ML20246D592
| ML20246D592 | |
| Person / Time | |
|---|---|
| Issue date: | 06/23/1988 |
| From: | Meyer D NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| To: | Shotkin L NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| Shared Package | |
| ML20245D160 | List: |
| References | |
| FRN-52FR6334, RULE-PR-50 AC44-2-15, NUDOCS 8905100269 | |
| Download: ML20246D592 (57) | |
Text
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'JNITED STATES
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NUCLEAR REGULATORY COMMISSION r,,
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I MEMORANDUM FOR:
Louis Shotkin Office of Nuclear Regulatory Research FROM:
David L. Meyer Regulatory Publications Branch Division of Freedom of Information and Publications Services Office of Administration and Resoures Management
SUBJECT:
REVIEW 0F SECY-88-162 - REVISION OF THE ECCS RULE CONTAINED IN APPENDIX K AND SECTION 50.46 0F 10 CFR PART 50 The Division of Freedom of Information and lications Services has reviewed SECY-88-162 which sets out the final amendn nts revising the ECCS regulations contained in Appendix K and Section 50.46 of Part 50. We have enclosed marked-up pages from the final rule that indicate several editorial comments.
- These changes should be made before the final rule is submitted for publication in the Federal Register.
As Alzonia Shepard of my staff mentioned in the telephone conversation with you on June 27, 1988, when the final rule is submitted for publication in the Federal Register, it should be a clean copy, free of the (Enclosure E) reference found at the bottom of each page and the underscoring used to indicate the comparative text in the codified section should be deleted. We have included an enclosure that describes the information and procedures needed to prepare and submit a rulemaking package for publication in the Federal Register.
If you have any questions concerning our comments or those in the marked copy, please contact Alzonia W. Shepard on x27651.
0 O.
w David L. Meyer Division of Freedom of Information and Publications Services Office of Administration and Resources Management ENCLOSURES: As stated s
8905100269 890504 i
PDR PR 1
50 52FR6334 PDR
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NUCLEAR REGULATORY COMMISSION 10 CFR Part 50 Emergency Core Cooling Systems; Revisions to Acceptance Criteria AGENCY:
Nuclear Regulatory Comission.
ACTION:
Final rule.
SultiARY: The Nuclear Regulatory Commission (NRC) is amending its regulations to allow the use of alternative methods to demonstrate that the emergency core cooling system (ECCS) would protect the nuclear reactor core during a postulated design basis loss-of-coolant accident (LOCA). The Commission is taking this action because research', performed since the current rule was written, has shown that calculations performed using current methods and in accor've with the current requirements result in estimates of cooling sy:,t.em performance that are significantly more conservative than estimates based on the improved knowledge gained from this research. While the existing methods are conservative, they do not result in accurate calculation of what would actuaily occur in a nuclear power plant
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during a LOCA and may result in less than optimal ECCS design and operating precedures.
In addition, the operation of some nuclear reactors is being unnecessarily restricted by the rule, resulting in increased costs of electricity generation.
This rule, while continuing to allow the use of current methods and requirements, also allows the use of more recent information and knowledge to demonstrate that the ECCS would protect the reactor during a LOCA.
This amendment, which applies to all applicants for and holders of construction permits or operating licenses for light water reactors, also relaxes requirements for certain reporting and reanalyses whict do not contribute to safety.
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Page 1 rENCLOSUR J
_-__________________-____-____D
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f EFFECTfVEDATEd' L. M. Shotkin, Office'of Nuclea-l
.FOR FURTHER INFORMATION CONT ET:
Regulatory Research, U.S. Nu: lear Regulatory Commission, Washingte,
-DC 20555,' telephone (301) 492-3530.
SUPPLEMENTARY INFORMATION:
BACKGROUND c
On March 3,1987, the Naclear Regulatory Commission published in g[p 8
the Federal / Register propose:! amendments (52 FR 6334) to 10 CFR Part JJA 50andApNndixK. These proposed amendments were motivated by tre fact that since the promulgation of Section 50.46 of 10 CFR Part' 50,
" Acceptance Criteria for Emergency Core Cooling Systems (ECCS) in Light Water Power Reactors," and the acceptable and required featares and models specified in Appendix K to 10 CFR Part 50, considerable research has been performed that has greatly increased the It is now confirmed understanding of ECCS perfonnance during a LOCA.
that the methods specified in Appendix K, combined with other analysis methods currently in use, are highly conservative and that the actual 1
cladding temperatures which would occur during a LOCA would be much In-soliciting lower than those calculated using Appendix K methods.
the public's comments on the proposed rule, the NRC specifically requested its views on questions posed by Commissioner Asselstine and The ACRS the Advisory Committee on Reactor Safeguards (ACRS).
requested that the Commission solicit the public's comments on rether That is:
the' existing rule should be "grandf athered" indefinitely.
Should the conservative ECCS evaluation method of Appendix K 1.
be permitted indefinitely or should this aspect of the ECCS rule be phased out after some period of time?
Commissioner Asselstine requested the public's comments on the following:
E"CLC:UPI : "
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2.
Should this ro e change include an. explicit c ree of s
conservatism that must be applied to the evaluation models?
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This rule change would allow a 5 to 10 percent increase in 3.
the fission product inventory that could be released from any core meltdown scenario.
Should this rule change explicitly prohibit any increase in approved power levels until all severe accident issues and unresolved safety issues are resolved?
4.
Should the technical basis for this proposed rule change be reviewed by an independent group such as the American Physical Society?
SUt94ARY OF PUBLIC C0f94ENTS The connent period for the proposed rule revision and the draft regulatory guide (52 FR 11385) expired on July 1,1987.
Twenty-seven letters addressing the proposed rule were received by the expiration date, as well as nine responses to the request for comments on questions in the regulatory guide. A number of late comments were also received. These were also considered to the extent that new and substantial comments were provided.
The public comment on the proposed rule revisions have been divided into thirteen categories and are summarized in the following paragraphs. Catagories one through four represent the responses to the specific questions posed by the ACRS and Connissioner Asselstine.
In general, consideration of the public comments resulted in no substantive revision to the proposed rule.
1.
Grandfathering of Conservative ECCS Methods of Appendix K (Question 1).
Twenty-one of the commenters specifically addressed the ARCS question concerning the grandfathering of the current Appendix K l
Page 3 JNCLOUIR L W w________.
Sevsnteen of these commenters recomendeu indeffini approach.
grandfathering of the existing Appendix K evaluation models.
I Most cited the known conservatism as the basis of their' recommendation.
In addition, several commenters stated that in light of the known conservatism not allow'ng continued use of existing Appendix K evaluation models would be unfairly burdensome to licensees who determine that they would not derive an economic benefit by performing realistic analysis of ECCS performance. The position of an additional commenter is unclear concerning grandfathering.
The remainir.g commenter was not opposed to grandfathering but thought the question is premature.
This commenter believes that indefinite use of existing ECCS evaluation methods should be considered when significant experience has been gained with the implementation of the new features of the rule but makes no recommendation as to what policy the Commission should pursue in the meantime.
The Commission agrees with the majority of the commenters that existing Appendix K evaluation models should be permitted indefinitely. The Commission also believes that the decision to permit continued use of such models can and should be made at this time because it believes that both methods provide adequate protection of the public health and safety.
As described in the regulatory analysis, the probability of a large break is so low, that the choice of best estimate versus Appendix K has little effect un public risk. The TMI action plan calls for industry to improve their small break LOCA evaluation models to be more realistic when evaluating the more probable small break accident scenario. This has been done within the context of f 50.46 and Appendix K compliance and was entirely appropriat'e since small breaks are not l!niting in c:esign basis performance and a better understanding of small break behavior is a desirable safety goal from a risk perspective. Therefore, the grandfathering provision has been retained in the final rule.
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. Specification of Expiicie Ogaree-of Conservatism (Quastion 2).
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The majority of the resconses to this question indicated tha; the proposed rule already contains conservatism.in the required-uncertainty evaluation.
The use of additional conservatism would be. inconsistent' wit 9 the objective of the rule wnich is to provide a realistic evaluation of plant response during a LOCA.
The NRC has not included an additional explicit degree of conservatism in this rule.
3.
Resolution of a11' Safety Issues prior to Allowing power Level L
Increases-(Question 3).
Some commenters pointed out that fission product inventory is not a direct function of total power, but rather it is the rate of fission product formatic, that is a direct function of power.
Fission product inventory
'available for release during a core meltdown would be a function of burnup, not total power.
Actually, the inventory of fission products is a complex function of both time and power and not as simple.as described by the-commenters.
Short lived isotopes, such as xenon and iodine, quickly reach an equilibrium inventory and total steady state inventory of these fission products is a direct function of Inventories of long-lived isotopes, such as strontiun and power.
cesium, are functions of total fuel burnup, as described by the commenters.
Intermediate-lived isotopic inventories are conclex functions of time, power, and integrated power.
In an i,* dependent study, doc'anented in chapter XII of NUREG 1230, the staff determined that the change in risk due to a 5% power increase is negligible.
The arguments above do not alter the Commission's position that the increase in fission products available for release during a core meltdown caused by a 5% power increase is negligible compared to.the uncertainty in fission product release. The Commission has decided not to delay the page 5 INCfat 10-f'
proposed rule revision pending resolution of all unresolved l
safety issues or severe accident issues and therefore will proceed with this final rulemaking, as planned.
Independent review of Technical Basis (Question 4).
Several L
4 commenters indicated that the technical basis for the proposed rule has had adequate review as the research was being performeo.
A number of commenters stated that it was the role of the ACRS to perform any review of the proposed rule revision because it is uniquely qualified due to its familiarity with the research.
