.202E-02 1.928E-03 PU240 2.269E-01 7.068E-03 PU241 1.030E+02 3.272E-03 PU242 3.954E-03 1.168E-04 AM241 3.427E+00 1.146E-01 AM242M 1.047E+01 4.490E-03 AM242 8.080E+05 9.170E+02 AM243 1.997E-01 6.440E-03 CM242 3.311E+03 1.219E+02 CM243 4.903E+01 1.806E+00 CM244 8.093E+01 2.832E+00 CM245 1.716E-01 5.721E-03 CM246 3.072E-01 1.008E-02 C 14 4.455E+00 1.307E-03 SR 90 1.388E+02 9.293E-01 ZR 93 2.515E-03 2.842E-07 TC 99 1.711E-02 1.024E-05 I129 1.768E-04 8.191E-08 CS135 1.104E-03 4.376E-07 CS137 8.655E+01 4.168E-01

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Table III Example Long-term Decay Heat Factors (GW-yr/g)

Isotopes Year Interval 5-1500 10-1500 20-1500 U232 70.15 66.85 60.72 U233 0.42 0.42 0.41 U234 0.27 0.27 0.26 U235 0.00 0.00 0.00 U236 0.00 0.00 0.00 U238 0.00 0.00 0.00 NP237 0.03 0.03 0.03 PU238 69.32 66.64 61.60 PU239 2.82 2.81 2.79 PU240 9.77 9.73 9.66 PU241 64.77 64.59 63.99 PU242 0.17 0.17 0.17 AM241 64.45 63.88 62.77 AM242M 126.07 124.49 121.28 AM242 0.03 0.00 0.00 AM243 8.98 8.95 8.88 CM242 69.46 66.74 61.67 CM243 68.52 60.99 48.41 CM244 70.76 60.10 44.03 CM245 13.24 13.21 13.15 CM246 13.54 13.49 13.39 C 14 1.79 1.78 1.77 SR 90 34.67 30.78 24.26 ZR 93 0.00 0.00 0.00 TC 99 0.02 0.02 0.02 I129 0.00 0.00 0.00 CS135 0.00 0.00 0.00 CS137 16.08 14.32 11.37

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Table IV Accumulation of spent fuel with time in the Korean fuel cycle scenario

Year PWR CANDU (kt) (kt) 2000 2.65 2.31 2010 4.05 3.37 2020 8.08 6.92 2030 13.39 10.47 2040 18.68 14.01 2050 23.99 17.10 2060 30.16 17.10 2070 36.24 17.10 2080 42.14 17.10 2090 48.05 17.10 2100 54.37 17.10

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Table V PWR spent fuel isotope inventories with time after discharge (g/tIHM)

