ML20205A503

Requests Concurrence on Encl Commission Paper.Submits Summary Re Request

ML20205A503
Person / Time
Issue date:	10/09/1998
From:	Roe J NRC
To:	Gray J, Paperiello C, Thadani A NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS), NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES), NRC OFFICE OF THE GENERAL COUNSEL (OGC)
Shared Package
ML20205A488	List: ML20205A481 ML20205A490 ML20205A497 ML20205A503 ML20205A511 ML20205A516 ML20205A522 ML20205A536 ML20205A562 ML20205A607 ML20205A624 ML20205A646 ML20205A666 ML20205A702 ML20205A732 ML20205A754 ML20205A952 ML20205A967 ML20205B021 ML20205B037 ML20205B046 ML20205B066
References
FRN-64FR12117, RULE-PR-21, RULE-PR-50, RULE-PR-54 AG12-1-005, AG12-1-5, NUDOCS 9903310004
Download: ML20205A503 (99)

Text

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pa n:e i UNITED STATES vl2-1 j NUCLEAR REGULATORY COMMISSION PDR

' WASHINGTON, D.C. ensas wi

l. k ..... p 8* October 9, 1998 MEMORANDUM TO: Carl. J. Paperiello, Director Office of Nuclear Materials Safety and Safeguards Ashok C. Thadani, Acting Director Office of Nuclear Research Joseph R. Gray, Associate General Counsel for Licensing and Regulation Office of the General Counsel Jesse L. Funches Chief Financial Officer David L. Meyer, Chief Rules and Directives Branch Division of Administrative Services Office of Administration l Brenda Jo. Shelton, Chief Information and Records Management Branch Office of the Chief Information Officer James Lieberman, Director

( Office of Enforcement FROM: Jack W. Roe, Acting Director I '

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Division of Reactor Project Manag men [

SUBJECT:

OFFICE REVIEW AND CONCURRENCE ON PROPOSED AMENDMENTS TO 10 CFR PARTS 21,50, AND 54; REGARDING USE OF AN ALTERNATIVE SOURCE TERM AT OPERATING REACTORS Your concurrence is requested on the attached Commission Paper. -

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The following is a summary of this request:

1. Iille: PROPOSED AMENDMENTS TO 10 CFR PARTS 21,50, AND 54; REGARDING USE OF AN ALTERNATIVE SOURCE TERM AT OPERATING REACTORS

2. NRR Task Leader: Stephen F. LaVie (415-1081)

3. Coon 17 ant Individuals: NRR - Richard. L. Emch, Jr. (415-1068)

Barry Zaleman (415-3467)

OGC - G. Mizuno (415-1639)

4. Reauested Action: Review and concurrence in Commission Paper CONTACT: Stephen F. LaVie, NRR/PERB 415-1081 9903310004 990325 64

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12117 PDR g

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5. Raouested comolation Date: October 30,1998 6.

nackground: The attached proposed rule would amend the Commission's rquiations in 10 CFR Parts 21,50, and 54. These amendments provide requirementt and acceptance criteria for the use of a revised source term as an altemative to the TID-14844 source term by operating reactors. Operating reactors would have ;he option to continue to use the TID-14844 source term, or could use an approved attemWve, such as that provided in NUREG-1465, " Accident Source Terms for Light-Water Nuc%Jr Power Plants." This action would allow interested licensees to pursue cost bendicial licensing actions to reduce regulatory burden without comprising the margin of safety of the facility. The amendment also makes conforming changes to eliminate the need for exemptions from certain requirements in 10 CFR Part 50.34(f) and from the dose criterion in 10 CFR Part 50, Appendix A, GDC-19, by applicants for construction permits, combined operating licenses, or design certifications, after January 10,1997.

In the staff requirements memorandum dated February 12,1997, the Commission approved the staff's approach, described in SECY-96-242 dated November 25,1996, to allow the use of the revised source term at operating reactors. The Commission directed the staff to commence rulemaking upon completion of the new source term rebaselining and to present the Commission with a rulemaking plan. SECY-98-158 forwarded this rulemaking plan for Commission review and approval. The rulemaking plan contained suggested language for the proposed rule. In the staff requirements memorandum dated September 4,1998 (SECY 98-158), the Commission directed the staff to expedite the rulemaking process and to provide a draft rule to the Commission by December 15,1998. This paper provides the requested proposed rule for Commission consideration. This rulemaking is being tracked as item VI.J in the August

( 25,1998 EDO response to issues raised within the Senate authorization context and July 17,1998 stakeholder meeting.

As a result of the accelerated schedule imposed on this proposed rulemaking, a copy of this proposed rule package will be forwarded to the ACRS on October 19,1998. In accordance with direction in the SRM, the proposed package will be released to the Public Document Room at that time. Although the requested completion date for this concurrence is October 30,1998, NRR would like to be notified by October 16,1998 of any major issues that should cause this release to be delayed.

7. Resources to implement.this rulemaking have been included in the Intemal  !

Program / Budget Review FY-1995-1999. Copies of inis concurrence package have been forwarded to the Office of Chief Financial Officer for coordination of resource issues per the EDO memorandum of June 14,1991, and to ACRS and OlG for information.

8. The positions conveyed in this package represent those of the Director of the OtCce of Nuclear Reactor Regulation.

Attachment:

"ommission Memorandum w/atts.

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5. Rnouested Comniatinn Data: October 30,1998 6.

Backnmund: The attached proposed rule would amend the Commission's regulations in 10 CFR Parts 21, 50, and 54. These amendments provide requirements and acceptance criteria for the use of a revised source term as an attemative to the TID 14844 source term by operating reactors. Operating reactors

' would have the option to continue to use the TID-14844 source terrr., or could use an approved attemative, such as that provided in NURF.G-1465," Accident Source Terms for Light-Water Nuclear Power Plants."

This action would allow interested licensees to pursue cost beneficiallicensing actions to reduce regulatory burden without comprising the margin of safety of the facility. The amendment also makes conforming changes to eliminate the need for exemptions from certain requirements in 10 CFR Part 50.34(f) and from the dose criterion in 10 CFR Part 50, Appendix A, GDC-19, by applicants for construction permits, combined operating licenses, or design certifications, after January 10,1997.

In the staff requirements memorandum dated February 12,1997, the Commission approved the staff's approach, described in SECY-96-242 dated November 25,1996, to allow the use of the revised source term at operating reactors. The Co.mmission directed the staff to commence rulemaking upon completion of the new source term rebaselining and to present the Commission with a rulemaking plan. SECY-98-158 forwarded this rulemaking plan for Commission review and approval. The rulemaking plan contained suggested language for the proposed rule. In the staff requirements memorandum dated September 4, 1998 (SECY-98-158), the Commission directed the staff to expedite the rulemaking process and to provide a draft rule to the Commission by December 15,1998. This paper provides the requested proposed rule for Commission consideration. This rulemaking is being tracked as item VI.J in the August 25,1998 EDO response to issues raised within the Senate authorization context and July 17,1998 stakeholder meeting.

As a result of the accelerated schedule imposed on this proposed rulemaking, a copy of this proposed rule package will be forwarded to the ACRS on October 19,1998. In eccordance with direction in the SRM, the proposed package will be released to the Public Document Room at that time. Although the requested completion date for this concurrence is October 30,1998, NRR would like to be notified by October 16, 1998 of any major issues that should cause this release to be delayed.

7. Resources to implemt.,nt this rulemaking have been included in the Intemal Program / Budget Review FY-1995-1999. Copies of this concurrence package have been forwarded to the Office of Chief Financial Officer for coordination of resource issues per the EDO memorandum of June 14,1991, and to ACRS and OlG for information.

8. The positions conveyed in this package represent those of the Director of the Office of Nuclear Reactor Regulation.

Attachment:

Commission Memorandum w/atts.

cc: w/atts H. T. Bell, IG J. Larkins, ACRS W. Deecher, OPA H. Miller, Region l/ ORA L. Reyes, Region ll/ ORA J. Caldwell, Region ill/ ORA E. W. Mershcoff, Region IV/ ORA DISTRIBUTION w/atteh ? Central f/c PERB r/f DOCUMENT NAME: G:\sfl\OFFCONC.WPD OFC PERB E SC:PERB 6 BC:PERB b AD:DRPM 6 NAME SLaVie h REmch Miller JRoe{ -

DATE 10/8/98 10/ T /98 10/ 9 /98 10/k /98v dici ~

OFFICE RECORD COPY l

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w EQB: The Commissioners FROM William D. Travers Executive Director for Operations SUBJECI: PROPOSED AMENDMENTS TO 10 CFR PARTS 21,50, AND 54; REGARDING USE OF AN ALTERNATIVE SOURCE TERM AT OPERATING REACTORG PURPOSE-To obtain Commission approval to publish a proposed rule to amend 10 CFR Parts 21,50, and 54 to provide for the use of altemative source terms at operating reactors. This proposed rule  ;

is in response to the staff requirements memorandum dated September 4,1998 (SECY 158).

SUMMARY

This paper and the accompanying attachments present, for Commission approval, a proposed rule to amend 10 CFR Parts 21,50, and 54. These amendments provide requirements and  ;

acceptance criteria for the use of a revised source term as an attemative to the TID-14844  !

source term by operating reactors. Operating reactors would have the option to continue to use l the TID-14844 source term, or could use an approved attemative, such as that provided in NUREG-1465," Accident Source Terms for Light-Water Nuclear Power Plants." This action would allow interested licensees to pursue cost beneficial licensing actions to reduce regulatory burden without comprising the margin of safety of the facility.

The amendment also makes conforming changes to eliminate the need for exemptions from ,

certain requirements in 10 CFR Part 50.34(f) and from the dose criterion in 10 CFR Part 50, Appendix A, GDC-19, by applicants for construction permits, combined operating licenses, or design certifcations, after January 10,1997.

Contact Stephen F. LaVie, NRR (301)415-1081 e

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. The Commissioners BACKGROUND:

in the staff requirements memorandum dated September 4,1998 (SECY-98-158), the Commission approved, with comments, the staffs proposed rulemaking plan for implementation of the revised source term at operating reactors. This SRM directed the staff to provide a draft rule to the Commission by December 15,1998.

Included in this package are the Federal Register notice for the proposed rule (Attachment 1),

the proposed Regulatory Analysis (Attachment 2), proposed Environmental Assessment (Attachment 3), draft congressional letters (Attachment 4), and draft public announcement (Attachment 5).

DISCUSSION:

In the staff requirements memorandum dated February 12,1997, the Commission approved the staffs approach, described in SECY-96-242 dated November 25,1996, to allow the use of the revised source term et operating reactors. The Commission directed the staff to commence rulemaking upon completion of the new source term rebaselining and to present the Commission with a rulemaking plan. SECY-98-158 forwarded this rulemaking plan for Commission review and approval. The rulemaking plan contained suggested language for the proposed rule. In the SRM, the Commission directed the staff to expedite the rulemaking process and to provide a draft rule to the Commission by December 15,1998. This paper  ;

provides the requested proposed rule for Commission consideration. This rulemaking is being tracked as item VI.J in the August 25,1998 EDO response to issues raised within the Senate authorization context and July 17,1998 stakeholder meeting.

As directed by the SRM, the NRC staff placed a copy of the draft proposed rulemaking package in the Public Document Room on the date that the copy was provided to the ACRS (October 19, 1998).

The proposed rule differs from the suggested rule language provided in the rulemaking plan. A explanation of the changes follows:

1. The proposed new section to Part 50 was referred to as Section 50.95. It was determined that this proposed section would be more appropriately located as Section 50.67. All cross references to Section 50.95 have been updated.

. 2. The definition of the term source form was relocated from the proposed new section to the existing Section 50.2.

3. The Requirements paragraoh in the new Section 50.67 was revised to change the analysis reference from the implied loss of coolant accident to ...an evaluation of the consequences of applicable design basis accidents previously analyzed in the safety ,

analysis report .." The revised language is more consistent with the staffs intent and practice. The revised language also provides for selective implementation by requiring only the applicable DBA analyses.

4. Proposed conforming changes have been included for Sections 50.65 and 54.4, in addition to the Sections 21.3 and 50.49 changes identified previously. These sections will i.ms. _ . . m.% - . h.. rm , . -

The Commissioners .( be amended to reflect the relocation of accident dose guidelines from Section 100.11 to Section 50.67.

5. The language of the proposed addition to Part 50, Appendix A, GDC-19, was revised to clarify the relationship of the 0.05 Sv (5 rem) TEDE dose criterion to the existing requirements in GDC-19.

. The proposed amendments are described in detail in the attached Federal Register notice

(Attachment 1). The proposed rulemaking will:

e allow holders of operating licenses issued prior to January 10,1997 (the effective date of the 10 CFR Part 100 amendment), to voluntarily revise the current accident source term used in their design basis radiological analyses via requesting a license amendment,

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e provide accident dose guideline of 0.25 Sv (25 rem) TEDE at the boundary of the exclusion area for any two hour period and 0.25 Sv (25 rem) TEDE at the outer boundary of the low population zone for the duration of the accident, for analyses based upon the revised source term, e provide a control room habitability dose criterion of 0.05 Sv (5 rem) TEDE for the duration of the accident, for analyses based upon the revised source term, e relocate these dose guidelines from Part 10O' to Part 50, e maintain the current requirements for those operating reactors than continue to use the  ;

TID-14844 source term, and l

• eliminate the need for' exemptions from certain requirements in Section 50.34(f) and Part 50, Appendix A, GDC-19 by applicants after January 10,1997 for construction permits, combined operating licenses, or design certifications, by removing explicit references to TID-14844 in Section 50.34, and by providing a control room habitability dose criterion of 0.05 Sv (5 rem) TEDE for the duration of the accident.

A Regulatory Analysis (Attachment 2) was prepared to evaluate the value/ impact of the proposed rulemaking. This analysis concludes that the public health and safety and the common defense and security would continue to be adequately protected if the proposed  ;

rulemaking were implemented. The analysis qualitatively determined that the potential values associated with the revised source term are substantial enough to justify the rulemaking, and clearly outweigh any reductions in values associated with the current accident source term.

An Environment Assessment (Attachment 3) was performed and it was determined that the proposed amendments, if adopted, would not be a major Federal action significantly affecting the quality of the human environment. An environmentalimpact statement is not required. The <

actual accident sequence and progression is not changed; it is the regulatory assumptions regarding the accident that will be affected by the change. The use of an attemative source I term alone cannot increase the core damage frequency (CDF) or the large early release

. frequency (LERF) or actual offsite or onsite radiation doses. An attemative source term could be used to justify changes in the plant design that might have an impact on CDF or LERF or might increase offsite or onsite doses. These potential changes are subject to existing requirements-

The Commissioners ' in the Commission's regulations and the associated potential for accident radioactivity releases to the environment would be maintained at the same magnitude. Thus, the protection of the public health and safety is not decre sed.

The NRC staff has deterrnined that the backfit rule,10 CFR 50.109, does not apply to this proposed regulation, and, therefore, a backfit analysis is not required for this proposed regulation. These amendments do not involve any provisions that would impose backfits as defined in 10 CFR 50.109(a)(1). This proposed regulation amends the Commission's regulations by establishing alternate requirements that may be voluntarily adopted by licensees.

Resources to develop and implement this rulemaking are included in the current NRC Five-Year Plan. Therefore,inis action involves no resource adjustments to the NRC Five-Year Plan.

No agreement state implementation problems are expected because the proposed rulemaking affects only the licensing and operation of nuclear power plants that are regulated by the NRC under Part 50, " Domestic Licensing of Production and Utilization Facilities."

COORDINATION:

The Office of the General Counsel has no legal objections to this paper. The Office of the Chief Financial Officer has reviewed this Commission paper for resource implications and has no objection. The Office of the Chief Information Officer has reviewed this proposed rule for information technology and information management implications and concurs in it. An information collection clearance has been prepared and wi!! be submitted to the Office of Management and Budget at the same time the rule is forwarded to the Federal Register for

(. publication. The NRC staff does not intend to coordinate this Rulemaking Plan with the Agreement States since this rulemaking is only applicable to licensees regulated by the NRC in accordance with Part 50. The ACRS and CRGR have reviewed this proposed rule.

RECOMMENDATION That the Commission:

1. Anorove the notice of proposed rulemaking for publication (Attachment 1)

2. Certify that this rule, if promulgated, will not have a negative economic impact on a substantial number of small entities to satisfy the requirements of the Regulatory Flexibility ,

Act,5 U.S.C. 605(b).

3. No.te:

a. The proposed rulemaking would be published in the Federal Register for a 75-day public comment period;

b. The draft Regulatory Analysis will be available in the Public Document Room (Attachment 2);

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- The Commissioners k c. The draft Environmental Assessment and a draft finding of no significant impact have been prepared (Attachment 3);

d. The Chief Counsel for Advocacy of the Small Business Administration will be notified of the Commission's determination, pursuant to the Regulatory Flexibility Act (5 U.S.C. 605(b)), that this proposed rule will not have a significant economic effect on a substantial number of small entities;

e. The appropriate Congressional committees will be informed (Attachment 4);

f. A public announcement will be issued (Attachment 6); and

g. Copies of the Fadaral Ragintar Notice of Proposed Rulemaking will be distributed to all Commission power reactor licensees. The notice will be sent to other interested parties upon request.

William D. Travers Executive Director For Operations Attachments: 1. Faderal Register Notice of Proposed Rulemaking

2. Draft Regulatory Analysis

3. Draft Environment Assessment and Draft Finding of No Significant impact )

4. Draft Congressional Letters i

5. Draft Public Announcement j 1

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Attachment 1 Federal Register Notice of Proposed Rulemaking

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I October 9,1998 DRAFT - PRE-DECISIONAL

[7590-01-P]

NUCLEAR REGULATORY COMMISSION 10 CFR Parts 21,50 and 54 RIN 3150 -

Use of an Attemative Source Term at Operating Reactors AGENCY: Nuclear Regulatory Commission.

ACTION: Proposed Rule.

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SUMMARY

The Nuclear Regulatory Commission (NRC) is proposing to amend its regulations to allow holders of operating licenses for nuclear power plants to voluntarily replace the ,

traditional source term used in design basis accident analyses with a revised source term.

