ML20035A997
| ML20035A997 | |
| Person / Time | |
|---|---|
| Issue date: | 02/26/1993 |
| From: | Murley T Office of Nuclear Reactor Regulation |
| To: | Tipton T NUCLEAR ENERGY INSTITUTE (FORMERLY NUCLEAR MGMT & |
| References | |
| NUDOCS 9303300326 | |
| Download: ML20035A997 (21) | |
Text
_
s 0
O(
f
'o,,
UNITED STATES NUCLEAR REGULATORY COMMISSION e
n
{
.,E WASHWGTON, D. C. 20555
}
\\...../
February 26, 1993 Thomas E. Tipton Vice President & Director Operations, Management and Support Services Division Nuclear Management and Resources Council 1776 Eye Street, N.W.
Suite 300 Washington, D.C.
20006-3706
Dear Mr. Tipton:
Thank you for your letter of December 7,1992 in which you requested the U.S.
Nuclear Regulatory Commission (NRC) to review your draft white paper,
" Implementation of the New EPA - Protective Action Guides (PAGs) in Existing
-Emergency Programs." We have completed our review and have enclosed our comments for your consideration.
The NRC issued Information Notice 92-38, " Implementation Date for the Revision to the EPA Manual of Protective Action Guides and Protective Actions for Nuclear Incidents," to inform licensees that they should implement the revised U.S. Environmental Protection Agency (EPA) " Manual of Protective Action Guides and Protective Actions for Nuclear Plants," by January 1, 1994. Members of NUMARC and our Emergency Preparedness Branch staff have worked together to determine which areas are affected by the revised EPA manual. This was also the subject of a round-table meeting on January 28 and 29,1993, hosted by Dusquesne Light Company and attended by NRC representatives.
The NRC believes that public protective actions are most effective when based upon plant conditions during the first few hours of an accident. The primary purpose of dose assessment and dose projections during an emergency at a nuclear power facility is to determine the adequacy of the initial proter.tive actions based on plant conditions and to form the basis for implementing further protective actions if needed.
However, early in a severe accident, such calculations, which include a source term model, an atmospheric dispersion model, and a dosimetry model, are always subject'to great uncertainties.
In a letter of October 15, 1991, transmitting the revised EPA Manual to emergency response planners, the EPA stated that guidance for protective actions is most useful when complexity of judgment required of decision-makers at the time of an accident is minimized. We find the suggested implementation could minimize this compitxity without sacrificing the quality of preparedness and response.
For example, NUMARC suggested using default correction factors to account for the additional contributions from inhalation and the ground shine components of the dose in the initial dose assessments performed in the control room before the emergency response facility is activated. This suggestion is reasonable because large uncertainties are associated with 9{f8 7S7
^
140100 DN 3
M f3 l
E.
Themas E. Tipton February 26, 1993 dose projectior.s and emergency dose projections should be simple, timely, and consistent.
We believe the NUMARC white paper, which focuses on the changes in the revised EPA Manual, could help both licensees and offsite agencies. Accordingly, I suggest that the Federal Emergency Management Agency (FEMA) also be kept informed of your efforts. The enclosed technical coments were prepared by Mr. Aby Mohseni of the Emergency Preparedness Branch, with information from other NRC offices. Mr. Mohseni can be reached at 301-504-2925 to answer any questions in that. regard.
We appreciate the efforts of NUMARC and its ad-hoc advisory comittee in preparing this document and expect that it will be useful to licensees and the public.
Sincerely, Thomas E. Murley, Director Office of Nuclear P.eactor Regulation
(
Enclosure:
Comments on NUMARC White Paper DISTRIBUTION Central Files RErickson PEPB R/F FKantor TMurley REmch FMiraglia tAMohsmi WRussell EJordan, AE0D JPartlow KBrockman, AE0D F',ongel
'ANelson, NUMARC E8utcher MGCrutchley (YT0930010)
LJCunningham NRR Mailroor (YT0930010)
PMcKee
- SEE PREVIOUS CONCURRENCES OFC EPS:PEPB:NRR SCE:PEPB:NRR C:PEPB:NRR TECH EDITOR D:DRSS:NRR NAME ASMohseni FKuntor l' :rickson JMain FJCongel DATE 02/17/93*
02/17/93*
02/17/93*
02/17/93*
02/18/93*
OFC ADT;NRR D4:d D @R, NAME WTIuNell FJ N glia TLMurley l
DATE S/tl/93 M /93 C
) /J ?/93
/
OFFICIAL RECORD COPY DRIVE /o0CUMENT NAME: G:\\0930010.YT
/,#
l, '-,
3 U
~
ENCLOSURE I
NRC COMMENTS ON THE NUMARC WHITE PAPER NUMARC Implementing Suggestions I.
Succestion To avoid confusion regarding " sum of EDE plus CEDE," the quantity TEDE (substituting EDE for DDE when whole body exposure is not uniform, e.g.,
ground contamination exposure) should be used for comparison to the shelter / evacuation PAG.
In addition, for consistency with 10 CFR 20 and to minimize the combination of dose components (for thyroid dose calculations),
the external dose equivalent be included with the [ thyroid) CDE.
NRC Comment We agree with the use of the total effective dose equivalent (TEDE) for comparison with the EPA plume PAGs.
In Section 5.4.3, " Comparison with Previously-Recommended PAGs," of the PAG manual, tha EPA stated that "the PAG for the thyroid is unchanged."
Therefore, we suggest that the external dose equivalent not be added to the
(
thyroid CDE. Thus, changing the calculation method for the thyroid dose may not be desirable. The NRC believes that adding the external dose equivalent to the thyroid CDE is of little value because of the uncertainties in dose projections and the fact that PAGs are projacted doses intended for offsite j
authorities to use in implementing protective actions. We recommend that NUMARC encourage consistency with offsite dose assessors.
2.
Suaaestion Utilities should base thyroid calculations on the child age group, rather than the adult age group specified by the EPA, and as consistent with the age group used by the offsite agencies in their EPZs.
NRC Comment Recognizing the large uncertainties associated with dose projection during the early phase, the NRC views the age group as an issue more of consistency than of risk. The NRC recognizes that some offsite agencies may opt to retain the age group they currently use for the thyroid calculations.
In the interest of consistency, the associated utilities may also retain a similar age group.
3.
Succestion Utilities should address the ground deposition dose component through the use of default correction factors in the dose assessment methodologies used in initial assessments in the control room.
Skin dose components should be omitted from these initial assessments.
If feasible and cost-effective (e.g.,
. (
computer based methods) all components and pathways should be addressed in methods used in initial or subsequent assessments. The method used for initial assessments in the control room should be kept a.s simple as is reasonable.
NRC Comment The dose projection model used in the control room should be as simple as is reasonable. The control room dose model may account for the ground shine dose component by a default correction factor. The EPA stated in Section 5.4.2 of the PAG manual that skin beta dose should seldom, if ever, be a controlling pathway during the early phase.
