ML20099J517

Applicant Exhibit A-150,consisting of Undated Pages 9-53 & 9-54 of Rept Re Late Somatic Effects of Inhaled beta- Emitting Radionuclides

ML20099J517
Person / Time
Site:	Limerick
Issue date:	05/22/1984
From:	AFFILIATION NOT ASSIGNED
To:
References
OL-A-150, NUDOCS 8411290097
Download: ML20099J517 (3)

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' Estimates of lung damage from inhaled beta-estitting radion 1 des [ sere-U 1

? adequately covered in the.RSS. Other useful references for fatdlitiesfrom ,

inhaled radionuclides are reports by Filipy et al. (1980) and Hahn (1979)".*

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h In the RSS, the dose-response relationship for early Q.

fatalitieslis. -

applied to a radiation dose that is the s m of the following: .

j 1. External dose from 'the passing cloud.

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} 2. External dose from contaminated ground (the duration of exposure to gassna rays emitted by deposited fission products, together with the degree of shielding, depends on the assumed emergency-response.

a strategy).

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3. Internal dose received during the first 7 days from inhaled radio-nuclides. -

I 4. For bone-marrow exposure only, half of the internal does from i inhaled radionuclides received from day 8 through day 30.

5. For lung exposure only, the internal dose frost inhaled radio-nuclides received frost day 8 through day 365.

It can be seen that this is a specifically defined dose commitment. The consequence modeler should be cautioned that redefining the dosimetry i assutptions used in' the analysis .would require redefinition of the dose-response relationships for early fatalities. Repair mechanisms may modify the effects of radiation exposure if the exposure is received over an ex-tended period'of time.

I_niuries

The various types of impairment listed at the beginning of this sec-tion are detailed in Appendix VI of the RSS. A sublethal dose, defined as-j the dose expected to cause a clinical response in 10, 50, or 90 percent of

the exposed population, was ostimated for the various morbidities. These 1 responses are not as easily determined as fatalities; thus the estimates have some subjectivity and increased uncertaincy.

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9 3 5.2 1, ate somatic Effects I

Late somatic effects consist of latent-cancer fatalities, nonfatal j cancers, illnesses, and benign thyroid nodules. The mes model included a latent period during which there.was no increase in cancers and a plateau i period with a uniform cancer rate for each cancer type.

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j. The estimates of latent cancer calculated by the CRAC code are based

. on the BEIR I report (NAS-NRC, 1972), with the leukemia and bone-cancer

! values modified to reflect new data that became available between 1972 and

{ 1975. The RSS developed three estimates of risk. The upper-bound estimate used the linear, no-threshold estimators from the EEIR I report (1972). The

j. g central estimate (see section 9.4.8 4) incorporated a dose-ef fectiveness i

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9-53 1

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factor for exposures delivered at low dose rates. The lower-bound estimate took into account the large uncertainty in estimating effects fra low doses and low dose rates and assumed a threshold of 10 or 25 rem for latent-cancer fatalities. The central-estimate approach is consistent with the BEIR III report (NAS-NRC, 1980), which used a linear-quadratic model to calculate risk estimators for latent-cancer fatalities. In addition, the BEIR III re-port published ranges that indicate some of the uncertainty associated with these factors. The upper and the lower bounds of the ranges were obtained with the linear model and the pure quadratic model, respectively. The risk estimates, based on the linear-quadratic model, of BEIR III (1980) are ap-proximately 2 times lower than the BEIR I (1972) estimates based on the lin-ear model. ,

Recently, Loewe and Mendelsohn (1980) conducted some preliminary reas-sesmaents of the dose data for' people exposed by the atomic bombs at Naga-saki and Hiroshima. Since the BEIR estimates were calculated fra these Japanese data, these reausessments could have some impact on the final esti-mates of latent-cancer risk. The Los Alamos National Laboratory is attempt-ing to redefine the source term from the two bombs. In conjunction with this effort, the Oak Ridge National Laboratory is recalculating dose esti-mates. Final resolution of the health-effects estimate will likely follow these efforts. It is importa.it that the consequence modeler be aware of these developments.

Except for leukemia, the latent-cancer fatalities presented in Table VI 9-4 of the RSS were calculated for a 30-year plateau period, whereas the BEIR.I report (1972) used the remaining lifetime as the plateau period for

" solid tumors." A comparison of the values obtained by assuming lifetime and 30-year plateaus is given in Table 9-9. (The lifetime. plateau is in-plemented in the CRAC2 code.)

Table 9-9. Expected latent-cancer deaths per 106 me.n-rem of external exposure Expected deaths per 106 man-rem CRAC CRAC2 health-effects health-effects Type of cancer modela modelb Leukemia 28 4 28.4 Lung 22 2 27.5 Stomach 10 2 12 7 Alimentary canal 34 42 Pancreas 34 4.2 Breast 25 6 31 7 Bone 6.9 10 1 Other 21.6 28.0 abased on a 30-year plateau period for all cancers except leukemia.

bBased on a lifetime plateau period for all cancers except leukemia. 1 I

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