The Commission agrees.that the technical basis has had adequate review, except for the uncertainty methodology which is new and untried except for the General Electric Company's use of an uncertainty evaluation of their SAFER code.
As a proof of principle and demonstration of feasibility, the ACRS and a second independent peer group has reviewed the uncertainty methodology developed by-the NRC for use in quantifying the uncertainty of NRC developed thermal hydraulic transient codes.
Both the ACRS and the peer group made generally favorable comments concerning the methodology; however, both groups recognized that a complete demonstration (i.e., application to small break LOCA and the reflood portion of large break LOCA) has n,t yet been accomplished and certain reviewers questioned whether such a demonstration could be performed successfully.
The only objectives of the NRC methodology demonstration are to demonstrate feasibility, to develop an audit tool, and to provide 4
the necessary experience to audit licensee submittals.
The staff
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- v does not believe that NRC demonstration of the methodology is a 3
prerequisite to this rulemaking.
Licensees wishing to adopt the best-estimate approach permitted as a result of this rule are neither required to use this methodology nor to model their own methodologies it. This methodology will play an important The NRC has part in the best-estimate model review process.
determined through twenty years of experience that independent analysis with independent methodologies is the most effective way Page 6 INCL 450RW
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to intelligently rwiew new vendor or licensee met...Jologies.
It is therefore appropriate that this new methodology be subjected l
to stringent technical scrutiny, as d'rected by the Commission.
The NRC staff is committed to complet ng this demonstration by d
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the time that it will be needed to review licensee submittals and is confident that such a demonstration. will be successful. Based on the paucity of negative response concerning the technical basis for the proposed rule revision and generally favorable review of the NRC uncertainty methodology, the Comission plans no further review of the technical basis.
5.
General Comments on proposed Rule.
Twenty-one commenters made coments of this nature.
The majority of the comments came from the nuclear industry of which 19 expressed support of the proposed rule.
The industry also strongly supports the specific ECCS rule approach proposed by the NRC.
One commenter neither supported nor opposed the proposed approach.
One negative coment was received from an anonymous individual within the nuclear industry who implied, without specifics, that the ECCS rule is not sound and that public comnent is not a fair hearing because expert insiders would be afraid to comment.
Based on the absence of any supporting justification for the negative nsponse and the unprecedented amount of research supporting the rule revision, the NRC does not consider this comment to be valid and has proceedea with this rulemaking with l
no major revisions.
One commenter suggested that fuel reload suppliers should not be required to complete full LOCA/ECCS analyses because the hydraulics are not changed by a fuel change.
l Although this point is valid, the Comission believes that it is an unworkable situation to allow fuel suppliers to make use of previous analyses performed by others.
It is believed that serious questions of accountability would arise in cases where Page 7 ENCLOSUP W
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errors are discovered in evaluation models, request, are made to
. revise plant technical specifications, or some ocher questions The NRC believes that shared regarding the analyses are raised.
responsibility for evaluation models would not be in the best interest of the public health and safety and therefore has not implemented the suggestion of this commenter.
The NRC received two requests for an extension of the comment period to allow time for review of NUREG-1230, which describes l
the'research supporting the proposed rule revision.
The NRC believes the comment period was sufficient since most of the research is not new and has been extensively reviewed in the Both commenters were contacted and told that comments past.
received after the comment period would be considered if time Comments from both parties were received late and permitted.
were indeed considered by the NRC.
6.
Reporting Requirements.
Some commenters viewed the proposed reporting procedures as new requirements needing consideration in the backfit analysis while others stated that they are a major relaxation and clarification of existing reporting requirements.
The NRC position is that the reporting requirements are new in the sense that they will now appear in the Code of Federal Regulations and therefore have been considered in the backfit In practice, these reporting requirements are indeed a analysis.
clarification and relaxation over the current interpretation of the existing requirements and therefore the net effect of these requirements will be to reduce the frequency for reporting and reanalysis.
A number of commenters requested that only significant errors or changes in the non-conservative direction or only those that result in exceeding the 2200 F limit be required to be reported.
In addition, a number of commenters suggested that the NRC require only annual reporting of significant errors or changes.
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The NRC considers a major error or change in any direction a cause for concern because it raises potential questions about the adequacy of the evaluation model as a whole.
Therefore, the NRC requires the reporting of significant errors or changes, in either direction, on a timely basis so that the Commission may make a determination of the safety significance. Thus, the final rule contains no change in this requirement.
One commenter recommended that the word "immediate" be deleted
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from the requirement to propose steps to be taken to demonstrate compliance in the event that the criteria in f 50.46(b} are exceeded.
The Commission considers this a very serious condition in which the plant is not in compliance with the regulations and may be operating in an unsafe manner. The word "immediate" reflects this seriousness and is further defined by reference in other sections of Part 50.
Several commenters questioned the need to report minor or inconsequential errors or changes, even on an annual basis, as required in the proposed rule.
While errors or changes which result in changes in calculated peak clad temperatures of less than 50 F are not considered to be of immediate concern, the NRC requires cognizance of ssch changes or corrections since they constitute a deviation from what previously has been reviewed and accepted.
The proposed anr.ual reporting is believed to be a fair compromise between the burden of reporting and the Commission's need to be aware of changes and error corrections being made to evaluation models. TFacefore, the annual reporting of minor errors remains in the final rule.
One commenter interpreted the use of the words "or in the application of such a model" as requiring reporting wren facility Page 9
-ENCLOSUP,0f'
changes (already reportable under 6 50;59), resulti..e in model input changes, occur.
The regulatory language referrea to is intended to ensure that applications of models to areas not contemplated during initial review of the model do not result in errors by extending a model The Commission does not beyond the range that it was intended.
believe that further clarification of this requirement is necessary and has not done so in the final rule.
Several commenters requested a further relaxation of the reporting requirement by changing the definition of significant code errors from 50 F to 100 F.
While justification for the 50 F criteria is largely judgmental, the NRC believes that it is sufficiently large to screen the code error corrections and changes which have little safety significance while providing a mechanism for timely reporting of 0
more serious errors and changes.
Since 50 F is a threshold for reporting and no further action is required pending NRC determination of safety significance, the Commission has retained this criteria in the final rule.
One commenter requested consideration for allowing that the cumulative effect of several errors and corrections be applied towards the 50"F threshold.
The requirement, which states that the 50*F criteria applies to the sum of the absolute magnitudes of temperature changes from numerous error corrections or model changes was formulated I
specifically because the Commission requires knowledge of serious deficiencies in evaluation models in use by licensees.
I Allowing errors or corrections which offset one another to relieve a licensee of the thirty-day reporting requirement, would be counter to this objective.
If this recommendation were accepted, two errors or changes, having a large impact on the
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calculated peak claading temperature. butLin the opposite direction, would not be reportable if the net magnitude of their difference was less than 50 F.
For this reason, and the fact that no further action (beyond reporting within thirty days) is required, the Commission retained this requirement in the final rule.
7.
Continued Use of Dougall-Rohsenow.
Five comments that addressed this aspect of the proposed rule were received.
One commenter believed that this correlation should not be permitted without further verification and should be phased out.
Other commenters supported continued use of the correlation subject to the provisions of the proposed rule.
The NRC position is that no safety concern is created by continued use of the correlation, as long as the evaluation model is overall conservative. Therefore, the Commission can not justify the burden of requiring licensees to modify their evaluation models and to perform reanalysis. As discussed in SECY 83-472, current evaluation models contain more conservatism than just those required by Appendix K.
However, error corrections or changes could alter the conservatism of the model.
Therefore, the Commission believes that.it is necessary to ensure continued overall conservatism in the evaluation models as a basis for continued use of the correlation. Therefore, the final rule does not modify this requirement except for the correction of a typographical error identified by one commenter.
8.
Uncertainty Evaluation. Tne comaents received on the uncertainty evaluation support the proposed rule, particularly the flexibility provided by a non-prescriptive requirement.
Therefore, the Commission is publishing the final rule without modification of this requirement.
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9.
Acceptance Criteria.
The three coments received on this topic were all supportive of the existing criteria, as contained in 5 50.46(b), and thus the Commission did not give consideration to altering them in the final rule.
10.
Cladding Materials. Three commenters requested that the Comission consider broadening the language of the rule to allow the use of a range of zirconium based alloys for cladding material.
The Comission believes that this modification is beyond the scope of the current rule revision and should be considered in a separate rulemaking action in which it would receive appropriate In addition, public review and comment prior to implementation.
zircaloy cladding material is specified in other portions of the Code of Federal Regulation, such as 6 50.44. Making a change of this type is more suitable in a broader regulatory context.
Therefore, the Comission is not broadening the definition of cladding materials within this rulemaking.
11.
Other Suggested Expansions to Rule Scope.
One commenter believes that hydraulic loads occurring during a LOCA could cause steam generator tubes to rupture and that the NRC should resolve steam l
generator tube integrity safety issues prior to publishing this rule.
Steam generator tubes are designed to withstand LOCA loads at allowed thinning, and there is no evidence to contradict this.
If anything, the problem would be with inspection techniques to y
detect the actual tube thinning and whether there is an unacceptably high probability that a tube rupture during a LOCA
- However, due to tube thinning is in excess of the design basis.
the risk from LOCA with concurrent tube rupture will not be As a result of the greatly affected by the proposed rule change.
comenter's concerns, this issue has been assigned as a generic
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issue-(GI-148) to be prioritized by the NRC staff.
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results of t e prioritization. process will determbe if further I
l action is re:uired.
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j A second comenter believes that the ECCS rule does not adequately acdress a plant's long term decay heat removal
.j capability, and recommends a "short/long term integrative analysis approach."