Thus the control room dose projection need not include the skin dose if so desired. The emphasis should be on consistency by accounting for the various dose components which contribute a significant fraction of the dose.
4.
Suaaestion The dose calculations performed in the TSC or EOF should include all significant dose components and organs (e.g., TEDE including CEDE, skin DE, thyroid CDE).
NRC Comment We agree. Unlike the dose projection system in the control room, which is expected to be used only during the early phase of an extent, the TSC/ EOF dose projection system should be able to adequately project the dose throughout the emergency, including the early phase, the iritermediate phase, and the final phase. Therefore, the dose projection systems should account for all significant dose components and organs as described in the EPA-400.
5.
Suaaestion Release and dose assessment procedures should be reviewed, and revised as necessary, to ensure that appropriate priority is given to quantification of the release by isotopic sampling and analysis. This should.be done given the sensitivity of some dose components (e.g., ground deposition exposure, thyroid uptake) to source term differences.
Such results will also aid in assessing in-field emergency worker exposures.
NRC Comment We agree. This suggestion applies to the Technical Support Center (iSC) and the Emergency Operations facility (EOF) rather than to the control room.
6.
Suaaestion Utilities should base the determination of monitor EALs for Unusual Event and Alert EAls on the methodology used by the utility to show compliance with 10
. l CFR 50 Appendix 1, with the appropriate multipliers that distinguish the emergency classes (e.g., "2xT/S," "200xT/S" for NUMARC EALs).
NRC Comment We agree.
7.
Succestion for Site Area and General Emergencies, base monitor EALs calculations on the plume EDE and the thyroid CDE, selecting the mest restrictive value for monitor / source term combinations. Use annual average meteorology. Skin dose and ground deposition can be discounted in settir.g monitor EALs.
.NRC Comment When the monitor setpoint for an Unusual Event or an Alert is reached, the licensees using the NUMARC scheme are expected to perform a dose assessment using real time meteorology to ensure that higher emergency classificatica thresholds are not exceeded.
i 8.
Succestion
(
Utilities should base Site Area and General Emergency EALs on the 1 rem TEDE or 5 rem thyroid CDE PAGs tabulated in Table 2-1 of the EPA PAG Manual. The rheltering guidance in the PAG Manual text, which calls for optional shelterir.g between I rem and 0.1 rem, should not be treated as a PAG.
NRC Comment We agree.
9.
Succestion Utilities should use the reading on SRDs (electronic dosimeters) as equivalent to the EDE (without adjustment) for field emergency worker monitoring purposes. Utility personnel designated as radiation workers ~ should continue to be monitored as provided for by dosimetry programs compliant to 10 CFR 20 and/or NVLAP requirements.
NRC Comment We agree.
10.
Succestion For control of emergency worker internal exposure, establish, prior to an event, a relationship between the external EDE and the CEDE and establish dosimeter limits at that value of EDE that would maintain the sum of EDE and CEDE below EPA limits for default accident source term (s).
~.
(
NRC Comment The conditions in which emergency workers might be subject to an unknown inhalation dose would most likely occur during a fast breaking accident j
leading to early core damage and containment failure.
In such an accident, a radioactive release may be postulated to be underway before the population at risk is evacuated.
Emergency workers would be assisting the public to evacuate and, in the process, could accrue an inhalation dose that could not be measured because of the rapid progression of the accident.
If the licensee does not have field data about the radioactive particles inhaled by the workers and members of the general public, the licensee can use its dose 3
projections, which are expected to account for the inhalation dose and for other pathways, to estimate the dose to emergency workers. While the ratios between external EDE and the CEDE are useful for bounding purposes, emergency dose projections may be used more readily for that purpose for the narrow range of accidents that may lead to the above conditions. The emergency worker inhalation dose would no longer be an issue when either the release is ended or the public evacuation is completed.
Emergencyworkersshouldcondyct subsequent emergency activities with more certainty of their total exposure (see NRC comment for Suggestion 11).
11.
Suaaestion Provision should be made for updating the dosimetry conversion factors as the incident progresses and release sampling and field monitoring data become available.
This updating should be done whenever significant changes in conditions or analysis results indicate it is prudent to do so. Results from surveys and analysis of field samples will identify which dose components need to be assessed. Such assessments may relieve the requirement for monitoring CEDE.
NRC Comment In those accident conditions in which significant particulates are released into the environment, all emergency workers, with a few exceptions, are expected not to remain in the " plume" after completing public evacuation.
If a release continues for a prolonged period of time with the public evacuation still underway, results from field sample analyses and field measurements provide a more accurate assessment and projection of the dose.
If field data are not available, the licensee may use available dose projections in estimating the dose accrued by the public or emergency workers during the evacuation process. When field data become available, the licensee
'The EPA divides the early phase into two periods (Section 5.2 of the EPA Manual): (a) the period immediately after the start of an incident, when little or no environmental data are available to confirm the magnitude of the
(
release, and (b) the subsequent period, when environmental or source term measurements permit a more accurate assessment of projected doses.
. (
should adjust the total effective dose equivalent incurred by emergency workers and use these adjusted values in scheduling rotations. However, these adjustments will not likely be necessary during the immediate period (see Footnote 1).
12.
Succestion Utilities should review their policies regarding gender-based limitation of emergency worker exposure and substitute policies based on the restriction of declared pregnant workers from emergency worker exposure.
NRC Comment NRC expects the utilities to comply with the existing requirements and guidelines.
Other NRC Coments A.
It is suggested that the white paper reference RTM-92 instead of RTM-91.
B.
The NRC encourages the use of the Dose Conversion Factors referenced in
(
the EPA-400 for consistency.
C.
Pace 7. Bullet 1.
Please be advised that containment bypass accidents could also lead to source terms with a significant particulate component.
Even if the iodines and particulates contribute less than 10 percent of the plume external exposure for a short puff release, the exposure to deposited material over the next 4 days may have a larger contribution.
D.
The white paper should indicate that the PAGs affected by the revised EPA-400 and discussed in the paper are the early chase PAGs.
E.
Pace 4. Paraaraoh 1.
It is suggested that a reference be made to the EPA PAG for administering KI at 25 rem, if included in offsite plans.
F.
Paae 5. Paraaraoh 2.
Please be advised that State and local authorities make the relocation decisions. The Federal agencies give support.
G.
Paae 6. Paraaraoh 3.
Since deposition modeling is very inexact, ground shine exposure projections can be revised based on field measurements as soon as they are available.
Later field sampling results can enhance the characterization of the derosition.
