ML20196K675

Forwards Fr Notice & Draft Environmental Assessment Re Proposed Rulemaking on 10CFR21,50 & 54 Concerning Use of Alternative Source Terms at Operating Reactors for Comment

ML20196K675
Person / Time
Issue date:	06/30/1999
From:	Lohaus P NRC OFFICE OF STATE PROGRAMS (OSP)
To:	GENERAL
References
NUDOCS 9907090297
Download: ML20196K675 (19)

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s&A **Q l g 4 UNITED STATES s-j 2

NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 June 30, 1999

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! STATE LIAISON OFFICERS PROPOSED RULEMAKING ON 10 CFR PARTS 21,50, AND 54 REGARDING USE OF l ALTERNATIVE SOURCE TERMS AT OPERATING REACTORS The United States Nuclear Regulatory Commission (NRC) has published in the Federal Reoister

- the enclosed proposed amendments to the Commission's rules in 10 CFR Parts 21, 50, and 54.

These amendments have been proposed to allow holders of operating licenses for nuclear power plants to voluntarily replace the traditional source term used in design basis accident analyses with alternative source terms. This action would allow interested licensees to pursue l cost beneficial licensing actions to reduce unnecessary regulatory burden without compromising i the margin of safety of the facility. The NRC has also proposed amending its regulations to revise certain sections to conform with the final rule published on December 11,1996, concerning reactor site criteria.

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 final rule would enable currently licensed power reactors ta p< opose applications of an altemative source term that could reduce unnecessary or inehetive requirements in the facility design basis, thereby reducing the regulatory burden. It is believed that this rulemaking will also result in an improvement in the allo ation of resources both for the J NRC and for industry. Also, there is an expectation that many of the alternative source term applications may provide concomitant improvements in overall safety and in reduced occupational exposure, as well as economic benefits. The NRC does not expect the rule will be used to obtain relief from emergency planning requirements under 10 CFR 50.47. The particular characteristics of the alternative source terms have been tailored specifically for l design basis analysis use and are not representative of the wide spectrum of possible events l that make up the planning basis of emergency preparedness. Therefore, an alternative source l term is insufficient by itself as a basis for requesting relief from emergency preparedness j l requirementsc l l

l Tne Environmental /.ssessment (EA) is summarized in the Statem .it of Consideration. The l l conclusion of the EA is the Commission's finding that no significant environmental impact will i l result from the proposed rule. The Federal Reaister notice and the environmental assessment are provided for your review and comment. The public comment period in the Federal Reaister ended on May 25,1999. Since we did not transmit these materials to you at the time the rule was pub!ished, I am requesting that, if you have any comments on the rule and its environmental impact, you please send them by August 9,1999. Comments received after t'is date will be considered if practical to do so, but the staff i* eble to assure consideraticn only for comments received by August 9,1999.

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State Liaison Officers JH 3 01999 l

You may use the following methods to transmit your comments: (1) you can mail your written -l comments to: Secretary, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, Attention: Rulemakings and Adjudications Staff; (2) you may fax your comments to ,

301-415-1672, or you may submit your comments via NRC's extemal website at the following URL location: btto://ruleforum llnl cov/cai-bin /rulemake and sele the subject rule.

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Ar Paul H. Lohaus, Director j Office of State Programs

Enclosures:

As stated s

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yl State Liaison Officers - ^

J3E 3 01999

-You may use the following methods to transmit your comments:- (1) you can mail your written comments to: Secretary, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, Attention: Rulemakings and Adjudications Staff; (2) you may fax your comments to

' 301415-1672, or you may submit your comments via NRC's extemal website at the following URL location: http://ruleforum.llnl oov/coi-bin /rulemake and select the subject rule.

Orl0MelSigned.By:

FAULH.LOHAUS

Paul H. Lohaus, Director Office of State Programs

Enclosures:

- As stated 1

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12117 Proposed Rules reder i nesister Vol. 64, No. 47 Thursday, March 11,1999 This section of the FEDERAL REGISTER function. Information on the use of the accident that would result in substantial contains notices to the public of the proposed Rulemaking Forum is available on the release of appreciable quantities of issuance of rules and regulations. The website For additional assistance on the fission products from the core to the purpose of these notices is to give interested use of the interactive rulernaking site, containment atmosphere. A note to mak ng r e adop of nal c r, tact Ms. Caml Gallagher, telephone: S 100.11 states that Technical rules. .,01-415-5905; or by Internet electronic Information Document (TID) 14844, mail to cag@nrc. gov. " Calculation of Distance Factors for p Certain documents related to this Power and Test Reactors," may be used NUCLEAR REGULATORY rulemaking, including comments as a source of guidance in denloping COMMISSION received and the environmental the exclusion area, the low population assessment :md finding of no significant zone, and the population center 10 CFR Parts 21,50, and 54 impact may be examined at the NRC distance, RIN 3150-AG12 Public Document Room 2120 L Street. The fit.sion product release from the NW, (Lower Level), Washington, DC. reactor core into containment is referred ,

Use of Alternative Source Terms at These same documents also may be to as the " source term" and it is l Operating Reactors viewed and downloaded electronically characterized by the composition and via the interactive rulemaking v ebsite magnitude of the radioactive material, AGENCY: Nuclear Regulatory established by NRC for this rulemaking. the chemical and physical properties of Commission. FOR FURTHER INFORMATION CONTACT: Mr. the material, and the timing of the ACTION: Proposed rule. Stephen F. LaVie Office of Nuclear release from the reactor core. The Reactor Regulation, U.S. Nuclear accident source term is used to evaluate

SUMMARY

The Nuclear Regulatory Regulatory Commission, Washington, the radiological consequences of design Conealssion (NRC) is proposing t DC 20555-0001; telephone: (301) 415- basis accidents (DBAs) in showing amead its regulations to al;ow holders 1081; or by Internet electronic mail to compliance with various requirements of operating licenses for nuclear power sfi@nrc. gov. of the NRC's regulations. Although SNMENTARONFORMADON: @nah ud h sh suhaMty radit o a source ter use n dest8n analys, the accident source term is a I Back basis accident analyses with alternative !!. Objfctives round design pemeter for accident mitigation source terms. This action would allow III. Alternatives features, equipment qualification, interested licensees to pursue cost IV. Section-by-Section Analysis control room operator radiation doses, beneficial licensing actions to reduce V. Future Regulatory Action and post-accident vital area access unnecessary regulatory burden without VI. Referenced Documents doses. The measurement range and compromising the margin of safety of VII. Draf: Finding of No Significant alarm setpoints of some installed plant the f acility, The NRC is also proposing EnvironmentalImpact: Availability instrumentation and the actuation of to amend its regulations to revise certain VIII. Paperwork Reduction Act Statement some plant safety featuas are based in sections to conform with the final rule 1 Reg "

[pegu r Fe b y Certification Part on the accident ' source term. The published on December 11,1996, TID-14844 source term was explicitly XI. Backfit Analysis concerning reactor site criteria, stated as a required design parameter for DATES: The comment period expires on I, Background several Three Mlle Island (TMI) related May 25,1999. Comments received after A holder of an operating license (i.e., requirements.

this date will be t.onsidered, if it is the licensee) for a light-water power The NRC's methods for caiculating practical to do so, but the NRC is able reactor is required by regulations issued accident doses, as described in to assure consideration only for by the NRC (or its predecessor, the U.S. Regulatory Guide 1.3, " Assumptions comments received on or before this Atomic Energy Commission, (AFC)) to Used for Evaluating the Potential date. submit a safety analysis report that Radiological Consequences of a Loss of ADDRESSES: Mall written comments to: contains assessments of the radiological Coolant Accide st for Boiling Water ,

Secretary, U.S. Nuclear Regulatory consequences of potential accidents and Reactors"; Reguatory Guide 1.4, j Commission, Washington, DC 20555- an evaluation of the proposed facility " Assumptions Used for Evaluating the '

0001, Attention: Rulemakings and site. The NRC uses this information in Potential Radiolog' cal Consequences of Adjudications Staff, Mail Stop Ol6C1, its evaluation of the suitability of the a Loss of Coolant Accident for Deliver comments to: One White Flint reactor design and the proposed site as Pressurized Water Rt actors"; and North,11555 Rockville Pike, Rockville, required by its regulations contained in NUREG-0800, "Stanoard Review Plan ,

Maryland, 20852, between 7:30 a.m. and 10 CFR Parts 50 and 100. Section for the Review of Safety Analysis 4:15 p.m. on Federal workdays. 100.11, which was adopted by the AEC Reports for Nuclear Power Plants," were You may also submit comments via in 1962 (27 FR 3509; April 12,1962), developed to be consistent with the the NRC's interactive rulemaking web requires an applicant to assume (1) a TID-14844 source term and the whole  ;

site, "Rulemaking Forum," through the fission product release fron. the reactor body and thyroid dose guidelines stated l NRC home page (http://www.nrc. gov), ccre, (2) the expected containment leak in S 100.11, in this regulatory l This site enables people to transmit rate, and (3) the site meteorological framework, the source term is assumed comments as files (in any format, but conditions to establish an exclusion area to be released immediately to the Wordperfect version 6.1 is preferred), if and a low population zone. This fission containment at the start of the ,

your web browser supports that product release is based on a major postulated accident. The chemical form .

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p. .