This revised source term was developed from the results of a major research effort to obtain a better understanding of fission-product transport and release mechanisms in light-water-reactors under severe accident conditions. This action would allow interested licensees to pursue cost beneficial 1: censing actions to reduce regulatory burden without comprising the margin of safety of the facility. The Commission is also proposing to amend its regulations to revise certain sections to conform with final 10 CFR Parts 50 and 100 rulemaking published on January 10,1997 (61 FR 65157).

l DATES: Comment period expires (publishing + 75 days). Comments received after this date will be considered if it is practical to do so, but the Commission is able to assure consideration only for comments received on or before this date.

October 9,1998 DRAFT- PRE-DECISIONAL ADDRESSES: Mail written comments to: Secretary, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, Attention: Rulemakings and Adjudications Staff, Mail Stop

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The NRC staff specifically requests comment on whether the technical aspects of the rule should be addressed through attemative approaches other than the proposed rule, such as i

a simple performance-based rule with a regulatory guide endorsing industry consensus standards to permit a more rapid regulatory response by the NRC to future developments and changes in the consensus standards.

Deliver comments to: One White Flint North,11555 Rockville Pike, Rockville, Maryland. l 20852, between 7:30 am and 4:15 pm on Federal workdays.

You may also provide comments via the NRC's interactive rulemaking web site, ,

"Rulemaking Forum," through the NRC home page (http://www.nrc. gov). This site provides the availability to upload comments as files (any format, but Wordperfect version 6.1 preferred), if your web browser supports that function. Information on the use the Rulemaking Forum is i

available on the website. For additional assistance on the use of the interactive rulemaking site, contact Ms. Carol Gallagher, (301) 415-5905; e-mail cag@nrc. gov.

Certain documents related to this rulemaking, including comments received and the environmental assessment and finding of no significant impact may be examined at the NRC Public Document Room,2120 L Street, NW. (Lower Level), Washington, DC. These same documents also may be viewed and downloaded electronically via the interactive rulemaking website established by NRC for this rulema' king, i

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October 9,1998 DRAFT - PRE-DECISIONAL FOR FURTHER INFORMATION CONTACT: Stephen F. LaVie, Office of Nuclear Reactor l

l Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001; telephone

. (301) 415-1081; or by Intemet electronic mail to st@nrc. gov.

l l SUPPLEMENTARY INFORMATION: .

1. Background.

II. Objectives.

Ill. Altematives.

IV. Section-by-Section Analysis.

V. Future Regulatory Action.

VI. Referenced Documents.

Vll. Finding of No Significant Environmental Impact; Availability.

Vill. Paperwork Reduction Act Statement.

l IX. Regulatory Analysis.

X. Regulatory Flexibility Certification.

l XI. Backfit Analysis.

1. BackgrCJnd A holder of an operating license (i.e., the licensee) for a light-water power reactor is required by regulations issued by the Commission (or its predecessor, the U.S. Atomic Energy Commission, (AEC)) to submit a safety ana!ycis report that includes assessments of the radiological consequences of potential accidents and an evaluation of the proposed facility site.

The Commission uses this information in its evaluation of the suitability of the reactor design FRN 3 i

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i October 9,1998 DRAFT - PRE-DECISIONAL and the proposed site as required by its regulations contained in 10 CFR Parts 50 and 100.

Section 100.11, which was adopted by the AEC in 1962 (27 FR 3509, April 12,1962), requires

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an applicant to assume (1) a fission product release from the reactor core, (2) the expected containment leak rate, and (3) the site meteorological conditions to establish an exclusion area and a low population zone. This fission product release is based on a credible major accident that would result in substantial release of appreciable quantities of fission products from the core to the containment atmosphere. A note to 9100.11 states that Technical information Document (TID) 14844, " Calculation of Distance Factors for Power and Test Reactors," may be used as a source of guidance in developing the exclusion area, the low population zone, and the population center distance.

The fission product release from the reactor core is referred to as the " source term," and is characterized by the radioactive material composition and magnitude, the chemical and physical properties of the material, and the timing of the release from the reactor core. The accident source term is used to evaluate the radiological consequences of design basis accidents (DBAs) in showing compliance with various requirements of the Commission's regulations. Although originally used for site suitability analyses, the accident source term is a design parameter for accident mitigation features, equipment qualification, control room operator radiation doses, and post-accident vital area access doses. The measurement range and alarm set points of some installed plant instrumentation and the actuation of some plant safety features are based in part on the accident source term. The TID-14844 source term was explicitly stated as a required design parameter for several TMl-related requirements.  !

The Commission's methods for calculating accident doses, as described in Regulatory I

Guide 1.3, " Assumptions Used for Evaluating the Potential Radiological Consequences of a '

Loss of Coolant Accident for Boiling Water Reactors," Regulatory Guide 1.4, " Assumptions i

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October 9,1998 DRAFT - PRE-DECISIONAL k Used for Evaluating the Potential Radiological Consequences of a Loss of Coolant Accident for Pressurized Water Reactors," and in NUREG-0800," Standard Review Plan for the Review of l Safety Analysis Reports for Nuclear Power Plants," were developed to be consistent with the TID-14844 source term and the whole body and thyroid dose guidelines stated in $ 100.11 of this chapter. In this regulatory framework, the source term is assumed to be released immediately to the containment at the start of the postulated accident. The chemical form of j the radiolodine released to the containment atmosphere is assumed to be predominantly l elemental, with small fractions of particulate and organic iodine forms. Radiation doses are calculated at the exclusion area boundary (EAB) for the first 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and at the low population 1

l zone (LPZ) for the assumed 30-day duration of the accident. The whole body dose comes l primarily from the noble gases in the source term, and the thyroid dose is based on inhalation of radioiodines, in analyses performed to date, the thyroid dose has generally been limiting, and the design of some engineered safety features, such as containment spray systems and the charcoal filters in containment, building exhaust, and control room ventilation systems, are i

predicated on these postulated thyroid doses. Subsequently, the Commission adopted the dose criteria in Criterion 19 of 10 CFR Part 50, Appendix A.

The source term in TID 14844 is representative of a major accident involving significant core damage, as might be postulated to occur for a large loss-of-coolant accident (LOCA).

While the LOCA is typically the maximum credible accident, Commission experience in reviewing license applications have indicated the need to consider other accident sequences of lesser consequence but higher probability of occurrence. Some of these additional accident l analyses may involve source terms that are a fraction of those specified in TID-14844. The DBAs were not intended to be actual event sequences, but rather, were intended to be surrogates to enable deterministic evaluation of the response of the plant engineered safety FRN 5

I October 9, f998 DRAFT - PRE-DECISIONAL features. There accident analyses are intentionally conservative in order to address known uncertainties in accident progression, fission product transport, and atmospheric dispersion.

Although probabilistic risk assessments can provide usefulinsights i.ito system performance and suggest changes in how the desired defense-in-depth is achieved, defense-in-depth has been and continues to be an effective way to account for uncertainties in equipment and human performance. The Commission's policy statement on the use of PRA methods (60 FR 42622) calls for the use of PRA technology in all regulatory matters in a manner that complements the Commission's determinisSc approach and supports the traditional defense-in-depth philosophy.

Since the publication of TID-14844, signhn: ant advances have been made in understanding the timing, magnitude, and chemical form of fission product releases from severe nuclear power plant accidents. Many of these insights developed out of the major research efforts started by the Commission and the nuclear industry after the accident at Three Mile Island (TMI). In 1995, the Commission published NUREG-1465, " Accident Source Terms for Light-Water Nuclear Power Plants," which utilized this research to provide more physically based estimates of the accident source term that could be applied to the design of future light-water power reactors. The Commission sponsored significant review efforts by peer reviewers, foreign research partners, industry groups, and the general public (request for public comment published in 57 FR 33374). The information in NUREG-1465 provides a representative accident source term for a boiling-water reactor (BWR) and for a pressurize'd -water reactor (PWR). These source terms are described in terms of radionuclide composition and magnituda, physical and chemical form, and timing of release. Where TID-14844 addressed three categories of radionuclides, the revised source terms categorize the accident release into eight groups by physical and chemical properties. Where TlD-14844 assumed an immediate release of the activity, the reused source term has five release phases that are postulated to FRN 6

October 9,1998 DRAFT - PRE-DECISIONAL occur over several hours, with the onset of major core damage occurring after 30 minutes.

Where TID-14844 assumed radioiodine to be predominantly elemental, the revised source term assumes radioiodine to be predominantly cesium iodide (Csi), an aerosol that is more amenable to mitigation mechanisms. For DBAs, the NUREG-1465 source term is comparable to the TID-14844 source term with regard to the magnitude of the noble gas and radioiodine release fractions. However, the revised source term provides a more representative description of the radionuclide composition and release timing. The Commission has determined (SECY-94-302 dated December 1994) that design basis analyses will address the first three release i phases - coolant, gap, and in-vessel. The ex-vessel and late in-vessel phases are considered to be unduly conservative for design basis analysis purposes. These latter releases could only result from core damage accidents with vessel failure and core-concrete interactions. The estimated frequencies of such scenarios are low enough that they need not be considered cr

( e for the purpose of meeting the requirements oi6100.11 or, as proposed herein, 6 50.67.

The objective of NUREG-1465 was to define a revised accident source term for regulatory application for future light water reactors. The Commission's intent was to capture the major relevant insights available from severe accident research to provide, for regulatory purposes, a more realistic portrayal of the amount of the postulated accident source term.

These source terms were derived from examination of a set of severe accident sequences for light water reactors (LWRs) of current design. Because of general similarities in plant and core design parameters, these results are considered to be applicable to evolutionary and passive LWR designs. The revised source term has been used in evaluating the Westinghouse AP-600 standard design certification application. (A draft version of NUREG-1465 was used in evaluating Combustion Engineering's (CE) System 80+ design.)

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October 9,1998 DRAFT - PRE-DECISIONAL The Commission considered the applicability of the revised source term to operating re. actors and determined that the current analytical approach b;: sed on the TID-14844 source term would continue to be adequate to protect public health and safety and that operating reactors licensed under this approach would not be required to re-analyze accidents using the revised source term. The Commission also concluded that some licensees may wish to use an altemative source term in analyses to support operational flexibility and cost-beneficial licensing actions. The Commission initiated several actions to provide a regulatory basis for operating reactors to voluntarily amend their facility design bases to enable use of the revised source in design basis analyses. First, the Commission solicited input on how an altemative source term might be implemented in November 1995, the Nuclear Energy Institute (NEl) submitted its  ;

generic framework, Electric Power Research Institute Technical Report TR-105909, " Generic Framework for Application of Revised Accident Source Term to Operating Plants." This report and the NRC response were discussed in SECY-96-242 (November 1996). Second, the Commission initiated a comprehensive assessment of the overall impact of substituting the NUREG-1465 source term for the tradiiionally used TID-14844 source term at two typical l facilities. This was done to evaluate the issues involved with a'pplying the revised source term at operating plants. SECY 98-154 (June 1998), described the conclusions of this assessment. '

Third, the Commission accepted license amendment requests related to implementation of the revised source term at a small number of pilot plants. Experience has demonstrated that evaluation of a limited number of plant-specific submittals improves regulation and regulatory guidance development. The review of these pilot projects is currently in progress. Insights from these pilot plant reviews will be incorporated into the regulatory guidance that will be developed in conjunction with this rulemaking. Fourth, the Commission initiated an assessment l

on whether rulemaking would be necessary to allow operating reactors to use an attemative FRN 8

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. e October 9,1998 DRAFT - PRE-DECISIONAL source term. The proposed rule described herein, and the supporting regulatory guidance that will be developed as part of this rulemaking, have resulted from this assessment. The Commission plans to issue the supporting regulatory guidance for public comment on the same date as the publication of the final rule.

This proposed rulemaking for use of an attemative source term is applicable only to those facilities for which a construction permit was issued before January 10,1997, under 10 CFR Part 50," Domestic Licensing of Production and Utilization Facilities." The regulations of this part are supplemented by those in other parts of Chapter 1 of Title 10, including Part 100, " Reactor Site Criteria." Part 100 contains language that qualitatively defines a required accident source term and contains a note that discusses the availability of TID-14844.  !

With the exception of 9 50.34(f), there are no explicit requirements in Chapter 1 of Title 10 to use the TID-14844 accident source term. Section 50.34(f), which addresses additional TMI-related requirements, is applicable only to a limited number of construction permit applications pending on February 16,1982, and to applications under Part 52.

An applicant for an operating license is required by 9 50.34(b) to submit a final safety cnalysis report (FSAR) that describes the facility and its design bases and limits, and presents a safety analysis of the structures, systems, and compor,ents of the facility as a whole.

Guidance in performing these analyses is provided in regulatory guides. In its review of the more recent applica'tions for operating licenses, the Commission has used the review procedures in NUREG-0800,

• Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants" (SRP). These review procedures reference or provide acceptable assumptbns and analysis methods. The facility FS R documents the assumptions and methods actually used by the applicant in the required safety analyses. The Commission's finding that a license may be issued is based on the review of the FSAR, as documented in the FRN 9

October 9,1998 DRAFT - PRE 4ECISIONAL Commission's safety evaluation report (SER). By their inclusion in the FSAR, the assumptions (including source term) and licensee's methods of evaluation become part of the design basis **

of tc ~ facility. From a regulatory standpoint, the requirement to use the TID-14844 source tam is expressed as a licensee commitment (typically to Regulatory Guides 1.3 or 1.4) documented in the facility FSAR, and thereby subject to the requirements of 6 50.59.

In January 1997, the Commission amended its regulations in 10 CFR Parts 21, 50, 52, 54 and 100 (61 FR 65157). That regulatory action provided site criteria for future sites; provide 6 a stable regulatory basis for seismic and geologic siting and the engineering design of future nuclear power plants to withstand seismic events; and relocated source term and dose requirements for future plants into Part 50. Since these dose requirements tend to affect reactor desigt, rather than siting, they are more appropriately located in Part 50. This decoupling of siting from design is consistent with the future licensing of facilities using standardized plan designs, the design features of which will be certified in a separate design certification rulemaking. This decoupling of siting from design was directed by Congress in the

%80 Authorization Act for the NRC. Since the revised criteria would not apply to operating reactors, the non-seismic and seismic reactor site criteria for operating reactors was retained as Subpart A and Appendix A to Part 100, respectively. The revised reactor site criteria was added as Subpart B in Part 100, with revised source term and dose requirements relocated to 9 50.34. The existing source term and dose requirements of Subpart A of Part 100 will remain

• As defined in 9 50.2 of this chapter, design bases means that information which identifies the specific functions to be performed by a structure, system, or component of a facility, and the specific values or ranges of values chosen for controlling param ters as reference bounds for design. These values may be (1) restraints derived from generally accepted " state of the art" practices for achieving functional goals, or (2) requirements derived from analysis (based on calculation and/or experiments) of the effects of a postulated accident for which a structure, system, or component must meet its functional goals. The Commission considers the accident source term to be an integral part of the design basis because it sets forth specific values (or range of values) for controlling parameters which constitute reference bounds for design.

FRN 10 )

p i

October 9,1998: DP. AFT - PRE-DECISIONAL in place as the licensing bases for those operating reactors that do not elect to use an attemative source term, in relocating the source term and dose requirements for future reactors to 9 50.34, the Commission retained the requirements for the exclusion area and the low population zone, but revised the associated numerical dose guidelines to replace the two different doses for the whole body and thyroid gland with the single, total effective dose equivalent (TEDE) value. The dose guidelines for the whole body and thyroid, and the immediate two hour exposure period, were largely predicated by the assumed source term being predominantly noble gases and radioiodines instantaneously released to the containment and the assumed single, critical organ method of modeling the internal dose used at the time of that Part 100 was originally published.

However, the current dose guidelines, by focusing on doses to the thyroid and whole body, assume that the major contributor to doses will be radioiodine. While this may be appropriate j i

with the TID-14844 source term, it may not be true for a source term based on a more complete understanding of accident sequences and phenomenology. The postulated chemical and physical form of radioiodine in the revised source term is more amenable to mitigation and, as such, radioiodine may not always be the predominant radionuclide in an accident release. The revised source term includes a larger number of radionuclides than did the TID-14844 source term. The whole body and thyroid dose guidelines ignores these contributors to dose. The Commission amended its radiation protection standards in Part 20 in 1991 (56 FR 23391),

replacing the single, critical organ concept for assessing intemal exposure with the total effective dose equivalent concept that assesses the impact of all relevant nuclides upon all body organs. TEDE is defined b be the deep dose equivalent (for extemal exposure) plus the committed effective dose equivalent (for intemal exposure). The deep dose equivalent (DDE) is comparable to the present whole body dose; the committed effective dose equivalent (CEDE) is 3

FRN 11 i

r October 9,1998 DRAFT - PRE-DECISIONAL the sum of the products of doses (integrated over a 50-year period) to selected body organs resulting from the intake of radioactive material multiplied by weighting factors for each organ that are representative of the radiation risk associated with the particular organ. The TEDE, using a risk-consistent methodology, assesses the impact of all relevant nuclides upon all body organs. While it is expected that in many cases, the thyroid could still be the limiting organ and radioiodine the limiting radionuclide, this conclusion can not be assured in all potential cases.

The revised source term postulates that the core inventory is released in a sequence of phases over 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />, with the more significant release commencing at about 30 minutes from the start of the event. The assumption that the two-hour exposure period starts immediately at the onset of the release is inconsistent with the phased release postulated in the revised source term.

The proposed rulemaking will extend the future LWR dose guidelines to operating reactors that elect to use an attemative source term.

( An accidental release of radioactivity can result in radiation exposure to control room operators. Normal ventilation systems may draw this activity into the control room where it can result in extemal and intemal exposures. Contro! room designs differ but, in general, design features are provided to detect the accident or the activity and isolate the normal ventilation intake. Emergency ventilation systems are started to minimize infiltration of contaminated air and to remove activity that has entered the control room. Di/sonnel exposures can also result  !

from radioactivity outside of the control room. However, because of concrete shielding of the )

control room, these latter exposures are generally not limiting. The objective of the control '

room design is to provide a location from which actions can be taken to operate the plant under normal conditions and to maintain it in a safe condition under accident conditions. General Design Criterion 19 (GDC-19), " Control Room," of Appendix A to Part 50 (36 FR 3255),

establishes minimum requirements for the design of the control room, including a requirement FRN 12

October 9,1998 DRAFT - PRE-DECISIONAL for radiation protection features adequate to permit access and occupancy of the control room under accident conditions. The GDC-19 criteria were established forjudging the acceptability of the control room design for protecting control room operators under postulated design basis accidents, a significant concem being the potential increases in offsite doses that might result from the inability of control room personnel to adequately respond to the event.