I
$DT BY:
1-5-83 : 3:0$PM :
An ARC-is 3/16 D
Imptementation of the New EPA PAGs In Existing Emergency Programs Purpose On October 28,1991, NUMARC distributed to member utilities the revised
[
Environmental Protecdon Agency Manual of Protective Aedon Guides and Protective Actions for Nuclear Incidents, EPA 520. Since then, the document has been re-issued as :T 2
EPA-400'. On May 12,1992, the NRC issued Information Notice 92-38. In this
' " " " ~
notice, the NRC notified licensees of a Comminion decision that the licensees may delay implementation of the guidance until January 1,1994. NUMARC has received numerous communications from utilities regarding implernentation of the revised guidance. The purpose of this white paper is to provide suggestions to utilities for implementing three aspects of the guidance in facility plans and procedures. The three aspects to be addressed include (1) modi 5 cations to dose assessment methodology, (2) effects on emergency aedon levels (EAI.4), and (3) emergency worker exposure control The suggestions address taese aspects as they apply to the plume czposure p.thway during the initial phase of the emergency response effort.
The EPA Manual provides recommendations to Federal, state, and local government agencies on the development of plans and procedures for pmtective measures.10 CFR 50.47(b)(10) requires that guidelines for the choice of protective actions during an emergency be consistent with Federal guidance. However, there may be differences in how the EPA Manual recommendations are implemented in each state or local entity.
Utilities will need to review the suggestions provided in this white paper for applicability to their facilities. Although many of the suggestions may be applicable to state programs, this white paper primardy addresses utility programs.
Disensrlon The revised EPA Manual contains guidance that differs from previous guidance in several aspects. One of the most significant areas of difference is in the dose quantities that the PAGs are exprerr,ed in and the calculational methodology used to determine these quantities. The revised PAGs are based on the effective dose equhalent concepts recommended by the International Comminion on Radiological Protection (ICRP) in 2
EPA, Manuel of Protective Action Guides and Protective Actions for Nuclear Incidenit. EPA-400 2
USNRC, Imniernentation Date for the Revision to the EPA Maruni of Protective Action Guides and Protective Actions for Nuclear Incidents. Information Notice 92-38 JNmrturrPEW52spuc tabeted #r: ats
SENT BY:
1- 0-83 : S:05PM :
NL W C-
- 4/16 u/29/92 r 2 s
their Publication-26, replacing the now outdated crideal organ concepts of ICRP H'.
5 Tne new 10 CFR 20 is based on these concepts as well. It is hnportant to note, however, g
that the revised EPA recommendations and NRC regulations are not completely consistent with each other or with the ICRP 26 recommendations. AdditionaDy, there are T some instances of differences in usaEe between different sections within the EPA PAG g
mamM ltself. These concepts will be expanded upon in this Wlan
.: p.
2:-.
I In previous radiation protection practice, exposures fro;n external ur.rrees and internally
- T' deposited sources were controlled separately. With regard to the internal exposure, only the dose to most the most edtical organ was assessed. In the previous EPA Manual, the hie Body PAG controlled the external exposure, while the thyroid was treated as the most critical organ for internal exposure. As the dose to the child thyroid was larger for a given uptake of radioiodine, as compaled to the consequences for other age groups, the child thyroid was the limiting critical organ.
In 1977, The ICRP issued new recommendations' for radiation protection practice in which external exposure and internal exposures were to be considered together in determining the detriment to the exposed individuals. Dere are several aspects to these recommendations, includmg-Regardless of the source of crposure, the doses to aD exposed organs are to be determined (i.e., dare erhalent. H). The dose equivalent to any particular organ could be due to exposure to radiation from radionuclides deposited in the organ -
or in adjacent organs, or from sources external to the body.
The individual dose equivalents were to be weighted on the basis of relative detriment and summed to determine an overall detriment to the individual (i.e.,
effeerive dose erhalent, EDE). %e values of the organ weighting factors are established such that the effective dose equivalent will be numerically equal to the whole body dose equivalent if the emaore is uniform over the body.
Exposure to internally deposited radionucUdes will continue over a period of time after uptake to the body. Such exposures commit the individual to an exposure, hence the dose quantities, commined dose eq&alent, CDE, and, commined effectrue dose egAah CEDE. For occupational exposure the period of exposure is taken to be 50 yezu, while for exposure of children, the period of czposure is taken to be 70 years. In actuality, the dose will be a function of the rate of uptake (acute or chronic), *he rate of biological elimination, and the radioactive 8
ICRP, Reco nmendat one of the Internationni Commluion on Radiolocical i
Protection. Publication 26,1977 d
ICRP, Recommendations of the Internationz) Committion on Radiolorical Protection Rencrt of Committee IL Publication 12,1960 J VptrT\\t7ePrW3\\tMFtAN Labeled By: ML5
SDT BY:
1-5-83 : 3:06PW ;
NUlWtC-
- r 5/16 i
n/29/92 Ps 3 D
decay half-life.
R He system of limits established by the ICRP were based on the sum of the external dose equivalent and the committed effective dose equivalent. (N.B.,
-lA there is sn assumption that the external exposure is unifann over the entire body. &
If the exposure is not uniform. EDE needs to be assessed.) AddidonaDy, for
-:j ecrtain radionuclide and organ combinations, the organ CDE could be more gg In 10 CFR 20, the NRC adopted the ICRP-26 concepts of dose equivalent, EDE c)E CEDE. However, the NRC introduced two additional quantities of interest here:
Deep dose equivalent (DDE). which is taken to be equivalent to the external dose equivalent and, if the exposure is uniform, to the e5ective dose equivalcat.
Total effective dose squhdent (7EDE) - whidi represents the sum of the arternal -
dose equivalent and the GDE.
The EPA PAGs are based on three radiological quantities: EDE CEDE, and CDE. 'Ibe EPA expresses the shelter / evacuation PAG in terms of the projected sum of the EDE from external exposure and the CEDE. The value of the PAG is set at i rem.he following dose components are included in this PAG:
EDE from external exposure to a radioactive plume (either overhead or submergence).
EDE from external exposure to radionuclides deposited on the ground by the plume (this exposure would likely not be uniform over the satire body).
CEDE from internal 5-:+9Fe due to inhaled radionuclides deposited in body.
(The EPA does not address ingestion in the early phase.)
The use of EDE in the first two components is deemed eyymydate. in that the exposure may not be uniform over the entire body - particularly for the ground exposure case. If the exposure were to be uniforni, the external dose equivalent could substitute for EDE.
For consistency with the 10 CFR 20 definitioniltYsuggist'ed that the quantity 7EDE (substituting EDE for DDE w 5en whole body ex@ not uniform, e.g., ground contamination exposure)', be used for comparison _to_1hchher/evamation PAG, his protocol will be followed in the remamder of this document.