12118 Federal Rcgister/Vol. 64, No.' 47/ Thursday, March 11,1999/ Proposed Rules of the radiolodine released to the understanding the timing, magnitude, requirements of S 100.11 or, as proposed l containment atmosphere is assumed to and chemical form of fission product herein. 9 50.67. q be predominantly elemental, with the releases from severe nuclear power The objective of NUREG-1465 was to remainder being small fractions of plant accidents. Many of these insights define revised accident source terms for particulate and organic iodine forms, developed out of the major research segulatory application for future light Radiation doses are calculated at the efforts started by the NRC and the water reactors. The NRC's intent was to exclusion area boundary (EAB) for the nuclear industry after the accident at capture the major relevant insights l first 2-hours and at the low population Three Mile Island (TMI). In 1995. the available from severe accident research

! zone (LPZ) for the assumed 30-day NRC published NUREG-1465, to provide, for regulatory purposes, a duration of the accident. The whole " Accident Source Terms for Light-Water more realistic portrayal of the amount of  ;

body dose comes primarily from the Nuclear Power Plants." which utilized the postulated accident source term.

noble gases in the source +erm. The this research to provide more physically These source terms were derived from thyroid dose is based on '.nhalation of based estimates of the accident source examining a set of severe accident radiolodines. In analyse. performed to term that could be applied to the design sequences for light water reactors date, the thyroid dose has generally of future light-water power reactors. The (LWRs) of current dealgn. Because of been limiting. The detign of some NRC sponsored significant review general similarities in plant and core engineered safety fea ures, such as efforts by peer reviewers, foreign design parameters, these results are containment spray rystems and the research partners, industry groups, and considered to be applicable to charcoal filters in the containment, the the general public (request for public evolutionary and passive LWR designs.

building exhaust, snd the control room comment was published in 57 FR The revised source term has been used ventilation syste ns, are predicated on 33374). In evaluating the Westinghouse AP-600 these postulated thyroid doses. The information in NUREG-1465 standard design certification Subequently, tne NRC adopted the presents a representative accident application. (A draft version of NUREG-whole body ar.d thyroid dose criteria in source term (" revised source term") for 1465 was used in evaluating Criterion 19 c.f 10 CFR Part 50, a boiling water reactor (BWR) and for a Combustion Engineering's (CE's) System Appendix A (36 FR 3255; February 20, pressalzed-water reactor (PWR). These 80+ design.)

1971). revised source terms are described in The NRC considered the applicability The source term in TID-14844 is terms of radionuclide composition and of the revised source terms to operating i representriive of a major accident magnitude, physical and chemical form. reactors and determined that the current l involving significant core damage and is and timing of release. Where TID-14844 analytical approach based on the TID- l typically postulated to occur in addressed three categories of 14844 source term would continue to be conjunction with a large loss-of-coolant radionuclides, the revised source terms adequate tc protect public health and i accident (LOCA). Although the LOCA is categorize the accident release into eight safety, and that operating reactors typically the maximum credible groups on the basis of similarity in licensed under this approach would not -

accident. NRC experience in reviewing chemical behavior Where TID-14844 be required to reanalyze accidents using license applications has indicated the assumed an immediate release of the the revised source terms. The NRC also need to consider other accident activity, the revised source terms have concluded that some licensees may sequences of lesser consequence but five release phases that are postulated to wish to use ca alternative source term higher probability of occurrence, Some occur over several hours, with the onset in analyses to support operational  ;

of these additional accident analyses of major core damage occurring after 30 flexibility and cost-beneficial licensing '

may involve source terms that are a minutes. Where TID-14844 assumed actions. The NRC initiated several fraction of those spacified in TID- radiolodine to be predominantly actions to provide a regubtory basis for 14844. The DBAs were not intended to elemental, the revised source terms operating reactors to voluntarily amend be actual event sequences, but rather, assume radiolodine to be predominantly their facility design bases to enable use were intended to be surrogates to enable cesium iodide (Cs!), an aerosol that is of the revised source term in des!gn deterministic evaluation of the response more amenable to mitigation basis analyses. First, the NRC solicited of the plant engineered safety features. mechanisms. Ideas on how an alternative source term These accident analyses are For DBAs, the NUREG-1465 source might be implemented. In November intentionally conservative in order to terms are comparable to the TID-14844 1995, the Nuclear Energy Institute (NEI) address known uncertainties in accident source term with regard to the submitted its generic framework, progression, fission product transport, magnitude of the noble gas and Electric Power Research Institute and atmospheric dispersion. Although radiolodine release tractions. However, Technical Report TR-105909, " Generic probabilistic risk assessments (PRAs) the revised source terms offer a more Framework for Application of Revised can provide useful insights into system representative description of the Accident Source Term to Operating performance and suggest changes in radionuclide composition and release Plants." This report and the NRC how the desired defense in depth is timing. The NRC has determined response were discussed in SECY achieved, defense in depth continues to (SECY-94-302, dated December 1994) 242 (November 199ti). Second, the NRC be an effective way to account for that design basis analyses will address initiated a comprehensive assessment of uncertainties in equipment and human the first three release phases--coolant, the overall impact of substituting the performance. The NRC's policy gap, and in vessel. The ex-vessel and NUREG-1465 source terms for the statement on the use of PRA methods late in-vessel phases are considered to traditionally used TID-14844 source (60 FR 42622; August 16,1995) calls for be unduly conservative for design basis term at three typical facilities. This was the use of PRA technology in all analysis purposes. These latter releases done to m c.!uate the issues involved regulatory matters in a manner that could only result from core damage with applying the revised source terms

, complements the NRC's deterministic accidents with vessel failure and core- at operating plants. SECY 98-154 (June j approach and supports the traditional concrete interactions. The estimated 1998) described the conclusions of this

defense in-depth philosophy, frequencies of such scenarios are low assessment. Third, the NRC accepted Since the publication of TID-14844, enough that they need not be considered license amendment requests related to significant advances have been made in for the purpose of meeting the implementation of the revised source

Fedcral Register /Vol. 64 No. 47/ Thursday, March 11, !999/ Proposed Rules 12119 terms at a small number of pilot plants. review of the FSAR, as documented in the low population zone, but revised the Experience has demonstrated that the Commission's safety evaluation associated numerical dose criteria to evaluation of a limited number of plant- report (SER). By their inclusion in the replace the two different doses for the specific submittals improves regulation FSAR, the assumptions (including the whole body and the thyroid gland with and regulatory guidance development. source term) become part of the design a single, total effective dose equivalent The review of these pilot projects is basis 8 of the facility. From a regulatory (TEDE) value. The dose criteria for the currently in progress. Insights from standpoint, the requirement to use the whole body and the thyroid, and the these pilot plant reviews will be TID-14844 source term is expressed as immediate 2-hour exposure period were incorporated into the regulatory a licensee commitment (typically to largely predicated by the assumed guidance that will be developed in Regulatory Guide 1.3 or 1.4) source term being predominantly noble conjunction with this rulemaking. documented in the facility FSAR, and is gases and radiolodines instantaneously Fourth, the NRC initiated an assessment subject to the requiremmts of 8 50.59. released to the containment and the on whether rulemaking would be in January 1997 (61 FR 65157), the assumed " single critical organ" method necessary to allow operating reactors to NRC amended its regulations in 10 CFR of modeling the internal dose used at use an alternative source term. The Parts 21, 50, 52, 54, and 100. That the time that Part 100 was originally proposed rule and the supporting regulatory action produced site criteria published. However, the current dose regulatory guidance that will be for future sites; presented a stable criteria, by focusing on doses to the developed as part of this rulemaking regulatory basis for seismic and geologic thyroid and the whole body, assume have resulted from this assessment. The : siting and the engineering design of that the major contributor to doses will NRC plans to issue the supporting future nuclear pow plants to be radiolodine. Although this may be regulatory guidance for public comment withstand seismic events; and relocated appropriate with the TID-14844 source on the same day as it publishes the final source term and dose requirements for term, as implemented by Regulatory rule. . future plants into part 50. Because these Guides 1.3 and 1.4, it may not be true This proposed rulemaking for use of dose requirements tend to affect reactor for a source term based on a more alternative source terms is applicable design rather than siting, they are more complete understanding of accident only to those facilities for which a appropriately located in Part 50. This sequences and phenomenology.

construction permit was issued before decoupling of siting from design is The postulated chemical and physical January 10.1997, under 10 CFR Part 50, consistent with the future licensing of form of radiciodine in the revised

" Domestic Licensing of Production and facilities using standardized plan source terms is more amenable to Utilization Facilities." The regulations designs, the design features of which miti 8ation and, as such, radiolodine of this part are supplemented by those will be certified in a separate design may not always be the predominant in other parts of Chapter I of Title 10, certification rulemaking. This radionuclide in an accident release. The including Part 100, " Reactor Site decoupilng of siting from design was revised source terms include a larger Criteria." Part 100 contains language directed by Congress in the 1980 number of radionuclides than did the that qualitatively defines a required Authorization Act for the NRC. Because TID-14844 source term as implemented accident source term and contains a the revised criteria would not apply to in regulatory guidance. The whole body note that discusses the availability of operating reactors, the non-seismic and and thyroid dose enteria ignore these TID-14844. With the exception of seismic reactor site criteria for operating contributors to dose. The NRC amended j S 50.34(f), there are no explicit reactors were retained as Subpart A and its radiation protection standards in Part regulrements in Chapter I of Title 10 to Appendix A to Part 100. respectively. 20 in 1991 (56 FR 23391; May 21,1991) use the TID-14844 accident source The revised reactor site criteria were replacing the single, critical organ term. Section 50.34(f), which addresses added as Subpart B in Part 100, and concept for assessing internal exposure additional TMI related requirements, is revised source term and dose with the TEDE concept that assesses the only applicable to a limited number of requirements were moved to S 50.34, impact of all relevant nuclides upon all construction permit applications The existing source term and dose body organs. TEDE is defined to be the pending on February 16.1982, and to requirements of Subpart A of Part 100 deep dose equivalent (for external applications under Part 52. will remain in place as the licensing exposure) plus the committed effective An applicant for an operating license bases for those operating reactors that dose equivalent (for internal exposure).