The GDC-19 criteria are expressed in terms of whole body dose, or its equivalent to any organ. The Commission did n:t revise the criteria when Part 20 was amended (56 FR 23391) instead deferring such action to individual facility licensing actions (NUREG/CR-6204). This position was taken in the interest of maintaining the licensing basis for those facilities already licensed. The Commission is proposing to replace the current GDC-19 dose criterion for future reactors and for operating reactors that elect to use an attemative source term with a criterion expressed in terms of 7 EDE. The rationale for this revision is similar to the rationale, discussed previously in this prea nble, for revising the dose guidelines for offsite exposures.

On January 10,1997 (61 FR 65157), the Commission amended 10 CFR Parts 21,50, 52,54 and 100 of its regulations to update the criteria used in decisions regarding power reactor siting for future nuclear power plants. The Commission intended that future licensing applications in accordance with Part 52 will utilize a source term, consistent with the source term information in NUREG-1465, and the accident TEDE guidelines in Parts 50 and 100.

However, during the final design approval (FDA) and design certification proceeding for the Westinghouse AP-600 advanced light-water reactor design, the NRC staff and Westinghouse determined that exemptions from 69 50.34(f)(vii), -(f)(viii), -(f)(xxvi), and -(f)(xxviii) and 10 CFR Part 50, Appendix A, GDC-19 we, a necessary. This rulemaking eliminates the need for these exemptions for future applicants under Part 52 by making conforming changes to Part 50, Appendix A, Criterion 19 and 6 50.34.

FRN 13

October 9,1998 DRAFT - PRE-DECISIONAL ll Objectives The objectives of this proposed regulatory action are to -

1. Provide a regulatory framework for the voluntary implementation of an altemative source term as a change to the design basis at currently licensed power reactors, thereby enabling potential cost-beneficial licensing actions while continuing to maintain existing safety margins and defense in depth:

2. Retain the existing regulatory framework for currently licensed power reactors licensees who choose not to implement an altemative source term, but continue to comply with I their existing source term;

3. Relocate source term and dose requirements that apply primarily to plant design into 10 CFR Part 50 for operating reactors that choose to implement an attemative source term; l

4. Implement conforming changes to 6 50.34(f) and Part 50, Appendix A, GDC-19 to eliminate the need for exemptions for future applicants under Part 52.

111. Alternatives The first attemative considered by the Commission was to continue using current regulations for accident dose guidelines and control room dose criteria. This is not considered to be an acceptable altemative. As discussed at 61 FR 65157, the Commission determined that dose guidelines expressed in terms of whole body and thyroid doses were inconsistent with the use of new source terms not based upon Tit >-14844. With regard to the exclusion area dose guideline, the Comrnission had previously determined (61 FR 65157) that the dose guideline applies to the 2-hour period resulting in the maximum dose.

FRN 14 I

J

)

October 9,1998 DRAFT - PRE-DECISIONAL The second altemative considered by the Commission was the replacement of the existing guidelines in section 100.11 and the existing criteria 10 CFR Part 50 Appendix A, GDC-19 with an entirely new regulation. This is not considered to be a desirable attemative because the provisions of the existing regulations form part of the licensing bases for many of the operating reactors. Therefore, these provisions must remain in effect for operating reactors that do not implement an attemative source term. In addition, this attemative would also be ir. consistent with the Commission philosophy of separating plant siting criteria and dose requirements.

The approach of establishing the requirements for use of an altemative source term in a new section to Part 50 while retaining the existing regulations in Part 100 Subpart A and Part 50 Appendix A GDC-19 was chosen as the best attemative.

The Commission considered attematives with regard to providing regulatory guidance to

{ support the new section to Part 50. The first attemative was to issue no additional regulatory guidance. This attemative was not considered to be acceptable because, in the absence of clear regulatory guidance, licensee efforts in preparing applications, and the NRC staff review of submitted applications, could be hindered by differences in interpretations and 'whnical positions. This could result in the inefficient use of licensee and staff resources, cause licensing delays, and could result in less uniform and less consistent reguietory implementation.

The second attemative was to replace the existing regulatory guides that address accident radiological consequences with new revisions. This is not considered to be an acceptable attemative because the provisions of the. existing regulatory guides form part of the licensing bases for many of the operating reactors. Therefore, these provisions must remain in effect for those operating :eacturs that do not implement an attemative source term. The third attemative was to issue r; new regulatory guide on the implementation of an altemative source term and FRN 15

.. . I October 9,1998 DRAFT - PRE-DECISIONAL which would include, in a series of appendices, revised assumptions and acceptable analysis methods for each design basis accident. The approach of issuing a new regulatory guide was chosen as the best attemative. To provide review guidance for the NRC staff, a new section on design basis radiological analyses using an altemative source term would be added to the Standard Review Plan.

IV Section by-Section Analysis (

A. Section 50.2 The proposed rule provides a definition of source tenn as it is used in 9 50.67. The NUREG-1465 source term is defined by five projected characteristics: (1) magnitude of radioactivity release, (2) radionuclides released, (3) physical form of the radionuclides released.

( (4) chemical form of the .adionuclides released, and (5) timing of the rat?'?ctivity release.

While all five characteristics should be addressed in applications propocing we G . u' tan A source term, there may be technically justifiable applications in which all five characteristos need not be addressed. The Commission intends to allow licensees flexibility in implementing an afternative source term consistent with maintaining a conservative, clear, logical and consistent plant design basis. The regulatory guide that supports this proposed rule will provide guidance on an acceptable analysis approach for showing compliance with this rule.

B. Section 50.67(a)

This paragraph would define the lice'nsees who may seek to revise their current radiological source term with an attemative source term. The proposed rule is applicable only to holders of nuclear power plant operating licenses that were issued under 10 CFR Part 50

.\

FRN 16

l October 9,1998 DRAFT - PRE-DECISIONAL prior to January 10,1997. The proposed rule would not require licensees to revise their current source term. The Commission considered the acceptability of the current TID-14844 source term at currently operating reactors and determined that the analytical approach based on the TID-14844 source term would continue to be adequate to protect pub'ic health and safety and that operating reactors licensed under this approach should not be required to re-analyze design basis accidents using a new source term. The proposed rule does not explicitly define I an attemative source term. In lieu of an explicit reference to NUREG-1465, footnote 1 to the proposed rule identifies the significant characteristics of an accident source term. The regulatory guide that will be issued to support this proposed rule will identify the NUREG-1465 source term at an acceptable alte'mative to that in TID-14844, and will provide implementation guidance. This approach provides for future revised source terms, should they be developed, and allows licensees to propose additional attematives for consideration by the Commission.

(,  ;

C. Section 50.67(b)(1)

This paragraph of f 50.67 would set forth the information that a licensee must submit as part of a license amendment to use an alternative source term. Because of the extensive use of the occident source term in the design and operation of a power reactor, and because of the

. i potentialimpact on postulated accident consequences and margins of safety of a change of such a fundamental design assumption, the Commission has determined that any change to the design basis to use an attemative source term should be reviewed and approved by the Commission in the form of a license amendment. Although the source term is a fundamental design assumption, generic analyses performed by the NRC staff in support of this proposed rule have indicated that there are potential applications which the Commission, with consideration of facility-specific evaluations, would find involved no significant hazards. The FRN 17

F * .

October 9,1998 DRAFT - PRE-DECISIONAL procedural requirements for the processing of a license amendment are provided in gg 50.90 through 50.92.

The Commission's regulations provide regulatory mechanism for a licensee to effect a change in its design basis in 50.59. That section allows a licensee to make changes to the facility as described in the FSAR without prior Commission approval, unless the proposed change is deemed to involve an unreviewed safety question (USQ), or involves a change to the technical specifications incorporated into the facility license. If a USQ is determined to exist, or if a change to the technical specifications is involved, the licensee must request Commission approval of the change using the license amendment process provided in g 50.90. The criteria i

for datermining that a USQ is involved are provided in 9 50.59. Signifiunt to this proposed rule is the criterion that a USQ would exist if the proposed change resulted in an increase in consequences of an accident or malfuncticn. In many applications, an attemative source term may reduce the postulated conse quences of the accident or malfunction. As such, the Commission determined that the ;egulatory framework of 9 50.59 does not provide assurance that this change in the design basis would be recognized as needing review by the NRC staff.

Once a licensee has been authorized to substitute an attemative source term in its design basis, subsequent changes to the facility that involve an alternative source term may be procesced under @ 50.59 or g 50.90, as appropriate. However, a subsequent change to the source term itself could not be implemented under 9 50.59.

The proposed rule calls for the applicant to perform analyses of the consequences of applicable design basis accidents previously analyzed in the safety analysis report and to submit a dascription of the analysis inputs, assumptions, methodology, and results of these analysis for Commission review. Applicable evaluations may include, but are not Smited to, those previously performed to show compliance with 9100.11,9 50.49, Part 50 Appendix A FRN 18

r October 9,1998 DRAFT - PRE-DECISIONAL l GDC-19,5 50.34(f), and NUREG-0737 requirements ll.B.2, ll.B.3, Ill.D.3.4. The regulatory guide that supports this proposed rule will provide guidance on the scope and extent of analyses used to show compliance with this rule and on the assumptions and methods used therein. It is not the intent of the Commission that all of the design basis radiological analyses for a facility be re-performed as a prerequisite for approval of the use of an attemative source term. The Commission does expect that the applicant will perform sufficient evaluations, supported by calculations as warranted, to demonstrate the acceptability of the proposed amendment.

D. Sections 50.67(b)(2)(i), ,ri), -(iii)

These subparagraphs sat forth the three criteria for Commission approval of the license amendment to use an alternative source term. A detailed rationale for the use of 0.25 Sv (25 rem) TEDE as an occident dose guideline and the use of the two-hour exposure period resulting in the maximum dose for future LWRs is provided at 61 FR 65157. The same considerations that formed the basis for that rationale are similarly applicable to operating reactors that elect to use an attemative source term. The Commission believes that it is technically appropriate and logical to extend the philosophy of decoupling of design and siting and the dose guidelines established for future LWRs to operating reactors that elect to use an alternative source term.

The Commission is proposing to replace the current GDC-19 dose cdterion for operating reactors that elec* tc use an attemative source term with a criterion of 0.05 SV (5 rem) TEDE for the duration ti '; as cident. This criterion is included in 9 50.67 rather than GDC-19 so as to co-locate all of the dose requirements associated with an attemative source term. The bases i

for the Commission's decision follow. First, the criteria in GDC-19 and that in the proposed rule FRN 19 l-

I~ . .- )

i October 9,1998 DRAFT - PRE-DECISIONAL are based on a primary occupational exposure limit. Second, The language in GDC-19: ".. 5 rem whole body, or its equivalent to any part of the body..."is subsumed by the definition of TEDE in 6 20.1003 and by the 0.05 Sv (5 rem) TEDE annual limit in 9 20.1201(a). Although the weighting factors provided in 9 20.1003 for use in determining TEDE differ in magnitude from the weighting factors implied in the 0.3 Sv (30 rem) thyroid criteria used for showing compliance l with GDC-19, these differences are the result ofimprovement in the science of assessing intemal exposures, and do not represent a reduction in the level of protection. Third, as discussed earlier in this preamble, the use of TEDE in conjunction w;th an altemative source term has been deemed to be appropriate and necessary. Fourth, the use of TEDE for the control room dose criterion is consistent with the use of TEDE in the accident dose guidelines for offsite exposure.

The Commission is not including a " capping" limitation, that is, an additional requirement I

that the dose to any individual organ not be in excess of some fraction of the total as provided for routine occupational exposures. The bases for the Commission's decision follow: First, this decision is consistent with the recent Part 100 rulemaking (61 FR 65157) with regard to doses to persons off site. Second, the use of 0.05 Sv (5 rem) TEDE as the control room criterion does not imply that this would be an acceptable exposure during emergency conditions, or that other

~

radiation protection standards of Part 20, including individual organ dose limits, might not apply.

This criterion is provided only to assess the acceptability of design provisions for protecting control room operators under postulated DBA conditions. The DBA conditions assumed in these analyses, while credible, generally do not represent actual accident sequences, but rather, are specified as conservative surrogates to create bounding conditions for assessing the acceptability of engineered safety features. Third,9 20.1206 permits a once-in-a-lifetime planned special dose of five times the annual dose limits. Also, Environmental Protecticn FKN 20 l .

l

o -

October 9,1998 DRAFT - PRE DECISIONAL Agency (EPA) guidance sets a limit of five times the annual dose limits for workers performing emergency services such as lifesaving or protecton oflarge populations. Considering the individual organ weighting factors of 20.1003 and assuming that only the exposure from a single organ contributed to TEDE, the organ dose, while exceeding that specified in

@ 20.1201(a), would be less than that considered acceptable as a planned special dose or as an emergency worker dose. The Commission is not - go ng that control room dose during an accident can De treated as a planned special expo. '5at the EPA emergency worker dose limits are an attemative to GDC-19 or the proposed rule. However, the Commission does believe that these provisions provide a useful perspective that supports the conclusion that the organ doses implied by the proposed 0.05 SV (5 rem) criterion can be considered to be acceptable given the relatively low probability of the events that could result in doses of this magnitude.

Although the dose criteria in the proposed rule will supersede the dose criteria in GDC-19, the other provisions of GDC-19 remain applicable l

E. 10 CFR Part 50, Appendix A, GDC-19 GDC-19 would be changed to include the TEDE dose criterion for control room design for applicants for construction permits, design certifications, and combined operating licenses after January 10,1997. The proposed change to GDC-19 is not related to the use of an altem6tive source %n et Operating reactors, but is included here to address a deficiency identified in the agaiatory framework for early site permits, standard design certifications, and combined licenses under Part 52. Sections 52.18,52.48, and 52.81 establish that applications filed under Part 52 Subparts A, R, and C, respectively, will be reviewed according to the standards set out in 10 CFR Parts 20,50,51,55,73, and 100 to the extent that those FRN 21

3 October 9,1998 DRAFT - PRE-DECISIONAL standards are technically relevant to the proposed design. Therefore, GDC-19 is pertinent to

- applications under Part 52. The recent Part 100 rulemaking (61 FR 65157) established accident TEDE guidelines (in 9 50.34) for applicants under Part 52, but did not change the existing control room whole body (or equivalent) dose criterion in GDC-19. Thus, exemptions from the dose criterion in the current GDC-19 were necessary in the design certification process for the Westinghouse AP-600 advanced light water reactor in order to use the 0.05 Sv (5 rem) TEDE criterion deemed necessary for use with an attemative source term, and exemptions would arguably be necessary for future applicants for construction permits, design certifications, and combined operating licenses. This proposed change will eliminate the need for such exemptions.

F. Sections 21.3, 50.2, 50.49(b)(1)(i)(C), 50.65(b)(1), and 54.4(a)(1)(iii)

These sections are being revised to ronform with the relocation of accident dose guidelines from 9100.11 to 9 50.67 for operating reactors that have amended their design bases to use an attemative source term.

H. Saction 50.34 A new footnote to 6 50.34 has been added to define what constitutes an accident source term. This new footnote is identical to the existing footnote 1 to $ 100.11, and is being added to provide for consistency between Parts 50 and 100.

I. Sections 50.34(f)(vii), -(viii), - (xxvi) and -(xxviit)

These paragraphs are being revised to remove an explicit reference to the " TID-14844 source term" with a more general reference to " accident source term." These changes FRN 22

October 9,1998 - DRAFT - PRE-DECISIONAL potentially affects two classes of applicants. The first affected class is facilities who obtain combined licenses under Part 52. Section 52.47(a)(ii) provides that applications for combined licenses must contain, inter alia, ' demonstration of compliance with any technically-relevant portions of the Three Mile Island requirements set forth in 6 50.34(f)." Section 50.34(f) contains several references to the TID-14844 source term. These references wculd be modified to delete the reference to TD-14844. This will clarify that applicants for combined licenses would not use the TID-14844 source term, but would use the source term in the design certification, if referanced, or else a source term which is justified in the combined license application.

The second affected class is the small subset of plants that had construction permits pending as of February 16,1982. With the proposed change, these plants could use either the TID-14844 source term or an attemative source term in its operating license application.

V. Future Regulatory Action The NRC is developing the following regulatory guides and standard review plan sections to provide prospective applicants with the necessary guidance for implementing the proposed regulation. The draft guide and draft standard review plan section will be issued to coincide with the publicatioa of th- Snal regulations that would implement this proposed  !

rulemaking. A notice of availability for these materials will be pblished in the Federal Register l l

at a future date.

l

1. Draft Guide DG-1081, " Revised Radiological Source Term for Evaluating the j l

Radiological Consequences of Design Basis Accidents at Boiling and Pressurized Water Reactors." I FRN 23

l October 9,1998 DRAFT - PRE-DECISIONAL i

{y _ 3 This guide is expected to provide regulatory guidance on the implementation of an l l attemative source term at operating reactors. The guide is expected to address issues involving limited or selective implementation of an attemative source term, PRA issues related !

l j to plant modifications based on an attemative source term, and provide guidance on the scope and extent affected DBA radiological analyses and associated acceptance criteria. The guide is j expected to include, in a series of appendices, revised assumptions and methcc , for each l

affected DBA. These appendices will supercede, for those facilities using an altemative source, the guidance of Regulatory Guides 1.3,1.4,1.25,1.77, and will supplement guidance in Regulatory Guide 1.89.

2. Standard Review Plan Section, "15.0.1 Radiological Consequence Analyses Using Revised Source Term."

/

This SRP section provides guidance to NRC staffin the review of the adequacy of j

licensee submittals requesting approval for use of an attemative source term.