Although the thyroid CDE is included in the CEDE, the EPA notes that the GDE does not adequately address non-fatal cancer induction, for which the thyroid is at a disproportionately higher risk. %erefore, the TEDE PAG is supplemented with a 5 rem CDE PAG on thyroid dose due to inhalation. De EPA does not require that the Ja\\tmsneptWVt\\prLAr Labeled 9r8 ILS
l g'.,, m d :s 6/16 SENT BY:
1-5-83 : 3:07PW 3 hLMARC-11/29/92 Pg 4
,/ h ?. --
S.p s
external dose equivalent to the thyroid be summed with the CDE to the thyroid. This D,
differs from 10 CFR 20 guidance that requires that the CDE be nummed with the 4
external dose equivalent to the affected organ. Summing the EDE with the thyroid CDE.W for decisions related to the umi4ation of stable iodine would be inappropriate as the
.;A PAG are to be compared to avoided dose. Since EDE is not avoided by stable iodine,it
.tr is not included in the dose calculations. For consistency with 10 CFR_21and_lo y
miMmh* the combinations of dose e---g==ntt It'Is suggested that the enemal dose i-iiiquivalent-be included 1rtth~tisiCDE.
g Although the previous EPA PAGs were sDent regardirig the age poup of the a5scted population, the child thyroid has become a de facto standard. In the new PAG manual, the EPA speci5cally identi5es the adult thyroid as the age poup of interest. De EPA justi5es this shift on the basis that (1) the uncertainty in the determination of dose distribution in the body exceeds the potential error due to age-specific parameters, and (2) there is suf5cient conservatism in the PAG values. While this is correct, she projected child thyroid dose is generally more conservative. Also, the EPA protocol ( -
7 appees to bypass population groups at a higher risk, e.g., children 7tTtherefore __.
suggested that utilities ~c5ntinue to use the child age poup.1CRP PublicationJ6s ;,, g resource for_ child thyroid CDE dose conversion factors'lt is hirther suggested that A
utilities review this matter with the appropriate nNahi~ agencies in their EPZs to develop a consistent basis.
De EPA has also identi5ed a 50 rem PAG on skin dose equivalent (DE). De EPA notes that the skin PAG will seldom be limiting. Under special conditions, e.g.,
inclement weather, all of these PAG values can be a(usted upwards with the concurrence of state oEcials. De EPA Manual also recommends consideration of sheltering for at projected TEDE below 1 rem but paater than 0.1 rem. His recommendation is not a PAG.
The significance of the thyroid CDE and the skin DE in comparison to the TEDE is
~
highly dependent on the projected mix of radionuclides in the release stream. In the guidance, the EPA provides that the relative importance of the individual components in '
the expected radionuclides mixes should be evaluated, and that those dose components that contribute less than 10% of the total dose can be ignored. This is a signi6 cant provision that needs to be considered when implementing the new PAGs in existing emergency response proFams and dose assessment methodologies. Nonetheless, where data for these dose components are available or aan be accessed in a cost effective marmer, the components abould be incorporated in dose mammarments.
s ICRP, Are Dependent Doses to Members of the Puhne from Inhalation of Radionuelides. Part 1, ICRP-56 4:wssweetnesueuw smetsar:as
' SENT BY:
1-5-83 : 3:08PM :
NLE RC-
- s 7/16
'11/29/92 P 5
^~
5
.D Dose Calculations 5
Generally dose calculation methods equate a release rate to a dose rate through the use of meteorological parameters and one or more dose rate conversion factors (DCFs). In 4
order to determine dose, a duration of exposure must be established. For the external
- 5
'f exposure from the plume, the==aam time is equivalent to the duration of the plume passage at the receptor location. For the inhalation a=tmpes, the inhalation period is
'=v equated to the duration of the plume passage at the receptor location, while the period W of aporwe is taken as 50 years 'Ibe method of calcalating these two contributors is a
essentially the same as performed currently.
Exposure to radiation from deposited materials will continue for those persons who were not evacuated until relocation occurs in the intermediate phase. Dependmg on the projected mix of radionuclides, the dose from deposited materials could be signincant.
De EPA Manual therefore concludes that it is appropriate to include the projected ground deposition dose in the early phase projections. In order to assess the ground deposition case, a period of -se needs to be established. 'Ibe deposition is, of course, a function of the releme dwndon and plume transit time. However, the esposae rime is longer due to the assumption that evacuation has not been (=niemented. 'Ibe EPA established the crponae dme as 4 days. It is important to r*=P that this need not imply a four day release dwarion-the release duration is based on the acmal or projected plant data. The four day time period represents the demarcation between the early and intermediate phases of the accident. De EPA believes that accurate sampling and anaJysis cannot be reasonsbly completed within the Srst four days. 'Ibe EPA does note that there may be unique characteristics at some facilities that would support different time periods. While it likely that utility Beld monitoring teams could obtain and analyze Seld samples in under four days, relocation decisions are made by state and Federal agencies. The capability of these agencies to perform these assessments varies.
For this reason, the default four day period appears to be reasonabic.
At face value, the new concepts appear to be involved and difficult to implement. It is important to note that numerous researchers have performed the effective dose equivalent calculations ofICRP-26 and have reduced the detailed calculations to simple DCFs - one overall DCF for each nuclide. It is NOT necessary for the done calculation methodology to address organ dose equivalents and organ weighting factors, or buildup and decay of deposited radionudides - this work has already been performed by others.' The DCFs provided for external exposure, ground deposition, and inhalation can be summed such that a single committed effective dose equivalent DCF is determined. The EPA PAG Manual provides a descripdon of how these factors can be see DOE /EH-0070, Erternal Dose Rate anvenion Facion for Neulation of Dose to Public. and EPA 520/146420,1imaing values of Radinnuclide intake and Air Concentration and Dose &nvenion Factors for Inheimtion. Submeninn-and Ingeetion).
drumankPpfWS\\DFLAN saheted a Es r
kautt-
]
, s_u m.
2-3-3,; s:o rx ;
- sens 11/s/c2 Ps 6 determined and provides references of data sources. Since most corr.mercial dose assessment methodologies generally involve a series of DCFs for the nuclides modeled.
R imp!ementing the new concepts for plume exposure and inhalation cases is reduced to substituting DCFs. Some nomenciature changes wGl be necessary in displays and w
printouts. There may be some additional complexity in more advanced models (e.g.,
particle-in cell), but aimilar L%ies apply.
sy
- =
The situation Mth regard to ground deposition is generally not as simple %e ground i.i deposition will need to be modeled on the basis of an assumed deposition velocity applied to the projected release rate and dispersion factors. De exposure from this deposition is then persisted for 4 days. De Class A models described in Appendia 2 to NUREG 0654' generally do not include deposition==mn*c his requirement was l
speci5ed for Cass B models. De changes to the Qass A models necessary to assess
]
ground deposition dose and to address additional particulate suelidas could bc significant. Additionally, band calculations used as backups to computer based methods could become complex and possibly prone to user error.
i
- At many faculties, there is more than one dose assessment capabGity. At these facuities, a simpli5ed method is often used for initial assessments in the control room, with the more detailed methods reserved for use in the 'ISC or EOF. While it is desirable fmm a technical standpoint to upgrade dose assessment models to address the new concepts, it is suggested that utDities may wish to address the ground deposition dose contnhrtion through the use of default correction factors rather than using detailed deposition modeling in the dose assessment methodologies used in initial mesmments. These correction factors should be detennined from the postulated default source terms used in emergency dose assessments. The deposition modeling capability should be included in methods used in assessments performed in the 'I5C and EOF. This protocol is 2
warranted on the follomsg basis:
For power reactors, it is unlikely that significant particulate releases can occur in absence of significant noble gas releases. Thus, it is unlikely that a PAR will be j
based solely on the ground deposition component.