Time after discharge (yr) Isotope 0.00 0.01 1.00 5.00 10.00 20.00 u232 2.52E-04 2.54E-04 3.61E-04 5.94E-04 6.73E-04 6.50E-04 u233 1.79E-03 1.79E-03 1.94E-03 2.54E-03 3.25E-03 4.69E-03 u234 1.66E+02 1.66E+02 1.67E+02 1.71E+02 1.77E+02 1.88E+02 u235 8.30E+03 8.30E+03 8.30E+03 8.30E+03 8.30E+03 8.30E+03 u236 4.06E+03 4.06E+03 4.06E+03 4.06E+03 4.06E+03 4.06E+03 u238 9.43E+05 9.43E+05 9.43E+05 9.43E+05 9.43E+05 9.43E+05 np237 4.31E+02 4.35E+02 4.43E+02 4.44E+02 4.48E+02 4.60E+02 pu238 1.40E+02 1.41E+02 1.52E+02 1.50E+02 1.44E+02 1.33E+02 pu239 5.31E+03 5.38E+03 5.41E+03 5.41E+03 5.41E+03 5.41E+03 pu240 2.12E+03 2.12E+03 2.12E+03 2.12E+03 2.13E+03 2.13E+03 pu241 1.39E+03 1.39E+03 1.33E+03 1.09E+03 8.58E+02 5.29E+02 pu242 5.43E+02 5.43E+02 5.43E+02 5.43E+02 5.43E+02 5.43E+02 am241 3.89E+01 3.96E+01 1.04E+02 3.36E+02 5.67E+02 8.83E+02 am242m 8.10E-01 8.10E-01 8.06E-01 7.91E-01 7.71E-01 7.34E-01 am242 1.15E-01 2.60E-03 1.04E-05 1.02E-05 9.95E-06 9.47E-06 am243 1.13E+02 1.13E+02 1.13E+02 1.13E+02 1.13E+02 1.13E+02 cm242 1.45E+01 1.44E+01 3.09E+00 8.24E-03 2.01E-03 1.91E-03 cm243 3.57E-01 3.57E-01 3.48E-01 3.16E-01 2.80E-01 2.19E-01 cm244 3.13E+01 3.14E+01 3.03E+01 2.60E+01 2.14E+01 1.46E+01 cm245 1.13E+00 1.13E+00 1.13E+00 1.13E+00 1.13E+00 1.13E+00 cm246 9.77E-02 9.77E-02 9.77E-02 9.76E-02 9.76E-02 9.74E-02 c14 2.94E-03 2.94E-03 2.94E-03 2.94E-03 2.93E-03 2.93E-03 sr90 5.33E+02 5.33E+02 5.20E+02 4.71E+02 4.17E+02 3.26E+02 zr93 7.04E+02 7.05E+02 7.05E+02 7.05E+02 7.05E+02 7.05E+02 tc99 7.99E+02 8.02E+02 8.03E+02 8.03E+02 8.03E+02 8.03E+02 i129 1.52E+02 1.52E+02 1.54E+02 1.54E+02 1.54E+02 1.54E+02 cs135 3.17E+02 3.18E+02 3.18E+02 3.18E+02 3.18E+02 3.18E+02 cs137 1.22E+03 1.22E+03 1.20E+03 1.09E+03 9.71E+02 7.70E+02

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Table VI CANDU spent fuel isotope inventories with time after discharge (g/tIHM)

Isotope Time after discharge (yr) 0.00 0.10 1.00 5.00 10.00 20.00 u232 4.35E-06 4.51E-06 5.48E-06 7.79E-06 8.51E-06 8.12E-06 u233 6.94E-05 7.02E-05 7.83E-05 1.17E-04 1.63E-04 2.58E-04 u234 5.00E+01 5.00E+01 5.00E+01 5.01E+01 5.03E+01 5.06E+01 u235 2.15E+03 2.15E+03 2.15E+03 2.15E+03 2.15E+03 2.15E+03 u236 7.81E+02 7.81E+02 7.82E+02 7.82E+02 7.82E+02 7.84E+02 u238 9.85E+05 9.85E+05 9.85E+05 9.85E+05 9.85E+05 9.85E+05 np237 2.70E+01 2.85E+01 2.85E+01 2.87E+01 2.92E+01 3.10E+01 pu238 3.78E+00 3.96E+00 4.24E+00 4.21E+00 4.05E+00 3.74E+00 pu239 2.48E+03 2.56E+03 2.56E+03 2.56E+03 2.56E+03 2.56E+03 pu240 1.01E+03 1.01E+03 1.01E+03 1.01E+03 1.00E+03 1.00E+03 pu241 2.17E+02 2.15E+02 2.06E+02 1.70E+02 1.34E+02 8.24E+01 pu242 6.16E+01 6.16E+01 6.16E+01 6.16E+01 6.16E+01 6.16E+01 am241 2.34E+00 3.38E+00 1.25E+01 4.86E+01 8.45E+01 1.34E+02 am242m 2.61E-02 2.61E-02 2.60E-02 2.55E-02 2.49E-02 2.37E-02 am242 8.78E-03 3.37E-07 3.35E-07 3.29E-07 3.21E-07 3.05E-07 am243 2.80E+00 2.82E+00 2.82E+00 2.81E+00 2.81E+00 2.81E+00 cm242 4.92E-01 4.27E-01 1.06E-01 2.77E-04 6.49E-05 6.17E-05 cm243 4.09E-03 4.08E-03 3.99E-03 3.62E-03 3.21E-03 2.51E-03 cm244 1.86E-01 1.87E-01 1.80E-01 1.55E-01 1.28E-01 8.71E-02 cm245 1.26E-03 1.26E-03 1.26E-03 1.26E-03 1.26E-03 1.26E-03 cm246 8.80E-05 8.80E-05 8.80E-05 8.79E-05 8.79E-05 8.78E-05 c14 7.62E-04 7.62E-04 7.62E-04 7.61E-04 7.61E-04 7.60E-04 sr90 1.21E+02 1.21E+02 1.18E+02 1.07E+02 9.48E+01 7.41E+01 zr93 1.59E+02 1.60E+02 1.60E+02 1.60E+02 1.60E+02 1.60E+02 tc99 1.97E+02 1.99E+02 1.99E+02 1.99E+02 1.99E+02 1.99E+02 i129 3.58E+01 3.65E+01 3.71E+01 3.71E+01 3.71E+01 3.71E+01 cs135 2.83E+01 2.87E+01 2.87E+01 2.87E+01 2.87E+01 2.87E+01 cs137 2.84E+02 2.84E+02 2.78E+02 2.53E+02 2.26E+02 1.79E+02

