ML20244D845
| ML20244D845 | |
| Person / Time | |
|---|---|
| Issue date: | 04/14/1989 |
| From: | Congel F Office of Nuclear Reactor Regulation |
| To: | Malsch M NRC OFFICE OF THE GENERAL COUNSEL (OGC) |
| References | |
| NUDOCS 8904240146 | |
| Download: ML20244D845 (8) | |
Text
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, , , L f - o UNITED STATES g
g g NUCLEAR REGULATORY COMMISSION p WASHINGTON. D. C. 20555
% . . . . . #' APR 141989 .
MEMORANDUM FOR: Martin G. Malsch, Deputy General Counsel for Licensing and Regulation Office of the General Counsel FROM: Frank J. Congel, Director i Division of Radiation Protection l dnd Emergency Preparedness )
Oifice of Nuclear Reactor Regulation j
SUBJECT:
COMMENTS ON EPA PROPOSED RULE, 40 CFR 61 In response to your request of March 10, 1989, we have reviewed EPA's proposed rule (40 CFR 61) which would establish environmental standards for radionuclides as hazardous air pollutants under Section 112 of the Clean Air Act. Our review focussed on the reasonableness of the proposed standards, the impact of the four proposed options on nuclear power plants and research/ test reactors, and the difficulties in demonstrating compliance with the standard.
N Our first comment relates to the applicability of the proposed standards.'The rule, as presently drafted, does not clarify whether the standards are applica-ble to accident situations. In our view, the proposed 40 CFR 61 should not apply to releases of radioactive materials caused by an accident; rather, they should apply only to releases arising from normal operations. The term " normal operation", as we define it, would include effluents associated with antici-pated operational occurrences, i.e., those conditions which are reasonably expected to occur during the operating lifetime of a facility.
Our other comments pertain to various provisions of the proposed standards and are detailed in the enclosure. In summary, our comments touch on the following points:
- 1. EPA could have justified a higher standard than 0.03, 3, or 10 mrem /yr based on recent standards promulgated by the ICRP and NCRP and the risk bases used by these agencies. To this end, we have suggested that a standard of 25-50 mrem /yr could be justified for the air pathway's share of a larger generally applicable standard (100 mrem /yr seems justified).
- 2. EPA has compounded a conservative proposal by making it apply to a maxi-mally exposed individual, rather than to the average of a critical popula-tion group, as the ICRP has long-ago recommended (and recently reaffirmed).
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- 3. In its-assessment of the reasonableness of the proposed standard, the EPA has defined model plants which are representative of nuclear power plants, as well as research and test reactors. Our. assessment of the effluents released from a representative sample of nuclear power plants during 1987 indicated that, on the average, some nuclear, power plants would not meet the 3 mrem /yr standard; a few might not meet the 16 mrem /yr standard. The 750-m distance used for the distance to the maximally exposed individual
'in the vicinity of a model research/ test reactor is unreasonable, in our judgement. 'The actual value could be 100 m or less, considering faculty and students as the population of interest. Thus, the relatively small
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. Ar-41 releases from these facilities could, for some siting situations,
'have a considerably higher impact than that characterized by EPA.
- 4. In determining compliance with'the standard, NRC licensees would have to continually keep track of the moving target represented by the maximally exposed individual. A critical group approach, as discussed above, would appear to be less subject to fluctuation with time.
We appreciate _this opportunity to comment on these important standards for
.. radionuclides releases. If we can provide any additional assistance, please let me know. ,
Ongind dgned by Rank J. 00*l Frank J. Congel, Director Division of Radiation Protection and Emergency Preparedness Office of Nuclear Reactor Regulation
Enclosure:
Comments on EPA 40 CFR 61 Distribution:
VStello, EDO JMTaylor, EDO JLBlaha, EDO HLThompson, E00 TEMurley/JHSniezek, NRR FJMiraglia, NRR SAVarga, NRR OMCrutchfield, NRR FPGillespie, WRR FJCongel, NRR LJCunningham, NRR THEssig, NRR.