)
j The severe accidents that are associated with significant particulate or iodine releases will likely be classified on the basis of plant status and appropriate protective actions implemented on this basis rather than on dose. His is 4
7 USNRC, Criteria for Preparation and Evaluation of RmAioloriem1 Fmergenev Retynte Plans and Preparedness in support of Nuclear Power Plants. NUREG-0654, Revision 1; 1980 Ja\\tWtt\\tPfPtrvt\\DF W Lemiad Br: RLE
~.
- ~ _ _. _ _ _ _ _ _ _ _ _. _. _ - _ _ _,
. ssi
- 2. h.m ; 3::;a ;
, age
, s l6 i
st/29/P2 Pg 7 D
consistent with NRC galdance in NUREG-1210', NUREO 1228', and RTM-91.
.ah l
For less severe events, the fraction of the source term that can be dassi5ed as g
l particulate is minor and the resulting doses are minor, such that the contribution j.W can be ignored as it would be less than 10% of the overall dose (as noted above). gy This conclusion is based on the noble gas, iodine, rs== fab fractions of j' E l
1.0,0.5,0.1 provided in existing licensing basis gtddance. Further, recent ir evaluations have shown the containment failute =g=vy for signi5 cant a
i particulate release will occur after several days if at all, and then only for the more severe events.
It is desirable to keep methods used in the initial assessments in the control room as simple as is reasonable. De more detailed assessments should be performed in the 'ISC and EOF.
With regard to the skin dose equivalent, a similar situation edsts. In orkr for the skin "
dose to be limiting, the released radioacdvity would need to include strong beta emitters
, in the absence of photon emitters, At commerdal nudcar power plants, such situations would be limited to ruptures of gaseous waste storage tanks or severe incidents involving decayed spent fuel. Standard technical sped 5 cations" limit the concentration of the tank contents so that offsite consequences from such failures will be less than 0.5 rem which is 1% of the EPA Manual skin dose equivalent PAG. In IN 9008", the NRC noted that offsite skin doses would be well below the EPA PAGs beyond one mile in the event of a severe accident involving decayed spent fuel. While data for closer in locations were not provided, these results pityvide support for accepting the EPA's conclusion that skin doses will seldom be limiting. While it is appropriate to upgrade dose assessment models to address the new concepts, it is suggested that utilities may wish to omit the skin dose assessments from the dose assessment methodologies used in initial assessments. ne capbility should be induded in methods used in assessments performed in the TSC or EOF.
l i
Martin, J.A., etal, Pilot Proeram NRC Severe Reactor Ancident Incident Remonse a
Traininc Manual Source Term Estimation Durina Incident Remante to Severe Nucler Power Plant Accidents. USNRC, NUREG 1210 v4 McKenna, TJ., and Gitter, J' Source Term Estimation Durtne incident Remome in Severe Nuclear Power Plant Aeridents. USNRC, NUREG-1228 i
- McKenna, etal., RTM 91 Remonte Techniemi Mannai, NUREG/BR.0150 j
" Sec. NUREG 0472, Radiological Ef!Iuent Technical Spedfications for PWRs, 1
u USNRC, KR-85 Hannh from Deenved Fuel NRC Information Notice 90-08 Labeled Sys 9Es J VDst\\nP(Ptps\\suPLAr 3
d
+ -
, __ j
' SDT' BY:
1-5-83 3:10PM ht3tARC-
- 010/16
,11/29/92Ps s D
3 Relationship to EAIJ For the Unusual Events and Alert dassl5 cations, the NUREG 06M and the NUMAR EAls' are based on multiples of technical speci5 cations. Dese have no direct link to the EPA PAGs. With regard to the new 10 CFR 20, the NRC staff has indicated that is revisions to the Offsite Dose Calculation Manual (ODCM) and RG 1.109' methodologyyh i
- while necessary on the long tenn - is not be*mg pursued at this time. De NRC staff believes that the edsting methodology is adequate as ithas demonstrated its ability to maintain population exposures at a low level.Rus, at the present time, there is no regulatory requirements to change the methodology of dose alculations maamisteA with gaseous release EAIA. It is noted that the location of the Site Boimday may change at some sites with the implementation of the new 10 CFR 20. If the site boundary is need, recalculation of release monitor set points used as EALs may be required. his effort would be driven by ODCM, rather than EAL concerns. Dere is a potential for a
~
change for liquid releases at these lower two levels in that ODCMs typically refer to the superseded 10 CFR 20 MPC values.
Dere is some confusion regarding the ODCM reference to Table 2 of Appaadi B to 10 CFR 20. Text in the new 10 CFR 20 requires that efDuent concentrations be maintained less than the Table 2 Appendix B values,- concentrations that are equivalent to 50 mrem /yr, whereas, the ODCM provides for 500 mrem /yr. De NRC staff has indicated that a Generic Letter is in development to reaffinn their intent to maintain a level of control comparable to existing ODCMs. His galdance is na~+=d to provide for efDuent concentration levels controlled to less than 10 times the Table 2 A,Wir B values. Pending issuance of this Generic letter, utBities should discans this issue with their respective NRC regional staff prior to revising EALs.
For Site Area and General' Emergencies, some change is likely. he NUMARC and NUREG 06M General Emergency EALs currently reference Whole Aody and Child Thyroid. For General Emergency, the EAls are specified in terms of the EPA PAG. De NUMARC Site Area Emergency is similarly based on the EPA PAG. Dus, changes in nomenclature and methodology from whole body and chDd thyrold to TEDE and thyroid -
CDE will be necessary. De NUREG46M Site Area Emergency EAL is not affected by '
the PAG changes.
For the Site Area and General Emergency cdassifications, the NUMARC methodology 1 NUMARC, Methndnloov for Develooment of Fmereenev Aedon IEvelt-l NUMARC/NESP 007 USNRC, Caleeladon of Annual Domes to Man frnm RouHne R t.=m of R=ctor 2
FM1uents for the Purnose of Evaluatine Comnliance with 10 Ln Pan 50. Annendir
}. Regulatory Guide 1.109, Revision 1; 1977 sn..sen as m==mwwww.=
er n:
3 3.e3 : 3:33p,,
.gy,c.,
urats2 vs 9 provides for a series of radiation monitor EAls that will trigger site spec 15c auessment M
procedures.The classi6 cation is made on the basis of the anessment if # can be g
l compiered within 15 minuter. These monitor EALs are to be based on anmint average 1:;-
l meteorology, while the==teatments are based on actual meteorology.