is required by 5 50.34(b) to submit a do not elect to use an alternative source The deep dose equivalent (DDE) is final safety analysis report (FSAR) that term. comparable to the present whole body describes the facility and its design in relocating the source term and dose dose; the committed effective dose bases and limits, md presents a safety requirements for future reactors to equivalent (CEDE) is the sum of the analysis of the structures, systems, and S 50.34, the NRC retained the products of doses (integrated over a 50-components of the facility as a whole. requirements for the exclusion area and year period) to selected body organs Guidance in performing these analyses resulting from the intake of radioactive is given in regulatory guides. In its  : As denned in 10 CFR Part 50,2, design bases material multiplied by weighting factors review of tLa more recent appbcations means that information which identifies the for each organ that are representative of for operating licenses, the NRC has used specinc funcuans to be performed by a structure. the radiation risk associated with the d

the review procedures in NUREG-0800. 7'"7,,'n",'"] ,"*"'i d*'lI8'i'"cn'h*

n m *(' particular organ.

" Standard Review Plan for the Review parameters as ret ,nce bounds for design. These The TEDE, using a risk-consistent of Safety Analysis Reports for Nuclear values may be ' estraints derived from generally methodology, assesses the impact of all Power Plants" (SRP). These review acceped "sta.. , the art" practk es for achieving yejeVant nuClldes upon all body organs.

procedures reference or provide '"",fl18d';",72,"7"!'[',dM[""sj Aitnough it is expected that in many

,n accepable assumptions and analysis of the effecu of a postulated accident for which a cases the thyroid could still be the methods. The facility FSAR documents structure. system. or component must meet its limiting organ and radiolodine the the assumptions and methods actually functional goals The NRC considers the accident limiting radionuclide, this conclusion

["','f '*"",j,$ h sf>.$ v P" used by the applicant in the required "1u ]ff I' 8"d0fbas cannot be assured in all potential cases. ;

safety analyses. The NRC's finding that values) for contmuing parametm inai consutu,e The revised source terms postulate that a license may be issued is based on the reference bounds for design the core inventory is released in a

12120 Fedtre_1 Rigitt:r/Vol. 64, No. 47/ Thursday, March 11,1999/ Proposed Rules 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 for future reactors and for operating not considered to be an acceptable the more significant release reactors that elect to use an ahernative alternative. As discussed in the commencing at about 30 minutes from source term with a criterion expressed statements of consideration for the final the start of the event. The assumption in terms of TEDE. The rationale for th; siting rule (61 FR 65157,65159; that the 2-hour exposure period starts revision is similar to the rationale, December 11,1996), the NRC immediately at the onset of the release discussed earlier in this preamble, for determined that dose criteria expressed is inconsistent with the phased release revising the dose criteria for offsite in terms of whole body and thyroid postulated in the revised source terms. exposures. doses were inconsister,t with the use of ,

The proposed rule would extend the On January 10,1997 (61 FR 65157), new source terms not based upon TID- j future LWR dose criteria to operating the NRC amended 10 CFR Parts 21,50, 14844. With regard to the exclusion area reactors that elect to use an alternative , 52,54, and 100 ofits regulations to {

dose guideline, the NRC had previously -

update the criterla used in decisions

~

source term, determined (id. at 65160) that the dose An accidental release of radioactivity regarding power reactor siting for future criterion applies to the 2. hour period can result in radiation exposure to nuclear power plants. The NRC resulting in the maximum dose.

control room operators. Normal intended that future licensing The second alternative considered by ventilation systems may draw this applications in accordance with Part 52 the NRC was the replacement of the activity into the control room where it utilize a source term consistent with the existing guidelines in S 100.11 and the can result in external and internal source term information in NUREG- existing criteria in 10 CFR Part 50 exposures. Control room designs differ 1465 and the accident TEDE criteria in Appendix A, GDC-19 with revised dose but, in general, design features are Parts 50 and 100. However, during the criteria. This is not considered to be a provided to detect the accident or the final d(sign approval (FDA) and design desirable alternative because the activity and isolate the normal certification proceeding for the provisions of the existing regulations ventilation intake. Emergency Westinghouse AP-600 advanced light. form part of the licensing bases fur l ventilation systems are activated to water reactor design, the NRC staff and many of the operating reactors. j minimize infiltration of contaminated Westinghouse determined that Therefore, these provisions must remain '

air and to remove activity that has exemptions were necessary from in effect for operating reactors that do entered the control room. Personnel SS 50.34(f)(2)(vii), (viii), (xxvi), and not implement an alternative source exposures can also result from (xxviii) and 10 CFR Part 50, Appendix term. In addition, this alternative would radioactivity outside of the control A, GDC-19. This rule would eliminate also be inconsistent with the NRC's room. However, because of concrete the need for these exemptions for future Philos0Phy of separating plant siting shielding of the control room, these applicants under Part 52 by making criteria and dose requirements.

latter exposures are generally not conforming changes to Part 50. The approach of establishing the  !

limiting. The objective of the control Appendix A, GDC-19 and S 50.34. requirements for use of alternative room design is to provide a location sot.rce terms in a new section to Part 50 from which actions can be taken to II, Objectives while retaining the existing regulations ,

operate the plant under normal The objectives of this proposed in Part 100 Subpart A and Part 50 conditions and to maintain it in a safe regulatory etion are to- Appendix A GDC-19 was chosen as the  !

condition under accident conditions. 1. Provide a regulatory framework for best alternative.

General Design Criterion 19 (GDC-19), the voluntary implementation of The NRC considered alternatives with

" Control Room," of Appendix A to 10 alternative source terms as a change to reyd to providing regulatory guidance CFR part 50 (36 FR 3255; February 20, the design basis at currently licensed to support the new section to Part 50.

1971), establishes minimum power reactors, thereby enabling The first option was to issue no requirements for the design of the potential cost-beneficial licensing additional regulatory guidance. This control room, including a requirement actions while continuing to maintain option was not considered to be for radiation prot action features existing safety margins and defense in acceptable because in the absence of adequate to permit access to and depth. clear regulatory guidance, licensee occupancy of the control room under 2. Retain the existing regulatory efforts in preparing applications and the accident conditions. The GDC-19 framework for currently licensed power NRC staff review of submitted criteria were established forjudging the stor lice..:ees who choose not to applications, could be hindered by acceptability of the control room design implement an alternative source term, differences in interpretations and for protecting control room operators but continue to comply with their technical positions. This could resuh in under postulated design basis accidents, existing source term. the inefficient use of licensee and NRC a significant concern being the potential 3. Relocate source term and dose staff resources, could cause licensing increases in offsite doses that might requirements that apply primarily to delays, and lead to less uniform and less result from the inability of control room plant design into 10 CFR Part 50 for consistent regulatory implementation.

personnel to adequately respond to the operating reactors that choose to The second option was to replace the event. Implement an alternative source term, existing regulatory guides that address The GDC-19 criteria are expressed in and the radiological consequences of terms of whole body dose, or its 4. Implement conforming changes to accidents with new revisions. This is equivalent to any organ. The NRC did S 50.34(f) and l' art 50 Appendix A, not considered to be an acceptable not revise the criteria when Part 20 was GDC-19 to eliminate the need for choice because the provisions of the amended (56 FR 23391) instead exemptions for future applicants under existing regulatory guides form part of deferring such action to individual Part 52. the licensing bases for many of the facility licensing actions (NUREC/CR- operating reactors. Therefore, these III'AI""'IV'5 6204). This position was taken in the Provisions must remain in effect for interest of maintaining the licensing The first alternative considered by the those operating reactors that do not basis for those facilities already NRC was to continue using current implement an alternative source twm.

licensed. The NRC is proposing to regulation; for accident dose criteria The third option was to issue a new replace the current GDC-19 dose criteria r nd control room dose criteria. This is regulatory guide on the imp % mentation

- 1 Federal Register /Vol. 64, No. 47/ Thursday, March 11,1999/ Proposed Rules 12121  !

of alternative source terms that would identifies the significant characteristics malfunction. In many applications, include revised assumptions and of an accident source terrr Tne alternative source terms may reduce the acceptable analysis methods for each regulatory guide that will be issued to postulated consequences of the accident ,

design basis accident in a series of support this proposed rule will identify or malfunction. For this reason, the NRC  !

appendices. The approach of issuing a the NUREG-1465 source terms as determined that the regulatory l new regulatory guide was determined to acceptable alternatives to the source framework of 5 50,59 does not provide i be the best option. To provide review term in TID-14844, and will provide assurance that this change in the design guidance for the NRC staff, a new implementation guidance. This basis would be recognized by the section on design basis radiological approach would prnvide for future licensee as needing review by the NRC analyses using alternative source terms revised source terms if they are staff. After a licensee has been would be added to the Standard Review developed and would allow licensees to authorized to substitute an alternative

)

Plan, propose additional alternatives for NRC source term in its design basis, IV. Section.by.Section Analysis

