ML19347A218
| ML19347A218 | |
| Person / Time | |
|---|---|
| Issue date: | 02/03/1995 |
| From: | Office of Nuclear Regulatory Research |
| To: | |
| Shared Package | |
| ML19347A207 | List: |
| References | |
| NRC-2021-000179 PROC-950203, NUDOCS 9502140347 | |
| Download: ML19347A218 (15) | |
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l AEB NON-PROGRAM PLANS l
RI :.,LATORY APPLICATION OF NEW SOURCE TERM AND REGULATORY STANDARDS l
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l 9502140347 950206 CF SUBJ j
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February 3,
'335 REGULATORY AFFL:CATICN CF NEW SOURCE TERMS l
STANDARD REACTC:R SAFETY ASSESSMENT l
STANDARD REACTOR DESIGNS C3JECTIVE The overall Standard Reactor Designs Cost Center includes activities to support future licensing activities associated with standard reactor designs; to ensure that certified standard reactor designs, when properly sited and constructed, will adequately protect the public health and safety and the environment; and to ensure that the combination of industry and NRC esearch establishes the technical bases' for timely and sound rulemak ing and regulatory decisions to support design certification activities.
This subactivity (REGULATORY APPLICATION OF NEW SOURCE TERMS) includes efforts.to update the accident source terms, including revising necessary regulatory documents to reflect the updated source terms, revise the agency's siting regulations and update the regulations to include requirements for plant performance for severe accidents.
Each of these activities is discussed in more detail below.
The Commission's current reactor site criteria, 10 CFR Part 100,
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require that an accidental fission-product release from the core into the containment be assumed to occur and that its offsite radiologae.t1 consequences be evaluated against t*.ie guideline doses given in Part 100.
The postulated source term is contained in Regulatory Guides 1.3 and 1.4 but is derived from the 1962 report
" Calculation of Distance Factors for Power and Test Reactors",
Technical Information Document (TID) 14844.
Regulatory Guides 1.3 l
and 3 specify a release into the containment of 100 percent of the core inventory of noble gases and 50 percent of the iodine fission products (with half of the iodine assumed to deposit on interior surfaces), and also assume the instantaneous appearance within containment and that the iodine is predominantly in elemental (1 ) form.
2 Use of the TID-14844 accident source term has not been confined to the evaluation of plant mitigation features and site suitability alone.
The regulatory applications of this source term covers a wide range, including the basis for (1) the post-accident radiation environment for which safety-related equipment should be qualified, (2) post-accident habitability requi ements for the control room, and (3) post-accident sampling systems and accessibility.
Substantial information has been developed updating our knowledge about LWR severe accidents and the behavior of the fission products which would be released into containment.
These studies have confirmed that although the TID-14844 source term is very substantial, and that its use has resulted in a very high level of l
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i plant capability, ncnetheless, based en severe accidents since :he-publication of TID-14844 almost thirty years ago, the present recipe can be substantially improved.
An integrated set of activities involving regulatory implementatien i
of updated source term information in connection with the review of Advance Light Water Reactors (ALWRs) is being pursued.
Parallel activities on updating the use of source terms for the design and siting of future plants are proposed.
These are 1) in the near F
term, performing reviews on a case-by-case basis with appropriate revisions to current practice incorporated as a part of the design l
certification rulemaking, and 2) instituting a partial decoupling l
of reactor siting and plant design via rulemaking changes to both l
Parts 50 and 100.
t The technical update of the TID-14844 source term is virtually complete.
The primary objective of this effort is to utilize current research insights regarding fission product release into j
containment and potential removal mechanisms to define a revised accident source term for regulatory application for future LWRs.
i This source term revision, as well as related insights from severe accidents regarding containment challenges and proposed design criteria, to may be implemented via a future ~ revision of Part 50 which will be applicable to future LWRs and will~ complete the decoupling of siting and plant design.
In addition, revisions to j
l existing regulatory documents to incorporate, as appropriate, the new source term information will also be pursued.