Q
=-
l w
i The monitor EAls may be determined by -n-dag that the dose rate at the she
- y@i l
boundary is equivalent to the TEDE PAG divided by a Sfault release duradon and back calculating to the monitor reading manadsted with the release necessary to achieve that 3r dose rate. The NUMARC EAL bases suggest using one bour as the release duradon in 2 the absence of any site-specific duration. Annual average meteorology (as discaned in Regulatory Guide 1.111) is used. The source term (s) used for these determinadons should be consistent with the default source term (s) used for emergency dose assessments. Depending on the iodine concentration in the default releases, the thyroid CDE may be more limiting and this should be determined. The EAL should be act at the most restrictive monitor reading, for either TEDE or CDE, maarwd=*eA with any j
default source term appropriate for the particular release path. It is suggested that the
. skin dose and ground deposition done be discounted in sety monitor EALvalues.
Since thyroid CDE is assessed, CEDE could also be omitted. Tbene suggesdons are
{
warranted on the basis of the same considerations discussed above for dose assessment i
modifications. It is also important to note that particulates and lodines are not predominant dose contributors in the spectrum of =4d me that are likely to be classified on the basis of monitored release rates. The severe accidents that will give rise i
to significant releases of particulates and iodines w!!! generally involve -....'. ed j
pathways. In any case, these events are more syyivydately classl5ed on tbc basis of plant status munements.
l i
In addition to the PAGs prmided in Table 21, the EPA provides guidance in the text of j
the manual that sheltering abould be considered at projected doses below I ram, but greater than 0.1 rem. The EPA explicitly notes that this gidd=+ *** not 6e constmed ar establishing et additionallower level MG pr shekering.
- As such, the optional implementation of sheltering below 1 rem has no effect on emergency 4
classifications or on emergency action levels that are based on the PAGs (or fractions j
thereof).
i Emeryney Worker Controls 1
The ICRP 26 dose control principles were aho applied to amergency worker radiation exposure controls. It is important to recognl e that the PAGs for the general public and i
dose limits for workers performing emergency services are based on different l
assumptions. Emergency workers may receive radiation=== nee under different circumstances, and these differences must be considered in assigning radiation exposure J
i Assuming a CDE of 5 rem and a weighting factor of 0,03, the CEDE would be 0.15 3
4 i
rem, a small fraction of the 1 rem TEDE.
sm.i.s en n.:
i m=uwswruma
y T
l
' soi BY:
1-5-83 : 3:10PM :
IGMtC-2810/16 l
11/29/92 Ps a D
~
Relationship to EA14 g
70 dagm tions, the NUREG 0654 and the NUMARC d For the Unusual Events and Alert ca 4
l EAli are based on multiples of technical speci5 cations. These have no direct link to
~$
the EPA PAGs. With regard to the new 10 CFR 20, the NRC staff has indicated that fp revisions to the Offsite Dose Calculation Manual (ODCM) and RG 1.109' methodology W j
- while ne~umry on the long term -is not being pursued at this time. The NRC staff i
j believes that the existing methodology is adequate as it has demonstrated its ability to i
maintain population 5-:+5es at a km level. Dus, at the present time, there is no regulatory requirements to change the methoNogy of dose calculations amandawA with l
gaseous release EAla. It is noted that the location of the She Rosaday may ^==== at
{
some sites with the implementation of the new 10 CFR 20. If the alte boundary is need, 1
recalculation of release monitor set points used as EAI.a may be required. nis effort l
would be driven by ODCM, rather than EAL concerns. Dere is a potential for a change for liquid releases at these lower two levels in that ODCMs typically refer to the i) superseded 10 CFR 20 MPC values.
i There is some confusion regarding the ODCM reference to Table 2 of Ap aar B to 10 p
)
CFR 20. Text in the new 10 CFR 20 requires that efDuent concentrations be maintained less than the Table 2 Appendix B values, - concentrations that are equivalent to 50 mrem /yr, whereas, the ODCM provides for 500 mrem /yr. De NRC staff has indicated i
that a Generic Letter is in development to reaffirm their intent to maintain a level of j
control comparable to axisting ODCMs. This guidance is crpected to provide for i
efDuent concentration levels controlled to less than 10 times tbc Table 2 App-a** B l
values. Pending issuance of this Genede Letter, utBities should discuss this issue with
]
their respective NRC :rgional staff prior to revising EAla.
i For Site Area and Geners! Emergencies, some change is likely. The NUMARC and j
NUREG4554 General Emergency EAIJ currently reference Whole Body and Child Thyroid For General Emergency, the EAls are sped 5ed in terms of the EPA PAG. The g
1 NUMARC Site Area Emergency is similarly based on the EPA PAG. Dus, changes in j
nomenclature and methodology from whole body and child thyroid to TEDE and thyroid -
i CDE will be necessary. The NUREG.0654 Site Area Emergency EAL is not sheted by -
j the PAG danges.
]
For the Site Area and General Emergency classifications, the NUMARC methodology
}
1 2 NUMARC, Meendatoev for Develonment of Kmermency Action Isvek j
j NUMARC/NESP.007 2 USNRC, CabinHon of Annual Dates to Man imm RauHne R,1,.
of R..cror
)
i EM1uents for the Pumose of Evalundne Comnlinnee with 10 CFR Part 50. Anoendir i
- 1. Regulatory Guide 1.109, Revision 1; 1977'
!j Javsstru m mon wupuu tan.s.s ey: ms i
j i
l W sn
- s-as : s::arx :
gmc
- ,33,13 j
up/92 Ps 9
~
2 l
provides for a series of radiadon monitor EA14 that w!!! trigger site specific assessment E
l procedures. The classi6 cation is made on the basis of the assessment if # can be g
li completed within 15 minuter. Dese monitor EAIJ are to be based on anmW sverage
- 1 meteorology, while the =<<***maats are based on actual meteorology.
4-.'
i=
The monitor EAls may be determined by assuming that the dose rate at the site i7 j
boundary is equivalent to the *IEDE PAG divided by a default release duration and back gi calculating to the monitor reading associated with the release necessary to achieve that
~l3 dose rate. De NUMARC EAL bases suggest using one bour as the release duration in 4
j the absence of any site-specific duration. Annual average meteorology (as discussed in Regulatory Guide 1.111) is used he source term (s) used for these determinations should be consistent with the default source ter.n(s) used for emergency dose anessments. Depending on the iodine concentration in the default releases, the thyroid CDE may be more limiting and this should be determined. He EAL abould be act at the most restrictive monitor r*= ding. for either TEDE or CDE, maar-I=**d with any default source term appropriate for the particular release path. It is suggested that the
. skin dose and ground deposition done be discounted in setting monitor EALvalues.
Since thyroid CDE is assessed, CEDE could also be omitted. %ese suggestions are warranted on the basis of the same considerations dit-*d above for done assessment modifications. It is also important to note that particulates and lodines are not predominant dose contributors in the spectrum of accidents that are likely to be classified on the basis of monitored release rates. De severe accidents that will give rise to significant releases of particulates and iodines w!!! generally involve unmonitored pathways. In any case, these events are more epyivydately classified on the basis of plant status assessments.