VI. Referenced Documents ,

Copies of NUREG-0737, NUREG-0800, NUREG-1465, and NUREG/CR-6204 may be i

purchased from the Superintendent of Documents, U.S. Govemment Printing Office, Mail Stop SSOP, Washington, DC 20402-9328. Copies also are available from the National Technical Information Service,5285 Port Royal Road, Springfield, VA 22161. A copy also is available for inspection and copying for a fee in the NRC Public Document Room,2120 L Street, NW.

(Lower Level), Washington, DC.

4 l FRN 24 I

L

[ . .

l l

October 9,1998 DRAFT - PRE-DECISIONAL Copies of issued regulatory guides may be purchased from the Govemment Printing Office (GPO) at the current GPO price. Information on current GPO prices may be obtained by contacting the Superintendent of Documents, U.S. Govemment Printing Office, P.O. Box 37082, Washington, DC 20402-9328. Issued guides also may be purchased from the National Technical Information Service on a standing order basis. Details on this service may be obtained by writing NTIS,5626 Port Royal Road, Springfield, VA 22161.

Copies of SECY-94-302, SECY-96-242, SECY-98-154, TID 14844, and TR-105909 are 1 l

available for inspection and copying for a fee at the NRC Public Document Room,2120 L I Street, NW. (Lower Level), Washington, DC. l i

Vll. Draft Finding of No Significant EnvironmentalImpact: Availability

( The Commission has determined under the National Environmental Policy Act of 1969,

]

as amended, and the Commission's regulations in Subpart A of 10 CFR Part 51, that this regulation is not a major Federal action significantly affecting the quality of the human environment and therefore an environmentalimpact statement is not required. This proposed rule would allow operating reactors to replace the traditional TID-14844 source term with a more realistic source term that is based on the insights from extensive accident research activities. The actual accident sequence and progression is not changed; it is the regulatory assumptions regarding the accident that will be affected by the change. The use of an attemative source term alone cannot increase the core damage frequency (CDF) or the large early release frequency (LERF) or actual offsite or onsite radiation doses. An attemative source term could be used to justify changes in the plant design that might have an impact on CDF or LERF or might increase offsite or onsite doses. These potential changes are subject to existing FRN 25

October 9,1998 DRAFT - PRE-DECISIONAL requirements in the Commission's regulations. Thus, the protection of the public health and safety would not decreased by this' proposed rulemaking. The proposed rule does not affect non-radiological plant effluents and has no significant environmental impact.

As discussed above, the determination of the Environmental Assessment is that there 1

will be no significant offsite impact to the public from this action. However, the general public should note that the NRC welcomes public participation. Also, the Commission has committed i

itself to complying in allits actions with President Executive Order #12898 " Federal Actions to l l

Address Environmental Justice in Minority Populations and Low-income Populations," dated

)

February 11,1994. In accordance with that Executive Order, the Commission has determined  !

that there are no disproportionate, high and adverse impacts on minority and low income parties. In the letter and spirit of Executive Order #12898, the Commission is requesting public comments on any environmental justice considerations or questions that the public thinks may  ;

be related to this proposed rule but somehow were not addressed. The Commission uses the

- following working definition of environmentaljustice: environmentaljustice means the fair treatment and meaningful involvement of all people, regardless of race, etimicity, culture, income, or educational level with respect to the development, implementation and enforcement of environmallaws, regulations and policies. Comments on any aspect of the Environmental Assessment including environmental justice may be submitted to the Commission as indicated under the ADDRESSES heading.

The draft environmental assessment and the draft finding of no significant impact on which this determination is based are available for inspection at the NRC Public Document Room,2120 L Street NW. (Lower Level), Washington, DC. Single copies of the environmental assessment and finding of no significant impact are available from Stephen F. LaVie, Office of FRN 26

October 9,1998 DRAFT - PRE-DECISIONAL Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, telephone (301) 415-1081, or by Internet electronic mail to sfl@nrc. gov. .

Vill. Paperwork Reduction Act Statement This proposed rule amends information collection requirements that are subject to the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq). This rule has been submitted to the Office of Management and Budget for review and approval of the information collection requirements.

The public reporting burden for this information collection is estimated to average 609 hours0.00705 days <br />0.169 hours <br />0.00101 weeks <br />2.317245e-4 months <br /> per response, including the time for reviewing instructions, searching existing data  !

sources, gathering and maintaining the data needed, and completing and reviewing the  !

information collection. However, because NRC expects licensees to submit a license

{

amendment request to use the new source term in lieu of submitting a less important  ;

amendment request, NRC does not project any change in burden for the current 10 CFR I Part 50. The U.S. Nuclear Regulatory Commission is seeking public comment on the potential impact of the information collections contained in the proposed rule (or proposed policy statement) and on the following issues:

1. Is the proposed information collection necessary for the proper performance of the l

functions of the NRC, including whether the information will have practical utility?

l l

2. Is the estimate of burden accurate?

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October 9,1998 DRAFT - PRE DECISIONAL

3. Is there a way to enhance the quality, utility, and clarity of the information to be collected?

l 1

4. How can the burden of the information collection be minimized, including the use of automated collection techniques?

Send comments on any aspect of this proposed information collection, including suggestions for reducing the burden, to the Records Management Branch (T-6 F33), U.S.

Nuclear Regulatory Commission, Washington, DC 20555-0001, or by Intemet electronic mail at BJS1@nrc. gov; and to the Desk Officer Office of Information and Regulatory Affairs, NEOB-10202, (3150-0011), Office of Management and Budget, Washington, DC 20503.

Comments to OMB on the information collections or on the above issues should be submitted by (insert date 30 days after publication in the Federal Register). Comments received after this date will be considered if it is practical to do so, but assurance of consideration cannot be given to comments received after this date.

Public Protection Notification if an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

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( IX. Regulatory Analysis The Commission has prepared a regulatory analysis on this regulation. Interested persons may examine a copy of the regulatory analysis at the NRC Public Document Room, 2120 L Street NW. (Lower Level), Washington, DC. Single copies of the analysis are available from Stephen F. LaVie, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, telephone (301) 415-1081, or by Intemet electronic mail to sfl@nrc. gov.

X. Regulatory Flexibility Certification As required by the Regulatory Flexibility Act of 1980,5 U.S.C. 605(b), the Commission

( certifies that this regulation does not have a significant economic impact on a substantial number of small entities. This proposed regulation affects only the licensing and operation of nuclear power plants. The companies that own these plants do not fall within the definition of "small entities" set forth in the Regulatory Flexibility Act or the size standards established by the NRC (April 11,1995; 60 FR 13344).

XI. Backfit Analysis 1

1 The NRC has determined that the backfit rule in 10 CFR 50.109, does not apply to this

{

proposed regulation, and, therefore, a backfit analysis is not required for this proposed  ;

l i regulation because these amendments do not involve any provisions that would impose backfits l

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- October 9,1998 DRAFT - PRE-DECISIONAL  ;

as defined in 10 CFR 50.109(a)(1). This proposed regulation amends the Commission's regulations by establishing altemate requirements that may be voluntarily adopted by licensees.

List of Subjects i

10 CFR Part 21 '

Nuclear power plants and reactors, Penalties, Radiation protection, Reporting and recordkeeping requirements.

10 CFR Part 50 Antitrust, Classified information, Criminal penalties, Fire protection, intergovemmental relations, Nuclear power plants and reactors, Radiation protection, Reactor siting criteria,

( Reporting and recordkeeping requirements.

I 10 CFR Part 54 Administrative practice and procedure, Age-related degradation, Backfitting, Classified information, Criminal penalties, Environmental Nuclear power plants and reactors, Reporting and recordkeeping requirements.

For the reasons set out in the preamble and under the authority of the Atomic Energy Act of 1954, as amended the Energy Reorganization Act of 1974, as amended, and 5 U.S.C.

552 and 553, the Commission is proposing the following amendments to 10 CFR Parts 21,50, and 54:

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4 4 October 9,1998 DRAFT - PRE-DECISIONAL

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PART 21 - REPOR' TING OF DEFECTS AND NONCOMPLIANCE i

1. The authority citation for Part 21 continues to read as follows:

AU1 HORITY: Sec.161, 68 Stat. 948;as amended, sec. 234,83 Stat. 444, as amended, sec.1701,106 Stat. 2951,2953 (42 U.S.C. 2201,2282,2297f); secs. 201, as amended,206, 88 Stat.1242, as amended, 1246 (42 U.S.C. 5841, 5846).

Section 21.2 also issued under secs. 135,141, Pub. L. 97 - 425, 96 Stat. 2232, 2241 (42 U.S C.10155,10161).

2. Section 21.3 is amended by revising paragraph (1)(1)(C) of the definition of Basic Component to read as follows:

5 21.3 Definitions.

As used in this part:

Basic Componert.

(1)(i)

(C) The capability to prevent or mitigate the consequences of accidents which could result in potential offsite exposures comparable to those referred to in

$Q 50.34(a)(1),50.67(b)(2), or g 100.11 of this chapter, as applicable.

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October 9,1998 DRAFT - PRE DECISIONAL PART 59 - DOMESTIC LICENSING OF PRODUCTION AND I UTILIZATION FACILITIES l

3. The authority citation for Part 50 continues to read as follows:

AUTHORITY: Secs. 102,103,104,105,161,182,183,186,189,68 Stat. 936,937, 938, 948, 953, 954, 955, 956, as amended, sec. 234, 83 Stat. 444, as amended (42 U.S.C.

2132,2133,2134,2415,2201,2232,2233,2236,2239,2282); secs. 201, as amended 202, 206,88 Stat.1242, as amended, 1244,1246 (42 U.S.C. 5841, 5842, 5846).

Section 50.7 also issued under Pub. L. 9509601, sec.10, 92 Stat. 2951 (42 U.S.C.

5851). Section 50.10 also issued under secs. 101,185,68 Stat. 955 as amended (42 U.S.C.

2131,2235), sec.102, Pub. L. 9109190,83 Stat. 853 (42 U.S.C. 4332). Sections 50.13, 50.54(dd), and 50.103 also issued under sec.108,68 Stat. 939, as amended (42 U.S.C. 2138).

Sections 50.23,50.35,50.55, and 50.56 also issued under sec.185,68 Stat. 955 (42 U.S.C.

2235). Sections 50.33a,50.55a and Appendix Q also issued under sec.102, Pub. L. 9109190, 83 Stat. 853 (42 U.S.C. 4332). Sections 50.34 and 50.54 also issued under sec. 204,88 Stat.

1245 (42 U.S.C. 5844). Sections 50.58,50.91, and 5'0.92 also issued under Pub. L. 9709415, 96 Stat. 2073 (42 U.S.C. 2239). Section 50.78 also issued under sec.122,68 Stat. 939 (42 U.S.C. 2152). Sections 50.800950.81 also issued under sec.184, 68 Stat. 954, as amended (42 U.S.C. 2234). Appendix F also issued under sec.187,68 Stat. 955 (42 U.S.C 2237).

4. Section 50.2 is amended by revising paragraph (1)(iii) of the definition of Basic Component and by adding in alphabetical order the definition for source term to read as follows:

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. ., l October 9,1998 DRAFT - PRE-DECISIONAL

$ 50.2 Definitions.

, As used in this part, Basic component * * *

(1)-

- (iii) The capability to prevent or mitigate the consequences of accidents which could result in potential offsite exposures comparable to those referred to in $$ 50.34(a)(1),

50.67(b)(2), or 100.11 of this chapter, as applicable.

t I

i Source term refers to the magnitude and mix of radionuclides released from the reactor l

core, their physical and chemical form, and the timing of their release.

5. Section 50.34 is amended by revising paragraphs (f)(vii), (f)(viii), (f)(xxvi), and (f)(xxviii), and adding new footnote 11 to read as follows:

$ 50.34 Contents of applications; technicalinformation (g)

(2)

(vii) Perform radiation and shielding design reviews of spaces around systems that may, as a result of an accident, contain accident source term"U radioactive materials, and FRN 33

g October 9,1996 DRAFT - PRE-DECISIONAL design as necessary to permit adequate access to important areas and to protect safety equipment from the radiation environment. (ll.B.2)

(viii) Provide a capability to promptly obtain and analyze samples from the reactor coolant system and containment that may contain accident source term"" radioactive materials without radiation exposures to any individual exceeding 5 rems to the whole body or 50 rems to the extremities. Materials to be analyzed and quantified include certain radionuclides that are indicators of the degree of core damage (e.g., noble geses, radioiodines and cesiums, and nonvolatile isotopes), hydrogen in the containment atmosphere, dissolved gases, chloride, and boron concentrations. (ll.B.3)

, (xxvi) Provide for leakage control and detection in the design of systems outside containment that contain (or might contain) accident source term"Uradioactive materials following an accident. Applicants shall submit a leakage control program, including an initial test program, a schedule for re-testing these systems, and the actions to be taken for minimizing leakage from such systems. The goalis to minimize potential exposures to workers and public, and to provide reasonable assurance that excessive leakage will not prevent the use of systems needed in an emergency. (Ill.D.1.1)

(xxviii) Evaluate potential pathways for radioactivity and radiation that may lead to control room habitability problems under accident conditions resulting in an accident source term"4 release, and make necessary design provisions to preclude such problems. (lli.D.3.4)

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October 9,1998 DRAFT - PRE-DECISIONAL

( " The fission product release assumed for these calculations should be based upon a major accident, hypothesized for purposes of site analysis or postulated from considerations of possible accidental events, that would result in potential hazards not exceeded by those from any accident considered credible. Such accidents have generally been assumed to result in substantial meltdown of the core with subsequent release of appreciable quantities of fission products.

6. Section 50.49 is amended by revising paragraph (b)(1)(i)(C) to read as follows:

$ 50.49 Environmental qualification of electric equipment important to safety for nuclear power plants.

{

(b) a (1)

(i)

(C) The capability to prevent or mitigate the consequences of accidents that could result in potential offsite exposures comparable to the guidelines in 50.34(a)(1), 50.67(b)(2), or

$100.11 of this chapter, as appTeable.

7. Section 50.65 is amended by revising paragraph (b)(1) to read as follows:

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October 9,1998 DRAFT - PRE 4ECISIONAL

$ 50.65 Requirements for monitoring the effectiveness of maintenance at nuclear power plants.

{

. . . . . l

, j

• *

• l (b)

(1) Safety-related structures, systems and components that are relied upon to remain functional during and following design basis events to ensure the integrity of the reactor coolant pressure boundary, the capability to shut down the reactor and maintain it in a safe shutdown condition, or the capability to prevent or mitigate the consequences of accidents thrt could result in potential offsite exposure comparable to the guidelines in g6 50.34(a)(1),50.67(b)(2),

or 100.11 of this chapter, as applicable.

8. Part 50 is amended to add 9 50.67, a new section, to read as follows:

$ 50.67 Accident source term.

(a) Applicability. The requirements of this section apply to all holders of operating l

' licenses issued prior to January 10,1997, who seek to revise the current accident source term used in their design basis radiological analyses.

(b) Requirements: (1) A licensee who seeks to revise its current accident source term in design basis radiological consequence analyses shall apply for a license amendment under 6 50.90. The application shall contain an evaluation of the consequences of applicable design basis accidentsm previously analyzed in the safety analysis report.

(2) The Commission may issue the amendment only if the applicant's analysis demonstrates with reasonable assurance that:

FRN 36

October 9,1998 . DRAFT - PRE-DECISIONAL (i) An individuallocated at any point on the boundary of the exclus'on area for any 2-hour period following the onset of'the postulated fission product release, would not receive a radiation dose in excess of 0.25 Sv (25 rem)(2) total effective dose equivalent (TEDE).

(ii) An individual located at any pc;nt on the outer boundary of the low population zone, who is exposed to the radioactive cloud resulting from the postulated fission product release (during the entire period of its passage), would not receive a radiation dose in excess of 0.25 Sv (25 rem) total effective dose equivalent (TEDE).

(iii) Adequate radiation protection is provided to permit access and occupancy of the control room under accident conditions without personnel receiving radiation exposures in excess of 0.05 Sv (5 rem) total effective dose equivalent (TEDE) for the duration of the accident. The dose criteria of Part 50 Appendix A GDC-19 do not apply.

' The fission product release assumed for these cal.:ulations should be based upon a major accident, hypothesized for purposes of design analyses or postulated from considerations of possible accidental events, that would result in potential hazards not j i

exceeded by those from any accident considered credible. Such accidents have generally l been assumed to result in substantial meltdown of the core with subsequent release of appreciable quantities of fission products.

2 The total effective dose equivalent (TEDE) of 0.25 Sv (25 rem) referred to above is specified for use with revised source terms since it utilizes a risk-consistent methodology to assess the radiologicalimpact of all relevant nuclides upon all body organs. The latent cancer risk of a radiation dose of 0.25 Sv (25 rem) TEDE is consistent with the latent cancer risk associated with exposures of 0.25 Sv (25 rem) to the whole body and 3.0 Sv (300 rem) to the thyroid. Risk of latent cancer fatality is used as the risk measure since quantitative health r

( FRN 37

r i October 9,1998 DRAFT - PRE-DECISIONAL objectives for it have been established in the Commission's Safety Goal Policy. However, the use of 0.25 Sv (25 rem) TEDE in these accident dose guidelines is not intended to imply that this value constitutes an acceptable limit for emergency doses to the public under accident conditions. Rather, this 0.25 Sv (25 rem) TEDE value has been stated in these guides as a reference value, which can be used in the evaluation of proposed design basis changes with I

respect to potential reactor accidents of exceedingly low probability of occurrence, and low risk of public exposure to radiation.

I

9. Part 50 Appendix A, General Design Criterion 19, is amended to read as follows:

Appendix A to Part 50 - General Design Criteria for Nuclear Power Plants l

Criterion 19- Controlroom. A control room shall be provided from which actions can i

be taken to operate the nuclear power unit safely under normal conditions and to maintain it in a safe condition under accident conditions, including loss-of-coolant accidents. Adequate radiation protection shall be provided to permit access and occupancy of the control room under accident conditions without personnel receiving radiation exposure;in excess of 5 rem whole bcdy, or its equivalent to any part of the body, for the duration of the accident.

Equipment at appropriate locations outside the control room shall be provided (1) with a design capability for prompt hot shutdown of the reactor, including necessary instrumentation and controls to maintain the unit in a safe condition during hot shutdown, and (2) with a potential capability for subsequent cold shutdown of the reactor through the use of suitable procedures.