Both the existing requirements and the proposed rule contain the requirement to provide for long term cooling subsequent to a LOCA. Small increases in power that may result from the proposed rule shou".. not greatly cnange decay heat removal requirements followb, a LOCA or any other accident l
or transient. Thus, the issue of decay heat removal is not materially impacted by this rulemaking. Moreover, any proposed increase in power resulting from this rule promulgation would be approved only after the licensee demonstrates that decay heat removal capacities remain adequate.
The Commission is planning no further_ action with regard to this issue.
12.
Acceptability of Models Approved Under SECY-83-472.
One commenter requests that the rule language be modified to state explicitly that ECCS evaluation models that have been previously approved under SECY-83-472 continue to be acceptable under this rele.
SECY 83-472 provides an alternative, acceptable method for developing ECCS evaluation models.
Licensees were still required, however, t.c demonstrate that evaluation models developed using the SECY-83-472 approach complied with the requirements of Appendix K to Part 50.
This final rule explicitly finds that ECCS evaluation models, which have been previously approved as satisfying the requirements of Appendix K, remain acceptable. Therefore, the Commission sees no need for further clarification of this issue.
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13.
Comments Received After Comment Period.
Six letters commenting the proposed rule were received subsequent to the end of the 09 comment period. The Commission considered these comments to the_
extent that the comments provided substantive information not previously considered.
One commenter believes that the proposed 5 50.46(a)(2; expands the discretion of the Director of the Office of Nuclear Reactor Regulation (NRR) by allowing imposition of immediate effective restrictions on reactor operation without a prior determination that such action is required to protect the public health, safety, or interest.
NRC's intent is not to alter the responsibilities of the Director of NRR but to simply retain the description of the scope of the authority that is currently found in f 50.46(a)(1)(v).
Furthermore, the provisions of 5 50,46(a)(2) do not specify the procedure to be followed by the Director of NRR. These procedures are set out in Part 2 and remain unchanged by this rulemaking.
One commenter believes that the rule is illegal because it is Dased solely on cost savings considerations and that there is nothing wrong with large conservatism.
The Commission disagrees with this assessment.
Safety factors are required to protect the health and safety of the public when uncer tainties in plant response exist. As these uncertainties are reduced, it is appror,riate to modify these safety factors to The provide store realistic evaluation of actual plant response.
large conservatism of Appendix K seeved the public well in 1974 when tnere was great uncertainty in ECCS performance.
- However, these conservatism are now known to be very large, and there is no need to "over regulate" by maintaining this unnecessary margin. This type of activity can often result in the expenditure of resources that would be better spent improving The benefits to safety, while difficult safety in other areas.
to quantify, are believed to be substantial. While cost savings may have been one factor resulting in the rule change, the Page 14 ENC'_050RE E h
Commission believes that the conservatism containeo in the acceptance criteria themselves, as well as those required in the uncertainty evaluation required in this rule, are adequate to protect the health and safety of the public.
This commenter also cites portions of the 1975 General Electric Company's Nuclear Reactor Study (Reed Report), which claims that l
there is a lack of understanding of phenomena and small safety margins.
Many of the conclusions of the " Reed Report" were valid in 1975 when it was written and due to this fact it was difficult to show that sufficient safety margins existed.
Most of the research discussed in NUREG-1230 has been conducted since the " Reed Report" was written and has resulted in significant improvement in understanding LOCA phenomena.
We now know that significant margin to the ECCS acceptance criteria exists, particularly for the BWR/6 which was of concern in the " Reed Report." The contents of this report have been reviewed by the Commission on several occasions, most recently in NUREG-1285, and the finding has been made that no new significant safety issues are identified.
For these reasons, the NRC is proceeding with this rulemaking, as proposed.
The same commenter also reconmends that credit for ECCS margins be taken in the Individual Plant Examinations (IPE) and not through generic rulemaking.
The Commission agrees that plant specific differences may justify the application of different margins and that these may be l
addressed through Individual Plant Examinations.
However, the requirement for licensees to evaluate ECCS performance and meet l
the acceptance criteria specified in 10 CFR 50.46(b) is generic.
The Commission believes that margins that may be reduced due to a better understanding of a reactor's response to a LOCA should be I
applied through a generic rulemaking action because it allows a broad range of technical review of the issues, enhances public page 15 ENCLCSURE E ' ~~
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i participation in the process, and provides a comple.e public Therefore, ve Commission has decided to proceed with record.
i the rulemaking as planned.
Finally, this commenter questions the experimental basis for this I
rule because full-scale ECCS bypass data is not yet availaole.
The 2D/30 tests which will provide this important data represent a small portion of the total research upon which this rule Significant research on ECCS bypass has already been relies.
completed in small scale vessels and the full-scale work is I
required only to confirm the smaller scale results and quantify One full-scale ECCS bypass any uncertainty due to scale effects.
test has already been completed under the 2D/3D program wnich showed that more margin exists than expected from the small scale Completion of the full-scale tests only affects the tests.
uncertainties in the calculations, and reduces them.
Uncertainties must be addressed by licensees in any analysis under the revised rule whether 2D/3D results are available or The Commission concludes that there is no need to delay the not.
final rule, while awaiting these data.
SUPT 4ARY OF RULE CHANGES lf qvM g
%Section 50.46kcceptance criteria for Emergency Core Cooling 4 SystemsforLightWaterReactors[
Section 50.46(a)(1) is amended and redesignated 6 50.46(a)(1)(i) to delete the requirement that the features of Section I of Appendix K This section now to Part 50 be used to develop the evaluation model.
requires that en acceptable evaluation model have sufficient supporting justification to show that the analytical technique realistically describes the behavior of the reactor system during a The NRC expects that the analytical technique will, to the LOCA.
extent practicable, utilize realistic methods and be based upon The amended rule also requires that the applicable experir.. ental data.
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. uncertainty of the calculation be estimated and accounted for when comparing the results of the calculation to the tercerature limits and other criteria of $ 50.46(b) so that there is a hign probability that the criteria would not be exceeded.
The Commission expects the realistic evaluation model to retain a degree of conservatism
' consistent with the uncertainty of the calculation. The final rule does not specifically prescribe the analytical methodr, or uncertainty evaluation techniques to be used.
However, guidance has been provided 1
in the form o' a Regulatory Guide.
As discussed in SECY-83-472, the NRC has, in ta.e past, found acceptable a method for estimating the uncertainty tnat was judged to be at least at the 95% probability level. This probability level of 95% is considered adequate to meet the high level of probability required by the rule.
It is also recognized that the probability cannot be determined using totally rigorous mathematical methods due to the complexity of the calculations. However, the NRC requires that any simplifying assumptions be stated so that the Commission may evaluate them to ensure that they are reasonable.
The NRC has independently developed
' and exercised a methodology to estimate the uncertainty associated with its own thermal-hydraulic safety codes. This methodology is described in the " Compendium of ECCS Research."2 This document also provides reference to the large body of relevant thermal-hydraulic research, documents NRC studies on the effects of reactor power increases on risk, and provides background information on the ECCS rule. While this method has not been reviewed for acceptability from the standpoint of safety licensing, it may provide additional guidance on how the uncertainty may be quantified.
In addition to providing guidance to industry, this work was undertaken to provide a proof of prirciple ard a tool to independently audit industry submittals.
Appendix K,Section II, " Required Documentation," remains generally f
epplicable, with only minor revisions made to be consistent with the 7%,
amended rule.
g A
y IRegulatory Guide, "Best Estimate Calculations of Emergency Core Cooling Systems Performance," was issued to all licensees.
2" Compendium of ECCS Research for Realistic LOCA Analysis,"
NUREG-1230, TBP.
Page 17 Pr' ""RE ?
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A new caragraph(ii) has been addGd to 6 50.46(a)(1) to allow the evaluation models as features of Section I of Appendix K to be used ia an' alternative to performing the uncertainty evaluation specified in the amendec 5-$0.46(a)(1)(i). This method would remain acceptable because Appendix K is conservative with respect to the realistic This would allow method proposed in the amended 5 50.46(a)(1)(i).
both current and future applicants and licensees to use existing evaluation models if they did not need or desire relief from current operating restrictions.
In 5 50.46, paragraphs (a)(2) and (3) have been revised to eliminate portions of those paragraphs concerned with historical implementation of the current rule. These provisions have been replaced as described in the following paragraphs [
Section 50.46(a)(2) has been revised to indicate that restrictions on reactor operation may be imposed by the Director of Nuclear Reactor Regulation, if the ECCS cooling performance evaluations are not consistent with the requirements of 55 50.46(a)(1)(i) and (ii). This section has been added to retain similar requirements that have been deleted from 5 50.46(a)(1)(i) by this rule revision. This section does not specify the procedures to be followed by the Director. These procedures are found in Part 2 and are unchanged by this rulemaking.
The current rule contains no explicit requirements concerning re-porting and r ennalysis when errors in evaluation models are discovered
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or chenges are made to evaluation models.
However, current practice f
has required reperting of errors and changes and reanalyses with the
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revised evaluation models.
Thi:3 final rule explicitly sets forth The requirements to be followed in the event of errors or changes.
definition of a significant change is currently talen from Appendix K, J
Section II.1.b which defines a significant change as one which changes calculated cladding temperature by more than 20 F.
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Page 18 j
The revised 5 50.46(a)(3) states specific requireme,,cs for reporting and reanalyses wher errors in evaluation models are discovered or changes are mace to evaluation models.
It requires Inat all. changes or errors in approved evaluation models be reported at le'ast annually and does not require any further action by the licensee until the error is reported. Thereaf ter, although reanalysis is not required solely because of such minor error, any subsequent calcu'.ated evaluation of ECCS performance requires use of a model with such error, and any prior errors, corrected. The NRC needs to be apprised of even minor errors or changes in order to ensure that they agree with 'the applicant's or licensee's assessment of the significance of the error or change and to maintain cognizance of modifications made subsequent to NRC review of the evaluation model.