1. "* * ' " " " ' ' 9"* "I ' ""E** * *' Y **

C. Section 50.67(b)(1) inv lve an alternative source term may j A. Section 50.2 ,

be processed under S 50.59 or S 50.90, as The general ,, definitions,, section for This paragraph of S 50.67 would state appropriate. However, a subsequent the information that a licensee must change to the source term itself could Part 50 would be supplemented by submit as part of a license amendment adding a definition of source term for not be implemented under S 50.59; in all application to use en alternative source ceses a change to the source term must '

the purpose of S 50.67. In NUREG-1465- term. Because of the extensive use of the be made tnrough a license amendment. c the source term is defined by five accident source term in the design and The proposed rule would require the projected characteristics: (1) Magnitude operation of a power reactor and the applicant to perform analyses of the of radioactivity release. (2) potential impact on nostulated accident consequences of applicable design basis radionuclides released, (3) physical consequences and margins of safety of a accidents previously analyzed in the

< form of the radicquclides release <.i. (4) change of such a fundamental design safety analysis report and to submit a chemical form of the radionuclides assumption, the NRC has determined description of the analysis inputs, released, and (5) timing of the that any change to the design basis to assumptions, methodology, and results radioactivity release. Although all five use an alternative source term should be of these analyses for NRC review, characteristics should be addressed in reviewed and approved by the NRC in Applicable evaluations may include, but applications proposing the use of an the form of a license amendment. are not limited to, those previously 1 alternative source term, there may be Changes to the source term, by itself, performed to show compliance with technicallyjustifiable applications in would ordinarily constitute a no S 100.11, S 50.49 Part 50 Appendix A which all five characteristics need not signif! cant hazards consideration. In GDC-19, S 50.34(f), and NUREG-0737 i be addressed. The NRC intends to allow addition, generic analyses performed by requirements ll.B.2, ll.B.3, III.D.3.4. The I licensees flexibility in implementing the NRC staff in support of this regulatory guide that supports this l alternative source terms consistent with proposed rule have indicated that there proposed rule will provide guidance on  !

maintaining a conservative, clear, are potential changes to the facility as . the scope and extent of analyses uvd to logical, and consistent plant design documented in the FSAR which would basis. The regulatory guide that constitute a no significant hazards show compliance with this rule and on the assumptions and methods used supports this proposed rule will contain consideration. However, such therein. It is not the NRC's intent that guidance on an acceptable basis for determinations would have to be made all of the design basis radiological defining the characteristics of an for each proposed change based upon analyses for a facility be performed alternative source term. facility-specific evaluations. The again as a prerequisite for approval of pr cedural requirements for processing the use of an alternative source term.

B. Section 50.67(a) a license amendment are given in The NRC does expect that the applicant This paragraph would define the 55 50.90 through 50.92. will perform sufficient evaluations, licensees that may seek to revise their The NRC's regulations provide a supported by calculations as warranted. t current radiological source term with an regulatory mechanism for a licensee to to demonstrate the acceptability of the I alternative source term. The proposed effect a change in its design bads in proposed amendment.

rule is applicable only to holders of S 50.59. That section allows a licensee to nuciear power plant operating licenses make changes to the facility as D. Sections 50.67(b)(2)(1), (11), (in) that were issued under 10 CFR Part 50 described in the final safety evaluation These subparagraphs would contain before January 10,1997. The proposed report (FSAR) without prior NRC the three criteria for NRC approval of rule would not require licensees to approval, unless the proposed change is, the license amendment to use an revise their current source term. The deemed to involve an unreviewed safety alternative source term. A detailed NRC considered the acceptability of the question (USQ), or involves a change to rationale for the use of 0.25 Sv (25 rem)

TID-14844 source term at current the technical specifications TEDE as an accident dose criterion and operating reactors and determined that incorporated into the facility license. If the use of the 2-hour exposure period the analytical approach based on the a USQ is determined to exist or if a resuliing in the maximum dose for TID-14844 source term would continue change to the technical specifications is future LWRs is provided at 61 FR G5157; to be adequate to protect public health involved, the licensee must request NRC December 11,1996. The same and safety, and that operating reactors approval of the ci mge using the license considerations that formed the basis for licensed under this approach should not amendment process detailed in S 50.90. that rationale are similarly applicable to be required to reanalyze design basis The criteria for determining that a USQ operating reactors that elect to use an accidents using a new source term. The is involved appear in S 50.59. alternative source term. The NRC proposed rule does not explicitly define Significant to this proposed rule is the believes that it is technically an attemative source term. in lieu of an criterion that a USQ would exist if the appropriate and logical to extend the explicit reference to FUREG-1465, proposed change resulted in an increase philosophy o. decoupling of design and Footnote 1 to the proposed role in consequences of an accident or siting, and the dose criteria established b_ _ _

12122 Fedircl Registir/Vcl. 64, No. 47/ Thursday, March 11,1999/ Proposed Rules for future LWRs to operating reactors features. Third S 20.1206 permits a did not change the existing control room that elect to use an alternative source once.in-a-lifetime planned special dose whole body (or equivalent) dose term. of five times the annual dose limits. criterion in GDC-19. Thus, exemptions The NRC is proposing to replace the Also, Environmental Protection Agency from the dose critetla in the current current GDC-19 dose criteria for (EPA) guidance sets a limit of five times GDC-19 were necessary in the design operating reactors that elect to use an the annual dose limits for workers certification process for the alternative source term with a criterion performing emergencv services such as Westinghouse AP-600 advanced LWR of 0.05 Sv (5 rem) TEDE for the duration lifesaving or protection of large in order to use the 0.05 Sv (5 rem) TEDE of the accident.This criterion would be popuhtions. Considering the individual criterion deemed necessary for use with included in 5 50.67 rather than GDC-19 organ weighting factors of 5 20.1003 and alternative source terms. Exemptions in order to co-locate all of the dose assuming that only the exposure from a would arguably be necessary for future requirements associated with alternative single organ contributed to TEDE, the applicants for construction permits, source terms. The bases for the NRC's organ dose, although exceeding the dose design certificat.ons, and combined decision are: first, that the criteria in specified in S 20.1201(a), would be less operating licenses. This proposed GDC-19 and that in the proposed rule than that considered acceptable as a change would eliminate the need for are based on a primary occupational planned special dose or as an these exemptions, exposure limit. Second. the language in emergency worker dose. The NRC is not GDC-19: "5 rem whole body, or its suggesting that control room dose E Secd ns 21.3,5&2 Sa4W(1)(#(CA

' equivalent to any part of the body" is - during an accident can be treated as a Sa65(W(1), and 54.4(a)(1)(li#

subsumed by the definition of TEDE in planned special exposure or that the These sections would be revised to S 20.1003 and by the 0.05 Sv (5 rem) EPA emergerey we r dose limits are conform with the relocation of accident TEDE annuallimit in S 20.1201(a). an alternative to GDC-19 m inc dose criteria from 5100.11 to S 50.67 for Although the weighting factors stated in proposed rule. H;we"er, the NRC does operating reactors that have amended S 20.1003 for use in determining TEDE believe that these provis!ons offer a their design bases to use an alternative differ in magnitude from the weighting useful perspective that supports the source term.

factors implied in the 0.3 Sv (30 rem) conclusion that the organ doses implied G. Section 50.34 thyroid criteria used for showing by the proposed 0.05 Sv (5 rem) compliance with GDC-19, these criterion can be considered to be A new footnote to S 50.34 would be differences are the result of acceptable due to the relatively low added to define what constitutes an improvement in the science of assessing probability of the events that could accident source term. This new footnote internal exposures and do not represent result in doses of this magnitude. is identical to the existing footnote I to a reduction in the level of protection. Although the dose criteria in the S 100.11, and is being added to provide Third, as discussed earlier, the use of proposed rule would supersede the dose for consistency between Parts 50 and TEDE in conjunction with alternative criteria in GDC-19, the other provisions 100.

source terms has been deemed of GDC-19 remain applicable. II. Sections 50.34(I)(2)(vil), (viii), (xxvi) appropriate and necessary. Fourth, the use of TEDE for the control room dose E.10 CFR Part 50, Appendix A GDC- and (xxvill) 19 These paragraphs would be revised to criterion is consistent with the use of TEDE in the accident dose criteria for GDC-19 would be changed to include replace an explicit reference to the offsite exposure. the TEDE dose criterion for control " TID-14844 source term" with a more The NRC is not including a " capping" room design for applicants for general reference to " accident source limitation, an additional requirement construction permits, design term." These changes potentially affect that the dose to any individual organ certifications, and combined operating two classes of applicants. The first not be in excess of some fraction of the licenses that submitted applications affected class is facilities that obtain total as provided for routine after January 10,1997 (the effective date combined licenses under part 52.

occupational exposures. The bases for of the 1996 rulemaking adopting the Section 52.47(a)(ti) states that the NRC's decision are: first, that this TEDE criterton), and for those licenses applications for combined licenses must non-inclusion of a " capping" limitation using an alternative source term under contain, inter alla, " demonstration of is consistent with the final rule 5 50.67. The proposed change to GDC- compliance with any technically-published in December 11,1996 (61 FR 19 addresses the use of alternative relevant portions of the Three Mile 65157), with regard to doses to persons source terms at operating reactors and a Island requirements set forth in offsite. Second, the use of 0.05 Sv (5 deficiency identified in the regulatory S 50.34(f)." Section 50.34(f) contains rem) TEDE as the control room criterion framework for early site permits, several references to the TID-14844 does not imply that this would be an standard design certifications, and source term. These references would be acceptable exposure during emergency combined licenses under part 52. modified to delete the reference to TID-conditions, or that other radiation Sections 52.18,52,48, and 52.81 14844. This would make it clear that protection standards of Part 20, establish that applications filed under applicants for combined licenses would including individual organ dose limits, part 52 Subparts A B, and C, not use the TID-14844 source term but might not apply. This criterion is respectively, will be reviewed according would use the source term in the provided only to assess the acceptability to the standards given in 10 CFR parts referenced design certification, or a of design provisions for protecting 20,50,51,55,73, and 100 to the extent source term that isjustified in the contral room operators under postulated that those standards are technically combined license application.