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100000

10000

1000

100 5y r 10y r 20y r Long-Term Heat, W-yr Heat, Long-Term 10

1 1 10 100 1000 10000 Year

Fig. 1 Long-term heat load of 1-ton of PWR spent fuel

8.0E+03

7.0E+03 PU238

r AM241 6.0E+03 PU241 5.0E+03 PU240 4.0E+03 PU239

3.0E+03

2.0E+03 Long-Term Heat, MW-y Heat, Long-Term 1.0E+03

0.0E+00 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100 Year

Fig. 2 Comparison of heat load contribution of main isotopes (PWR, 5-yr cooling)

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8.0E+03

7.0E+03 PU238

r AM241 6.0E+03 PU241 5.0E+03 PU240 4.0E+03 PU239

3.0E+03

2.0E+03 Long-Term Heat, MW-y Heat, Long-Term 1.0E+03

0.0E+00 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100 Year

Fig. 3 Comparison of heat load contribution of main isotopes (PWR, 10-yr cooling)

8.0E+03

7.0E+03 PU238 r 6.0E+03 AM241 PU241 5.0E+03 PU240 4.0E+03 PU239 3.0E+03

2.0E+03 Long-Term Heat, MW-y Heat, Long-Term 1.0E+03

0.0E+00 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100 Year

Fig. 4 Comparison of heat load contribution of main isotopes (PWR, 20-yr cooling)

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12000 5-yr 10000 10-yr 20-yr 8000

6000

4000

Long-Term Heat, MW-yr Heat, Long-Term 2000

0 2000 2020 2040 2060 2080 2100 Year

Fig. 5 Comparison of total heat load for cooling times (PWR)

1.0E+04 Total 8.0E+03

6.0E+03

4.0E+03

Long-Term Heat, MW-yr Heat, Long-Term 2.0E+03

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig. 6 Total heat load at the year of 3500 (10-yr cooling, PWR)

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100000 5yr 10000 10yr 20yr

1000

100

Long-Term Heat, W-yr Heat, Long-Term 10

1 1 10 100 1000 10000 Year

Fig. 7 Long-term heat load of 1-ton of CANDU spent fuel

6.0E+02 PU238

r 5.0E+02 AM241 PU241 4.0E+02 PU240 3.0E+02 PU239

2.0E+02

Long-Term Heat, MW-y Heat, Long-Term 1.0E+02

0.0E+00 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100 Year

Fig. 8 Comparison of heat load contribution of main isotopes (CANDU, 5-yr cooling)

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6.0E+02 PU238

r 5.0E+02 AM241 PU241 4.0E+02 PU240 3.0E+02 PU239

2.0E+02

Long-Term Heat, MW-y Heat, Long-Term 1.0E+02

0.0E+00 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100 Year

Fig. 9 Comparison of heat load contribution of main isotopes (CANDU, 10-yr cooling)

6.0E+02 PU238 r 5.0E+02 AM241 PU241 4.0E+02 PU240 3.0E+02 PU239

2.0E+02

Long-Term Heat, MW-y 1.0E+02

0.0E+00 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100 Year

Fig. 10 Comparison of heat load contribution of main isotopes (CANDU, 20-yr cooling)

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800 700 5-yr 10-yr 600 20-yr 500 400 300

Total Heat, MW-yr 200 100 0 2000 2020 2040 2060 2080 2100 Year

Fig. 11 Comparison of total heat load for cooling times (CANDU)