I USER OFFICE NEED(S) (IF ANY) l In a staff requirements memorandum (SRM) dated January 25, 1991, l
the Commission approved the staff's proposed plan to revise Part l
lot to delete the source term and calculations of dose and to specify site criteria directly; to issue an interim revision to Part 50 in parallel which retains the present source term and dose calculation (but not for siting); to update the source term derived i
i from TID-14844; and finally, in a secor.'. phase of rulemaking, to revise Part 50 to incorporate severe
.cident and revised source term insights for future plants.
i SCHEDULE FOR COMPLETION OF ACTIVITIES / PRODUCTION OF DELIVERABLES f
(FY 95-FY 98)
The most recent st:tus of this activity is contained in two Commission papers, SECY-94-300, " Proposed Issuance of Final NUREG-
- 1465,
' Accident Source Terms for Light-Water Nuclear Power Plants'",
dated December 15,
- 1994, and SECY-94-194,
" Proposed Revisions to 10 CFR Part 100 and 10 CFR Part 53, and New Appendix S to 10 CFR Part 50," dated July 27, 1994. At this time, the status of the specific prog _'ammatic items is as follows:
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Rerised Acciden: Scurce Tern SECY-94-300,
" Proposed Issuance of Final NUREG-1465,
'Acciden:
Source Terms for Light-Water Nuclear Power Plants * ", dated December 15, 1994 provides a final NUREG-1465 with revised accident source terms for nuclear power plants based on the understanding of light-water-reactor severe accident and fission product behavior.
This program's primary effort is to utilize current research insights regarding fission product release into containment and potential removal mechanisms to define a revised accident source term for regulatory application for future reactors.
Issuance of the final NUREG is expected in FY 1995.
In FY 1995-FY
- 1998, activities will involve evaluating and
- revising, as appropriate, regulatory documents (eg.,
Regulatory Guides) to incorporate the revised source term.
This will include activities in FY 1995 and FY 1996 to revise Regulatory Guides 1.3 and 1.4.
19 CFR Parts 100 and 50 In FY 1995, issue a revised proposed rule revising the site criteria in 10 CFR Part 100 and relocating the current 10 CFR Part l
100 dose criteria to 10 CFR Part 50.
The non-seismic part of the l
proposed rule changes issued for public comment on 20 October 1992 was withdrawn due to its highly prescriptive and inflexible format.
l An updated version of the rule presenting a more limited decoupling of reactor design and siting which emphasizes the role of siting in l
the NRC's defense-in-depth policy (see SECY-94-194 dated July 27, 1994) was issued for comment (59 FR 52255) on October 17, 1994.
In FY 1996 issue the final rule revising site criteria.
j Procosed Rule on ALWR. Severe Accident Performance During FY 1995 - FY 1996, af ter the Final Safety Evaluation Reports are issued for the GE ABWR and CE System 80+ designs, develop a recommendation of the need for a draft generic rule to address licensing requirements fcr protection against severe accidents in advanced light water reactors. This recommendation is discussed in detail in Secy-93-226, "Public Comments on 57 FR 44513 - Proposed i
Rule on ALWR Severe Accident Performance", dated August 18, 1993 and the Staff Requirements Memorandum dated September 14, 1993.
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FIN LIST AND FTE (FY 94-FY 97)
STANDARD REACTCR DESIGNS ACTIVITX1 Standard Reactor Safety Assessment Subactivity: Regulatory Application of New Source Terms-FY95 ELR1 FY97 FY98 New Source Terms
-Funds (in $1000s) 400 195 100 95 FTE 3.0 2.0 10 1.0 EIN Contractor Title l
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L2035 SNL Source Term Removal Mechanisms 40 0
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B6331 BNL Siting & Large Release j
0 0
0 0
W6353 BNL Risk Impacts of Revised' Source Term 100 0
0 0
J6024 SNL Updated Site Census Data 0
0 0-0 W6093 ORNL Grand Gulf MELCOR, Deck 0
0 0
0 UNDES Source T. Followup 260 195 100 95 i
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?!N tescrictions FIN L2035
' Source Term Removal Mechanisms" During FY 1995, complete che quartet of NUREG/CR reports intended to provide additional technical basis for producing a more realistic source term.
These four reports will develop generic mathematical expressions for 1) the decontamination f actor as a function of pool water depth for a pool overlying corium on a concrete floor; 2) ' aerosol deposition due to natural processes inside containment: 3) the effectiveness of containment sprays to remove particulates, and 4) aerosol and vapor removal by BWR suppression pools.
This effort will be used as part of the basis for revising Regulatory Guides 1.3 and 1.4 (LOCA radiological a
assumptions for BWRs and PWRs).
They should also play a role in reviewing ALWR credit sought for source term removal mechanisms.