I FRN 38 I

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October 9,1998 DRAFT - PRE-DECISIONAL Applicants for construction permits under this part, or a design certification or combined license under Part 52 of this chapter who apply on or after January 10,1997, shall meet the requirements of this criterion, except that with regard to control room acceas and occupancy, adequate radiation protection shall be provided to ensure that radiation exposures shall not exceed 0.05 Sv (5 rem) total effective dose equivalent (TEDE) as defined in 9 50.2 of this chapter for the duration of the accident.

PART 54 - REQUIREMENTS FOR RENEWAL OF OPCRATING LICENSES FOR NUCLEAR POWER PLANTS

10. The authority citation for Part 54 continues to read as follows:

AUTHORITY: Secs.102,103,104,161,181,182,183,186,189,68 Stat. 936,037,

( 938, 948, 953, 954, 955, as amended, sec. 234, 83 Stat.1244, as amended (42 U.S.C. 2132, 2133, 2134, 2135, 2201, 2232, 2233, 2236, 2239, 2282); secs 201, 202, 206, 88 Stat.1242, 1244, as amended (42 U.S.C. 5841,5842), E.O.12829,3 CFR,1993 Comp., p. 570; E.O.

12958, as amended,3 CFR,1995 Comp., p. 333; E.O.12968,3 CFR,1995 Comp., p. 391.

11. Section 54.4 is amended by revising paragraph (a)(1)(iii) to read as follows:

$ 54.4 Scope.

(a)

(1)

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t October 9,1998 DRAFT- PRE DECISIONAL l

I (iii) The capability to prevent or mitigate the consequences of accidents which could result in potential offsite exposures 'comparable to those referred to in 50.34(a)(1),

50.67(b)(2), or 9100.11 of this chapter, as applicable.

Dated at Rockville, Maryland, this [**"]th day of [""],1998.

For the Nuclear Regulatory Commission.

John C. Hoyle, Secretary of the Commission.

Attachment 2 Draft Regulatory Analysis

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October 6,1998 DRAFT- PRE-DECISIONAL

~

REGULATORY ANALYSIS REVISION OF 10 CFR PARTS 21,50, AND 54 Use of an Alternative Source Term at Operating Reactors

1. STATEMENT OF PROBLEM This regu!atory analysis addresses a proposed rulemaking that will revise 10 CFR Parts 21, 50, and 54. This rulemaking was initiated to enable holders of power reactor operating licenses issued prior to January 10,1997 to voluntarily amend their facility design basis to replace the current accident source term in design basis radiological consequence analyses with an alternative source term. While this proposed rulemaking is based on the accident source terms provided in NUREG-1465, Accident Source Terms forLight-WaterNuclearPowerPlants, which will be endorsed by the NRC staff in a proposed regulatory guide, the rulemaking will refer to attemative source term to provide for a future attemative to NUREG -1465. {ln this analysis, revised source term refers to NUREG-1465.) This rulemaking also incorporates proposed conforming revisions to 10 CFR Part 50 to ehlinate the need for certain exemptions from Part 50 requirements for future applicants under Part 52. In addition to future applicants under Part 52, the proposed conforming change to 550.34(f) affects the small class of applicants for which a construction permit or manufacturing license was pending on February 16,1982. This proposed change would allow this small class of applicants to use an attemative to the TID 14844 source term in showing compliance with $50.34(f).

This regulatory analysis is presented in two parts, corresponding to the two considerations stated above.

RA-1

October 6,1998 DRAFT-PRE DECISIONAL A. Use of an Alternative Source Term at Operating Reactors

1. Rankground

\

a. Accident Source Term A holder of an operating license (licensee) for a light-water power reactor was required by regulations issued by the NRC (or its predecessor, the U.S. Atomic Energy Commission) to submit a safety analysis report, in support of its license application, that included assessments of the radiological consequences of potential accidents and an evaluation of the proposed facility site. The NRC staff used this information in its evaluation of the suitability of the reactor design and the proposed site as required by its regulations contained in 10 CFR Parts 50 and i 100. Section 100.11 requires an applicant to assume (1) a fission product release from the '

core, (2) the expected containment leak rate, and (3) the site meteorological conditions to

- establish an exclusion area and a low population zone. A footnote to $100.11 provides guidance that the fission product release be based on a credible major accident that would result in substantial release of appreciable quantities of fission products from the core to the l

containment atmosphere. A note to 9100.11 references Technical information Document (TID) 14844, Calculation of Distance Factors for Power and Test Reactors, published in 1962 by the U.S. Atomic Energy Commission, as a source of guidance and as a point of departure for addressing site-specific considerations. This fission product release, known as the TID-14844 accident source term, was used to evaluate the radiological consequences of design basis accidents (DBAs) to determine compliance with various requirements in 10 CFR Parts 50 and 100 in all of the operating reactors licensed to date. Although originally used for site suitability analyses, the accident source term is a design parameter Sr a::cident mitigation features, r

i equipment qualification, control room operator radiation doses, and post-accident vital area RA-2.

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October 6,1998 1 DRAFT - PRE-DECISIONAL

{

access doses. The TID-14844 source term was explicitly stated as a required design

{( parameter for several TMI-related requirements. The NRC considers the accident source term to be an integral part of the design basis since it was a significant input to a large portion of the

- plant design.

The NRC staffs methods for calculating accident doses, as described in Regulatory Guide 1.3, Assumptions Used for Evaluating the Potential Radiological Consequences of a Loss of Coolant Accident for Boiling WaterReactors, and Regulatory Guide 1.4, Assumptions Used for Evaluating the Potential Radiological Consequences of a Loss of Coolant Accident for Pressurized Water Reactors, and in the Standard Review Plan, were developed to be consistent with the TID-14844 source term and the whole body and thyroid dose guidelines stated in 100.11. In this regulatory framework, the source term is assumed to be released immediately to the containment at the start of the postulated accident. The chtnnical form of the radioiodine released to the containment atmosphere is assumed to be predominantly elemental, with small fractions of particulate and organic !odine forms. Radiation doses are calculated at the exclusion area boundary (EAB) for the first two hours and at the low population zone (LPZ) for the assumed 30-day duration of the accident. The whole body dose comes primarily from the noble gases in the source term, and the thyroid dose is based on inhalation of radioiodines. In analyses performed to date, the thyroid dose has generally been limiting. and the design of some engineered safety features, such as containment spray systems and containment, ventilation exhaust, and control room charcoal filters, are predicated on these postulated thyroid doses. This regulatory framework has provided a consistent analytical approach for evaluating the spectrum of potential consequences from DBAs.

Since the publication of TID-14844, significant a' dvances have been reade in understanding the timing, magnitude, and chemical form of fission product releases from severe nuclear power RA-3

[

l October 6,1998 (

DRAFT - PRE-DECISIONAL l plant accidents. Many of these insights developed out of the major research effort started by l the NRC and the industry after the accident at Three Mile Island (TMI). In 1995, .he NRC l i

published NUREG-1465, which utilized this research to provide more physically based l

estimates of the accident source term that could be applied to the design of future light-water i power reactors. Iri NUREG-1465, the NRC staff provides a representative accident source i term for a boiling-water reactor (BWR) and for a pressurized-water reactor (PWR). These source terms are described in terms of radionuclide composition and magnitude, physical and chemical form, and timing of release. Where TID-14844 addressed three categories of radionuclides, the revised source terms categorize the accident release into eight groups by i physical and chemical properties. Where TID-14844 assumed an immediate release of the activity, the revised source term has five release phases that are postulated to occur over several hours, with the onset of major core damage occurring after 30 minutes. Where TID-14844 assumed radioiodine to be predominantly elemental, the revised source term assumes radiciodine to be predominantly cesium iodide (Csi), an aerosol that is more amenable to mitigation mechanisms. For DBAs, the NUREG-1465 source term is comparable to the TID-14844 source term with regard to the magnitude of the noble gas and radiciodine release fractions. However, the revised source term provides a more representative description of the radionuclide composition and release timing. In SECY-94-302, Source Term-Related Technical .

and Licensing Issues Pertaining to Evolutionary and Passive Light-Water-Reactor Designs, the NRC staff determined that the first three phases (coolant, gap, and early in-vessel) are

. appropriate for design basis evaluations.

The NRC staff initiated several actions to provide a regulatory basis for operating reactors to voluntarily amend their facility design bases to enable use of an alternative source term in design basis analyses. First, the NRC staff solicited input on how such a source term might be implemented. In November 1995, the Nuclear Energy Institute (NEl) submitted its generic RA-4

Octob@r 6,1998 DRAFT - PRE-DECISIONAL framework, Electric Power Research Institute Technical Report TR-105909, Generic Framework for Application of Revised Accident Source Term to Operating Plants. This report and the NRC response were discussed in SECY-96-242 (November 1996). Second, the NRC staff initiated a comprehensive assessment of the overall impact of substituting the NUREG-1465 source term for the TID-14844 source term at two typical facilities. This was done to evaluate the issues involved with applying this revisted source term at operating plants. SECY 98-154 (June 1998), described the conclusions of this assessment. Third, the NRC staff accepted license amendment requests related to implementation of this revised source term at a small number of pilot plants. The review of these pilot projects is currently in progress.

, insights from these pilot plant reviews will be incorporated into the regulatory guidance that will be developed in conjunction with this rulemaking. Fourth, the NRC staff initiated an assessment on whether rulemaking would be necessary to allow operating reactors to use an altemative source term. The proposed rule described herein, and the supporting regulatory guidance that will be developed as part of this rulemaking, have resulted from this assessment.

The NRC staff plans to issue the supporting regulatory guidance for public comment on the same date as the publication of the final rule.

b. Accident Dose Guidelines and Control Room Dose Criteria in Part 50, Appendix A, GDC-19, the NRC staff presents radiation dose criteria that are used to assess the suitability of the plant design with regard to maintaining control room habitability during DBAs. In $100,11, the NRC staff presents radiation dose guidelines that are used to assess the suitability of the plant design with regard to offsite exposures during design basis events. The dose guidelines for the whole body and thyroid, and the immediate two hour exposure period, were largely predicated by the assumed source term being predominar.tly

(

noble gases and radio!odines instantaneously released to the containment and the assumed RA-5

October 6,1998 DRAFT - PRE-DECISIONAL i

single critical organ method of modeling the intemal dose used at the time of that Part 100 was originally published. However, the current dose guidelines, by focusing on doses to the thyroid l l

and whole body, assume that the major contributor to doses will be radioiodine. While this may I I

be appropriate with the TID-14844 source term, it may not be true for a source term based on a more complete understanding of accident sequences and phenomenology. The postulated chemical and physical form of radioiodine in the revised source term is more amenable to i

mitigation and, as such, radioiodine may not always be the predominant radionuclide in an '

accident release. The revised source term includes a larger riumber of radionuclides than did the TlD-14844 source term. The whole body and thyrcid dose guidelines ignores these I contributors to dose, in the period since these regulations were issued, there have been significant developments in the principles and scientific knowledge underiying standards for radiation dose limitation and assessment. These developments include not only updated scientific information on

~

radionuclide uptake and metabolism, but also reflect changes in the basic philosophy of radiation protection. In 1991, the NRC staff revised 10 CFR 20,, Standards for Protection Against Radiation, to reflect these developments. The accident dose guidelines in 100.11 and Part 50, Appendix A, GDC-19, were not changed at the time that Part 20 was revised as the requisite revision to the licensing basis of each operating power reactor was not deemed to be l warranted. The standards in Part 20 include the dose quantity, totaleffective dose equivalent (TEDE), which is defined as the deep dose equivalent (for extemal exposure) plus the committed effective dose equivalent (for intemal exposure). The deep dose equivalent (DDE) is comparable to the present whole body dose; the committed effective dose equivalent (CEDE) is the sum of the products of doses (integrated over a 50-year period) to selected body organs resulting from the intake of radioactive material multiplied by weighting factors for each organ that are representative of the radiation risk associated with the particular organ. The TEDE, RA-6

Octob:r 6,1998 DRAFT - PRE-DECISIONAL using a risk-consistent methodology, assesses the impact of all relevant nuclides upon all body organs. While it is expected that the thyroid could still be the limiting organ, radioiodine could still be the limiting radionuclide, and that the current whole body and thyroid guidelines could provide adequate protection, this conclusion can not be assured in all potential cases. The NRC staff recommended in SECY-96-242 that dose guidelines expressed in terms of TEDE be required if a licensee elects to use the revised source term. In a staff requirements memorandum dated February 12,1997, the Commission directed the NRC staff to incorporate TEDE in this proposed rulemaking.

The dose guideline for the EAB in g100,11 is specified with a two-hour exposure period commencing immediately following the onset of the fission product release. This exposure period was predicated, in part, on the traditional source term assumption that the activity would

. . be immediately available for release at the onset of the accident. The combination of these two assumptions resulted in the maximum postulated dose. The revised source term postulates a  ;

release that occurs in phases, with the significant release starting after about 30 minutes and continuing for about 90 minutes (through the early in-vessel phase only). Because of this, an exposure period starting at the onset of the fission product release may not represent the limiting case. The NRC staff recommended in SECY-96-242 that dose guidelines expressed in .

terms of the worst two-hour dose be considered if a licensee elects to use the revised source term. In a staff requirements memorandum dated February 12,1997, the Comraission direciso

'he NRC staff to incorporate the worst two-hour dose in this proposed rulemaking.

2. Frinting Rennlainrv Framework

a. Accident Source Term

. RA-7 I

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i

October 6, %8 DRAFT - PRE DECISIONAL The proposed rulemaking for implementation of an alternative source term is applicable only to those facilities for which a operating licence was issued before January 10,1997, under 10 CFR Part 50. The regulations of this part are supplemented by those in other parts of Chapter 1 of Title 10, including Part 100. Part 100 contains language that qualitatively defines l a required accident source term and contains a note that discusses the availability of TID-14844. However, this note did not mandate the use of TID-14844. With the exception of

$50.34(f), which addresses additional TMI-related requirements, there are no explicit provisions in Title 10 requirhg the use the TID-14844 accident source term. Section 50.34(f)is applicable only to a limited number of construction permit and manufacturing license applications pending  !

on February 16,1982, and to applications under Part 52.

i Regulatory Guides 1.3 and 1.4, give the methods and assumptions acceptable to the NRC staff for assessing the consequences of DBA loss of coolant accidents (LOCAs) as required by k

a, %100.11. These regulatory guides provide guidance involving accident uource terms, much of which is derived from TID-14844. Other guides specify accident source terms either directly or by reference to Regulatory Guides 1.3 and 1.4. None of these guides, however, explicitly refers to TID-14844. The Commission publishes regulatory guides to describe methods acceptable to the NRC staff forimplementing specific parts of the Commission's regulations. Compliance with these guides is not required and spplicants are allowed to propose alternatives for NRC staff consideration. Although NRC staff licensing reviews have Lcen based on Regulatory Guides 1.3 and 1.4, the option for a licensee to propose attematives has been, and remains as, a possible regulatory mechanism to implement a source term other than the one in TID-14844.

An applicant for an operating license is required by 950.34 to submit a f..' safety analysis report (FSAR) that describes the facility and its design bases and limits, and that includes a RA-8

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October 6,1998 DRAFT- PRE DECISIONAL l

[ safety analysis of the site and of the facility. Guidance in performing these analyses is provided l l

in regulatory guides. In its review of the more recent applications for operating licenses, the NRC staff has used the review procedures in NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants (SRP). These review procedures \

reference or provide acceptable assumptions and analysis methods. Although compliance with the SRP is not required, in practice, many applicants adhere to the guidance in the interest of j facilitating NRC staff review. Operating license applications docketed after May 17,1982, are required in $50.34(g) to include an evaluation of the fer.ility for conformance with the SRP. The facility FSAR documents the assumptions and meth xis actually used by the applicant in the required safety analyses. The NRC staff's finding ti at a license may be issued is based on the review of the FSAR, as documented in the staff's safety evaluation report (SER). Through inclusion in the FSAR, these assumptions (including source term) and the licensee's methods of evaluation become part of the design basis of the facility.

Thus, from a regulatory standpoint, the requirement to use the TID-14844 source term is a licensee commitment (typically expressed as a committnent to Regulatory Guides 1.3 or 1.4) documented in the facility FSAR. The licensee may effect a change in its licensing basis, including the FSAR, by applying for an amendment of its 1 cense under 5550.90-50.92, or on its own volition within the provisions of $50.59. Because of the extensive use of the accident source term in the design and operation of a power reactor, and because of the potentialimpact on postulated accident consequences and margins of safety of a change of such a fundamental design assumption, the NRC has concluded that an attemative source term should be

! implemented via a license amendment under gg50.90-50.92. I RA-9 l

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b. Accident Dose Guidelines and Control Room Dose Criteria

. The accident dose guidelines for operatirg reactors licensed prior to January 10,1997, are provided in $100.11. These guidelines are expressed in terms of whole body and thyroid dose.

Two guidelines are provided. The first is for the exclusion area boundary for the two-hour

- period immediately following the onset of radioactivity release. The second is for the low population zone for the duration of the event. General Design Criterion 19 (GDC-19), Control Room, of Appendix A to Part 50, establishes minimum requirements, for the design of the control room, including a requirement for radiation protection features adequate to permit access and occupancy of the control room under accident conditions. The GDC-19 criteria are 1

expressed in terms of 0.05 Sv (5 rem) whole body dose, or its equivalent to any organ. SRP Section 6.4, Contro/ Room Habitability Systems, provides guidance that defines equivalent as 0.3 Sv (30 rem) thyroid and 0.3 Sv (30 rem) skin.

In January 1997, the NRC amended its regulations in 10 CFR Parts 21,50,52,54 and 100.

That regulatory action provided site criteria for future sites and relocated source term and dose requirements for future plants into 650.34. The guidelines of $100.11 remain in place as the licensing basis for operating reactors licensed prior to January 10,1997. In relocating the source term and dose requirements for future reactors to $50.34, the NRC retained the requirements for the exclusion area and the low population zone, but revised the associated numerical dose guidelines to replace the two different doses for the whole body and thyroid I

gland with the single, total effective dose equivalent (TEDE) value. The dose guideline for the exclusion area boundary was ' expressed in term of the two hour period that yielded the maximum dose. The NRC did not, at that time, amend the control room dose criterion in GDC-19.