7.0E+02 Total 6.0E+02

5.0E+02

4.0E+02

3.0E+02

2.0E+02 Long-Term Heat, MW-yr Heat, Long-Term 1.0E+02

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig. 12 Total heat load at the year of 3500 for cooling times (10-yr cooling, CANDU)

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APPENDIX

Heat Load of Each Isotope

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5.0E+06 U232 U233 4.0E+06 U234 U235 3.0E+06 U236 U238 2.0E+06 Heat (W-yr) Heat

1.0E+06

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A1 Long-term heat of U isotopes (PWR, Cooling time=5yr)

4.5E+03

4.0E+03 NP237 PU238 3.5E+03 PU239 3.0E+03 PU240 PU241 2.5E+03 PU242 2.0E+03

Heat (MW-yr)Heat 1.5E+03

1.0E+03

5.0E+02

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A2 Long-term heat of Np and Pu isotopes (PWR, Cooling time=5yr)

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1.4E+03 AM241 1.2E+03 AM 242M 1.0E+03 AM242 AM243 8.0E+02

6.0E+02 Heat (MW-yr)Heat 4.0E+02

2.0E+02

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A3 Long-term heat of Am isotopes (PWR, Cooling time=5yr)

1.2E+02 CM242 1.0E+02 CM243 CM244 8.0E+01 CM245 CM246 6.0E+01

Heat (MW-yr)Heat 4.0E+01

2.0E+01

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A4 Long-term heat of Cm isotopes (PWR, Cooling time=5yr)

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1.0E+03

9.0E+02 C 14 8.0E+02 SR 90 ZR 93 7.0E+02 TC 99 6.0E+02 I129 5.0E+02 CS135 4.0E+02 CS137 Heat (MW-yr)Heat 3.0E+02 2.0E+02 1.0E+02 0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A5 Long-term heat of fission products (PWR, Cooling time=5yr)

4.5E+03 4.0E+03 NP237 PU238 3.5E+03 PU239 3.0E+03 PU240 2.5E+03 PU241 AM241 2.0E+03 CM244 1.5E+03 SR 90 1.0E+03 CS137 Long-Term Heat, MW-yr Heat, Long-Term 5.0E+02 0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig. A6 Comparison of Long –Term Heat for 5-yr Cooling (PWR)

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6.0E+06 U232 5.0E+06 U233 U234 4.0E+06 U235 U236 3.0E+06 U238

Heat (W-yr) Heat 2.0E+06

1.0E+06

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A7 Long-term heat of fission products (PWR, Cooling time=10yr)

3.5E+03 NP237 3.0E+03 PU238 2.5E+03 PU239 PU240 2.0E+03 PU241 PU242 1.5E+03 Heat (MW-yr)Heat 1.0E+03

5.0E+02

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A8 Long-term heat of Np and Pu isotopes (PWR, Cooling time=10yr)

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2.5E+03 AM241 AM242M 2.0E+03 AM242 AM243 1.5E+03

1.0E+03 Heat (MW-yr)Heat

5.0E+02

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A9 Long-term heat of Am isotopes (PWR, Cooling time=10yr)

8.0E+01

7.0E+01 CM242 CM243 6.0E+01 CM244 CM245 5.0E+01 CM246 4.0E+01

3.0E+01 Heat (MW-yr)Heat 2.0E+01

1.0E+01

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A10 Long-term heat of Cm isotopes (PWR, Cooling time=10yr)

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8.0E+02 7.0E+02 C 14 SR 90 6.0E+02 ZR 93 5.0E+02 TC 99 I129 4.0E+02 CS135 3.0E+02 CS137 Heat (MW-yr)Heat 2.0E+02 1.0E+02 0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A11 Long-term heat of fission products (PWR, Cooling time=10yr)

3.5E+03 NP237 3.0E+03 PU238 2.5E+03 PU239 PU240 2.0E+03 PU241 AM241 1.5E+03 CM244 SR 90 1.0E+03 CS137 Long-Term Heat, MW-yr Heat, Long-Term 5.0E+02

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig. A12 Comparison of Long –Term Heat for 10-yr Cooling (PWR)

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3.0E+06 U232 2.5E+06 U233 U234 2.0E+06 U235 U236 1.5E+06 U238