In addition to the PAGs provided in Table 2-1, the EPA provides guidance in the text of the manual that sheltering should be considered at projected doses below I ram, but greater than 0.1 rem. De EPA explicitly notes that this guidance
- k~dd not 6e construed ar establishing an additional lower level PAG pr sheltering.
- As such, the optional implementation of sheltering below 1 rem has no effect on emergency classifications or on emergency action levels that are based on the PAGs (or fractions thereof).
Emergency Worker Controls De ICRF 26 dose control principles were also applied to emergency worker radiation I
exposure controls. It is important to recognize that the PAGs for the general public and dose limits for workers performing emergency services are based on different assumptions. Emergency workers may receive radiation ernt=are under different circumstances, and these differences must be considered in assigning radiation exposure Assuming a CDE of 5 rem and a weighting factor of 0,03, the GDE would be 0.15 3
rem, a small fraction of the 1 rem TEDE.
san.i.e m er :
m=uwnn mma L
t
i limits. Generally, increased --;-:+5e is justi5ed if the coHective dose avoided by the I
a.
l
' emergency operation is signi5cantly larger than that incurred by the workers involved.
i's The term coEccstwe dase refers to the sum of the exposures roccived by several persons,
- ~;
l l
in this case, the general population.
M
[%
f i
As used in this h'aant, emergency workers can be employees or comractors for the utility, or mry be employees or volunteers for offsite agencies. In some cases, members MT of the public (e.g., farmers who re enter the affected areas) me,y be considered iW emergency workers. While the topics addressed in this section apply primarDy to offsite 15.1 personnel, it h applicable to some utility personnel such as 5 eld monitoring teams, etc.)
This section may aho be useful to stuities called upon to assist affaite agencies with l
j preparedness for emergency worker monitoring.1he methods am-A in this section do not apply, however, to in plant axposure monitoring which should aantinue to be performed using methods compliant with 10 GR 20 requii+===
Not all members of emergency response organizations wDI necessarDy be emergency workers with regard to increased radiation exposure. The EPA pild aa speci5es that,
~
l in the absence of special activities (e.g., life saving, etc.), the exposure of emergency workers is restricted below the limits (Le., sum of EDE and CEDE, or as used berein, the TEDE) set forth in Federal Guidance Report 11', namely,5 rem. For personnel i
involved in activities to protect valuable property, when lower dose 4 not pr** ele, the limit is 10 rem. For personnel involved in lifesaving activides, the EPA rdd--
1 establishes no upper limit If the rescue personnel are volunteers and have been briefed in the risks of their exposure, otherwise, dose from lifesaving activities is limitad to 25 rem. Although 10 CFR 20 does not establish dose limits for emergency workers, there are controls required when such an acere has occurred. The new 10 CFR 20 provides an exposure category caBed Mamed Speelat h-n, for which higher radiation exposures can be authorized for special activities that are sufEciently evaluated and controlled in a deliberate p1*= alas procesr Since by its very nature, emergency exposures are not plana *A emergency worker exposure is not to be controlled as planned special exposures. However, dose received during emergencies is deductible l
from the planneA special exposure limit.
]
)
It is important to note that the EPA guidance Manribe these dose limits to be abe sum of external effective dose equivalent and comm! tied effective dose equivalent (i.e.,
i TEDE) to non pregnant adults from exposure and intake. Additionallimits are provided for lens of eye, skin, and organ doses. Issues have been raised regarding the feasibility of monitoring the TEDE of emergency workers in the field. Instrumentation in use today is not calibrated in terms of EDE. Further, monitoring the worker uptake of radioactivity in the 5 eld is largely impr=6hle. Thus, assessing the GDE is also impracticable in a l
2 Eckerman, K.E., etal,ymitiae Valnet of Radionnelid: Intake and Air On-ntration 1
and Dose Conversion Factors for Inhalation Submersion. mad Incestian USEPA Federal Guidance Report 11,1988 4
J VptesytPLP0fVI\\BFLAN
&aluated era RLI i
nrs/m Ps 11 l
s._
D real-time sense. Note that the issue here is not one of post exposure evaluation, but l
rather one of exposure control. For exarnple,'when do I need to remove this indMdual g from the 5 eld?" Techniques such as whole body counting or results from breathing zone l
air samplers are useful only for post erraare evaluation. Pocket M=*ters do'not E-assess CEDE. De emanare of in plant utility personnel should continue to be controlled in accordance with eMas plant procedmes-iF i.
In 10 CFR 20, the NRC de5nes the annual dose limits in terms of the total effective W
dose equivalent (TEDE), which is defined as the sum of the deep dose equivalent (DDE) and the CEDE. The NRC defined deep dose agukalernt to the dose equivalent from external emanare at a thsue depth of 1 cm. If one assumes, as the NRC did in their de5nition of TEDE, that the esposure is uniform, then the DDE k equivalent to l;
EDE. His is a useful, conservative simpli5 cation! While HD badges may have integral 51ters that enable estimates of the DDE, the design of typical self-reading or electronic dosimeters (SRDs), do not provide for measurement of DDE. Nonetheless, the dose indicated by the SRD wDl be conservative. 'Ibc EDE is based on the sum of the
~
individual organ dose equivalents, each multiplied by an empirical w*tgMag factor appropriate for the organ. Since the weighting factors aD sum to 1.0, and since attenuation in body tissue reduces the radiation dose to the selocsed organs, a done rate measured on the body surface will generally be larger than the correspaaMag EDE. It is suggested that utilities use the reading on ERDs as equivalent to the EDE (without adjustment) for 5 eld emergency worker monitoring purposes. Utility personnel designeed ts radiation workers should continue to be anonitored as provided for by dosimetry programs compliant to 10 CFR 20 and/or NVLAP requir--*
De hsue with regard to the GDE is not as simple. It is unfeasible to provide individual monitoring for airborne uptake in the Seld. Inhalation can occur during plume transit, or can occur due to resuspension of mntamination deposited on the ground. Air concentrations will vary widely, both tuuyerelly and spatially, maMag control of *waa*uee i
by derived air concentrations unfeasible. A method of controHing emergency worker i
CEDE is to establish, for each default acddent source terms, a relationship between the ertemal EDE and the CEDE. Emergency worker dosimeter limits would then be set at that value of EDE that would maintain the sum of EDE and CEDE below EPA limits.
^
I For some accident sequences, the ratio of noble gas nuclides to iodine and particulate nuclides is such that very low dosimeter limits will be required in order to limit the CEDE. His will likely create manpower shortages. For this reason, EDE-to CEDE ratios should be developed for the more likely accident sequences with provision to adjust the ratios if the less likely sequences do occur.