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in a staff requirements memorandum dated February 12,1997, the Commission directed

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that the amended dose guidelines be made applicable to operating plants choosing to use the revised source term. Therefore, an altemative source term cannot be implemented without a modification of the accident dose guidelines and the GDC-19 criteria. It is this needed modification that makes the proposed rule necessary.

B. Conforming Changes for Part 52 Part 52 governs the issuance of early site permits, standard design certifications, and combined licenses for nuclear power facilities. Part 52 is used in conjunction with applicable requirements of Part 50. The TMI-related requirements in $50.34(f) were specifically incorporated by i

reference in $52.47(a)(ii). This incorporation by reference is necessary because 50.34(f) limits

. applicability to specifically identified facilities for which an application for a construction permit was pending on February 16,1982. The NRC staff expects that future plants will use the revised source term, or an approved attemative, in supporting safety analyses. Since 9 50.34(f)(vii), -(f)(viii), -(f)(xxvi), and -(f)(xxviii) contain specific references to the TID-14844 source term, these sections need to be revised. The control room habitability criteria in Part 50, Appendix A, GDC-19 were incorporated by reference in gS2.47(a)(i). This criterion is expressed in terms of whole body dose or its equivalent to any part of the body rather than in terms of TEDE. Exemptions from these requirements were necessary for the AP600 final design approval and design certification. The proposed rulemaking will address changes to these affected sections in order to avoid the need for exemptions for subsequent applicants under Part 52.

The conforming changes to $50.34(f) would also be applicable to the small subset of l

specifically listed applicants that had a construction permit application pending on February 16,  !

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October 6,1998 DRAFT - PRE-DECISIONAL 1982. The NRC does not expect these applications to be pursued further. However, should one of these applications be re-activated, the applicant would, in effect, be given the option of using an approved attemative to the TID-14844 source term.

11. OBJECTIVE OF PROPOSED RULE A. Use of an Alternative Source Term at Operating Reactors The objective of this proposed regulatory action is to provide a regulatory framework for the voluntary implementation of an attemative source term as a change to the design basis at currently licensed power reactors, thereby enabling potential cost-beneficial licensing actions while continuing to maintain existing safety margins and defense in depth.

This will be accomplished by:

e providing revised accident dose guide!!nes and control room habitability dose criteria that are consistent with the characteristics of the revised source term and reflect updated scientific information on radionuclide uptake and metabolism, and also reflect current radiation protection standards, and e requiring submittal for a license amendment that contains and evaluation of the consequences of applicable design basis accidents previously analyzed in the safety analysis report.

Since the proposed rule is voluntary and will not be a backfit, the licensing bases for operating reactors that do not adopt an attemative source term trust remain in the regulation.

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October 6,1998 DRAFT - PRE-DECISIONAL Therefore, the proposed rule is designated as a new section,950.67, applicable to operating reactors licensed prior to January 10,1997 that are proposing to use an alternative source tetm. The existing requirements in Part 100 and GDC-19 are maintained for operating reactors that continue to use the TID 14844 source term.

The NRC staff will be preparing a regulatory guide and a SRP section in support of this rule.

The drafts of these guidance documents will be issued for public comment at the time the final l

l rule is published (Septernber 1999). '

B. Conforming Changes for Part 52 l

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The objective of this proposed regulatory action is to eliminate the need for applicants under I l

, Part 52 to request exemptions from certain of the NRC's regulations. The need for these l exemptions was identified during the Westinghouse AP-600 advanced reactor design certification proceeding.

This will be accomplished by:

e Explicit references to the TID-14844 source term in $50.34(f) will be revised to read accident source term. A footnote will be added to define an accident source term in generic terminology (similar language to corresponding footnote in Part 100).

e Part 50 Appendix A, GDC-19 will be revised to incorporate a revised dose criterion that is applicable only to applicants for construction permits under this part, or a design certification or combined license under Part 52 of this che,*er who apply on or after January 10,1997.. The current dose criterion will remain in effect for those operating RA - 13

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October 6,1998 DRAFT - PRE-DECISIONAL reactors that continue to use the TID-14844 source term.

II. IDENTIFICATION OF ALTERNATIVE APPROACHES l

A. Use of an Alternative Source Term at Operating Reactors l The no-action attemative of retaining the existing accident source term was not considered in the development of the proposed rulemaking. In SECY-96-242, the staff provided recommendations to the Commission on how the revised source term could be implemented at

operating reactors. The staff requirements memo on SECY-96-242 directed the staff to

(1) complete the re-baselining study, (2) complete pilot plant evaluations, (3) commence rulemaking, and (4) include the TEDE terminology and the worst two-hour methodology.

l l The first alternative considered by the NRC was to continue using current regulations for accident dose guidelines and control room dose criteria. This is not considered to be an acceptable attemative. The NRC had previously determined in the January 1997 Part 50 and Part 100 final rulemaking that dose guidelines expressed in terms of whole body and thyroid doses were inconsistent with the use of the revised source term. With regard to the exclusion area dose guideline, the NRC also determined that the dose guideline applies to the two hour period resulting in the maximum dose.

The second attemative considered by the NRC was the replacement of the existing  !

guidelines in $100.11 and the existing criteria 10 CFR Part 50 Appendix A, GDC-19 with an entirely new regulation. This is not considered to be an acceptable attemative because the i

provisions of the existing regulations form part of the licensing bases for many of the operating ,

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October 6,1996 DRAFT - PRE-DECISIONAL implement an attemative source term, in addition, this rulemaking alternative would also be inconsistcnt with the Commission philosophy of separating plant siting criteria and dose requirements. The approach of establishing the requirements for use of an altemative source term in a new section to Part 50 while retaining the existing regulations in Part 100 Subpart A and Part 50 Appendix A, GDC-19 was chosen as the best rulemaking attemative.

The NRC considered attematives with regard to providing regulatory guidance to support the new section to Part 50. The first altemative was to issue no additional regulatory guidance.

This alternative was not considered to be acceptable because, in the absence of clear regulatory guidance, licensee efforts in preparing applications, and the NRC staff review of submitted applications, could be hindered by differences in interpretations and technical positions. This could result in tho inefficient use of licensee and staff resources, cause

, licensing delays, and could result in less uniform and less consistent regulatory implementation.

The second altemative was to replace the existing regulatory guides that address accident radiological consequences with new revisions. This is not considered to be an acceptable attemative because the provisions of the existing regulatory guides form part of the licensing bases for many of the operating reactors. Therefore, these provisions must remain in effect for operating reactors that do not implement an attemative source term. The third rulemaking alternative was to issue a new regulatory guide on the implementation of a revised source terms and which would include, in a series of appendices, revised assumptions and acceptable analysis methods for each design basis accident. The approach of issuing a new regulatory guide was chosen as the best altemative. To provide review guidance for the NRC staff, a new section on design basis radiological analyses using an attemative source term would be added to the Standard Review Plan.

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October 6,1998 DRAFT - PRE-DECISIONAL B. Conforming Changes for Part 52 f

Since these revisions are conforming changes for an earlier issued rulemaking, the no-action altemative was not considered to be acceptable. No reasonable alternative was identified for the necessary $50.34(f) revisions. The reference to TID-14844 needs to be removed.

With regard to a revised control room dose criterion, the revised criterion could have been implemented via a change to Part 52 (that cross-references Part 50); a change to $50.34(a), or a change to GDC-19. A change to GDC-19 was deemed to be the simplest and clearest

-approach and, therefore, considered to be the acceptable attemative.

111. EVALUATION OF VALUES AND IMPACTS The NRC has determined that the public health and safety and the common defense and security would continue to be adequately protected if the propcsed rulemaking were implemented. The NRC has qualitatively determined that the potential values associated with the revised source term are substantial enough to justify the rulemaking, and clearly outweigh ,

any reductions in values associated with the current accident source term. This proposed rulemaking is voluntary for operating reactors. (The conforming changes for Part 52 will be mandatory on future applicants.) The basis for these conclusions are provided in the sections to follow.

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A. Use of an Alternative Source Term at Operating Reactors

1. Values l

This proposed rule would allow operating reactors to voluntarily replace the traditional TID-14844 source term with a source term that is based on the insights from extensive accident '

research activities. The accident source term is a design parameter for accident mitigation features, equipment qualification, control room operator radiation doses, and post-accident vital area access doses. The design of some engineered safety features, such as containment spray systems and containment, ventilation exhaust, and control room charcoal filters, are largely predicated on the radiation doses postulated using these source terms. It is expected that an alternative source term, with its improvements in understanding of chemical / physical

, form and release timing, could be used to effect reductions in operational and maintenance requirements associated with some of these systems. These reductions would have economic benefit.

The implementation of an attemative source term does not, in of itself, have economic value. It is the modifications to the facility structures, systems, components, and procedures, enabled by an attemative source *.erm that give rise to the associated values and impacts.

Since this is a voluntarily action on the part of the licensee, it is expected that the licensee will not pursue applications of an attemative source term unless it is perceived to be in their benefit to do so. Given this conclusion, and given the large number of possible applications varying in scope and extent, the NRC has not performed quantitative value-impact analyses. In 1996, NEl informally polled the industry to determine the uses and frequency that licensees might apply l the NUREG-1465 source term. Although the poll was informal and does not constitute any RA - 17 i

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October 6,1998 ORAFT - PRE-DECISIONAL 1

commitment to act, the results of the poll provide an indication of the level of interest in the l proposed rulemaking. The responses received represented 43 operating power reactors. Of l

these,41 reactors plan to use the revised source term to pursue plant modifications. I Anticipated applications included the following:

I e change in allowable leak rate (24 plants) e change in isolation valve actuation timing (31 plants) e simplification of filtration units (27 plants) e change in mitigation system actuation timing (22 plants) e change in equipment qualification (2 plants)

There is an expectation that'many of the altemative source term applications may provide concomitant improvements in overall safety and in reduced occupational exposure, as well as economic benefits. Due to the wide range of possible applications and the voluntary nature of this rulemaking it is not reasonable to quantify possible outcomes. Reductions in occupational exposures may be realized through reductions in maintenance efforts associated with maintaining unnecessarily limiting leakage, timing, or filtration requirements. Improvements in overall safety may be realized through reduced emergency diesel generator loading, improved containment ventilation system performance due to lessened filter flow resistance, and closer synchronization of mitigation feature actuation with the onset of major fission product release, to provide three examples. There may be improvements in safety margins realized due to the upgrading of analysis assumptions, methods, and acceptance criteria.

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Octob:r 6,1998 DRAFT - PRE-DECISIONAL lt is believed that the proposed rulemaking will result in an improvement in the allocation of resources both for the NRC and for industry. The industry will be allowed to propose applications of an altemative source term that could reduce unnecessary or ineffective requirements in the facility design basis.. Limited resources could be diverted to safety issues of greater significance.

2. Cosis Since the implementation of an alternative source term is a voluntarily action on the part of the licensee, it is expected that the licensee will not pursue applications of an attemative so ;.o term unless it is perceived to be in their benefit to do so. Given this conclusion, and gben the large number of possible applications varying in scope and extent, the NRC has not performed quantitative value-impact analyses.

3. Imoacts The implementation of the NUREG-1465 source term at an operating power reactor would replace the traditional TID-14844 source term with a source term that is based on the insights from extensive accident research activities. The actual accident sequence and progression is not changed; it is the regulatory assumptions regarding the accident that will be affected by substituting the revised source term. Use of an alternative source term alone cannot increase the core damage frequency (CDF) or the large early release frequency (LERF) or actual offsite or onsite radiation doses. (While actualdoses would not increase, analysis resu!!s may show an increase in some postulated doses because additional radionuclides will be considered and dose modeling will be more comprehensive.) The accident source term is used in analyses l performed to assess the adequacy of the plant design to contend with a DBA in order to ensure RA-19 l

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October 6,1998 DRAFT - PRE-DECISIONAL adequate defense in depth and adequate safety margins. An altemative source term could be used to justify changes in the plant design that could have an impact on CDF or LERF or could increase offsite or onsite doses. These potential changes are subject to existing requirements in the Commission's regulations. The supporting regulatory guide for this rulemaking will discuss the need for an evaluation of the impacts of an altemative source term implementation, including consideration of reductions in defense in depth, safety margins, or both. Consistent  ;

with Regulatory Guide 1.174, An Approach for Using Probabilistic Risk Assessmentin Risk-Informed Decisions on Plant-Specific Changes to the Current Licensing Basis, the draft guide will indicate that consideration of PRA insights may be necessary if the proposed changes to the design basis are not addressed in currently approved NRC staff positions.

The Commission directed the NRC staff to perform an assessment of the impacts c' implementing the NUREG-1465 source term at operating reactors. The results of this study were presented to the Commission in SECY-98-154, Results of the Revised (NUREG-1465)

Source Term Re-Baselining for Operating Reactors. The ma}or areas examined included the '

effect on individual offsite and control room dose, the effect on doses used in equipment environmental qualification, and the effect of potential modifications tnat might be enabled by the revised source term. The study also assessed the margin afforded by the revised source term in comparison to assessments performed using the integrated seve,re accident assessment code, MELCOR. The study indicated that the impact of implementing the revised source term at operating reactors will produce lower postulated doses in the majority of cases.

The Commission inteno to address the exceptions in the regulatory guidance that will be developed to support the proposed rule and in the processing of the individuallicense amendments. The MELCOR analyses indicated that the design basis dose calculations still have a substantial margin (a factor of two or greater) even though the postulated dose may be less than that indicated by calculations using the current source term. The study also indicated RA - 20

Octob3r 6,1998 i DRAFT - PRE-DECISIONAL that many of ti a plant systems that are likei, to be considered for modification are not involved in risk sigr"Nont sequences and are, therefore, not likely to have a substantial offsite risk impact usi. g a measure such as large early release frequancy. At the present time, the only approved attemative to the TID-14844 source term is that in NUREG-1465. The Commission expects that any future proposed attemative source term will be subjected to the same level of scrutiny as was used in the approval of NUR'EG-1465.

On the basis of these considerations, the NRC staff does not believe that the proposed rulemaking willinvolve a significant increase in the probability or consequences of accidents previously analyzed, nor willit create a new or different type of accident or result in a significant reduction in safety margin.

4. Backfit Considerations

, The NRC has determined that the backfit rule,10 CFR 50.109, does not apply to this proposed regulation, and, therefore, a backfit analysis is not required for this proposed rulemaking because these amendments do not involve any provisions that would impose backfits as defined in 10 CFR 50.109(a)(1). The proposed $50.67 amends the Commission's regulations by establishing attemate requirements that may be voluntarily adopted by operating reactors licensed prior to January 1997 td nave, or are proposing to adopt an attemative

. source term.

5. Imanets on Other Procrams. Acencies The proposed rulemaking does not affect federal, state, or local government agencies, or agreement state licensees, because the rulemaking affects only the licensing and operation of RA - 21

r October 6,1998 DRAFT - PRE-DECISIONAL nuclear power plants that are regulated by the NRC under Part 50. Within the NRC, the cognizant office is Nuclear Reactor Regulation, which is sponsoring this proposed rulemaking.

No other NRC office is affected by this proposed rulemaking.

B. Conforming Changes for Part 52

1. Values The proposed conforming changes will eliminate the need for future applicants under Part 52 to apply for exemptions from certain paragraphs in $50.34(f) and Part 50 Appendix A, GDC-

19. This will eliminate the costs associated with preparing and processing an exemption request. By eliminating the need for exemptions, the integrity of the regulations is improved.

2. Costs Since the conforming changes will eliminate the need for future applicants under Part 52 to apply for exemptions from certain paragraphs in 650.34(f) and Part 50 Appendix a, GDC-19, it is expected that costs will be reduced, not increased.

3. Imnacta Since these are conforming changes for regulations already promulgated, there can be no significant increase in the probability or consequences of accidents previously analyzed, nor will a new or different type of accident be created, nor will there be a significant reduction in safety margins.

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p October 6,1998 DRAFT - PRE-DECISIONAL The proposed conforming changes to 950.34(f) would also be applicable to the small subset of specifically listed applicants that had a construction permit application pending on February 16,'1982. The NRC does not expect these applications to be pursued further. However, should one of these applications be re-activated, the applicant would be given the option of using an approved alternative to the TID-14844 source term. Should affected applicant choose to use an attemative source term, the impact discussion and conclusions above for the proposed 50.67 would apply.

4. Backfit Considerations The NRC has determined that the backfit rule,10 CFR 50.109, does not apply to this proposed regulation, and, therefore, a backfit analysis is not required for this proposed regulation because these amendments do not involve any provisions that would impose backfits as defined in 10 CFR 50.109(a)(1).

• The proposed changes to 950.34(f) , by removing the explicit reference to TID-14844, allows future applicants under Part 52 to use an attemative source term without the need for exemptions, and will allow the small class of applicants for which a construction permit or manufacturing license was pending on February 16,1982, to use an approved alter.lative to the TID-14844 source term in showing compliance with 950.34(f). With the exception of the Westinghouse AP-600 final design approval process, there are no pending Part 52 applications. (Westinghouse requested an exemption from the affected paragraphs in 95134(f) to use the revised source term.)

• The proposed change to Part 50 Appendix a, GDC-19, will require future applicants under Part 50 or Part 52 after January 10,1997 to show compliance with the 0.05 Sv (5 RA - 23

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l October 6,1998 DRAFT - PRE-DECISIONAL rem) TEDE dose criterion. There are no applicants in this status at the present time.

5. Imnacts on NRC staff. Other Prnorams. Aaencias I The proposed rulemaking does not affect federal, state, or local govemment agencies, or agreement state licensees, because the rulemaking affects only the licensing and operation of l nuclear power plants that are regulated by the NRC under Part 50. Within the NRC, the cognizant office is Nuclear Reactor Regulation, which is sponsoring this proposed rulemaking.

No other NRC office is affected by this proposed rulemaking.