Heat (W-yr) Heat 1.0E+06

5.0E+05

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A13 Long-term heat of U isotopes (PWR, Cooling time=20yr)

2.0E+03 1.8E+03 NP237 1.6E+03 PU238 PU239 1.4E+03 PU240 1.2E+03 PU241 1.0E+03 PU242 8.0E+02 Heat (MW-yr)Heat 6.0E+02 4.0E+02 2.0E+02 0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A14 Long-term heat of Np and Pu isotopes (PWR, Cooling time=20yr)

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3.5E+03 AM241 3.0E+03 AM 242M 2.5E+03 AM242 AM243 2.0E+03

1.5E+03 Heat (MW-yr)Heat 1.0E+03

5.0E+02

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A15 Long-term heat of Am isotopes (PWR, Cooling time=20yr)

4.0E+01 CM242 3.5E+01 CM243 3.0E+01 CM244 CM245 2.5E+01 CM246 2.0E+01 1.5E+01 Heat (MW-yr)Heat 1.0E+01 5.0E+00 0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A16 Long-term heat of Cm isotopes (PWR, Cooling time=20yr)

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5.0E+02 4.5E+02 C 14 4.0E+02 SR 90 3.5E+02 ZR 93 TC 99 3.0E+02 I129 2.5E+02 CS135 2.0E+02 CS137 Heat (MW-yr)Heat 1.5E+02 1.0E+02 5.0E+01 0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A17 Long-term heat of fission products (PWR, Cooling time=20yr)

3.5E+03 NP237 3.0E+03 PU238 PU239 2.5E+03 PU240 2.0E+03 PU241 AM241 1.5E+03 CM244 1.0E+03 SR 90 CS137 Long-Term Heat, MW-yr Heat, Long-Term 5.0E+02

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig. A18 Comparison of Long –Term Heat for 20-yr Cooling (PWR)

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12000 5-yr 10000 10-yr 20-yr 8000

6000

4000

Long-Term Heat, MW-yr Heat, Long-Term 2000

0 2000 2020 2040 2060 2080 2100 Year

Fig. A19 Comparison of Total Long –Term Heat for Cooling Time (PWR)

1.0E+04 9.0E+03 NP237 PU238 8.0E+03 PU239 7.0E+03 PU240 6.0E+03 PU241 5.0E+03 AM241 CM244 4.0E+03 SR 90 3.0E+03 CS137 Total

Long-Term Heat, MW-yr Heat, Long-Term 2.0E+03 1.0E+03 0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig. A20 Long-Term Heat at year 3500 (PWR, Cooling time = 10 yr)

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5.0E+05 U232 U233 4.0E+05 U234 U235 3.0E+05 U236 U238 2.0E+05 Heat (W-yr) Heat

1.0E+05

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A21 Long-term heat of U isotopes (CANDU, Cooling time=5yr)

2.5E+02 NP237 2.0E+02 PU238 PU239 PU240 1.5E+02 PU241 PU242 1.0E+02 Heat (MW-yr)Heat

5.0E+01

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A22 Long-term heat of Np and Pu isotopes (CANDU, Cooling time=5yr)

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6.0E+01 AM241 5.0E+01 AM 242M AM242 4.0E+01 AM243

3.0E+01

Heat (MW-yr)Heat 2.0E+01

1.0E+01

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A23 Long-term heat of Am isotopes (CANDU, Cooling time=5yr)

2.5E-01

CM242 2.0E-01 CM243 CM244 1.5E-01 CM245 CM246 1.0E-01 Heat (MW-yr)Heat

5.0E-02

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A24 Long-term heat of Cm isotopes (CANDU, Cooling time=5yr)

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8.0E+01 C 14 7.0E+01 SR 90 ZR 93 6.0E+01 TC 99 I129 5.0E+01 CS135 4.0E+01 CS137 3.0E+01 Heat (MW-yr)Heat 2.0E+01

1.0E+01

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A25 Long-term heat of fission products (CANDU, Cooling time=5yr)

NP237 2.5E+02 PU238 PU239 2.0E+02 PU240 PU241 1.5E+02 AM241 CM 244 SR 90 1.0E+02 CS137

Long-Term Heat, MW-yr Heat, Long-Term 5.0E+01

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig. A26 Comparison of Long –Term Heat for 5-yr Cooling (CANDU)