DBA conditions. The DBA conditions relevant to the proposed design. The second affected class is the small assumed in these analyses, although Therefere, GDC-19 is pertinent to subset of plants that had construction credible, generally do not represent applications under part 52. The final permits pending on February 16,1982.

actual accident sequences but are rule that became effective on January 10, With the proposed change, these plants specified as conservative surrogates to 1997 (61 FR 65157; December 11,1996), could use either the TID-14844 source create bounding conditions for assessing established accident TEDE criteria (in term or an alternative source term in the acceptability of engineered safety 5 50.34) for applicants under part 52 but their operating license applications.

A-

Federal Register /Vol 64, No. 47/ Thursday, March 11,1999/ Proposed Rules 12123 V. Future Regulatory Action Copies of issued regulatory guides (E.O.) 12898, " Federal Actions to The NRC is developing the following may be purchased from the Government Address Environmental Justice in regulatory guides and Standard Review Printing Office (GPO) at the current GPO Minority Populations and Low-income Plan sections to provide prospective Price. Information on current GPO Populations," dated February 11,1994.

applicants with the necessary guidance prices may be obtained by contacting in accordance with that Executive for implementing the proposed the Superintendent of Documents, U.S. Order, the NRC has determined that regulation. The draft guide and draft Government Printing Office, P.O. Box there are no disproportionately high and Standard Review Plan section will be 37082, Washington, DC 20402-9328. adverse impacts on minority and low issued to coincide with the publication Issued guides also may be purchased income parties. In the letter and spirit of the final regulations that would from the National Technical Information of E.O.12898, the NRC is requesting implement this proposed rulemaking. A Service (NTIS) on a standing order public comments on any environmental notice of availability for J ese materials basis. Details on this service may be justice considerations or questions that will be published in the i ederal obtained by writing NTIS,5826 Port the public thinks may be related to this Register at a future date. Royal Road, Springfield VA 22161. proposed rule, but that somehow were Copies of SECY-94-302, SECY not addressed. The NRC uses the

1. Draft Guide DC-1081, " Alternative 242 SECY-98-154. TID 14844, and TR- following wor king definition of Radiological Source Terms for 105909 are available for inspection and environmentaljustice: Environmental Evaluating the Radiological copying for a fee at the NRC Public justice means the fair treatment and Consequences otDesign Basis Accidents Document Room 2120 L Street, NW at Bolling and Pressurized Water meaningful involvement of all people' (Lower Level) Washington, DC. ren,ardless of race, ethnicity, culture, VIL Draft Finding of No Significant income, or educational level with This guide is expected to present EnvironmentalImpact: Availability respect to the development, regulatory guidance on the implementation and enforcement of implementation of an alternative source The NRC has determined under the National Environmental Policy Act of environmental laws, regulations, and term at an operating reactor. The guide policies. Comments on any aspect of the 1969, as amended, and the NRC s is expected to adit ess issues invol' d limited or selective implementatio af regulations in Subpart A of 10 CFR Part environmental assessment, including 51, that this regulation is not a major environmentaljustice, may be an alternative source term and submitted to the NRC as indicated probabilistic risk assessment (PRA) Federal action significantly affecting the quality of the human environment and, under the ADDRESSES heading.

issues related to plant modifications based on an attemative source term, and therefore, an environmental impact The draft environmental assessment statement is not required. This proposed and the draft finding of no significant le would allow operating reactors to impact on which this determination is xtent af e ed BA ra loloE al replace the traditional TID-14844 based are available for inspection at the P" s urce term with a more realistic source NRC Public Document Room 2120 L ti a. The gui e is ex ted o Street NW (Lower Level), Washington.

include revised assumptions and term based on the insights gained from extensive accident research activities. DC. Sin 8;e copies of the environmental methods for each affected DBA in a The actual accident sequence and assessment and finding of no significant series of appendices. These appendices will supersede the guidance in Pmgression would not be changed; it is impact are available from Mr. Stephen the regulatory assumptions regarding F. LaVie, Office of Nuclear Reactor Regulatory Guides 1.3,1.4,1.25, and the accident that would be affected by Regulation, U.S. Nuclear Regulatory the change. The use of an alternative NRC, Washington, DC 20555-0001, egula ory de .89 for t se telephone: 301-415-1081, or by Internet facilities using an alternative source s urce term alone cannot increase the term. c re damage frequency (CDF) or the electronic mail to sfl@nrc. gov.

large early release frequency (LERF) or VIII. Paperwork Reduction Act i

2. Standard Review Plan Section,15.0.1, actual offsite or onsite radiation doses-Statement

" Radiological Consequence Analyses An alternative source term could be Using Alternative Source Terms" used tojustify changes in the plant This proposed rule increases the This SRP section presents guidance to design that might have an impact on burden on licensees by requiring that NRC staff in the review of the adequacy CDF or LERF or that might increase when seeking to revise their current oflicensee submittals requesting nffsite or rmsite doses. These potential accider source term in design basis approval for use of an alternative source changes are subject to existing radiologcal consequence analyses, they term. requirements in the NRC's regulations. apply for an amendment under S 50.90.

Thus, the level of protection of public The public hurden for this information VI. Referenced Documents health and safety provided in NRC collection is estimated to average 609 Copies of NUREG-0737 NUREG- regulations would not be decreased by hours per request. Becausuhe burden 0800, NUREG-1465, and NUREG/CR- this proposed rule. The proposed rule for this information collection is i 6204 may be parchased from the would not affect non-radiological plant inalgnificant. Office of Management and Superintendent of Documents, U.S. effluents and would have no significant Budget (OMB) clearance is not required.

Governraent Printing Office, Mall Stop environmental impact. Existing requirements were approved by SSOP, Washington, DC 20402-9328. As discussed above, the the Office of Management and Budget, Copies also are available from the determination of the environmental approval number 3150 0011.

National Technical Information Service, assessment is that there would be n 5285 Port Royal Road, Springfield, VA Public Protection Notification significant offsite impact on the public 22161. A copy also is available for from this action. Ilowever, the general if an information collection does not

!nspection and copying for a fee in the public should note that the NRC display a cunently valid OMB control NRC Public Document Room,2120 L welcomes public participation. Also, the number, the NRC may not cor' duct or Street, NW (Lower Level), Washington, NRC has committed itself to complying sponsor, and a person is not equired to DC. in all its actions with Executive Order respond to, the informatior, collection.

12124 Feder:1 R: gist:r/Vol. 64, No. 47/ Thursday, March 11,1999/ Proposed Rules IX. Regulatory Analysis reactors, Reporting and recordkeeping 2239). Section 50.78 also issued under sec, requirenents. 122,68 Stat. 939 (42 U.S.C. 2152). Sections The Commission has prepared a 50.80-50.81 also issued under sec.184,68 regulatory analysis on this regulation. Fo e r asons oted in t reamble Stat. 954, as amended (42 U.S.C. 2234).

Interested persons may examine a copy Y Appendix F also issued under sec.187,68 l i of the regulatory analysis at the NRC Energy Act of 1954, as amended, the Stat. 955 (42 U.S.C 2237). l Pubhc Document Room,2120 L Street En r R r8 " "

NW, (Lower Level), Washington, DC.

, d and 5 C. 3 he Cs 4. Section 50.2 is amended by )

Single copies of the analysis are proposing the following amendments to republishing the introductory text, by {

10 CFR Parts 21' 50, and 54- reviSin8 Paragraph (1)(111) of the j available from Mr. Stephen F, LaVie, '

definition of Basic component and by Office of Nuclear Reactor P.egulation, adding in alphabetical order the PART 21-REPORTING OF DEFECTS U.S. Nuclear Regulatory Commission

• definition for Source term to read as AND NONCOMPLIANCE Washington, DC 20555-0001, telephone: follows:

301-415-1081, or by Internet electronic 1. The authority citation for part 21 mall to sfl@nrc. gov. continues to read as follows: 5 50.2 Definitions.

X. Regulatory Flexibility Certification Authority: Sec.161, 68 Stat. 948, as As used in this part, amended, sec. 234,83 Stat. 444, as amended. * * * *

• As required by the Regulatory sec.1701,106 Stat. 2951,2953 (42 U.S.C. Basic component * *

• Flexibility Act of 1980,5 U.S.C. 605(b), 2201,2282,22970; secs. 201, as amended, 200. 88 Stat.1242, as amended, 1246 (42 (1) * * * .

the Commission certifies that this (lii) The capability to prevent or regulation will not hwe a significant U 584l 58 mitigate the consequences of accidents economic impact on a substantial 2l2 de m m which could result in potential offsite 141, Pub. L.97-425,96 Stat. 2232,2241 (42 number of small entities. This proposed U.S.C.10155,10161). exposures comparable to those referred regulation will affect only the licensing to in S 50.34(a)(1), S 50.67(b)(2), or and operation of nuclear power plants. 2. Section 21.3 is amended b) S 100.11 of this chapter, as applicable. '

The companies that own these plants do republishing the introductory text and , , , , ,

not fall within the definition of "small revising Paragraph (1)(1)(C) of the definition of Basic component to read as Source term refers to the magnitude entities" found in the Regulatory . and mix of radionuclides released from Flexibility Act or within the size f II WS the reactor core to the reactos standards established by the NRC (April $ 21.3 Definitions. containment, their physical and i1,1995; 60 FR 18344). chemical form, and the timing of their As used !n this part:

XI. Backfit Analysis Basic component. (1)(1) * *

• release.