1 IV. DECISION RATIONALE A. Use of an Alternative Source Term at Operating Reactors I

The decision to create a new section in Part 50, i.e., $50.67, and to include the following  ;

provisions: the need for a license amendment, the accident dose guidelines $50.34(a)(1)(ii),

and the 0.05 Sv (5 rem) TEDE dose criterion for the control room, was based on the following rationale:

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a. The objective of providing a regulatory framework for the voluntary implementation of an altemative source term as a change to the design basis at currently licensed power reactors, thereby enabling potential ost-beneficial licensing actions while continuing to l maintain existing safety margins and defense in depth.

b. The need for accident dose guidelines and control room habitability dose criteria that are l consistent with the characteristics of the revised source term, and that reflect updated RA - 24

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October 6,1998 DRAFT - PRE-DECISIONAL i

scientific information on radionuclide uptake and metabolism and current radiation l protection standards. '

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c. The provision that an altemative source term be implemented in facility's design basis l

via a license amendment addresses NRC staff concem that the current language of

@50.59 could be interpreted as allowing this change without prior staff approval. The NRC is currently considering changes to 50.59. The approach taken in @50.67 is not inconsistent with the proposed language in @50.59.

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d. The results of the NRC staff re-baselining study that did not identify any significant concems related to implementation of the revised source term.

e. The Cominission philosophy of separating plant siting from plant design as evidenced by the January 1997 Part 50 and Part 100 final rule.

f. The need to maintain the existing licensing basis for the operating reactors that continue to use the TID-14844 source term.

B. Conforming Changes for Part 52 The decision to address needed conforming changes to Part 50, and to include the 0.05 Sv (5 rem) TEDE dose criterion for the control room, was based on the following rationale:

a. The desire to eliminate the need for exemptions frr7 compliance with the affected sections.

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b. The need for control room habitability dose criteria that are consistent with the characteristics of the revised source term, and that reflect updated scientific information on radionuclide uptake and metabolism and current radiation protection standards V. IMPLEMENTATION I In the interest of facilitating stakeholder participation in this rulemaking and in the interest of allowing interested licensees to proceed with the development of applications, the Commission decided to separate development of the proposed rule and the proposed draft guide and draft SRP section. This regulatory analysis addresses only the proposed rule. The following are the major milestones:

Proposed rule to Commission 12/15/98

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Final rule, draft guide, draft SRP section to 7/30/99 Commission Final guide, SRP section to Commission 1/24/00 As this is a voluntary rulemaking for operating reactors, there is no effective date or required schedule >r implementation on the part of licensees. No backfit is involved.

The proposed rule language is provided in the Federal Reg l ster entry for which this regulatory analysis applies. The accident dose guidelines and the control room dose criteria in the proposed rule are readily quantifiable and enforceable. These guidelines and criteria are performance based, e.g., the proposed rule does not prescribe how to meet the requirement.

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October 6,1998 DRAFT - PRE DECISIONAL VI. REFERENCES

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1. Accident Source Terms forLight-Water NuclearPowerPlants, NUREG-1465, February 1995

2. Calculation of Distance Factors for Power and test Reactor Sites, Technical information Document (TID) 14844, March 1962

3. Results of the Revised (NUREG-1465) Source Term Re-Baselining for Operating Reactors, SECY-98-154, June 1'998 l

4. Amendments to 10 CFR Parts 50, 52, and 100, and Issuance of New Appendix S to Part 50, SECY-96-118, May 1996

5. Use of the NUREG-1465 Source Term at Operating Reactors, SECY-96-242, November 1996

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Attachment 3 Draft Environmental Assessment Draft Finding of No Significant impact

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ENVIRONMENTAL ASSESSMENT AND FINDING OF NO SIGNIFICANT IMPACT REVISION OF 10 CFR PARTS 21,50, AND 54 l l The Nuclear Regulatory Commission is proposing to amend its regulations to allow the holders of operating licenses at currently operating reactors to voluntarily amend their design bases to replace the current accident source term with the revised source term in NUREG-1465, Accident Source Terms for Light-Water Nuclear Power Plants.

-l Identification of Action The Commission is proposing to amend 10 CFR Part 50 by adding a new section, $50.67, to address the use of an alternative accident source term. Section 50.67 will apply to all holders of operating licenses issued prior to January 10,1997, that seek to amend their facility design basis to replace the current accident source term with an attemative source term on or after the effective date of the final regulation. These licensees will be required by 650.67 to perform an evaluation of the radiological consequences of the design basis accidents previously analyzed in the safety analysis report, and to request a license amendment under @50.90. Acceptance criteria for the accident radiological consequence analyses have been provided in s50.67.

These criteria include accident dose guidelines for evaluation of releases of radioactivity to the environment and the resulting exposures to persons off-site, and dose criteria for plant personnel occupying the control room during postulated accidents.

The proposed rule amends a current regulation by establieUng attemate requirements that may I

be voluntarily adopted by licensees. The Commission cc.~ aded that the existing analytical j approach based on the current source term continues to be adequate to protect public health I and safety, therefore, the Commission does not intend to backfit the revised source term or the changes in accident dose guidelines and control room habitability criteria on operating power reactors. Since the proposed revision to the regulation will not be a backfit, the bases for l existing nuclear power plants must be preserved. For this reason, the current accident dose 1

L guidelines in @100.11 and the current control room habitability criteria of Appendix A to Part 50 will remain in effect for those licensees that do not apply for the use of an alternate source term.

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October 6,1998 DRAFT - PRE-DECIMONAL The Commission is also proposing to amend 10 CFR Part 50 by revising Gem A GDC-19 to use a dose criterion based on total effective dose equivalent. The revised criterion, which will be in addition to the current dose criterion in GDC-19, is applicable only to applicants for construction permits under this part, or applicants for a design certification or combined license under 10 CFR Part 52, who apply on or after January 10,1997.

Need for the Action use of an Altemative Source Term Current operating light-water reactors were licensed, in part, on the basis of safety analyses that used fission product release assumptions presented in the Technical Information Documertt (TID) 14844, " Calculation of Distance Factors for Power and Test Reactor Sites" (1962). Although initially applied to the evaluation of proposed reactor sites, these fissian product release assumptions, known collectively as the " source term," have been used in several regulatory applications related to light-water reactors. This source term was a key input to many of the design analyses associated with currently operating reactors and is a significant component of the design basis for these facilities. During the period since the publication of TlD-14844, significant advances have been made in understanding the timing, magnitude, physical form, and chemical form of fission product releases from severe nuclear power plant accidents. In 1995, the NRC published NUREG-1465," Accident Source Terms for Light-Water Nuclear Power Plants," which utilized these source term insights to produce revised estimates of the accident source term. These source terms are described in terms of radionuclide composition and magnitude, physical and chemical form, and timing of release. For design basis accident assessments, the NUREG-1465 source term is comparable to the TID-14844 source term with regard to the magnitude of the noble gas and radioiodine release fractions.

However, the revised source term provides a more representative description of the radionuclide composition and release timing.

The objective of NUREG-1465 was to define a revised accident source term for regulatory application for future light water reactors. The Commission's intent was to capture the major relevant insights available from severe accident research to provide, for regulatory purposes, a j more realistic portrayal of the amount of the postulated accident source term. These source terms were derived from examination of a set of severe accident sequences for light water EA-2

. . 1 Octobir 6,1998 DRAFT - PRE-DECISIONAL reactors of current design. Because of general similarities in plant ano core design parameters, j

( these results are considered to be applicable to evolutionary and passive LWR designs. The l Commission considered the applicability of the revised source term to operating reactors and determined that the currant analytical approach based on the TID-14844 source t'erm would continue to be adequate to protect public health and safety and that operating reactors licensed 1 under this approach would not be required to re-analyze design basis accidents using the l revised source term. The Commission also concluded that some licensees may wish to use an altemative source term in analyses to support operational flexibility and cost-beneficial licensing actions. These actions could reduce regulatory burden.

In January 1997, the Commission amended its regulations in 10 CFR Parts 21,50,52,54 and 100 (61 FR 65157). That regulatory action provided site criteria for future sites and relocated source term and dose requirements for future plants into Par 150. Since these dose requirements tend to affect reactor design rather than siting, they are more appropriately located in Part 50. Since the revised criteria would not apply to operating reactors, the non-seismic and seismic reactor site criteria for operating reactors was retained as Subpart A and Appendix A to Part 100, respectively. The revised reactor site criteria was added as Subpart B in Part 100, with revised source term and dose requirements relocated to $50.34. The existing source term and dose requirements of Subpart A of Part 100 will remain in place as the licensing bLoes for those operating reactors that do not elect to use the revised source term.

The Commission retained the requirements for the exclusion area and the low population zone, but revised the associated numerical dose guidelines to replace the two different doses for the whole body and thyroid gland with the single, total effective dose equivalent (TEDE) value. The dose guidelines for the whole body and thyroid, and the immediate two hour exposure period, were largely predicated by the assumed source term being predominantly noble gases and radioiodines instantaneously released to the containment and the assumed single, critical organ method of modeling the intemal dose used at the time that Part 100 was originally published.

However, the current dose guidelines, by focusing on doses to the thyroid and whole body, assume that the major contributor to doses will be radioiodine. While this may be appropriate with the TlD-14844 source term, it may not be true for a source term based on a more complete l understanding of accident sequences and phenomenology. The postulated chemical and physical form of radioiodine in the revised source term is more amenable to mitigation and, as such, radioiodine may not always be the predominant radionuclide in an accident release. The revised source term includes a larger number of radionuclides than did the TfD-14844 source term. The whole body and thyroid dose guidelines ignore these contributors to dose. The l

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Octob:r 6,1998 DRAFT - PRE-DECISIONAL TEDE, using a risk-consistent methodology, assesses the impact of all relevant nuclides upon all body organs. While it is expected that in many cases, the thyroid could still be the limiting organ and radioiodine the limiting radionuclide, this conclusion can not be assured in all potential cases. The revised source term postulates that the core inventory is released in a sequence of phases over 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />, with the more significant release commencing at about 30 minutes from the start of the event. The assumption that the two-hour exposure period starts immediately at the onset of the release is inconsistent with the phased release postulated in the revised source term. A detailed rationale for the use of 0.25 Sv (25 rem) TEDE as an accident dose guideline and the use of the two-hour exposure period resulting in the maximum dose for future LWRs is provided at 61 FR 65157. The considerations that formed the basis for that rationale are also applicable to operating reactors that elect to use the revised source term.

The Commission believes that it is technically appropriate and logical to extend the dose guidelines, established for future LWRs using the revised source term, to operating reactors that elect to use the same revised source term.

The Commissicn determined that, for use with the revised source term, accident dnse 1

guidelines and control room habitability should be expressed in terms of TEDE, and that the two hour exposure period be based on the two hour period that yields the maximum dose. The proposed @50.67 incorporates these acceptance criteria.

l Conforming Change to 10 CFR Part 50. Anoendix A GDC-19 The proposed change to 10 CFR Part 50, Appendix A, GDC-19 is not related to the use of an attemative source term at operating reactors, but is included here to address a deficiency

~

identified in the regulatory framework for early site permits, standard design certifications, and  ;

combined licenses under Part 52. Sections 52.18,52.48, and 52.81 establish that applications filed under Part 52 Subparts A,3, and C, respectively, will be reviewed according to the standards set out in 10 CFR Parts 20,50,' 51,55,73, and 100 to the extent that those i standards are technically relevant to the proposed design. Therefore, GDC-19 is pertinent to q, lications under Part 52. The recent Part 100 rulemaking (61 FR 65157) established accident i.iDE guidelines (in $50.34) for applicants under Part 52, but did not establish a revised control room dose criterion. Therefore, exemptions from the dose crite "on in the current GDC-19 were necessary in the design certification process for the Westinghouse AP-600 advanced light water reactor in order to use the 0.05 Sv (5 rem) TEDE criterion deemed necessary for use with the revised source term. The proposed change will eliminate the need for exemptions by future EA-4

Octob@r 6,1998 DRAFT - PRE-DECISIONAL applicants under Part 52. The proposed change is also applicable to future applications under Part 50 that are filed on or after January 10,1997.

Environmentalimpacts of the Action The implementation of an attemative source term at an operating power reactor would replace the traditional TID-14844 source term with a source term that would be based on the insights from extensive accident research activities. The actual accident sequence and progression is not changed; it is the regulatory assumptions regarding the accident that will be affected by substituting an a!!emative source term. Use of an altemative source term alone cannot increase the core damage frequency (CDF) or the large early release frequency (LERF) or actual offsite or onsite radiation doses. (While actualdoses would not increase, analysis results may show an increase in some postulated doses because additional radionuclides will be considered and dose modeling will be more comprehensive.) The source term is used in analyses performed to assess the adequacy of the plant design to contend with a DBA in order to ensure adequate defense in depth and adequate safety margins. The attemative source term could be used to justify changes in the plant design that could have an impact on CDF or f LERF or could increase offsite or onsite doses. These potential changes are subject to existing

( requirements in the Commission's regulations. Thus, the protection of the public health and safety would not be decreased by this proposed rulemaking.

The Commission directed the NRC staff to perform an assessment of the impacts of implementing the revised source term at operating reactors. The results of this study were presented to the Commission in SECY-98-154,"Results of the Revised (NUREG-1465) Source Term Re-Baselining for Operating Reactors." The major areas examined included the effect on individual offsite and control room dose, the effect on doses used in equipment environmental qualification, and the effect of potential modifications that might be enabled by the revised source term. The study also assessed the margin afforded by the revised source term in comparison to assessments performed using the integrated severe accident assessment code, MELCOR. The study indicated that the impact of implementing the revised source term at operating reactors will produce lower postulated doses in the majority of cases. The Commission intends to address the exceptions in the regulatory guidance that will be developed to support the proposed rule and in the processing of the individual license amendments. The MELCOR analyses indicated that the design basis dose calculations still have a substantial margin (a factor of two or greater) even though the postulated dose may be less than that EA-5

October 6,1998 DRAFT - PRE-DECISIONAL indicated by calculations using the current source term. The study also indicated that many of the plant systems that are likely to be considered for modification are not involved in risk significant sequences and are, therefore, not likely to have a substantial offsite risk impact using a measure such as large early release frequency.

There is an expectation that many of the altemative source term applications may provide concomitant improvements in overall safety and in reduced occupational exposure, as well as economic benefits. Due to the wide range of possible rpplications and the voluntary nature of this proposed rulemaking it is not reasonable to quantify possible outcomes. Reductions in occupational exposures may be realized through reductions in maintenance efforts associated with maintaining unnecessarily limiting leakage, timing, or filtration requirements. Improvements in overall safety may be realized through reduced emergency diesel generator loading, l improved containment ventilation system performance due to lessened filter flow resistance, and closer synchronization of accident mitigation feature actuation with the onset of major fission product release, to provide three examples. There may be improvements in safety margins realized due to the upgrading of analysis assumptions, methods, and acceptance criteria.

The radiological consequences of DBAs will not be increased by the use of the revised source term. The proposed dose guidelines are comparable, in level of protection, to the existing guidelines. The proposed rule does not affect non-radiological plant effluents and has no other environmental impact. Therefore, the Commission concludes that there are no significant non- '

radiological environmental impacts associated with the amendments to the regulations.

Alternatives to the Action As required by Section 102(2)(E) of NEPA (42 U.S.C.A. 4332(2)(E)), the staff has considered possible attematives to the proposed action. Most of the alternatives considerr "are related to administrative datails such as location of the proposed rule and the means o, evz Mg regulatory guidance. These attematives are neutral with regard to environmentai . and will not be considered further. With regard to enviromental impacts, the alternatives can be reduced to (1) retain the existing accident source term, i.e., the no-action alternative, and (2) allow the use of the revised source term.

~

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October 6,1998 DRAFT - PRE-DECISIONAL The first alterr.ative considered by the Commission was to retain the existing accident source

(' term, i.e., the no-action alternative. This was not considered to be an acceptable alternative, as it would preclude the use of an alternative source term by operating reactors and the potential l reductions in regulatory burden. This rulemaking alternative would also preclude potential i concomitant improvements in overall safety and in reduced occupational exposure. The enviromental impact of postulated DBA would be unchanged. The foreclosure of potential concomitant improvements could prevent some actions that could reduce the risk and/or consequences of accidents. Since it is not possible to predict the source term applications that may voluntarily be proposed by license with any degree of certainty, this aspect is not evaluated further.

The second alternative considered by the Commission was to allow the voluntary use of the revised source term at operating plants, including the use of dose guidelines and dose criteria consistent with the characteristics of the revised source term. This altemative would establish the requirements for use of an altemative source term in a new section to Part 50 while retaining the existing regulations in Part 100 Subpart A and Part 50 Appendix A GDC-19. The proposed approach of was chosen as the best rulemaking altemative it is believed that the proposed rulemaking will result in an improvement in the allocation of resources both for the NRC and for industry. The industry will be allowed to propose applications of an attemative source term that could reduce unnecessary or ineffective requirements in the facility design basis. The NRO and the industry stand to gain from having appropriate regulatory requirements and guidance needed to facilitate preparation and NRC staff review of licensee submittals. Limited resources could be diverted to safety issues of greater significance. The environmental impacts of the proposed use of the revised source term were addressed earlier

~

in this assessment and it was concluded that there would be no significant environmental impact. Given the conclusion of no significant impact and the economic benefits that could be achieved, this attemative is clearly superior to the no-action altemative.

Alternative Use of Resources No attemative use of resources was considered. The proposed rule applies only to existing operating reactors and the use of an alternative source term for analysis purposes has no impact on the use of resources. Although this rule also makes conforming changes related to future plant licensing, the environmental impact of the future plant licensing would, by regulation, be assessed as part of the plant . censing.

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October 6,1998 DRAFT - PRE-DECISIONAL Agencies and Persons Consulted I

The NRC staff developed the proposed rulemaking. No outside agencies or consultants were used in developing this proposed rulemaking package. The NRC staff also obtained advice from the NRC Advisory Committee on Reactor Safeguards.

Draft Finding of No Significant impact The Commission has made a draft determination under the National Environmental Policy Act of 1969, as amended, that the proposed amendments to 10 CFR Parts 21, 50, and 54 to allow the holders of operating licenses at currently operating reactors to voluntarily amend their design bases to replace the current accident source term with an attemative source term, do not have a significant effect on the quality of the human environment and that an environmental impact statement is not required.

