:.F 6 00D 5 February 1986 !"

Secretary of the Commission U. S. Nuclear Regulatory Commission Nashington, DC 20555 Attn: Docketing and Service Branch

Re: Comment on Proposed Ruies for 10 CFR 19 et al.

Dear Sir or Madam: Please refer to the definition of the , in Section 20.4 (4), on page 1127 of the proposed rules for 10 CFR 19 et al. Contrary to your statement, the sievert is NOT in general equal to a / . The definition, if uncorrected, will cause confusion and could result in erroneous measurements. At the same time, I can understand how your definition was taken verbatim from some presumably reliable source. I am enclosing a recent letter-to-the-editor in Nuclear News which refers to the history of the defective definition. I am also enclosing a page from a 1985 NCRP Repor t which correc tly discusses the definition of the sievert.

| Insofar as revised wording is concerned, I suggest that ! since you have exhaustively defined the rem, it is only aecessary further to say,

( 4) " Sievert" (Sv) is G60211OOS4 G60206 a unit of dose equivalent. PDR PR One sievert is equal to 19 SOFR51992 I>UH 10 0 r ems .

Please understand that the opinions expressed in this comment are my own, and are not represented to be those of | the University of California.

g Sincerely

j j Uh ? /kO ctf K St G ||?)0) 0 / ' &jjj N/1)$10f QQC4f9Ml!~'i6 \ -+' ... Lawrence Rbby ,~ t t, 90 Professor , * . , ...... 'd ,, _

, ,- ~ oil, typically saving about $300,- ' on th3 sievert ...d.,. ., t, p.g wi,1 r o,, t P., ,..r. e ~' .ers the controversy (see NUCLEAR News, EBR-II is a -metal fast breeder May 1982, p. 74) over the definition ctor with a thermal rating of 62.5 of the sievert as specified by the 16th t and an electrical ratmg of 20 General Conference on Weights and M 'e. For expenmental convenience, Measures (CGPM). Discussion in this th electrical production is now about and other journals, plus the intercession 17 MWe, of which about 5 MWe is of many professionals, finally con- consumed un the Argonne-West site; vinced U.S. government authorities the remainder goes out on the elec- that a problem did, in reality, exist. trien! grid of the Idaho National Engi. Hence, in the latest edition of NBS neciing Laboratory (INEL), which is Special Publication 330, there appears servrd by Idaho Company. (At a clarifying paragraph following the times of low power usage on the INEL, wording adopted by the 16th CGPM. EBbil puts out a surplus of power Although the controversial defic tion that goes to non.INEL Idaho Power Outcries explained t is a scant nine words ("ne sievert is customers.) , With reference to the lett< r by equal to the joule per kilogram."), the I?uring the maximum winter-heating Meyer Steinberg on page 33 is the clarification requires about 100 words months, EBR II also furnishes up to 14 (00 lb/h of steam for space - May 1985 issue of NUCLEAR NEWS: If to set the meaning straight. Readers , Israel considers itself at war wit $ Iraq will enjoy hearing that a similar patch ing nd plant uses; this is equivalent and wishes to bomb Iraqi researth in- job has been proposed for the inter. to bout 1 MWt. In summer, the stitutes and industrial installationn, that national scene. Last June, the Consulta- requ ement for reactor steam drops is not unusual for a country at war- tive Committee on Units (CCU) pro- belo * 5000 lb/h. - I regret that any country is ever i t war posed to the International Committee ne reactor steam is taken upstream with another, but usually refrain from on Weights and Measures (CIPM) that of tile turbine at a of 1250 comment on the way that war is con- because a "possible confusion" exists psig. and is reduced to 100 ps,gi for ducted, provided the Geneva ccnven- with respect to the difference between plani and space beating uses. The tion is followed- the and the sievert, in that they maximum reduction in electrical out. The outcry by many people, hclud- both have been defined as formally put electricity, this writha was not at this bombin g, but the resolutions adopted by the CGPM has been a very economical trade.off at two other features. First, representa- regarding the gray and the sievert. The for Argonne National Laboratory, the tives of the State of Israel-which, b) number of words in the French text of operator of EBR II, and also for the not signing NPT, has rejectei the the footnote is again about 100, and it taxpayers. mithod accepted by a majority af the makes use of the noble phrase, "Alin In 1980 EBR II was granted the nations of the world--