('C) The cape ' .y to prevent or * * * *

• The NRC has determined that the mitigate the consequences of accidents 5. Section 50.34 is amended by backfit rule in 10 CFR 50.109, does not which could result in potential offsite revising paragraphs (f)(2)(vil), (viii),

i apply to this proposed regulation and exposures comparable to those referred (xxvi), and (xxviii) to read as follows: i that a backfit analysis is not required for to in S 50.34(a)(1), S 50.67(b)(2), or I this proposed regulation because these S 100.11 of this chapter as applicable. $ 50,34 Contents of applications; techr:Icel amendments do not involve any . . . . . Information.

provisions that would impose backfits * * * *

• as defined in 10 CFR 50.109(a)(1), This PART 50-DOMESTIC LICENSING OF (f) * *

• proposed regulation amends the NRC's PRODUCTION AND UTILIZATION (2) * *

• regulations by establishing alternate FACILITIES (vil) Perform radiation and shielding requirements that may be voluntarily design reviews of spaces around adopted by licensees. 3. The authority citation for part 50 systems that may, as a result of an continues to read as follows: accident, contain accident source term H List of Subjects radioactive materials, and design as Authority: Secs. 102,103,104,105,161, 10 CFR Part 21 182.183,186,189. 68 Stat. 936,937,938, necessary to permit adequate access to 948,953. 954,955,956, as amended, sec. important areas ai.4 to protect safety Nuclear power plants and reactors, 234,83 Stat. 444, as amended (42 U.S.C. equipment from the radiation Penalties, Radiation protection. 2132,2133,2134,2135,2201,2232,2233, environment. (JI.B.2)

Reporting and recordkeeping 2236, 2239,2282); secs. 201, as amended. (viii) Provide a capability to promptly requirements. 202. 206,88 Stat.1242, as amended,1244, obtain and analyze samples from the 10 CFR Part 50 t on 7a e lub.L.95-

$ reactor coolant system and containment 9601, sec.10. 92 Stat. 2951 (42 U.S.C. 5851). that may contain accident source term 12 Antitrust, Classified information, Section 50.10 also issued under secs.101, radioactive materials without radiation Criminal penalties, Fire protection, 185,68 Stat. 955 as amended (42 U.S.C. 2131, exposures to any individual exceeding 5 Intergovernmental relations Nuclear 2235), sec.102, Pub. L. 91-9190, 83 Stat. 853 rems to the whole body or 50 rems o power plants and reactors, Radiation (42 U.S.C. 4332). Sactions 50.13. 50.54(dd).

protection, Reactor siting criteria, and 50.103 also issued under sec.108,68 nThe fission product release assumed for these Reporting and recordkeeping Stat. 939, as amended (42 U.S.C. 2138). calculations should be based upon a major accident.

requirements. Sections 50.23, 50.35, 50.55. and 50.56 also hypothesized for purposes of site analysis or issued under sec.185,68 Stat. 955 (42 U.S.C. postulated from considerauons of possible 10 CFR Part 55 223). Sections 50.33a,50.55a and Appendix accidental events, that would result in potenda!

Q also issued under sec,102, Pub. L. 91- hazards n t exceeded by those from any accident Administrative practice and Se considned cnMeluch accidents han gennaHy procedure, Age-related degradation, 9190' 50.34 and 83 Stat.

50.54 also 853 issued(42 underU.S.C. $"E"ja' $Nr'eN,'"S)p$NUe 204, 4332)sec.ctions Backfitting, Classified information, 88 Stat.1245 (42 U.S.C. 5844). Sections quantioes of rissic.n productt

' Criminal penalties, Environmental 50.58, 50.91, and 50 92 also issued under n See footnote il to paragraph (f)(2)(vit) of thh protection Nuclear power plants and Pub. L. 97-9415,96 Stat. 2073 (42 U.S.C. secuan.

I ,

Fedcral Register /Vol. 64, No. 47/ Thursday, March 11,1999/ Proposed Rules 12125 the extremities. Materials to be analyzed remain functional during and following (iii) Adequate radiation protection is and quantified include certain design basis events to ensure the provided to permit access to and radior;uclides that are indicators of the integrity of the reactor coolant pressure occupancy of the control room under degree of core damage (e.g., noble gases, boundary, the capability to shut down accident conditions without personnel radiolodines and cesiums, and the reactor and maintain it in a safe receiving radiation exposures in excess nonvolatile isotopes), hydrogen in the shutdown condition, or the capability to of 0.05 Sv (5 rem) total effective dose l containment atmosphere, dissolved prevent or mitigate the consequences of equivalent (TEDE) for the duration of gases, chloride, and boron accidents that could result in potential the accident.

concentrations. (ll.B.3) offsite exposure comparable to the 9. Part 50 Appendix A,IL, General

. . . . . guidelines in S 50.34(a)(1), S 50.67(b)(2), Design Criterion 19, is revised to read as (xxvi) Provide for leakage control and or S 100.11 of this chapter, as follows:

detection in the design of systems applicable.

• * * *

• Appendix A to Part 50--General Design outside containment that contain (or might contain) accident source term i3 8. Part 50 is amended by adding Criteria for Nuclear Power Plants radioactive materials following an S 50.67 to read as follows: ,,,

accioent. Applicants shall submit a

$ 50.67 Accident source term. Criterion 19-Contm/ room. A control leakage control program, including an initial test program, a schedule for re- (a) Applicability. The requirements of room shall be provided from which actions testing these systems, and the actions t this section apply to all holders of can be taken to operate the nuclear power operating licenses issued prior to unit safely under normal conditions and to be taken for minimizing leakage from january 10.1997, who seek to revise the maintain it in a safe condition under accident such systems. The goal is to minimize c ndiu ns. including lowo0 coolant potential exposures to workers and current accident source term used in accidents. Adequate radiation protection

' 8 " i it acces and public, and to provide reasonable rne t? I 11censee hh shj pt assurance that excessive leakade will seeks to revise its current accident accident conditions without personnel not prevent the use of systems needed source term in design basis radiological receiving radiation exposures in excess of 5 in an emergency. (lli.D.I.1) consequence analyses sinll apply for a rem whole body, or its equivalent to any part license amendment under S a0.90. The of the body, for the duration of the accident.

(xxvill) Evaluate potential pathways application shall contain an evaluation Equipment at appropriate locations outside for radioac'ivity and radiation that may of the consequences of applicable the control room shall be provided (1) with lead to control room habitability design basis accidents I previously "Mt{jgncapabili

, ,t9 for prom hot shutdown problems under accident conditions analyzed in the safety analysis report.

resulting in an accident source termu Instrumentation and controls to maintain the (2) The NRC may issue the unit in a safe condition during hot shutdown, release, and make necessary design amendment only if the applicant's and (2) with a potential capability for provisions to pteclude such problems, analysis demonstrates with reasonable subsequent cold shutdown of the reactor (Ill.D.3.4) assurance that: through the use of suitable procedures.

6. Sec. tion 50.49 is amended by (1) An individuallocated at any point Applicants for construction permits under revising paragraph (b)(1)(1)(C) to read as on the boundary of the exclusion area this part or a design certification or combined follows: for any 2-hour period following the license under part 52 of this chapter who onset of the postulated fission product apply on or after January 10.1997, or holden s

$ 50.49 Environmental quellfication of release, would not receive a radiation d perating licenses using an alternative olectric equipment important to safety for s um erm under S 50.67, shall meet the nuclear power plants. dose in excess of 0.25 Sv (25 rem) 2 total requirements f this criterion, excapt that j w e8ad m contml mmn accus anci effective doseuallocated (11) An indivi ehutvalent at ar(TEDE)iyoccupancy, Point adequate radiation protection y

(b) * *

• on the outer boundary of the low shall be provided to ensure that radiation 1

(1) * *

• population zone, who is exposed to the exposures shall not exceed 0.05 Sv (5 rem)

(i) * *

• radioactive cloud resulting from the total effective dose equivalent (TEDE) as j (C) The capability to prevent or postulated fission product release defined in 5 50.2 for the duration of the j mitigate the consequences of accidents (during the entire period of its passage), accident.

that could result in potential offsite would not receive a radiation dose in * * * *

• l exposures compa+able to the guidelines excess of 0.25 Sv (25 rem) total effective  !

In S 50.34(a)(1), S 50.67(b)(2), or S 100.11 dose equivalent (TEDE). PART 54-REQUIREMENTS FOR  !

of this chapter, as applicable. RENEWAL OF OPERATING LICENSES

• * * *

• 8 The Assion product release assumed for these FOR NUCLEAR POWER PLANTS crJculations should be based upon a major accident.