Past experience has shown that many errors or changes to evaluation models are very minor and the burden of immediate reporting cannot be justified for these minor errors because they do not affect the immediate safety'or operation of the plant. The NRC therefore requires periodic reporting to satisfy NRC's need to be apprised of changes or errors without imposing an unnecessary burden on the applicant or licensee.
This report is to be filed within one year of discovery of the error and must be reported each year thereafter until a revised evaluation model or a revised evaluation correcting minor errors is approved by the NRC staff.
Significant errors require more timely attention since they say be important to the safe operation of the plant and raise questions ac to the adequacy of the overall evaluation model.
Thir final rule defines a significant error or change as one which results in a calculeteo peak fuel chdding temperature different by more than 50 F, i
or an accumulation of errors and changes such that the sum of the I
absolute magnitude of the temperature changes is greater than 50 F.
I More timely reporting (30 days) is required for significant errors or changes. This definition of a significant change is based on NRC's judgement concerning the importance of errors and changes typically f
reported to the NRC in the past. This final rule revision also allows the NRC to determine the schedule for reanalysis based on the l'
Page 19 ENCLOSURE E
____ _}
i importance to safety relative to other applicant or license 2 Errors or changes that result in the calculated plant i
requirements.
J performance exceeding any of tne criteria of s 50.46(b) mean that tre 1
j plant-is not operating within tne requirements of the regulations are i
l recuire immediate reporting as required by j 50.55(e), 5 50.72 and 5 50.73 and immediate steps to bring the plant into compliance with 9 50.46.
v I
AppendixKECCSEvaluationModels(d Amendments have been made to Appendix K,Section I.C.5.b, to modify the post-CHF heat transfer correlations listed as acceptable.
The "McDonough" reference has been replaced with a more recent paper by the same authors entitled "An Experimental Study of Partial Film Boiling Region With Water at Elevated Pressures in a Round Vertical Tube" which is more generally available and which includes additional data.
The heat transfer correlation of Dougall and Rohsenow, listed as y an acceptable heat transfer correlation in Appendix K, paragraph _.
w I.C.5.b, has been removed, since research performed si_nce Appendix K -
was written has shown that this correlation overpredicts heat transfer coefficients under certain conditions and therefore can produce nonconservative results.
A number of applicants and licensees currently use the Dougall-Rohsenow correlation in approved evaluation The NRC has concluded that the continued use of this model s.
correlation can be allowed. This is appropriate (even though parts of the approved evaluation model, Dougall-Rohsenow, are known to be nonconservative) because the existing evaluation models are known :o contain a large degree of overall conservatism even while usirg the l
E%ugalk-Rohsenow correlation.
This large overail ccuservatism has been demonstrated through comparisons between evaluation model calculations and calculations using NRC's best estimate computer Thus requiring that the applicants and licensees remove the codes.
f Dougall-Rohsenow correlation from their current evaluation models The stipulation cannot be justified as necessary to maintain safety.
ENCLOS.RE E Page 20
that the Dougall-Rohsenow correlation will cease to be acceptable for previously approved evaluation models applies only when changes to the model are made which reduce the calculated peak clad temperature by 50 F or more. 'However, the requirement to report any changes or culmination of changes, such that the sum of the absolute magnitudes of the respective temperature changes is greater than 50 F, still applies.
A new Section'I.C.5.c has been added to Appendix K to state the Commission's requirements regarding continued use of the Dougall-Rohsenow correlation in existing evaluation models.
Evaluation models which make use of the Cougall-Rohsenow correlation and have been approved prior to the effective date of'this rule may continue to use this correlation as long as no changes are made to the evaluation model which significantly reduce the current overall conservatism of the evaluation model.
If the applicant or licensee submits proposed changes to an approved evaluation model, or submits corrections,.to errors in the evaluation model which-significantly reduce the existing overall conservatism of the model, continued use of'the Dougall-Rohsenow correlation under conditions where nonconservative heat transfer coefficients result would no longer. be acceptable.
For this purpose, a significant reduction in overall conservatism has been defined as a " net" reduction in calculated peak clad temperature of at least 50 F from that which would have been calculated using' existing evaluation models. A reduction in calculated peak clad temperature could potentially result in an incres:e in the actual allowed peak power in the plant. An increase in allowed plant peak power with a known nonconservatism in the analysis would be unacceptable. This. definition of a significant recuction in cverall conservatism is based on a judgement regarding the size of the existing overall conservatism.in evaluation model calculations relative to the conservatism required to account for overall uncertainties in the calculations.
Appendix K,Section II.1.b, has been removed since this requirement has been clarified in the amended 5 50.46(a)(3).
Page 21 ENCLOSURE E
LikGwise, Appendix K, Section M.5, has been amended to account for tne fact that iot all eva.luation models will be reauired to use the
. features of Appendix K,Section I.
These minor changes to Appendix K do not affect any existing approved evaluation models since the j
changes are either " housekeeping" in nature or are changes to f
" acceptable features," not " required features."
l AVAILABILITY OF DOCUMENTS l
1.
Copies of NUREGs.1230 and 1285 may be purchased from the Superintendent of Documents, U.S. Government Printing Office, j
P.O. Box 37082, Washington, D.C. 20013-7082. Copies are also j
available from the National Technical Information Service 5285 Port Royal Road, Springfield, VA 22161. A copy is also f
available for public inspection and/or copying at the NRC Public Document Room 1717 H Street NW., Washington, DC 20555.
p/yl 2.
Copies of SECY-83-472, an information report entitled " Emergency Core Cooling Systems Analysis Methods," dated November 17, 1983, I
is available for inspection and copying at the NRC Public f55 i
t ib Documents Room 1717 H Street NW., Washington, DC.20555.
Single ggy l
copies of this report may be obtained by writing (give%me and M,g address of the contact).
f, ',
- v p \\.\\ 51 Regulatory Gulde, "Best Estimate Calculations of Emergency Core \\ q f./pF.
3.
\\v a
Cooling Systems Performance" may be obtaiged by
\\
Division of J haic_, information (Nd=:5E[cStd,U.S.
D({
"l Nuclear Regulatory Commission, Washington, DC 20555.
~., Y."j,
cr q[L 4.
The Paraphrased Summary of Public Comments on ECCS Rule is g
available for public inspecti.on at the NRC PLblic Documents Room, 1717 H Street NW., Washington, DC 20555.
FINDING OF NO SIGNIFICANT. ENVIRONMENTAL IMPACT:
AVAILA81LITY l
The Comission has determined under the National Environmental Policy Act of 1969, as amended, and the Commission's regulations in i
i Page 22 ENCLOSURE E l
Subpart A of 10 CFR ParB 51, that this rule is not a major Federal
~ ction significantly af'ecting the quality of the human environment a
The and therefore an environmental impact statement is not-required.
local primary effect of the rule is to allow an increase in the peat power in the reactor. This could be used either to tailor the power shape within the reactor or to increase the total power. Changing the power shape without changing the total power has a negligible effect L
. on the environmental impact. The total power could also be increased, but is expected to be increased by no more than about 5% due to hardware limitations in existing plants. This 5% power increase is not expected to cause difficulty in meeting the existing environmental The only change in non-radiological waste will be an increase limits.
For
'in waste heat. rejection commensurate with any increase in power, stations' operating with an open (once through) cooling system, this additional heat will be directed to a surface water body.
Discharge
'of:this heat is regulated under the Clean Water Act administered by
.the U.S. Environmental Protection Agency (EPA) or designated state agencies.
It is not intended that NRC approval of increased power level affects in any way the responsibility of the licensee to comply with the requirements of the Clean Water Act. The environmental
. assessment and finding of no significant impact on which this determination is based are available for inspection at the NRC Public-Document Room,1717 H Street NW, Washington, DC.
Single copies of the environmental assessment and the finding of no significant impact are available from L. M. Shotkin, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, Washington DC. 20555, telephone (301) 492-3530.
PAPERWORK REDUCTION ACT STATEMENT This final rule amends information collection requirements that are subject to the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et These reporting requirements were approved by the Office of seq.).
Management and Budget (Approval Number 3150-0011).
Page 23 ENCLOSURE E
\\
?
v REGULATORY ANALYSIS
/
j t
f[F s~
(
'Ji The Commission has prepared a regulatory analysis for this final
,,k regulation which examines the costs and benefits of the alternatives p
, N.'
considered and ir available for inspection and copying at the NRC Public !
Document Room, 1717 H Street NW, Washington, DC.
Single copies of the
$p#
analysis may be obtained from L. M. Shotkin, Office of Nuclear Regula-tory Research, Washington, DC. 20555, telephone (301) 492-3530.
REGULATORY FLEXIBILITY CERTIFICATION As required by the Regulatory Flexibility Act of 1980, 5 U.S.C.
605(b), the Commission certifies that this rule will not have a significant economic impact upon a substantial number of small entities.
This rule affects only the licensing and operation of nuclear power plants. The companies that own these plants do not fall within the scope of the definition of 'small entities" set forth in the Regulatory Flexibility Act or the Small Business Size Standards set out in regu-lations issued by the Small Business Administration in 13 CFR Part 121.
Since these companies are dominant in their service areas, this rule does not fall within the purview of the Act.
BACKFIT ANALYSIS Except for the reporting requirements, a backfit analysis is not required by 10 CFR 50.109 because the rule does not require applicants or licensees to make a change but only offers additional options.
Nonetheless, the factors in 10 CFR 50.109(c) have been analynd for the entire rule.
1.
Statement of the specific objectives that the backfit is designed to achieve.
The objective of the rule is to modify 10 CFR 50.46 and Appendix K to permit the use of realistic ECCS evaluation models.