JEWigginton, NRR WDTravers, NRR RJBarrett, NRR RMBernero, NMSS RECunningham, NMSS ES8eckford,RES BMMorris., RES MRKnapp, RI JPStohr, RII CENorelius, RIII LABBeach, RIV RAScarana, RV RLAnderson, TTC 0FMossLurg, ECO 4319 MCBridgers, E00-4319 JAWarren, NRR 26 Central Files PDR EDO R/F RPB R/F
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SC:RPB:DREP 'RPB: EP D:DREP q THEssig:bt Cunningham FJCongeTV .
04/6/89 04 /89 04/j%/89
. ENCLOSURE Comments on EPA 40 CFR 61 Rulemaking Office of Nuclear Reactor Regulation In revieving the standards (40 CFR 61) proposed by EPA to implement the Clean Air Act, we focussed on three areas: a) the reasonableness of the proposed standards, b) the impact of the four options presented in the proposed stan-dards on licensees under the purv.iew of NRR, and c) difficulties with demon-strating compliance with the standard.
Reasonableness of the Standard The standard contains four approaches (10, 10, 3, and 0.03 mrem /yr) to estab-lish an effective dose equivalent (EDE) for maximally exposed members of the general public. We have examined these four approaches in light of recommenda-tions from other recognized standards promulgating organizations, viz., the National Council on Radiation Protection and Measurements (NCRP) and the International Commission on Radiological Protection (ICRP).
On the subject of risk associated with dose equivalent limits for individual members of the public, the ICRP stated in its Publication 43: l l J l l I
" Members of the public are exposed to a large nun:ber of hazards and the l 1
i I magnitude of radiation risks must be con:,idered in the context of other l l
l risks. The Commission states that: 'On this basis, a risk in the range i
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of 10 8 to 10 5 per year would likely be acceptable to an individual member of the public.'"
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.- This risk range was used by the ICRP to continue recommending a "...whole body dose equivalent limit of 0.5 rem /yr, as applied to critical- groups. . . ."
In a similar manner, the NCRP stated in its Publication No. 91 that:
"This recommendation [0.1 rem /yr] is designed to limit the exposure of members of the public to reasonable levels of risk comparable with risks
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from other common sources, i.e., about 10 5 annually."
Based on the above discussion.and information contained in EPA rulemaking package, similar acceptable risks to the public have been used to reach marked-ly different recommendations for E0E standards:
Organization Annual Risk Recommended EDE Scope
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NCRP 10 5 100 mrem /yr all pathways
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EPA 2-3 x 10 6 10 mrem /yr air pathways only
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ICRP 10 6-10 5 500 mrem /yr all pathways The risks referenced by NCRP and ICRP bracket that used by EPA, yet the recom-mended EDE is substantially lower. Thus, it appears that EPA would have been
-justified in recommendfog an EDE greater than 10 mres/yr. If the EPA proposal I
had considered radiation exposures from airborne radioactive materials in the j
context of the total exposure from facility operation, i.e., exposures from air, water, and direct radiatian pathways, it is our view that a recommended EDE on the order of 25-50 mrem /yr from the air pathway would be a justifiable a
L share of an overall EDE of 100 mrem /yr.
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4 One other area which warrants comment in terms of the reasonableness of the standard is the point of application of the recommended EDE. The EPA has recommended that the EDE be determined for the maximally exposed individual in the vicinity of each site.
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The.ICRP recommended in its Publication No. 26 that "The dose equivalent lir'ts... apply to the dose equivalent...in the case of exposure of the popula-tion, to the average,of...these quantities over a group of individuals" (empha-sis added). The group of individuals to which the ICRP referred is the critical group. This group, as defined in ICRP Publication 43, is to be
... representative of those individuals in the population expected to receive the highest dose equivalent; the group should be small enough to be relatively homogeneous with respect to age, diet, and those aspects of behavior that affect the doses received." The ICRP further stated that "...the dose equiva-lent limits are intended to apply to the mean dose equivalent in a reasonably homogeneous group...."; that "...the critical group would not consist of one individual nor would it be very large for then homogeneity would be lost....";
and that "...in habit surveys it is not necessary to research for the most exposed individual within the critical group in order to base the controls on that one person. The results of a habit survey at a particular point in time should be regarded as an indicator of an underlying distribution and the value )
1 adopted for the mean should not be unduly influenced by the discovery of one or )
i two individuals with extreme habits." Contrary to this guidance, the EPA )
stated in Appendix A to Volume I of the rulemaking package that "The location of one or more persons on the assessment grid which provides the greatest lifetime risk (all pathways considered) was chosen for the nearby individuals."