7. Section 50.65 is amended by hypothesized rur purposes of design anaiyses or 10. The authority citation for part 54 revising paragraph (b)(1) to read as postulated from constderations of possible continues to read as follows; follows: accidental events, that would resuh in potenttal hazards not exceeded by unnse from any accident Authority: Secs. 102,103,104,161,181,

$ 50.65 Requirements for monitoring the constdered credible Such accidents have generally 182,183.186.189,68 Stat. 936,937,938. j effectiveness of maintenance at nucioar been assmned to result in substantial melutown of 948,953,954,955, as amended, sec. 234,83 l power plants. the core with subsequent release of appreciable Stat.1244, as amended (42 U.S C. 2132. 2133, i

, , , , , quantitles of fission products 2134.2135.2201,2232.2233,2236,2239, 2The use of 0.25 Sv (25 rem) TfDE is not 2282); secs 201,202,206. 88 Stat.1242,1244.

(b) * *

• Intended to imply that this value constitutes an as amended (42 U.'i C. 5841,5842), E.O.

(1) Safety-related structures, systems acceptable limit for emergency doses to the pubhc M829,3 CFR 1993 Comp.. p. 570; E.O.  ;

and companents that are relied upon to ",*Ij'gjd*"d',

3 , j,"j,$'N'in $ se t [n$s 12958, as amended. 3 CFR,1995 Comp., p.  !

a referem value. which can be used in the 333; E.O.12968, 3 CFR.1995 Comp., p. 391. l u See footnote iI to paragraph (f)(2)(vti) of this evaluation of proposed design basis chenges with secuon- respet.t to potential reactor accidents of exceedingly !1. Section 54.4 is amended by l u See foomote 11 to paragraph (f)(2)(vil) of this low probability uf occurrerne and low risk of public revising paragraph (a)(1)(ill) to read as j nectkm, exposure to radiation- follows:

l I

12126 Federal Register /Vot 64, No. 47/ Thursday, March II,1999/ Proposed Rules 554.4 scope, SUPPLEMENTARY INFORMATION: patterns. The FAA establishes Class E (a) * *

• Comments invited airspace where necessary to contain (1) * *

• aircraft transitioning between the Interested parties are invited to terminal and en route environments.

T W mitigate the conse uenc s of acc dents Participate in this proposed rulemaking The intended effect of this proposal is

" i WS- d i d to provide safe and eff cient which could result in potential offsite har"g m e a es fe d

"[g"5 o 34(a 1 S 6 (2)- r Comments that provide the factual basis promote safe flight operations under supporting the views and suggestions S 100.11 of this chapter, as applicable. Instrument Flight Rules (IFR) at the  :

presented are particularly helpful in Constrip Airport and between the developing reasoned regulatory terminal and en route transition stages.

Dated at Rockv111e, Maryland. this 5th day decisions on the proposal. Comments of March 1999. The area would be depicted on are specially invited on the overall aeronautical charts for pilot reference.

For the Nuclear Regulatory Commission. regulatory, aeronautical, economic, Annette Vietti-Cook, The coordinates for this airspace docket environmental, and energy related are based on North American Datum 83.

Secretaryohhe Commission. aspects of the proposal.

Class E airspace areas extending upward Communications should identify the

[FR Doc. 5L6058 Filed 3-10-99; 8:45 amj from 700 feet or more above the surface sumo cooe neo-os-u airspace docket number and be I of the earth, are published Paragraph submitted in triplicate to the address 6005, of FAA Order 7400.9F dated listed above. Commenters wishing the September 10,1998, and effective FAA to acknowledge receipt of their September 16,1998, which is DEPARTMENT OF TRANSPORTATION comments on this notice must submit, with those comments, a self-addressed incorporated by reference in 14 CFR 71,1, The Class E airspace designation Federal Aviation Administration stamped postcard on which the listed in this document would be following statement is made: published subsequently in the Order.

14 CFR Part 71 " Comments to Atrspace Docket No. 99- The FAA has determined that this ANM-02." The postcard will be date/ proposed regulation only involves an (Airspace Docket No. 99-ANM-02] time stamped and returned to the established body of technical commenter. All communications regulations for which frequent and Proposed Revision of Class E received on or before the specified Alespace; Colstrip, MT routine amendments are necessary to closing date for comments will be keep them operationally current. It.

AGENCY: Federal Aviation c nsidered before taking action on the therefore, (1) is not a "significant pmp sed rule. The proposal conta'ned regulatory action" under Executive Administration (FAA). DOT. in this notice may be changed in the ACTION: Notice of proposed rulemaking Order 12866: (2) is not a "significant light of comments received. All rule" under DOT Regulatory Policies (NPRM). comments submitted will be available and Procedures (44 FR 11034: February f r examinati n at the address listed 26,1979); and (3) does not warrant

SUMMARY

This proposal would amend the Colstrip. MT, Class E area and a both We and ak & closing preparation of a Regulatory Evaluation date for comments. A report as the anticipated impct is so minima!.

provide additional controlled airspace summarizing each substantive public to accommodate the development of Since this is a routine matter that will .

c ntact with FAA personnel concerned only affect air traffic procedures and air l new Standard instrument Approach Procedures (SIAP) utilizing the Global with this rulemaking will be filed in the navigation, it is certified that this rule.

docket. when promulgated, will not have a Positioning System (GPS) at the Colstrip, Airport. Availability of NPRM's significant economic impact on a 1 DATES: Comments must be received on Any person may obtain a copy of this 5"b$ " ""'

NPRM by submitting a request to the under e e I of eR 1 or before April 26.1999.

Federal Aviation Administration. Flexibility Act' ADDRESSES: Send comments on the proposal in triplicate to: Manager, Airspace Branch, ANM-520,1601 Lind List of Subjects in 14 CFR Part 71 Airspace Branch, ANM-520, Federal Avenue SW, Renton, Washington Airspace, incorporation by reference, Aviation Administration, Docket No. 98055-405u. Communications must Navigation (air).

99-ANM-02,1601 Lind Avenue SW, identify the notice number of this Renton, Washington, 98055-4056. NPRM. Persons interested in being The Proposed Amendment The official docket may be examined placed in a mailing list for future In consideration of the foregoing, the in the office of the Assistant Chief NPRM,s should also request a copy of Federal Aviation Administration Counsel for the Northwest Mountain Advis ry Circular No. Il-2A, which proposes to amend 14 CFR part 71 as Region at the same address. describes the application procedure. rollows:

An infornial docket may also be The Proposal examined during normal business hours PART 71-DESIGNATION OF CLASS A, The FAA is considering an CLASS B, CLASS C, CLASS D, AND in the office of the Manager. Air Traffic amendment to Title 14 Code of Federal Division. Altspace Branch, at the CLASS E AIRSPACE AREAS; Regulations, part 71 (14 CFR part 71) by AIRWAYS; ROUTES, AND REPORTING address listed above. revising Class E airspace at Colstrip- POINTS FOR FURTHER INFORMATION CONTACT: MT, in order to accommodate two new Dennis Ripley, ANM-520.6. Federal GPS SIAP to the Colstrip Airport. This 1. The authority citation for 14 CFR Aviation Administration, Docket No. amendment would provide additional part 71 continues to read as follows:

99-ANM-02,1601 Lind Avenue SW. airspace by lowering the Class E area to Authority: 49 U S C.10G(g). 40103. 40113.

Renton, Washington 98055-4056; the west in order to meet current criteria 40120. E O 10854,24 FR 9565. 3 CFR,1959-telephone number: (425) 227-2527. standards associated with SIAP holding 1963 Comp., p 389.

7 .

DRAFT ENVIRONMENTAL ASSESSMENT REVISION OF 10 CFR PARTS 21,50, AND 54 The Nuclear Regulatory Commission (NRC)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 a revised source term from NUREG-1465, Accident Source Terms forLight-WaterNuclearPowerPlants.

Identification of Action The NRC is proposing to amend 10 CFR Part 50 by adding a new section, @50.67, to address the use of alternative accident source terms. Section 50.67 would apply to all holders of operating licenses issued before January 10,1997, that seek to amend their facility design basis to replace the current accident source term with an alternativa source term on or after the publication date of the final regulation. These licensees would be required by @50.67 to evaluate the radiological consequences of the design basis accidents previously analyzed in the i safety analysis report, and to request a license amendment under @50.90. Acceptance criteria for the accident radiological consequence analyses appear in @50.67. These criteria are accident dose guidelines for evaluation of releases of radioactivity to the environment and the resulting exposures to persons offsite, and dose criteria for plant personnel occupying the control room during postulated accidents.

The proposed rule amends a current regulation by establishing alternate requirements that licensees may voluntarily adopt. The NRC concluded that the existing analytical approach I

based on the current source term continues to be adequate to protect public health and safety; therefore, the NRC does not intend to backfit the alternative source terms or the changes in accident dose guidelines and control room habitability criteria on operating power reactors.

Because the proposed revision to the regulation would not constitute a backfit, the bases for existing nuclear power plants must be preserved. For this reason, the current accident dose guidelines in @100.11 and the current control room habitability criteria of Appendix A to 10 CFR Part 50 would remain in effect for those licensees that do not apply for the use of an alternate source term. l The NRC is also proposing to amend 10 CFR Part 50 by revising 10 CFR Part 50, Appendix A, GDC-19 to use a dose criterion based on total effective dose e;quivalent. The revised criterion, which would be an alternative 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, that apply on or after January 10, i997, or holders of operating licenses using an alternative source term.

Need for the Action Use of Alternative Source Terms 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 Docu-ment (TID) 14844, Calculation of Distance Factors for Power and Test Reactor Sites (1962).

Although initially applied to the evaluation of proposed reactor sites, these fission product release assumptions, known collectively as the " source term," have been used in several EA-1 l-

@ r- -

l l regulatory applications related to light-water reactors. This source term was a key input to a 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 TID-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 compo-sition and magnitude, physical and chemical form, and timing of release. For design basis accident assessments, the NUREG-1465 source terms are comparable to the TID-14844 source term with regard to the magnitude of the noble gas and radiolodine release fractions.