More realistic estimates of ECCS performance, based on the improved knowledge gained from recent research on ECCS Page 24 ENCLOSURE E
performance, may remove unnecessary operating restrictions. Also experience with the previous versior of 5 50.46.has demonstrated that a clearer. definition of reporting requirements for changes and errors is very desirable.
2.
General description of the activity that would be reouired by the licensee or applicant in order to complete the backfit.
The amendment allows alternative methods to be used to demonstrate that the ECCS would protect the nuclear reactor core during a postulated design basis loss-of-coolant accident (LOCA).
While continuing to allow the use of current Appendix K methods and requirements, the rule also allows the use of more recent information and knowledge currently available to demonstrate that the ECCS would perform its safety function during a LOCA.
If an applicant or licensee elects to use a new realistic model they will be required to provide sufficient supporting justification to validate the model and include comparisons to experimental data and estimates of uncertainty.
In accounting for the uncertainty, the analysis would have to show, with a high level of probability, that the ECCS performance criteria are not exceeded. Whether or not a licensee or applicant chooses to use realistic analysis, complete with an uncertainty analysis, each licensee must comply with the requirement to report changes to their evaluation models (i.e., less than 50 F change in calculated peak cladding temperature) annually to the NRC.
In addition, significant changes (those which have a greater than 50 F change in calculated peak cladding temperature) have to be reported within 30 days.
3.
. Potential change in risk to the public from the accidental l
offsite release of radioactive materials.
The rule could result in increased local power within the reactor core and possibly increases in total power.
Power increases on the order of 5 will have an insignificant effect on Page 25 ENCLOSURE E
t
~ isk. One effect of. increased power could be to inc ease the r
fission produt: 'nventory.
A five percent power ine ease would result in a less than five percent increast in fiss'sn products.
Thus, less tha #ive percent more fission products c'ght be released durir;' core melt scenarios and potentially released to the environmen-during severe accidents.
The rule still requires that fuel rod peak cladding temperature (p T) remain below 2200 F.
Reactors chcosing to increase power my about five percent will be operat'ng with less The margin between tne PCT and the 2200 F limit than previously.
increased risk represented by this decrease in marg'n and increase in fission product inventory is negligible and falls In addition, within the uncertainties of pRA risk estimates.
other safety limits, such as departure from nucleate boiling (DNB), and operational limits, such as turbine design, will limit The the amount of margin reduction permitted under the rule.
rule could also potentially reduce the risk from pressurized thermal shock by allowing the reactor to be operated in a mannar which reduces the neutron fluence to the vessel.
potential impact on radiological exposure to facility employees.
4.
Since the primary effect of the rule involves the calculational methods to be used in determining the ECCS cooling performance, it is expected that there will be an ' significant impact on the radiological exposure to f acility employees.
Because of the reduced LOCA restrictions resulting from the new calculations it is possible for the plant to achieve more efficient operation and improited fuel utilization with improved maneuvering capabilities.
As a result, it is conceivable that there could be a reduction in radiological exposure if the fuel reloads can be reduced.
This effect is not expected to be very significant.
ENCLOSURE E Page 26
5.
Installation and continuing costs associated with the cackfit, including the cost of facility down times or the cos ef construction delay.
LOCA considerations resulting from the present Me are re-stricting the optimum production of nuclear electric :ower in some plants. These restrictions can be placed into 7e following i
three categories:
(1) Maximum plant operating power, (2) Operational flexibility and operational ef'iciency of the plant, and (3) Availability of manpower to work on other activities.
The effect of the rule will vary from plant to ;lant.
Some plants may realize savings of several million dollars per year in fuel and operating costs.
Significantly greater eco-omic benefit would be realized by plants able to increase total pcwer as a result of this final rule. The regulatory analysis cited above indicates that the total present value of the energy replacement cost savings for a five percent power upgrade would <ary between 18 and 127 million dollars depending on the plant. Additional information concerning these potential cost savings are included in the regulatory analysis.
The costs associated with the new reporting rea,irements are deemed to be minimal.
Although the existing Appendia K has no official reporting requirements, paragraph II.1.b was interpreted by the staff to require a reanalysis and report to Nic when significant changes are made which change the peak cladding temperature by more then 20 F.
Therefore, this rule change, by changing the definition of significant changes to 50'F, is actually a relaxation of current practices.
The annual reporting of changes that are not significant is not viewed by the NRC as a major burden since no other action is required.
Page 27 ENCLOSURE E
The potential safety impact of changes in plant or operational 6.
complexity including the effect on other proposed and existing regulatory requirements.
There are safety benefits derivable from alternative fuel management schemes that could be utilized.
The higher power peaking factors that would be allowed with the final rule provide greater flexibility for fuel designers when attempting to reduce neutron flux at the vessel wall.
This can result in a corresponding reduction in risk from pressurized thermal shock.
The reduced cladding temperatures that would be calculated under the revised rule offers the possibility of other design and operational changes that could result from the lower calculated ECCS equipment numbers, sizes or surveillance temperatures.
requirements might be reduced and still meet the ECCS design criteria (if not required to meet other licensing requirements).
Another option may be to increase the diesel / generator start time duration.
In sumary, the effect of this rule on safety would have both potential positive and negative aspects. The potential for reduction of EC system capability in existing or new plants is
/
However, several positive aspects may also be realized f
present.
under the final rule. The net effect on safety would be plant However, the probability of a large break LOCA is so specific.
low that the choice of best estimate versus Appendix K would have little effect on public risk.
The estimated resource i,arden on the NRC associated with the_
7.
proposed backfit; and the availability of such resources.
i The major staff resources required under the final rule are to review the realistic models and uncertainty analysis required by the revised ECCS Rule.
Based on previous experience with the ENCLOSURE E Page 28
General Electric Company's SAFER model and the learning that has resulted from these efforts, t is estimated that approximately one staff year would be required to review each generic model submitted.
There are four maj:r reactor vendors (GE already has a revised evaluation model app oved under the existing Appendix K for both jet pump and non-jet ; ump plants and may update their methodology under this new rule) and several fuel suppliers and utilities which perform their cwn analyses and potentially might submit generic aodels for review.
However, it is expected that only 3 or 4 generic models wou'd be submitted since not all plants would ber.efit from this rule. Thus, about 3-4 staff years would be required to review the expected generic models.
Once a generic model is approved, the plant specific review is very short.
In addition, several vendors are currently planning to submit realistic models in conjunction with the use of SECY-83-472. Therefore, staff resources would be expended to review these models in any event.
Since these models would not change as a result of the revised ECCS rule, there should be no net increase in resources required over that already planned to be expended.
In summary, while it is difficult to estimate accurately, it is expected that the rule change will have a small overall impact en NRC resources.
4 8.
The potential impact of differences in facility type, design or age on the relevancy and practicality of the backfit.
The degree to which the rule would affect a particular plant dependr on how limited the plant is by the LOCA restrictions.
General Electric Company (GE) plants do tend to be limited in operation by LOCA restrictions and would benefit from relief from LOCA restrictions. However, this relief is already available for most GE plants w rough the recently approved SAFER evaluation p !
model. Any additional relief due to a rule change would be of
-i little further benefit. Westinghouse (W) plants would appear to directly benefit from relaxation of LOCA limits.
W plants j.
represent the largest number of plants, with 47 plants operating y
t l
J Fage 29 ENCLOSURE E j
i l
and 10 additional piants being constructed. W indicates that The most of these plants are limited by LOCA considerations.
potential benefit for plants of B&W and CE design is uncertain at this time.
Whether the proposed backfit is interim or final and if interim, 9.
the justification for imposing the proposed backfit on an interim basis.
The rule, whea made effective, will be in final form and not I
interim form.
It will continue to permit the performance of ECCS cooling calculations using either realistic models or models in accord with Appendix K.
LIST OF SUBJECTS IN 10 CFR PART 50 Antitrust, Classified information, Fire prevention, Incorporation by reference, Intergovernmental relations, Nuclear power plants and reactors, Penalty, Radiation protection, Reactor siting criteria, Reporting and Recordkeeping requirements.
For the reasons set out in the preamble and under the authority of the Atomic Energy Act of 1954, as amended, the Energy Reorganization Act of 1974, as amended, and 5 U.S.C 552 and 553, the l
l NRC is adopting the following amendments to 10 CFR Part 50.
PART 50-DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION FACILITIES 1.
The authority citation for Part 50 continues to read as l
follows:
l l
AUTHORITY: Se cs. 102, 103, 104, 105, 161, 182, 183, 186, 189, 68 i
Stat. 936, 937, 938, 948, 953, 954, 956, 956, as amended, sec. 234, 83 l
Stat.1244, as amended (42 U.S.C. 2132, 2133, 2134, 2135, 2201, 2232, I
2233, 2236, 2239, 2282); secs. 201, as amended, 202, 206, 88 Stat.
1242, as amended, 1241, 1246, (42 U.S.C. 5841, 5842, 5846).
1 Page 30 ENCLOSURE E
)
and 10 additional 9 ants being constructed. W indicates that 1
The most of these ' plants are ilmited by LOCA considerations.
potential benefit for plants of B&W and CE design is uncertain at j
this time.
I Whether the proposed backfit is interim or final and if interim, 9.
the justification for imposing the proposed backfit on an interim basis.
The rule, wher made effective, will be in final form and not It will continue to permit the performance of ECCS interim form.
cooling calculations using either realistic models or models in accord with Appendix K.
LIST OF SUBJECTS IN 10 CFR PART 50 Antitrust, Classified information, Fire prevention, Incorporation by reference, Intergovernmental relations, Nuclear power plants and reactors, Penalty, Radiation protection, Reactor siting criteria, Reporting and Recordkeeping requirements.