FIN E6331. "Sitino and Larce Release Definition" During FY 1995, publish a NUREG/CR which provides the technical basis used to assist in developing a staff recommendation on siting.
FIN W6353, " Risk Tmoacts of Revised Source Term" i
During FY 1995, complete a study which will be used as a technical basis for providing risk insights on use of the revised source i
term.
These insights will then be used during FY 1995 to develop revisions to Regulatory Guides 1.3 and 1.4, as appropriate.
j FIN J6024. "Uedated Site Census Data" l
Complete in FY 1995 this effort to provide support for revision of 10 CFR Parts 50 and 100 relating to siting criteria versus design criteria.
Part of the siting criteria concerns potential changes to acceptable population densities around the site and the distance population centers need to be away from the site.
FIN W6093. " Grand Gulf MELCOR De k" l
l Complete in FY 1995, this ef fort to provide an updated MELCOR input deck.
FIN (UNDES), " Source Term Followuo"
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During FY 1995-FY 1998, provide support for additional activities in this area.
These activities will include revisions to source term related regulatory documents, and additional support for long term Part 50 changes, if needed.
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January 31, 1995 REGULATORY APPLICATICN CF NEW SOURCE TERMS - EMERGENCY PLANNING STANDARD REACTOR SAFETY ASSESSMENT STANDARD REACTOR DESIGNS l
OBJECTIVE The overall Standard Reactor Designs Cost Center includes activities to support future licensing activities associated with standard reactor designs; to ensure that certified standard reactor designs, when properly sited and constructed, will adequately protect the public health and safety and the environment; and to i
ensure that the combination of industry and NRC research establishes the technical bases for timely and sound rulemaking and regulatory decisions to support design certification activities.
This subactivity (REGULATORY APPLICATION OF NEW SOURCE TERMS-EMERGENCY PLANNING) includes ongoing revisions to emergency preparedness regulations. [EP EWAS i PARTTOF3 PREVIOUS E PLAN ZIN ? THIS AREA.
IT HAS1BEENTUPDATEDiBUT=MOREsAPPROPRIATELY: BELONGS:AS'PART OF. REACTOR SAFETY ASSESS. MENT; AND REpULATION DEVELOPMENT, ACTIVITYtl USER OFFICE NEED(S) (IF ANY) l l
Activities in this area respond to: 1) a request from R. Bernero to
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E. Beckjord dated October 10, 1989; and 2) petitions for i
rulemaking.
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l SCHEDULE FOR COMPLETION OF ACTIVITIES / PRODUCTION OF DELIVERABLES (FY 95-FY 98)
SECY-93-006, " Proposed Amendments to 10 CFR Part 72 To Establish l
the Emergency Preparedness Licensing Regulations for Independent Spent Fuel Storage Facilities (;SFSI) and Monitored Retrievable Storage Facilities (MRS)",
dated Janua /
19, 1993 contains recommendations to the Commicsion for emergency planning licensing i
regulations for the subject facilities.
During FY 1995 publish final regulations.
l During FY 1995, issue proposed rule to modify exercise requirements l
in emergency preparedness regulations to resolve a petition for l
rulemaking from VEPCO.
Also during FY 1995, evaluate a petition from VEPCO on requirements for frequency of audits of emergency preparedness programs During FY 1994, RES supported NRR in developing a plan for l
simplifying emergency preparedness for ALWRs.
During FY 1995-l FY 1996, develop the technical bases for simplified emergency preparedness regulations for ALWRs, as needed.
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FIN LIST AND FTE (FY 94-FY 97) l STANDARD REACTOR DESIGNS l
ACTIVITY: Standard Reactor Safety Assessment l
Subactivity: Regulatory Application of New Source Terms FY95 FY96 FY97 EY98 i
New Source Terms l
Funds (in $1000s) 0 0
0 0
l FIN Contractor Title W6359 BNL Ep Simplification for Advanced Reactors 0
0 0
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FIN Descriotions FIN W6359, "Radiolocical Emercency Resoonse Plans for Advanced Feactors" During FY 1995, complete studies which will be used as a technical basis to support consideration of simplifying emergency preparedness regulations for ALWRs.