It is suggested that utilities establish, prior to an event, a relationship between the I
j ertemal EDE and the CEDE and establish dosimeter limits at that value of EDE that would maintain the sum of EDE and CEDE below EPA limits for default accident i
source term (s). Ideally, there would be single ratio that encompasses all cases.
However, it may be r*-ary to determine multiple ratios if the single value becomes Labeled pr: E B J a%8Bett\\tMMWB\\EIPLAN J
-. - ~.. -...
,c._n._,.n-,..
n_.,
--en4
W BD 1-5-83 3:14Py :
NLEUtC-
- r14/16 u/29/92 r u s
-D too restrictive. Control of CEDE by the =dmistration of stable iodine h only a partial response in ligh, of the remote possibility of the presence of other significant internal gt emitters, e.g., Cesium.
g The use of TLDs and SRDs to estimate CEDE is extremely dependent on source term
.E mix and would be accurate only to the extent that the iodine / particulate to-noble gas if ratios were appropriate. The use of overly conservative source terms could result in
?
EDE to CEDE ratios and dosimeter limits that could sipificantly impact the emergency 17 response effort. For these reasons, it k suggested that sop'ce term (s) used for these determinations be selected carefully.The use of source terms developed with highly conservative assumptions, e.g., licensing basis postulated acddents, should be avoided.
NUREG 1228 discusses emergency response source term development and may be a useful reference.
i As the actual source term would likely differ from the projected source term (s), and could vary as a function of time and meteorology, It is suggested that provisions be made
~
-for updating the dosimetry conversion factors as the incident progresses and dose assessment and field monitoring data become available. This update should be done whenever conditions or analysis results change @mifi%. This protocol could, for exzmple, elimhte the need to consider CEDE if no iodine is found in the actual release.
Table 2 2 and associated text on page 2-16 specify that emergency worker dose limits are the sum of external effective dose equivalent and committed effective dose equivalent to non pregnant adults, and that performance of emergency services should be limited to non pregnant adults. In the recent decision in Johnson Controls, the Supreme Court determined that an employer may not exclude a fertile female employee from performing certain Jobs because of an employer's concern for th: health of a fetus the woman might conceive. It is therefore reasonable to conclude that any policy that bars all woinen in their reproductive years from participating in emerEency situations may constitute sex discrimination in violation of Title VII of the Crvil Rights Act. In keeping with 10 CFR 20.1208, utilities may consider implementing this EPA guidance with regard to decimed pregnant workers. It is suggested that utilities review their policies regarding gender based limitation of emergency worker exposure and substitute policies based on the restriction of decimed pregnest utility workers from emergency worker exposure. The exposure of female offsite agency personnel is controlled by state -mn=2re control programs.
Implementatka Suggestions Dose Cab!ations 1.
To avoid confusion regarding " sum of EDE plus CEDE *, the quantity 7EDE (substituting EDE for DDE when whole body czposure is not uniform, e.g.,
toested ry: es.s J: m s wPtatr m re tAs
' - ~ '
,g,[
i 2"
- o.as, o.i m,
.u /2p/92 Ps u (N
On ground contamination expontre) should be used for comparison to the shelter / evacuation PAG. In addition, for consistency with 10 CFR 20 and to$
-R
- /
j minimin the combinations of dose con.yonem)s, the esternal dose equivale i
included with the CDE.
L>h, ;. k fe 1/L-nA dw-cd D a~,
.g Utilities should base thyroid calculations e child age group, rather than the i
2.
. / adult age group speci5ed by the EPA, and as consistant with the age group used g
2 4
g.f
,, by the offsite agencies in their EPZs g
b
+
Utilities should address the ground depostdon dose n- ;= =i through abe use of 3.
default correction factors in the dose assessment methodologies used in initial aceuments in the control room. Skin dose components should be omitted from these initial nueuments. If feasible and cost.cffeedve (* 5., computer based i
methods) all components and pathways should be addressed in snethods used in initial or subsequent assessments. he method used for initial =taearm** in the J
~
control room should be kept as simple as is reasonable.
%e dose calculations performed in the 15C or EOF should include all signi5 cant 4.
dose components and orgam (e.g., TEDE includbqg CEDE, skin DE, thyroid l
4 CDE).
l S.
Release and dose sawmement procedures should be reviewed, and revised as necessary, to ensure that appropriate priority is given to quantf5 cation of the release by isotopic sampling and analysis. This should be done given the sensitivity of some dose components (e.g., ground deposition oye.ure, thyroid l
nptake) to source term differences. Such results wiB also aid in assessing in-Seld emergency worker Pres.
Fmereenev Actinn 11veh
' Utilities should base the determinadon of monitor EAla for Unusual Event and 6.
Alert EAls on the methodology used by the utility to show compliance with 10 CFR 50 Appendix I, with the appropriate multipliers that distinguish the j
emergency classes (e.g., *2r T/5, *200x T/S" for NUMARC EA14).
1 7.
For Site Area and General Emergencies, base monitor EALs calculations on the plume EDE and the thyroid CDE, seleedng the most restrictive value for monitor / source term combinations. Use annual average meteorology. Skin dose l
and ground deposition can be discounted in setdag monitor EAls.
Utilities should base Site Area and General Emergency EALs on the 1 rem
~
8.
'IEDE or 5 rem thyroid CDE PAGs tabulated in Table 2-1 of the EFA PAG Mamt:1. The sheltering guidance in the PAG Manual text, which calls for optional sheltering between 1 rem and 0.1 rem, should not be treated as a PAG.
Lametes era me J,weresseemme w L__
l M BY#
1-5-83 : 3:15PM POWtC-
- s16/16
~
11/29/92 Pg 14 1
D l
Fmereenev Worker Fmmre
'N Utilities should use the reading on SRDs (electronic dosimeters) as equivalent to
- e l
9.
the EDE (without adjustment) for Seld emergency worker monitoring purposes. ii Utility personnel designated as radiation workers should eontinue to be monitored M
'y as prtwided for by dosimetry programs compliant to 10 CFR 20 and/or NVIAF t
2.;f requirements.
3 For control of emergency worker internal -yo.we establish, prior to an event, a m 10.
relationship between the external EDE and the CEDE and establish dosimeter 4
limits at that value of EDE that would maintain the sum of EDE and CEDE below EPA limits for default accident source term (s),.
Provision should be made for Wad =3 the dosimetry conversion factors as the l
11.
incident progrenes and release sampling and Seld monitoring data become l
svailable, This Wada; should be done whenever signi5 cant changes in 1
conditions or analysis results indicate it is prudent to do so. Results from.wcjz and analysis of Beld samples will identify which dose components need to be DE.
assessed. Such assessments may relieve the requiih for monitoring 12.
Utilities should review their polides regarding gender-based limitadon of emergency worker exposure and substitute policies based on the restriction of decland pregmmt workers from emergency worker y=e.
W l
1 i
NM OY3 EI J2W\\EPEPEWI\\WW l
- _ _, _. - - - _.. _. - _ _ _., _ _ _ _. _ _... _.. _,. _.....,