For the reasons set out in the preamble and under the authority of the Atomic Energy Act of 1954, as amended, the Energy Reorganization Act of 1974, as amended, and 5 U.S.C 552 and 553, the NRC is adopting the following amendments to 10 CFR Part 50.
PART 50-DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION F The authority citation for Part 50 continues to read as 1.
follows:
Secs.102,103,104,105,161,182,183, '36,189, 68 AUTHORITY:
as amended, sec. 234, 83 Stat. 936, 937, 938, 948, 953, 954, 955, 956, Stat.1244, as amended (42 U.S.C. 2132, 2133, 2134, 2135, 2201, 2232, 2233, 2236, 2239, 2282); secs. 201, as amended, 202, 206, 88 Stat.
1242, as amended, 124A, 1246, (42 U.S.C. 5841, 5842, 5846).
ENCLOSURE E Page 30
Section 50.7 also issued under Pca. L.95-601, sec.10, 92 Stat.
t l
2951 (42 U.S.C. 5851).
Section 50.10 also issued under secs. 101, 185, 68 Stat. 936, 955, as amended (42 U.S.C. 2131, 2235); sec. 102, Pub. L.91-190, 83 Stat. 853 (42 U.S.C. 4332).
Sections 50.23, 50.35, 50.55, 50.56 also issued under sec.185, 68 Stat. 955 (42 U.S.C.
2235).
Sections 50.33a, 50.55a, and Appendix Q also issued under sec. 102, Pub. L.91-190, 83 Stat. 853 (42 U.S.C. 4332).
Sections 50.34 and 50.54 also issued under sec. 2.04, 88 Stat 1245 (42 U.S.C. 5844).
Sections 50.58, 50.91, and 50.92 also issued under Pub. L.97-415, 96 Stat. 2073, (42 U.S.C. 2239).
Section 50.78 also issued under sec. 122, 68 Stat. 939 (42 U.S.C. 2152).
Sections 50.80-50.81 also issued under sec.184, 68 Stat. 954, as amended (42 U.S.C. 2234).
Section 50.103 also issued under sec.108, 68 Stat. 939, as amended (42 U.S.C.
2138).
Appendix F also issued under sec.187, 68 Stat. 955 (42 U.S.C.
2237).
For the purposes of sec. 223, 68 Stat. 958, as amended (42 U.S.C.
2273), SS 50.10(a), (b), and (c), 50.44, 50.46, 50.48, 50.54, and 50.80(a) are issued under sec.161b, 68 Stat. 948, as amended (42 U.S.C. 2201(b)); $$ 50.10(b) and (c) and 50.54 are issued under sec.161i, 68 Stat. 949, as amended (42 U.S.C. 2201(i)); and 56 50.9, 50.55(e), 50.59(b), 50.70, 50.71, 50.72, 50.73, and 50.78 are issued under sec.1610, 65 Stat. 950, as amended (42 U.S.C. 2201(o)).
2.
In 5 50.46, paragraph (a) is revised to read as follows:
9 50.46 Acceptance criteria for emergency core cooling systems for light-water nuclear power reactors.
(a)(1){il [Except-as-provided-in-paragraph-f alf 23-and-f 3)-of this-section-] Eack boiling and pressurized light-water nuclear power reactor fueled widk uranium oxide pellets within cylindrical Zirdaloy cladding must be provided with an emergency core cooling system (ECCS) that must be desipsed such that its calculated cooling performance following postulated loss-of-coolant accidents conforms to the criteria set fo'rth in paragraph (b) of this section.
ECCS cooling Page 31 ENCLOSURE E
performance must be calculated in accordance with an acweptable evaluation model and must be calculated for a number of postulated loss-of-coolant accidents of different sizes, locations, and other properties sufficient to provide assurance that the most severe
[ Appendix-K-postulated loss-of-coolant accidents are calculated.
EEES-Evaluation-Medels--sets-forth-eertain-reenired-and-acceptable features-of-evaluatien-models-] Except as provided in paragraph (a)(1)(ii) of this section, the evaluation model must include sufficient supporting justification to show that the analytical technique realistically describes the behavior of the reactor system Comparisons to applicable during a loss-of-coolant accident.
experimental data must be made and uncertainties in the analysis method and inputs must be identified and assessed so that the This uncertainty in the calculated results can be estimated.
uncertainty must be accounted for, so that, when the calculated ECCS cooling performance is compared to the criteria set forth in paragraph (b) of this section, there is a high level of probability that the criteria would not be exceeded.
Appendix K, part II, Required Documentation, sets forth the documentation requirements for each
[Eenfermance-with-the-eriteria-set-ferth-in evaluation model.
f d
paragraph-fb)-ef-this-sectien-with-EEES-cooling-performance-caleu ate in-accordance-with-an-acceptable-evaluation-model--may-require-that r e s tr i cti o n s -b e-imp o s e d-e n-r e s ete r-e p e r ati o n-]
_(ii) Alternatively, an ECCS evaluation model may be developed in conformance with the reouired and acceptable features of Appendix K ECCS Evaluation Models._
l The Director of Nuclear Reactor Regulation may impose (2) restrictions on reactor operation if it is found that the evaluations l
of ECCS cooling performance submitted are not consistent with I
paragraphs (a)(1)(i) and (ii) of this section.
i i
_(3)(i) Each applicant for or holder of an operating license or construction permit shall estimate the effect of any change to or error in an acceptable evaluation model or in the application of such ENCLOSURE E Page 32
a model to determ"o if the change or error is significaric.
For this purpose, a signif" ant change or error is one which results in a calculated peak fuel claddino temperature different by more than 50 F from the temperat' ae calculated for the limiting transient using the last acceptable medel, or is a cumulation of changes and errors such that the sum of tre absolute magnitudes of the respective temperature changes is greater than 50 F.
(ii) For eact c,hange to or error discovered in an acceptable evaluation model c-in the application of such a model that affects the temperature calculation, the applicant or licensee shall report the nature of the change or error and its estimated effect on the limiting ECCS analysis to the Commission at least annually as specified in 6 50.4.
If the change or error is significant, the applicant or licersee shall provide this report within 30 days and include with the report a proposed schedule for providing a reanalysis or tak'no other action as may be needed to show compliance with 6 50.46 reau'rements.
This schedule may be developed using an integrated scheduling system previously approved for the facility by the NRC.
For those facilities not using an NRC approved integrated
/
scheduling system, a schedule will be established by the NRC staff within 60 days obeceipt of the proposed schedule.
Any change or error correction that results in a calculated ECCS performance that does not conform o the criteria set forth in paragrapF (b) of this section is a repe-table event as described in 66 50.55(e), 50.72 and 6 50.73. The affected applicant or licensee shall propose immediate steps to demonstrate compliance or bring plant design or operation into compliance w#th 6 50.46 requirements.
In 10 CFR Part 50j Appendix K, paragraph II.1.b is deleted, 3.
paragraph II.1.c is redesignated II.1.b, the text of paragraph I.C.5.b and paragraphs II.1.b and 11.5 are revised, and a new section I.C.S.c is added to read as follows:
Page 33 ENCLOSURE E I
l^
............. ~..
APPENDIX K - ECCS EVALUAT10N MODE'.S REQUIRED AND ACCEPTABLE FEATURES OF THE EVALUATION I,
C.
Blowdown Phenomena ***
Post-CHF Heat Transfer Correlations.***
5.
The Groeneveld flow film boiling correlation (equation 5.7 o' b.
D. C. Groeneveld, "An Investigation of Heat Transfer in the Liquid Deficient Regime," AECL-3281, revised December 1969)[7-the-BengaH-Rehsenew-fiew-fHm-be+ Hag-eerrelatien-f R:-S -BengaH-and-W:
M:-Rehsenewy.uFHm-BeiHng-en-the-inside-of-Vertf eal-Tabes-with-Bonare Flen-ef-Finid-at-hewinaHtiest.MIT-Report-Number-9079-267-Gambridge:
\\d j u
Massachusetts;-September-1963);) and the Westinghouse correlation of I~
steady-state transition boiling (" Proprietary Redirect / Rebuttal J 't q'
Testimony of Westinghouse Electric Corporation," USNRC Docket RM-50-1, N( $
pagr 25-1, October 26,1972) are acceptable for use in the post-CHF In addition, the transition boiling correlation of
,3 g-J" q q boiling regimes.
3J McDonough, Milich, and King (J. B. McDonough, W. Milich, E. C. King, 4d-Q
[u Pa r tial-F Hm-BeiH ng-w i th-W ate r - at-2000 - p s i g -i n-a- Re u nd-Ve r T-Technical-Repert-62-fNP-6976)7-fi958)] "Ar_
y {v Taber.MSA-Research-Gerp:
u Experimental Study of Partial Film Boiling Region with Water at j
g-Elevated Pressures in a Round Vertical Tube," Chemical Engineering Progress Symposium Series, Vol. 57, No. 32, pages 197-208, (19611 is i, y Use of all these Y
f suitable for use between nucleate and film boiling.
s.. A 1 correlations i,_s [ shah-be) restricted as follows:
Q(%.: Ns ih4
) wnich j
Evaluation models approved after (
c.
make use of the Dougall-Rohsenow flow film boiling correlation (R. 5.
Dougall and W. M. Rohsenow, " Film Boiling on the Inside of Vertical Tubes with Upward Flow of Fluid at low Qualities, MIT Report Cambridge, Massachusetts, September 1963) may not use 9079 26, Number this correlation under conditions where nonconservative predictions of Evaluation models that make use of the Douga'l-heat transfer result.
)
Rohsenow correlation and were approved prior to (
continue to be acceptable until a chang'e is made to, or an error is ENCLOSU.i E Page 34
E-
{
l
/
corrected iny the evaluation model that results in a significant reduction in the overall conservatism in the evaluation model.