However, the revised source' terms provide a more representative description of the radionuclide composition and release timing, ,

The objective of NUREG-1465 was to define revised accident source terms for regulatory '

application for future light water reactors. The NRC'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 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 NRC considered the applicability of the revised source terms to (swrating reactors and determined

. that the current analytical approach based 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 reanalyze design basis accidents using the revised source terms. The NRC also concluded that some licensees may wish to use alternative source terms in analyses to support operhtional flexibility and cost-beneficiallicensing actions. These actions could reduce unnecessary regulatory burden.

r in January 1997, the NRC amended its regulations in 10 CFR Parts 21,50,52,54, and 100 (61 FR 65157).' That regulatory action provided siting criteria for future sites and relocated source term and dose requirements for future plants into Part 50. Because these dose require-ments tend to affect reactor design rather than siting, they are more appropriately located in Part 50. Because the revised criteria would not apply to operating reactors, the non-seismic and seismic reactor site criteria for operating reactors were retained as Subpart A and Appendix j A to Part 100, respectively. The revised reactor site criteria were added as Subpart B in Part 100, and revised source term and dose requirements were relocated to $50.34. The existing j source term and dose requirements of Subpart A of Part 100 would remain in place as the 1 licensing bases for those operating reactors that do not elect to use an alternative source term.

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 the thyroid gland with a single, total effective dose equivalent (TEDE) value.

The dose guidelines for the whole body and thyroid, and for the immediate 2-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 pubEshed. However, the current dose guidelines, by focusing on doses to the thyroid and

' whole body, assume that the major contributor to doses would be radioiodine. Although this may 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 EA-2

P , .

postulated che'mical and physical forms of radiolodine in the revised source terms are more amenable to m ' itigation and, as such, radiobdine may not always be the predominant radionuclide in an accident release. The revised source terms include a larger number of radionuclides than did the TID-14844 source term as implemented in regulatory guidance. The whole body and thyroid dose guidelines ignore these contributors to dose. The TEDE, using a '

~r isk-consistent me.thodologyiassesses the impact of all relevant nuclides upon all body organs.

- Although it is expected that, in many cases, the thyroid could still be the limiting organ and radioiodine the limiting radionuclide, this conclusion cannot be assured in all potential cases.

The revised source terms postulate that the core inventory is released in a sequence of phases over several hours; with the more significant release commencing at about 30 minutes from the start of the event. The assumption that the 2-hour exposure period starts immediately at the. onset of the release is inconsistent with the phased release postulated in.the revised source terms. "A detailed rationale for the use of 0.2L Sv (25 rem) TEDE as an accident dose guideline and the use of the 2-hour exposure period resulting in the maximum dose for future light water reactors (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 NRC believes that it is technically appropriate and logical to extend the dose I

guidelines, established for future LWRs using the revised source term to operating reactors that

elect to use the same revised source term.

. The NRC determined that, for use with the revised source terms, accident dose guidelines and control room habitability should be expressed in terms of TEDE, and that the 2-hour exposure period should be based on the 2-hour period that yields the maximum dose. The proposed 650.67 incorporates these acceptance criteria.

- Conformina Chanoe to GDC-19 The proposed change to GDC-19 is not related to the use of alternative source terms at l operating reactors but is included to address a deficiency identified in the regulatory framework for early site perrnits, 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, B, and C, respectively, would be reviewed according to the standards given in 10 CFR Parts 20, i 50, 51, 55, 73, and 100 to the extent that those standards are technically relevant to the I proposed design. Therefore, GDC-19 is pertinent to applications under Part 52. The recent )

J

' Part 100 rulemaking (61 FR 65157) established accident TEDE guidelines (in $50.34) for applicants under Part 52, but did not establish a revised control room dose criterion. Therefore, ,

I 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 the revised source terms.  !

The proposed change would eliminate the need for exemptions by future applicants under Part  !

52. The proposed change would also be applicable to future applications under Part 50 that are filed on or after January 10,1997. ,

Environmentalimpacts of the Action The implementation of an alternative 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 gained from extensive accident research activities. The actual accident sequence and progression are not changed; it is the regulatory assumptions regarding the accident that would be affected by substituting an alternative source term. Use of an alternative source term done EA-3

~ . 1 cannot increase the core damage frequency (CDF) or the large ently release frequency (LERF) j or actual offsite or onsite radiation doses. (Although actualdoses would not increase, analysis '

results may show an increase in some postulated doses because additional radionuclides would be considered and dose modeling would be more comprehensive.) The source term is used in analyses performed to assess the adequacy of the plant design to contend with a design basis j accident (DBA) in order to ensure adequate defense in depth and adequate safety margins. l The alternative source term could be used to justify changes in the plant design that could have an impact on CDF or LERF or that could increase offsite or onsite doses. These potential changes are subject to existing requirements in the NRC's regulations. Thus, the level of 1 protection of public health and safety provided by the NRC's regulations would not be j decreased by this proposed rulemaking. j

\

The Commission directed the NRC staff to assess t'le imoacts of implementing the revised j 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 enablec by the revised source term. The study also assessed the margin afforded by the revised source term in comparison to assessments performed 'ssing the integrated severe accident assessment code, MELCOR. The study indicated inat the impact of implementing the revised source term at operating reactors would produce lower postulated doses in the majority of cases. The NRC intends 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 best estimate MELCOR analyses )

indicated that the design basis dose calculations using the revised source terms still have a substantial margin (a factor of two or greater). 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 LERF.

1 There is an expectation that many of the alternative source term applications may provide concomitant improvements in overall safety and in reduced occupational exposure, as well as economic benefits. In light of the wide range of possible applications and the voluntary nature of this proposed rule, it is not reasonable to quantify possible outcomes. Occupational '

exposures may be reduced through reductions in maintenance efforts associated with maintaining unnecessarily limiting leakage, timing, or filtration requirements. Overall safety '

may be improved through (1) reduced emergency diesel generator loading, (2) improved contain-ment ventilation system performance due to removal of filter media, and (3) closer synchronization of accident mitigation feature actuation with the onset of major fission product release. There may be improvements in safety margins realized due to the upgrading of l analysis assumptions, methods, and acceptance criteria. I The radiological consequences of DBAs would not be increased by the use of the revised source term. The proposed dose guidelines are comparable, in level of protection, to the l existing guidelines. The proposed rule would not affect non-radiological plant effluents and would have no other environmental impact. Therefore, the NRC concludes that there would be no significant non-radiological environmental impacts associated with the amendments to the regulations.

Alternatives to the Action EA-4

-rf . , l As required by Section 102(2)(E) of National Environmental Policy Act (NEPA) (42 U.S.C.A.

4332(2)(E)), the NRC staff has considered possible alternatives to the proposed action. Most of the altematives considered were related to administrative details such as location of the proposed rule and the means of providing regulatory guidance. These altematives are neutral

- with regard to environmental impact and will not be considered further. With regard to

' environmental impacts, the alternatives can be reduced to (1) retain the existing accident source term, i.e., the no-action attemative, and (2) allow the use of the revised source term. )

)

The first alternative considered by the NRC was to retain the existing accident source term,

'l.e., the no-action altemative.' This was not considered to be an acceptable alternative, because it would preclude the use of an alternative source term by operating reactors and the potential reductions in regulatory burden. This rulemaking alternative would also preclude s potential concomitant improvements in overall safety and in reduced occupational exposure.

The environmentalimpact of a 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. - Because it is not possible to predict the source term 3 applications that may voluntarily be proposed by license with any degree of certainty, this espect is not evaluated further.

The second alternative' considered by the NRC 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 alternative would establish .

the requirements for use of are altemative source term in a new section to Part 50 while retaining the existing regulations in 10 CFR Part 100 Subpart A and GDC-19. The proposed )

. approach was chosen as the best rulemaking alternative. It is believed that the proposed rule would result in an improvement in the allocation of resources both for the NRC and for industry.

The industry would be allowed to propose applications of an alternative source term that could reduce unnecessary or ineffective requirements in the facility design basis. The NRC 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 environmentalimpacts 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 environmentalimpact. Given the conclusion of no significant impact and the economic benefits that could be achieved, this alternative is clearly superior to the no-action alternative.

t Alternative Use of Resources No alternative use of resources was considered. The proposed rule would apply 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 licensing.

Agencies and Persons Consulted The NRC steff developed the proposed rule and this environmental assessment. No l outside agencies or consultants were used in developing this assessment. The NRC staff l obtained advice from the NRC Advisory Committee on Reactor Safeguards, l I" EA-5 i

hy , . .

' Conclusion 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 alternative source term, would not have a

' significant effect on the quality of the human environment. I

This conclusion is based on the following:  !

1. " The foiegoing environmental assessment.

-2. The proposed accident revised source term and the proposed accident dose guidelines -

, t were incorporated into the NRC'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. Because the proposed rule would be a logical extension of these provisions to operating reactors, a similar finding is  :

appropriate. j

3. - The revised source term reflects the significant advances that have been made in ,

understanding the timing, magnitude, and chemical form of fission product releases i from severe nuclear power plant accidents. This alternative source term provides more physically based estimates of the accident source term. The NRC sponsored significant review efforts by peer reviewers, foreign research partners, industry groups, and the general public (57 FR 33374).

References

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

1995' j

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

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 Par 1 50, SECY-96-118, May 1996 EA-6 1

.