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February 3 1995' f
REACTOR REGULATORY STANDARDS REACTOR SAFETY ASSESSMENT AND REGULATION DEVELOPMENT REACTOR REGULATION
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OBJECTIVE This activity (REACTOR REGULATORY STANDARDS) includes developing and revising
.l regulations, policy statements. and regulatory guides for nuclear power plant l
regulation.
The specific activities under this. area have been initiated in i
response to user office (NRR) requests.
USER OFFICE NEED(S) (IF ANY)
Reculatorv Guide 1.78 In recent licensing actions. licensees have requested changes to the toxic limits for certain hazardous chemirah to values greater than specified in RG.
1.78. " Assumptions for evaluating the Habitability of-Nuclear Power Plant Control Room during a Postulated Hazardous Chemical Release." Based on work i
done in support of Generic Issue 83. " Control Room Habitability" it is recognized that RG. 1.78 is out-of-date both with respect to the chemical limits and the number of chemicals considered. As a result of these concerns.
NRR initiated a Users' Request to revise RG.1.78 in August 1991- (Memorandum i
from Frank Gillespie to Bill Morris. " Revision to Regulatory Guide 1..-78."
dated August 23. 1991).
SCHEDULE FOR COMPLETION OF ACTIVITIES / PRODUCTION OF DELIVERABLES (FY 95-FY 98)
The revision to RG 1.78 is currently scheduled to result in a draft regulatory I
guide published for comment in FY 1995 and a final regulatory guide published in FY 1996.
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.I FIN LIST (FY 95-FY 98)
REACTOR REGULATION ACTIVITY: Reactor Safety Assessment and Regulation Development Suiictivity: Regulatory Standards FY95 FY96 FY97 FY98 Reactor Reg. Standards i
Funds (in $1000s) 40 0
0 0
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FIN Contractor Title W6308 PNL Regulatory Guides 1.78 Revision 40 0
0 0
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FIN DESCRIPTIONS FIN W6308. PNL. "Reculatory Guide 1.78 Revision" During FY 1995-FY 1996. develop the technical bases for updating to current knowledge the Regulatory Guides which address toxic chemicals and explosive mixtures. This work will include revisions to Regulatory Guides 1.78. 1.95.
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February 3. 1??5 i
i REACTOR REGULATORY STANDARDS REACTOR SAFETY ASSESSMENT AND REFULATION DEVELOPMENT l
REACTOR REGULATE 0N-i OBJECTIVE l
This activity (REACTOR REGULATORY STANDARDS) includes developing and revising
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regulations. policy -statements. and regulat' guides for nuclear power planu 3
regulation. The specific activities under area have been initiated in i
response to user office (NRR) requests.
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USER OFFICE NEED(S) (IF ANY)
Reculatorv Guide 1 91 i'
In the 16 years since the last revision to RG.1.91. " Evaluations of Explosions Postulated to occur on Transportation Routes near Nuclear Power Plants". experience at existing plants and more recent information on'the hazards involved have indicated the need to revise RG. 1.91. As=a result. NRR issued a Users' Request to revise this guide in March 1994. (Memorandum from i
William Russell to Eric Beckjord "NRR User Need for Revision of Regulatory Guide 1.91. Rev.1. " Evaluations of Explosions Postulated to occur on i
Transportation Routes near Nuclear Power Plants.'" dated March 31, 1994.
l SCHEDULE FOR COMPLETION OF ACTIVITIES / PRODUCTION OF DELIVERABLES (FY 95-FY 98) l i
The user request for revision to RG 1.91 was received March 31. 1994. A Task l
Action Plan has not yet been developed for this activity due to resource constraints.
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F:'1 LIST (FY 95-FY 98)
REACTCR REGULATION ACTIVITY: Reactor Safety Assessment and Regulation Development Subactivity: Regulatory Standards FY95 FY96 FY97 FY98 Reactor Reg. Standards Funds (in $1000s) 0 175 200 186 i
FIN Contractor Title UNDES UNDES Regulatory Guide 1.91 Revision 0
175 0
0 L2163 UNDES tmplementing Improvements to Regulations O
0 200 186 I
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FIN CESCRIPTICNS FIN (UNDES)- "Reculatory Guide 1 91 Revision" During FY 1995 - FY 1997. initiate and develop the technical bases for updating Regulatory Guide 1.91 in response to NRR users request.
FIN (L2163). "Imolementino Imorovements to Reculations" During FY 1995-FY 1998, provide support as needed to Office user requests related to control room habitability and other similar areas.
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