At that time continued use of the Dougall-Rohsenow co.rrelation under conditions where nonconservative predictions of heat transfer result will no longer be acceptable.
For this purpose, a significant reduction in the overall conservatism in the evaluation model would be a reduction in the calculated peak fuel cladding temperature of at least 50 F from that which would have been calculated on
'(
) due either to individual changes or error i
'/
corrections or the net effect of an accumulation of changes or error corrections.
l 1
II.
REQUIRED DOCUMENTATION 1.a.
b.
A complete listing of each computer program, in the same I
form as used in the evaluation model, must be furnished to the Nuclear Regulatory Commission upon request.
5.
General Standards for Acceptability - Elements of evaluation models reviewed will include technical adequacy of the calculational methods, including : for models covered by 6 50.46(a)(1)(ii),
compliance with required features of Section I of this Appendix K [and prevision-of-a-level-ef-safety-and-murgin-of-conservatism-comparable te-ether-acceptable-evaluatien-models--taking-inte-aceount-significant differences-in-the-reaeters-te-which-they-apply-] : and, for models covered by 6 50.46(a)(1)(i), assurance of a high level of probability that the performance criteria of 6 50.46(b) would not be exceeded.
Dated at Rockviile, MD this day of
, 1988.
For the Nuclear Regulatory Commission.
Samuel J. Chilk, Secretary of the Commission.
Page 35
. ENCLO_SURE-E'~~
4 Appendix A - Submitting Rulemaking Documents for Federal Register Publication This appendix describes the information and procedures needed to prepare and submit the packages that are required when a rulemaking document is readied for publication in the Federal Register.
The packages necessary to ensure the prompt, complete implementation of Comission and Executive Director for Operations (EDO) rulemaking actions are the Federal Register notice package and the Congressional letter package.
The staff office originating the rulemaking action is responsible for preparing the required packages. The originating office shall submit the packages required to complete action on a rulemaking action to the Rules and Procedures Branch, Division of Rules and Records (DRR), Office of Administration and Resources Management (ARM) (Mail stop: MNBB 4000). The required packages are normally submitted as follows:
(1)
If the rulemaking action was approved by the Commission and is to be signed by the Secretary of the Commission, the packages are submitted to DRR at least two working days before the response date indicated in the Staff Requirements Memorandum.
(2)
If the rulemaking action was approved and signed by the EDO under the rulemaking authority delegated to the EDO, the packages are submitted to DRR within 5 days of the ED0's signature.
The Federal Register Notice Package Each packKge submitted to DRR for the transmittal of a rulemaking document for publication in the Federal Register must contain the items discussed below.
t November 1987 i
(a) Transmittal memorandum.
The transmittal memorandum for the package is sent from the originating office to David L. Meyer, Chief, Rules and Procedures Branch, DRR, ARM (see Sample 1). The memorandum should indicate, as appropriate, the following:
(1) The effective date for a final rule.
(2) The date by which comments must be received for an advance notice of I
proposed rulemaking or a proposed rule.
(3). Any places in the notice after the "DATE" line in the preamble where an effective date, a coment period expiration date, or any other date must be inserted before Federal Register publication.
(4) The need for expedited publication, if applicable.
(5) The need for special 0FR publication, such as printing the rule as a separate part of the Federal Register, if applicable.
(6) Whether DRR should dispatch Congressional letters to GPA/CA.
(
(7) Whether DRR should dispatch a public announcement to GPA/PA.
(8) Whether an Environmental Impact Statement, Regulatory Analysis, or other analysis is to be sent to the PDR.
(9) Whether a marked-up copy of Federal Register notice or errata sheet showing Comission-requested and other changes is enclosed for transmittal to the Office of the Secretary.
(10) Whether, in the case of a rule signed by the EDO, an item for the Daily or Weekly Information Report has been submitted to the EDO.
A-2 November 1987 l
(b) Federal Register notice.
The appropriate number of copies of the Federal Register notice to be included in the package depends upon the person who signs the notice.
(1) If the Federal Register notice is to be signed by the Secretary of the Comission and the notice is --
(i) 14 or fewer pages, include the original copy of the notice; (ii) 15 or more pages, include the original and 2 copies.1 (2) If the Federal Register notice is signed by the Executive Director for Operations include the signed original and 5 copies of the notice;
('c).Public announcement.
A public announcement, if appropriate, is prepared by the originating office in consultation with the Office of Government and Public Affairs. Two
(
copies of any PJblic Announcement must be received by DRR.
(d) Marked copy of rule.
A marked-up copy of the Federal Register notice that indicates any changes made to the rule after the Comission acted on it is prepared by the originating office. The changes may have been directed by the Commission or may have been necessary to include essential editorial and format corrections.
]
1 The Office of the Secretary makes additional copies of the Federal Register notice after it is signed.
A-3 November 1987 f
(
)
(e) Letter requesting expedited publication.
(
A letter is sent to the Office of the Federal Register (OFR) requesting and justifying expedited publication if, because of exigent circumstances, it is necessary. Normal publication is three days after receipt by the OFR, The letter, which must fully indicate why expedited publication is necessary, is addressed to Martha B. Girard, Director, Executive Agencies Division Office of the Federal Register, Washington, DC 20408. The letter must accompany the i
document for which expedited publication is requested.
The Congressional letters Package Congressional letters must be prepared for every significant NRC rule in accordance with Section 303 of the Atomic Energy Act of 1954, as amended, to
' keep the Congress " fully and currently infonned." (See Sample 2 for a list of the current standard addressees in Congress). The office preparing the rulemaking package is responsible for identifying the Congressional oversight 7
comittees that must be notified of this action.
see i
Sample 3)
M6
(
fP 4%Y N 1 N e M ee w te opp,vpr.. E R.. f t....... The Congressional package for each rulemaking action forwarded for Federal Register publication must contain the following items:
2 1.
One original letter plus enclosures to the Chairman of each Congressional Committee with oversight responsibility for the rule; 2 Enclosures usually consist of the Federal Register notice and the Public Announcement. However, if the Federal Register notice is to be signed by the Secretary of the Comission, copies of the FRN need not be included in the Congressional letters package transmitted to DRR.
(
A-4 November 1987 f
2 2.
One copy of the original letter to the Chaiman plus enclosures to the ranking minority member of each appropriate Congressional Comittee 3
with oversight responsibility for the rule; 3.
One original and three copies of the concurrence page for only
)
one of the Congressional Comittee letters. On the concurrence page type:
" Identical letters sent to (and list the remaining Congressional Comittees Chairinan and ranking minority members)."
(
l A-5 November 1987
i Sample 1 - The transmittal memorandum.
1 l
MEMORANDUM FOR:
David L. Meyer, Chief Rules and Procedures Branch Division of Rules and Records Office of Administration FROM:
F. F. Gillespie, Director Division of Risk Analysis and Operations Office of Nuclear Regulatory Research 4
SUBJECT:
IMPLEMENTATION OF C0leilSSION ACTION: PROPOSED NEW 10 CFR PART 39 By memorandum dated February 28, 1987, the Secretary of the Cosuiission indicated that the Commission (with all Commissioners agreeing) has approved the proposed rule on well-logging set out in SECY-87-11.
Please implement the Commission's action by arranging for publication of the enclosed proposed rule in the Federal Register allowing 90 days for public comment.
Enclosed is a marked-up copy of the Federal Register notice showing Connission-requested and other changes for transmittal to the Office of the Secretary.
(
Also enclosed is a Congressional letter package for transmittal to GPA/CA and-two copies of the public announcement for transmittal to GPA/PA.
In addition, enclosed are copies of the environmental assessment and finding of no significant impact and the draft regulatory analysis for transmittal to the PDR.
F. P. Gillespie, Director Division of Risk Analysis and Operations Office of Nuclear Regulatory Research
Enclosures:
1.
FR Notice and 2 Copies 2.
Marked-up Copy of FR Notice 3.
Congressional Letter Package 4.
Environmental Assessment 5.
Draft Regulatory Analysis l-A-6 November 1987
Sample 2 - List of standard Congressional addressees.
The Honorable Philia R. Sharp Chairman Subcommittee on Ene gy and Power Comittee on Energy and Comerce United States House of Representatives Washington, DC 205~.5 cc: The Honorable ~arlos J. Moorhead l
The Honorable John !. Breaux, Chairman Subcommittee on Nuclear Regulation Comittee on Envirceent and Public Works United States Senate Washington, DC 20510 cc: The Honorable Alan K. Simpson The Honorable Morris K. Udall, Chaiman Subcommittee on Ene gy and the Environment Committee on Interior and Insular Affairs United States House of Representatives Washington, DC 20515 cc: The Honorable Manuel Lujan, Jr.
i
(
A-7 November 1987
9 Sample 3 - Congressional letter.
(
The Honorable John B. Breaux, Chairman Subcommittee on Nuclear Regulation Committee on Environment and Public Works United States Senate Washington, DC 20510
Dear Mr. Chairman:
The NRC has sent to the Office of the Federal Register for publication the enclosed proposed amendment to the Commission's rules in 10 CFR Part 50. The amendment, if adopted, would require licensees of nuclear power plants for which an operating license has been granted to establish, document, and implement procedures to ensure that personne'l with unescorted access to protected areas are not under the influence of drugs, alcohol, or otherwise unfit for duty because of mental or temporary physical impairments that could affect their performance in any way contrary to safety.
The Commission is issuing the proposed rule for public connent and has specifically requested comments with respect to the scope, level of
- specificity, and methods of implementation of the rule.