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5.0E+05 U232 U233 4.0E+05 U234 U235 3.0E+05 U236 U238 2.0E+05 Heat (W-yr) Heat

1.0E+05

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A27 Long-term heat of U isotopes (CANDU, Cooling time=10yr)

1.8E+02 1.6E+02 NP237 PU238 1.4E+02 PU239 1.2E+02 PU240 1.0E+02 PU241 8.0E+01 PU242

Heat (MW-yr)Heat 6.0E+01 4.0E+01 2.0E+01 0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A28 Long-term heat of Np and Pu isotopes (CANDU, Cooling time=10yr)

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1.0E+02 AM241 AM 242M 8.0E+01 AM242 AM243 6.0E+01

4.0E+01 Heat (MW-yr)Heat

2.0E+01

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A29 Long-term heat of Am isotopes (CANDU, Cooling time=10yr)

1.6E-01 CM242 1.4E-01 CM243 1.2E-01 CM244 1.0E-01 CM245 CM246 8.0E-02 6.0E-02 Heat (MW-yr)Heat 4.0E-02 2.0E-02 0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A30 Long-term heat of Cm isotopes (CANDU, Cooling time=10yr)

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6.0E+01 C 14 SR 90 5.0E+01 ZR 93 TC 99 4.0E+01 I129 CS135 3.0E+01 CS137

Heat (MW-yr)Heat 2.0E+01

1.0E+01

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A31 Long-term heat of fission products (CANDU, Cooling time=10yr)

NP237 1.8E+02 PU238 1.6E+02 PU239 1.4E+02 PU240 PU241 1.2E+02 AM241 1.0E+02 CM 244 8.0E+01 SR 90 CS137 6.0E+01 4.0E+01 Long-Term Heat, MW-yr Heat, Long-Term 2.0E+01 0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig. A32 Comparison of Long –Term Heat for 10-yr Cooling (CANDU)

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5.0E+05 U232 U233 4.0E+05 U234 U235 3.0E+05 U236 U238 2.0E+05 Heat (W-yr) Heat

1.0E+05

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A33 Long-term heat of U isotopes (CANDU, Cooling time=20yr)

1.8E+02 NP237 1.6E+02 PU238 1.4E+02 PU239 1.2E+02 PU240 PU241 1.0E+02 PU242 8.0E+01

Heat (MW-yr)Heat 6.0E+01 4.0E+01 2.0E+01 0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A34 Long-term heat of Np and Pu isotopes (CANDU, Cooling time=20yr)

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1.6E+02 1.4E+02 AM241 AM 242M 1.2E+02 AM242 1.0E+02 AM243 8.0E+01 6.0E+01 Heat (MW-yr)Heat 4.0E+01 2.0E+01 0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A35 Long-term heat of Am isotopes (CANDU, Cooling time=20yr)

8.0E-02 CM242 7.0E-02 CM243 6.0E-02 CM244 CM245 5.0E-02 CM246 4.0E-02 3.0E-02 Heat (MW-yr)Heat 2.0E-02 1.0E-02 0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A36 Long-term heat of Cm isotopes (CANDU, Cooling time=20yr)

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4.0E+01 C 14 3.5E+01 SR 90 ZR 93 3.0E+01 TC 99 2.5E+01 I129 CS135 2.0E+01 CS137 1.5E+01 Heat (MW-yr)Heat 1.0E+01 5.0E+00 0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A37 Long-term heat of fission products (CANDU, Cooling time=20yr)

NP237 1.8E+02 PU238 1.6E+02 PU239 PU240 1.4E+02 PU241 1.2E+02 AM241 1.0E+02 CM244 SR 90 8.0E+01 CS137 6.0E+01 4.0E+01 Long-Term Heat, MW-yr Heat, Long-Term 2.0E+01 0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig. A38 Comparison of Long –Term Heat for 20-yr Cooling (CANDU)

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800 700 5-yr 10-yr 600 20-yr 500 400 300

Total Heat, MW-yr 200 100 0 2000 2020 2040 2060 2080 2100 Year

Fig. A39 Comparison of Total Long –Term Heat for Cooling Time (CANDU)