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In conclusion, we feel first that EPA has recommended EDE standards for the general public which are lower than that needed to provide adequate protection of the public from airborne releases of radioactive materials; and second, that EPA has compounded an already conservative standard by imposing it on the most highly exposed individual, considering all pathways in the offsite population.
Impact of the Proposed Standard Volume 2 of the 40 CFR 61 rulemaking package contains radionuclides release
. rates for a model BWR and model PWR in Tables 4-25 and 4-26, respectively. The values are shown in units of pCi/yr for several radionuclides. In most cases, the values presented appear to be several orders of magnitude too low. The doses based on these releases (Table 4-28) are not, however, also on the low side. This discrepancy should be resolved, since these data may be used to support a conclusion that the 3 and 10 mrem /yr approaches to establishing an EDE standard can easily be met.
Because of the time constraints imposed by the comment period for the rulemaking proceeding, we were not able to compute the EDE for the maximally exposed individual at each nuclear power plant and research/ test reactor site based on actual effluents from each facility. Based on the evaluation of the EDE for representative sample of nuclear power reactor plants using effluent releases during 1987, we conclude that most nuclear power plants could not meet the 0.03 mren EDE standard, assuming operation with currently installed equip-ment and use of current procedures. Using the same assumptions, we estimate that many plants do not meet the 3 mrem /yr EDE standard. The foregoing conclu-sions were based on a sample size of 15 plants. The EDE calculated for the j 4
E-s maximally exposed individual ranged from 0.04-10 mrem /yr for our sample; the mean EDE was 1.7 mrem /yr, with a standard deviation of 2.8.
Time constraints also did not permit us to perform an evaluation of the EDE received by the maximally exposed individual in the vicinity of research and test reactors. While we agree with EPA's statement that Ar-41 is the principal radionuclides released from theses facilities, we cannot generally support the statement that the maximally exposed individual typically resides 750 m from the release point. Siting practices have been sus that the faculty and student population are often situated much closer to the efiluent release point (albeit on a non-continuous basis). On-campus dose rate measurements demon-strated, for example, that certain students and faculty could receive up to about 10 mrem /yr (credit taken for occupancy time) from Ar-41 rele ased from a university research reactor (now being decommissioned) which had been operating at only 100 kW; this exposure situation arose primarily due to the relatively dose proximity of classrooms to the effluent release point.
Difficulties in Demonstrating Compliance Because of requirements already imposed by the NRC on nuclear power plant licensees in the area of offsite dose calculations, no major difficulties are anticipated in the procedural aspect of demonstrating compliance with the EDE standard; most, if not all, of the data needed as input to the EPA's COMPLY code are already being gathered as inputs to licensee's dose models. Research and test reactor licensees are not generally required to make offsite dose calculations, but should be able to with minimal difficulty using the COMPLY code.
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What may cause difficulty in some cases, however, is the need to be continually aware of l'ocations of the maximally exposed individual from inhalation, immer-sion, and ingestion perspectives. For both power and research/ test reactors, this awareness process constitutes a moving target. Power reactors currently maintain an awareness of receptor locations in each sector in the vicinity of the plant, and are thus somewhat accustomed to living with such moving targets.
Research and test reactors, on the other hand, do not typically maintain an awareness of distances to receptor locations in each sector; such a requirement would potentially pose a burden on them in maintaining an awareness of tran-sient, but very nearby, receptor locations.
An alternative approach to determining compliance with the standard would be to determine tha average exposure of a critical group, as discussed earlier. Once formulated, a critical group approach should be easier to implement and be relatively consistent as a function of time, yet provide an appropriate assess-ment of the EDE received by the more highly exposed individuals.
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