This draft determination is based on the following:

1. The foregoing environmental assessment.

2. The proposed accident revised source term and the proposed accident dose guidelines were incorporated into the Commission's regulations in Parts 50 and 100 for future plant licensing by a final rulemaking on January 10,1997. The environmental assessment for that final rule made a finding of no significant impact. The proposed rule is a logical extension of these provisions to operating reactors, and a similar finding is appropriate.

3. The revised source term reflects the significant advances have been made in understanding the timing, magnitude, and chemical form of fission product releases from severe nuclear power plant accidents. This attemative source term provides more physically based estimates of the accident source term. The Commission sponsored significant review

' efforts by peer reviewers, foreign res.earch partners, industry groups, and the general public (57 FR 33374).

l 9

I lt 1

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l l

l . .

October 6,1998 DRAFT - PRE-DECISIONAL References

1. " Accident Source Terms for Light-Water Nuclear Power Plants," NUREG-1465, February 1995

2. " Calculation of Distance Factors for Power and test Reactor Sites," Technical Information i

Document (TID) 14844, March 1962

3. "Results of the Revised (NUREG-1465) Source Term Re-Baselining for Operating Reactors," SECY-98-154, June 1998

4. " Amendments to 10 CFR Parts 50,52, and 100, and issuance of New Appendix S to Part 50," SECY-96-118 May 1996 r

i l

I EA-9 i

m

(

Attachment 4 l

l Draft Congressional Letters

(

C

+

The Honorable Dan Schaefer, Chairman  !

Subcommittee on Energy and Power )

Committee on Commerce . )

United States House of Representatives Washington, DC 20515

Dear Mr. Chairman:

Enclosed for the information of the Subcommittee are copies of a Public Announcement and a i proposed amendment to 10 CFR Parts 21,50, and 54. The proposed rule would allow holders of operating licenses at currently operating reactors to voluntarily amend their design bases to ,

replace the current accident source term with the revised source term in NUREG-1465, Accident Source Terms for Light-WaterNuclearPowerPlants. The Commission is also  ;

l proposing some changes to various sections of its regulations to conform with revisions implemented earlier. i

. Since the publication of the current accident source term in 1962, significant advances have been made in understanding the timing, magnitude, and chemical form of fission product releases from severe nuclear power plant accidents. Many of these insights developed out of the major research effort started by the _NRC and the industry after the accident at Three Mile lsland (TMI). The proposed rule would enable currently licensed power reactors to propose

(. applications of the revised source term that could reduce unnecessary or ineffective requirements in the facility design basis, thereby reducing the regulatory burden. It is believed that the proposed rulemaking will result in an improvement in the allocation of resources both for the NRC and for industry. Also, there is an expectation that many of the revised source term applications may provide concomitant improvements in overall safety and in reduced occupational exposure, as well as economic benefits.

The NRC staff has determined that the public health and safety and the common defense and security would continue to be adequately protected if the proposed rulemaking were implemented.

Sincerely, L,

x Dennis K. Rathbun, Director Office of Congressional Affairs

Enclosure:

Federal Register Notice ec: Representative Ralph Hall 4 l(L. .

i

i

. .' i f

'i t

The Honorable James N. Inhofe, Chairman

- Subcommittee on Clean Air, Wetlands, Private Property and Nuclear Safety Committee on Environment and Public Works .

United States Senate Washington, DC 20510

Dear Mr. Chairman:

Enclosed for the information of the Subcommittee are copies of a Public Announcement and a proposed amendment to 10 CFR Parts 21,50, and 54. The proposed rule would allow holders of operating licenses at currently operating reactors to voluntarily amend their design bases to replace the current accident source term with the revised source term in NUREG-1465, Accident Source Terms forLight-WaterNuclearPowerPlants. The Commission is also l

proposing some changes to various sections of its regulations to conform with revisions l implemented earlier.

l Since the publication of the current accident source term in 1962, significant advances have

- been made in understanding the timing, magnitude, and chemical form of fission product releases from severe nuclear power plant accidents. Many of these insights developed out of

(, the major research effort started by the NRC and the industry after the accident at Three Mile Island {TMl). The proposed rule would enable currently licensed power reactors to propose applications of the revised source term that could reduce unnecessary or ineffective requirements in the facility design basis, thereby reducing the regulatory burden. It is believed that the proposed rulemaking will result in an improvement in the allocation of resources both for the NRC and for industry. Also, there is an expectation that many of the revised source

. term applications may provide concomitant improvements in overall safety and in reduced occupational exposure, as well as economic benefits.

The NRC staff has determined that the public health and safety and the common defense and i

security would continue to be adequately protected if the proposed rulemaking were implemented.

Sincerely, Dennis K. Rathbun, Director Oifice of Congressional Affairs

Enclosure:

Federal Register Notice cc: Senator Bob Graham

(

Attachment 5 Draft  !

l Public Announcement

(

C

)

,/ j DRAFT PUBLIC ANNOUNCEMFNT l NRC PROPOSES CHANGES TO ALLOW USE OF REVISED SOURCE TERM AT OPERATING REACTORS The Nuclear Regulatory Commission is proposing to amend its regulations to allow holders of operating licenses for nuclear power plants to voluntarily replace the traditional source term used in design basis accident analyses with a revised source term. This revised source term was developed from the results of a major research effort to obtain a better understanding of fission-product transport and release mechanisms in light-water-reactors under severe accident conditions. This action would allow interested licensees to pursue cost beneficial licensing actions to reduce regulatory burden without comprising the margin of safety 1 l

of the facility. In addition, the Commission is also proposing to amend its regulations to revise !

certain sections to conform with final 10 CFR Parts 50 and 100 rulemaking published on January 10,1997.

Since the publication of the current accident source term in 1962, significant advances  !

have been made in understanding the timing, magnitude, and chemical form of fission product releases from severe nuclear power plant accidents. Many of these insights developed out of the major research effort started by the NRC and the industry after the accident at Three Mile Island (TMI). The proposed rule would enable currently licensed power reactors to propose applications of the revised source term that could reduce unnecessary or ineffective requirements in the facility design basis, thereby reducing the regulatory burden. It is believed that the proposed rulemaking will result in an improvement in the allocation of resources both for the NRC and for industry. Also, there is an expectation that many of the revised source term applications may provide concomitant improvements in overall safety and in reduced occupational exposure, as well as economic benefits.

The NRC staff has determined that the public health and safety and the common F defense and security would continue to be adequately protected if the proposed rulemaking l

were implemented.

The Commissioners I

c. The draft Environmental Assessment and a draft finding of no significant impact have been prepared (Attachment 3);

d. The Chief Counsel for Advocacy of the Small Business Administration will be notified of the Commission's determination, pursuant to the Regulatory Flexibility Act (5 U.S.C. 605(b)), that this proposed rule will not have a cignificant economic effect on a substantial number of small entities; 1

e. The appropriate Congressional committees will be informed (Attachment 4);

)

1

f. A public announcement will be issued (Attachment 6); and  !

g. Copies of the Federal Register Notice of Proposed Rulemaking will be distributed to all Commission power reactor licensees. The notice will be sent to other interested parties upon request.

William D. Travers Executiv3 Director For Operations Attachments: 1. Federal Register Notice of Proposed Rulemaking

2. Draft Regulatory Analysis

3. Draft Environment Assessment and Draft Finding of No Significant impact

4. Draft Congressional Letters

5. Draft Pubi;c Announcement DOCUMENT NAME: OAlavie\prcmritr.wpd, fr_ entry.wpd, reganal.wpd, envasmt.wpd, congitrs.wpd OFC PERB E SC:PERB E BC:PERB E BC:PGEB Te:h Editor (A)D:DRPM NAME SLaVie REmch CMiller TEssic

• RSanders JRoe DATE /0/ 119 8 / /98 / /98 / /98 / /98 / s98 OFC BC:PPRB D:NRR AD:RES D:NMSS OGC OE NAME RVillafranco SCollins AThadani CPaperiello JGray JLieberman DATE / /98 / /98 / /98 / /98 / /98 / /98 OFC OCFO OClO ADM OEDO NAME JFunches BShelton DMeyer WTravers DATE / /98 / /98 / /98 / /98 / /98 / /98 r OFFICIAL RECORD COPY lt i

l 6 l NRC IDRM 670

• U.S. NUCLEAR REGULATORY COMMISSION FPR ACW2 -1 '

'INFORMATION REQUIRED FOR MAKING AN INSIGNIFICANT BURDEN DETERMINATION TO SUPPORT A DECISION THAT OMB CLEARANCE IS NOT REQUIRED TITLE OF COLLECTION: Attach document containing proposed information collection (s).

Proposed Rule, Use of an Alternative Source Term at Operating Reactors,10 CFR Parts 21,50, and 54 l

l DESCRIPTION OF COLLECTION For rulemakings, provide. for each section that adds. deletes, or modifies information collections. all information requested in the tCble below. For all other collections, provide a general description of the information collection or a description of all modification (s) to the existing collection, and include allinformation specified in the table.

SGetion Number i Revised Revised Total Number of ll Hours Current - of Burden Burden Burden (Rules , Current perl Number Hours per Hours Description of Change Only) ' Respondents lResponseiRespondents Response Change l l The proposed rulemaldng would require that a 50.67(b) 0 1 0 1 0 609 0 licensee who seeks to revise its current accident source term in design basis radiological consequence analysis apply for a license amendment under 10 CFR 50.90. The application shall contain an evaluation based on the new accident source term of the consequences of applicable design basis accidents previously analyzed in the safet.s analysis report. Because use of the revisetl accident sotree term is likely to result in o cost i

sasings to nuclear power plant licensees NRC

, estimates that 41 licensees may apply f. a license amendment to use the revised s rce term. The current burden and numbe ' '

anticipated license amendments is cov rt .

under Psrt 1 of the 10 CFR Part 50 su 2 porting statement (3150-0011). Despite the number of regulations which have been implemented that either require or allow a licensee to si bmit amendments to its license, the number af amendments submitted annually and t eir burden have remained fairly constant ver the years, if the NRC were to receive licen e amendment applications for the new so rce l term,the burden would be as stated. Hunever, because a licensee normally submits a set j number of amendments and prioritizes which amendments are most important to safety or to l ,

realize cost savings, the licensee would choose i i to submit a license amendment for a revised source term in lieu of submitting an

, amendment requesting a less important change.

'Thus, there would be no additional burden to submit the amendment for a revised source term.

I t The proposed rule would make conforming 50.34(f) 0 .

0 0 0 0 changes to eliminate the need for the submittal

& I .of exemption requests by future applicants App. A. l  !  ; under Part $2. No applications are anticipated GDC-19 i within the next 3 years, hence no immediate i  ;

burden reduction is expected.

! i

l. i.

NRC F DRM 610 (4-1We; PR>NIED ON REC % LEO FAPER Trus form was cosenso using informs

NRC FORM 670 U.S. NUCLEAR REGULATORY COMMISSION I4 1996)

INFORMATION REQUIRED FOR MAKING AN INSIGNIFICANT BURDEN DETERMINATION .

TO SUPPORT A DECISION THAT OMB CLEARANCE IS NOT REQUIRED l (Continued)

NEED FOR/USE OF COLLECTION:

The information submitted with each license amendment application is required for NRC review to ensure that the accident design basis remains adequate and to make the findings required by the Atomic Energy Act of 1954, as amended,and the Commission's rules and regulations. These findings are required to ensure that issuance of the amendment will not cause undue risk to the health and safety of the public.

PUBUC COMMENT:

Has NRC had any consultation with the public, industry groups, or other agencies, etc., regarding this Q- YES ~ NO -

proposed collection? If yes, explain and indicate how any issues were addressed and resolved. ]

Public comments have been solicited through Federal Register notices. i l

1 1

l l

I Does NRC expect to receive comments on this collection? If yes, explain. ]YES y NO j

i l

l i

Are the information collections considered controversiar? If yes, explain. ]YES y NO I

i EXPECTED IMPLEMENTATION DATE: 09/01/1999 DATE OClO APPROVAL SIGNATURE Brenda Jo. Shelton .. ._ // . 10/> 7/1998 NRC Clearance Offcer/OClO , , Q // ,

./ m

NRC FORM 670 i U.S. NUCLEAR REGULATORY COMMsSSION bk h (2. -k.

INFORMATION REQUIRED FOR MAKING AN INSIGNIFICANT BURDEN DETERMINATION TO SUPPORT A DECISION THAT OMB CLEARANCE IS NOT REQUIRED TITLE OF COLLECTION: Attach document containing proposed information collection (s).

Prcposed Rule, Use of an Alternative Source Term at Operating Reactors,10 CFR Parts 21,50, and 54 EUIPTiON OF COLLECTION For rulemakings, provide, for each section that adds, deletes, or modifies information collections. all information requested in the tibl2 below. For all other collections, provide a general description of the information collection or a desenption of all modification (s) to the existing collection, and include all information specified in the tab;e.

Stetion Revised Total Number Number of l CurrentBurden

• Revised Number Burden Burden Description of Change (Rulis Current Hours per of Hours per Hours Only) Respondents Response Respondents Response Change The proposed rulemaking would require that a 50.67(b) 0 , 0 0 609 0 licensee who seeks to revise its current accident

!  ! source term in design basis radiological consequence analysis apply for a license amendment under 10 CFR 50.90. The application shall contain an evaluation based

' on the new accident source term of the consequences of applicable design basis accidents previously analyzed in the safety

• analysis report. Because use ef the revised accident source term is likely to result in a cost

savings to nuclear power plart licer. ees NRC l l

' estimates that 41 licensees ms rpply for a

' > license amendment to use the ' vised source

!  ! term. The current burden a :d ' umber of

! , anticipated license amendments is covered

- under Part 1 of the 10 CFRPart 50 supporting i A /@ statement (3150-0011). Despite the number of l V regulations which have been implemented that

'

• either require or allow a licensee to submit t '

amendments to its license, th number of

$ 1 h[ '

4 amendments submitted annu lly and their burden have remained fairly onstant over the years, if the NRC were to rec sive license i

l Yf p. amendment applications for the new source term, the burden would be as stated. However, '

because a licessee normally submits a set y

[ number of amendments and prioritizes which f

.I amendments are most important to safety or to p f ,

realize cost savings, the licensee would choose

! to submit a license amendment for a revised  !

source term in lieu of submitting an

! amendment requesting a less important change.

'Thus, there would be no additional burden to l l

> submit the amendment for a revised source term, r

The proposed rule would make conforming }

i 0

changes to eliminate the need for the submittal 0 1 0 0 0 50.34(f) .

of exemption requests by future applicants  :

I

& under Part 52. No applications are anticipated l App.A. I I i

.within the next 3 years, hence no immediate i i

GDC-19 .

'  : burden reduction is expected. l I

1

• . e i i I .i Trus form was aes.gnea usmg Warna NRC FORM 670 t4-1996) PRINTEo ON RiCYCLLD PAPEft

1. l l

1

.t NRC FORM 670 U.S. NUCLEAR REGULATORY COMMisslON

+ me> l INFORMATION REQUIRED FOR MAKING AN INSIGNIFICANT BURDEN DETERMINATION l TO SUPPORT A DECISION THAT OMB CLEARANCE IS NOT REQUIRED l (Continued)

NEED FOR/USE OF COLLECTION:

The information submitted with each license amendment application is required for NRC review to ensure that the accident design basis remains adequate and to make the findings required by the Atomic Energy Act of1954, as amended,and the Commission's rules and regulations. These findings are required to ensure that issuance of the an: ender.ent will not cause  ;

undue risk to the health and safety of the public.

PUBLIC COMMENT:

Has NRC had any consultation with the public, industry groups, or other agencies, etc., regarding this- Q YES -

NO proposed collection? If yes, explain and indicate how any issues were addressed and resolved.

Public comments have been solicited th ough Federal Register notices.

1 11 l

l Does NRC expect to receive comrnents an this collection? If yes, explain. ,] YES g NO

)

1 Are the information collections considered controversial? If yes, explain.

]YES Q NO l

t EXPECTED IMPLEMENTATION DATE: 09/01/1999 slGNATURE , DATE 0C10 APPROVAL 10/.> 7/1998 Brenda Jo. Shatton .. //

NRC Clearance Ofncer/OClO , ( g _ j_/ _j ,

vx

.4

^M OFFICE CONCURRENCES / COMMENTS FOR SECY-98-289 PROPOSED AMENDMENTS TO 10 CFR P. ARTS 21,50, AND 54 REGARDING USE OF ALTERNATIVE SOURCE TERMS AT OPERATING REACTORS I

i l

. A l The Commissioners d. The Chief Counsel for Adocacy of the Small Business Administration will be notified of the Commissbn's dete,mination, pursuant to the Regulatory FNxibility Act (5 U.S.C. 605(b)), that this proposed rule will not have a significant economic effect on a substantial number of small entities;

e. The appropriate Congressional committees will be informed (Attachment 4);

f. A public announcement will be issued (Attachment 5); and

g. Copies of the Federal Register Notice of Proposed Rulemaking will be distributed to all Commission power reactor licensees. The notice will be sent to other interested parties upon request.

Otel signed ty i Woun D.Trowes William D. Travers Executive Director For Operations Attachments: 1. Federal Register Notice of Proposed Rulemaking

2. Draft Regulatory Analysis

3. Draft Environment Assessment and Draft Finding of No Significant impact

4. Draft Congressional Letters

5. Draft Public Announcement 4 DOCUMENT NAME: 0:\DRPM\PERB\RPS\LAVIE\premritr.wpd, fr_ entry.wpd, reganal.wpd, envasmt2.wpd, congltrs.wpd

• indicates prior concurrence OFC PERB .

E SC:PERB E BC:PERB E Tech Editor (A)D:DRPM D:NRR ()ph NAME SlaVie h REmc [ [ h CMiller rds RSanders* J SCollins DATE // /6/98 ///2098 ll /8/98 10/8/98 /98 h /98

\

OFC AD:RES ADM OClO OGC OE OCFO NAME AThadani* DMeyer* BShetton* STrebey* JLieberrnan* JFunches* l DATE 10/30/98 10/27/98 10/27/98 11/6/98 10/30/98 10/29/98 OF fOED NAME/ WTrah DATE r.. L "FICIAL RECORD COPY