NP 237 7.0E+02 PU238 PU239 6.0E+02 PU240 5.0E+02 PU241 AM241 4.0E+02 CM244 SR 90 3.0E+02 CS137 Total 2.0E+02 Long-Term Heat, MW-yr Heat, Long-Term 1.0E+02

0.0E+00 2000 2020 2040 2060 2080 2100 Year

Fig.A40 Long-Term Heat at year 3500 (CANDU, Cooling time = 10 yr)

서 지 정 보 양 식

수행기관보고서번호 위탁기관보고서번호 표준보고서번호 INIS 주제코드

KAERI/TR-3031/2005

제목/부제 Long-Term Heat Load Calculation Methodology for Spent Nuclear Fuel

연구책임자 및 부서명 정창준 (건식공정핵연료기술 개발부)

연구자 및 부서명

출 판 지 대전 발행기관 한국원자력연구소 발행년 2005.7.

페 이 지 47 p. 도 표 있음( V ), 없음( ) 크 기 26 Cm.

참고사항

공개( ), 대외비( ), 비밀여부 보고서종류 기술보고서 __ 급비밀 , 소내만 공개 ( O )

연구위탁기관 계약 번호

초록 (15-20줄내외 )

본 보고서는 핵연료 주기 동적 분석에 적용될 수 있는 단기 및 장기 열 부하 계산 방법론에 대해 기술하고 있다. 열 부하 계산을 위해 경수로 및 중수로 사용후 핵연료의 각 동위 원소 별 붕괴열 및 재고량 자료를 생산하였다 . 그리고, 각기 다른 동위 원소의 특정 시간 구간에 대해 장기 열부하량을 평가하기 위해 붕괴열 적분 계산을 수행하였다 . 이 방법론을 경수로 및 중수로가 동시에 운전되고 있는 한국 핵연료 주기에 대해 적용하였다 . 계산 결과, actinide 핵종 특히 plutonium 및 americium 열부하에 주로 영향을 미치는 것으로 나타났다 . 한국 핵연료 주기에 대한 적용 결과, 5 년의 냉각 기간을 갖는 경수로 사용후 핵연료의 열 부하는 2100 년까지 발생하는 사용후 핵연료 양을 고려할 때 9600 MW-yr 로 평가되었다 . 한편, 중수로 사용후 핵연료의 열 부하는 경수로 사용후 핵연료에 비해 현저히 낮은 것으로 나타났다 .

주제명키워드 붕괴 열, 장기-열 부하, 핵연료 주기, 동적 분석, 경수로 중수로, 사용후 (10단어내외) 핵연료

BIBLIOGRAPHIC INFORMATION SHEET

Performing Org. Sponsoring Org. Standard Report No. INIS Subject Code Report No. Report No. KAERI/TR-3031/2005

Title/Subtitle Long-Term Heat Load Calculation Methodology for Spent Nuclear Fuel

Main Author Jeong, Chang Joon (Dry Process Fuel Tech. Development Div.) Researcher and

Department

Publication Publication Daejeon Publisher KAERI 2005. 7. Place Date Page 47 p. Fig. & Tab. Yes ( V ), No ( ) Size 26 Cm.

Note Classified Open ( ), Restricted ( ), Report Type Technical Report __ Class Document, Internal Use Only ( O ) Sponsoring Org. Contract No.

Abstract (15-20 Lines)

This report describes a general methodology for calculations of the short-term and long-term integrated decay heat factors that can be implemented in fuel cycle system dynamic analysis. For the heat load calculation, the decay heat and isotope inventory data are generated for pressurized water reactor (PWR) and Canada deuterium uranium (CANDU) reactor spent fuels. Then the decay heat integral calculations are performed for estimating the long-term heat load for the different isotopes of interest over flexible periods of time. Application of the methodology to the Korean fuel cycle scenarios which include both PWR and CANDU spent fuels is also presented. From the calculation results, it is known that the actinides dominate the long-term heat load, especially Pu and Am isotopes. For the Korean fuel cycle scenario, the PWR spent fuel long-term heat until 1500 yrs with a 5-yr cooling time is estimated to be 9600 MW-yr. The long-term heat of the CANDU reactor spent fuel is much smaller compared with that of the PWR.

Subject Keywords decay heat, long-term heat load, fuel cycle, dynamic analysis, (About 10 words) pressurized water reactor, CANDU reactor, spent nuclear fuel