NUCLEAR NEWS / JULY 1985 21 g . _ - - _ . - _

, . , 16 / 3. CONVENTIONAL AND SI IJNITS 3.3 DOSE EQt?iVALENT / 1 Calculation in InternationalSystem units confusion since it may obscure the differences among the quantitie Calculate the rate at 3 meters from a 1 TBq source. * ' l'. = 2.53 x 10-'" C kg-' m' s-' Bq-' * # '# #9" "' # " '" 10,, Bq The fluence rate of at middle latitudes and sea leve X. = 2.53 x 10-'' C kg-' m2 s-' Bq-8 x produced by the insteraction of cosmic with the ' (3m)2 atmosphere may be taken as 7 x 10-8cm-8 s - '. Calculate the maximus = 2.81 x 10-7 C kg-' s-'. dose equivalent in a semi. infinite tissue. equivalent slab from a year exposure to neutrons. Calculation in conventional units For the casmic ray spectrum the fluence-to. dose equivale 3.3 Dose Equivalent conversion s taken as (Shaw et al 1969): The quantity dose equivalent is defined by the ICRU (1980) as H/+ = 1.27 x 104 rem cmt follows: The dose equivalent, H, is the product of D, Q, and N at the This is based on the annual maximum dose equivalent in the 30.cr point of interest in tissue where D is the , Q is the thick slab from cosmic ray neutrons. Remembering that the numbe quality factor and N is the product of all other modifying factors, of in one year is about 3.16 x 10', this becomes: # = DQN. 11 = 7 x 10-' cm-2 s- * x 1.27 x 10-* rem em' The special name sievert, symbol Sv, has been adopted for the Si x 3.16 x 10' s unit of dose equivalent in the field of . For a given irradiation, the numerical value in per kilogram for the two = 2.8 x 10-3 rem. quantities D and H may differ, depending on the values of Q and N. Calculation in SI units To avoid any risk of confusion, the special names for the respective units should be used; i.e., D should be expressed in grays and 11 should Recalling that there are 10* cm2 in one m*, the annual fluence o be expressed in , cosmic ray neutrons is: 1 sievert = 100 rem. + = 7 x 10-8 cm- - ' s ' x 10* cm8 m-8 x 3.16 x 107 s Further ICRU reports which are helpful in understanding the = 2.21 x 10' m-2 definition of the quantity " dose equivalent" are ICRU Report 33 entitled Radiation Quantatics and Units (ICRU,1980), and ICRU The fluence to dose equivalent conversion. H/+, for the spectrum o cosmic ray neutrons is: Report 25 entitled Conceptual Basis for the Determination of Dose Equivalent (ICRU,1976), and ICRU Report 39 entitled Determination H/ + = 1.27 x 10-'' Sv m2 , of Dose Equivalents Resulting from External Radiation Sources (ICRU' and the annual dose equnvalent is 1935). An absorbed dose of I from photons results approximately in a H = 2.21 x 10' m-r x 1.27 x 10-'' Sv m' dose eqmvalent of I rem. This leads to the numerical relationship that = 2.s x 10-5 Sv = 26 pSv. an exposure of 1 R to soft tissue produces approximately an absorbed dose of I rad and a dose equivalent of I rem. This convenient " rule of Comparing the two calculations and remembering that 1 Sv = li thumb' associated with conventional units. however, can lead to , rem we see that they are in agreement.

"SI Units Radiation3 Protection and Measurements", NCRP Report No. 82, ]985 in