Sincerely, Eric S. Beckjord, Director Office of Nuclear Regulatory Research
Enclosure:
As stated cc: Senator Alan K. Simpson l
(
A-8 Novenber 1987
A c 4 4 - 2.
PD ft AFFIRMATION V0TE cc 31,3ja Taylor RESPONSE SHEET FYI:
Seckford,RES vf.Shotkin, RES TRehm T0:
SAMUEL J. CHILK, SECRETARY OF THE COMMISSION y
X WL* C l AUS4~N FROMA COMMISSIONER CARR 7 ev me.s ey - v 6 4 Y L.
SUBJECT:
SECY-88-162 - REVISION OF THE ECCS RULE CONTAINED IN APPENDIX K AND SECTION 50.146 0F 10 CFR PART 50 APPROVED DISAPPROVED ABSTAIN NOT PARTICIPATING REQUEST DISCUSSION COMAENTS:
?
01
~
r 6'e {s r
CX 3
U h
SIGNATURE 7.i4-81, DATE E
!LO.
ENTERED ON "AS"
/1/
/
/
NRC-SECY FORM MAY, 1987
AcH4-2 p, z AFF1RMATI0h V0TE
{
RESPONSE SHEET a
r FYI:
B,eckjord, RES AShotkin,RES T0:
SAMUEL J. ClilLK, SECRETARY OF THE COMMISSION TRehm 4
J#-fA' N l
FROM:
CHAIRMAN ZECH p u m qs s*M e GE7L
SUBJECT:
SECY-88-162.- REVISION OF THE ECCS RULE CONTAINED IN APPENDIX K AND SECTION 50.46 0F 10 CFR PART 50 APPROVED DISAPPROVED ABSTAIN NOT PARTICIPATING REQUEST DISCUSSION COMMENTS:
~
f 1
fk
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g/'
i
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p PN d
3
,r 2[
SIGNATUR DATE YES ENTERED ON "AS"
/ %/
/
/
NRC-SECY FORM MAY, 1987
A c q <i-t pg AFFIRMATION
/0TE cc:
Stello Taylor RESPONSE SHEET FYI:
Beckjord, RES t
/ Shotkin, RES TRehm T0:
SAMUEL J,' CHILK, SECRETARY OF THE COMMISSION ygg
)(gintog: lao 6 EN FROM:
COMMISSIONER ROGERS To v m A 5J/A N
-2 o 6 m
SUBJECT:
SECY-88-162 - REVISION OF THE ECCS RULE CONTAINED IN APPENDIX K AND SECTION 50.116 0F 10 CFR PART 50 APPROVED Ay AW DISAPPROVED ABSTAIN NOT PARTICIPATING REQUEST DISCUSSION COMMENTS:
These rule amendments are the final products of an excellent, complex and very costly program of research and analysis.
The research program has led to a much better and deeper understanding of the behavior of safety-critical elements of nuclear reactors.
These rule amendments can result in safer nuclear power plants.
I approve the publication in the Federal Recister of the final amendments as given in Secy 88-162.
l However, I urge the staff to exercise the utmost care in approving changes in any present requirements for operating power reactors which have resulted from current rules, e.g.
flux shape monitoring.
Each " benefit" that is sought by a l
licensee under the new Appendix K and 50.46 methodology that i
requires a change in plant technical specifications must be reviewed case-by-case to examine the impact of such a change on all parts of the plant taken as a total system.
u.a A
SIGNATURE 6 i
O h (f, l 90 dATE YES
!LO.
l
~
l Et:TERED ON "AS"
/
/
/
/
NRC-SECY FORM MAY, 1987
A c q q - 2.
PDz AFFIRMATI0N V0TE cc:
Stello Taylor RESPONSE SHEET FYI:
Beckjord, RES LShotkin. RES TRehm T0:
SAMUEL J..CHILK, SECRETARY OF THE COMMISSION FROM:
COMMISSIONER ROBERTS
SUBJECT:
SECY-88-162 - REVISION OF THE ECCS RULE CONTAINED IN APPENDIX K AND SECTION 50.46 0F 10 CFR PART 50 APPROVED X/w/ mods DISAPPROVED ABSTAIN NOT PARTICIPATING REQUEST DISCUSSION
- ~
COMMENTS:
See attached modifications, SkVM*M ypK LA a s Ew p Jrn &s3 /6^/
,0 a-a sert._
rE o
v
&/N
\\\\
1 g c> W / '
P e
SI NATURE
, u/e
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DATd YES-
r u
errors' are discovered in evaluation models, requssts aro made to resise plant technical specifications, or some other questions.
regarding th'e analyses 'are raised. The NRC believes that sha' red k.\\
responsibility for evaluation models would not be in the'best interest of the public health and safety and therefore has not implemented the suggestion of th,is commenter.
The NRC received two requests for an extension of the coment' period to allow time for review of NUREG-1230, which describes the research supporting the proposed rule revision.
The NRC believes the comment period was sufficient since.mos,t of the research is not' new and has been extensively reviewed in the past. _Both commenters were contacted and told that comments received after the comnient' period would be considered if time.s permitted. Coments from both' parties were received late and were indeed considered tiy the NRC.'
,.e.
+
Some'commenters viewed the proposed 6.
Reporting Requirements.
reporting procedures as new requirements needing consideration in the backfit analysis'while others stated that they are a major relaxation and clarification of existing reporting requirements.
The NRC position is that the reporting requirements are new in the sense that they will now appear in the Code of Federal Regulatios,{d:.t..cefe..h...Leen;;;;id:r:dinh.L.dfit
~
= :1y:ic. In practice, these reporting requirements are indeed a clarification and relaxation over the current interpretation of the existing requirements and therefore the net,effect of these requirements will be to reduce the frequency for reporting an'd reanalysis.
A number of commenters requested that only significant errors or changes in the non-conservative direction or only those that result in exceeding the 2200 F limit be required to 6'e reported.
l In addition, a number of commenters suggested that the NRC f
require only annual reporting of significant errors or changes.
ENCL'05URE E
{
Page 8
x I
~
~
.a i,
REGULATORY ANALYSIS, t
9 The' Commission has prepared a regulatory analysis for this final i
regulation which examines the costs and benefits of the alternatives k
considered and.is available for inspection and copying at the NRC Public Document Room, 1717 H Street NW, Washington, DC. Single copies of the
' analysis may be obtained from L. M. Shotkin, Office of Nuclear Regula-tory Research, Washington, DC. 20555, telephone (301) 492-3530.
REGULATORY FLEXIBILITY CERTIFICATION
' As required by the Regulatory Flexibility. Act of 1980, 5 U.S.C.
605(b), the dommission certifies that this rule will not have a significant. economic impact.upon a substantial number of small entities.
This rule affects only the licensing and operation of nuclear power plants. The companies that own these plani!s do not fall within the scope of the definition of "small enti, ties," set forth in the Regulatory
~
' Flexibility Act or the' Small Business Size Standards set out in regu-lations issued by the Small Business Administration in 13 CFR Part 121.
Since these companies are dominant in their service areas, this rule does not fall within the purvie'w of the Act.,
BACKFIT ANALYSIS Grept far tha remu..e reaui...i.;-fg backfit analysis is not required by 10 CFR 50.109 because the rule does not require applicants or licensees to make a change but only offers additional option Nonetheless, the factors in 10 CFR 50.109(c) have been analyzed cla4(icde.,
the' entire rule.
rd4*NA [ H NI$
'N $M, L
'I.
Statement of the specific objectives that the backfit is designed to achieve.
The objective of the rule is to modify 10 CFR 56.46 and
- Appendix K to permit the use of realistic ECCS evaluation models.
More realistic estimates of ECCS performance, based. on the improved knowledge gained from recent research on ECCS Page 24 ENCLOSURE E
1h Kr,b PUNbt, PLEASE d
REFER TO:
M880714A
/c' " %"'o, UNITED STATES
[.]
,,g 'j NUCLEAR REGULATORY COMMISSION.
)
WASHtNGTON. D C. 20555 ACTION - Beckjord, RES
- /4
.j July 22, 198.8 Cys:
Stello Taylor OFFICE OF THE Rehm SECRETARY Murley Thompson Shotkin,'RES MEMORANDUM FOR:
Victor Stello, Jr.
1 Executive Director for Opergtions FROM:
Samuel J. Chilk, Secretar
/
SUBJECT:
STAFF REQUIREMENTS _
BRIEF ON FINAL RULE ON 10 CFR PART 50.46 ECCSGA EPTANCE CRITERIA (APPENDIX K), 10:00 A.M.,
HURSDAY, JULY 14, 1988, COMMISSIONERS' CONFERENCE ROOM, ONE WHITE FLINT NORTH, ROCKVILLE, MARYLAND (OPEN TO PUBLIC ATTENDANCE) (SECY-88-162)
The Commission was briefed by the staff on final rulemaking amendments to the Commission's acceptance criteria for emergency core cooling systems for light water nuclear power reactors (10 CFR 50.46 and Appendix K to Part 50).
Commissioner Rogers recommended that the staff use this rule-making opportunity to clarify the meaning of conservatism as it is applied to this activity.
Commissioner Rogers also cautioned the staff to proceed slowly when implementing this rule, if approved.
The consequence of any approved change should be assessed in areas outside the loss of coolant accident arena.
cc:
Chairman Zech Commissioner Roberts Commissioner Carr Commissioner Rogers OGC GPA PDR - Advance DCS - P1-124 Rec'd Off. EDO Da'e I
+*~
l u. fir-Time dh A G A 2-
- ^
QG(/IV/V/ Y l~
4
) C' 9800322 I
AC WJ 7.
FDA f#@ RfCg%,
L UNITED STATES ACTION - Beckjord, RES 3"
NUCLEAR REGULATORY COMMISSION S
W ASHIN GTON. D.C. 20555 CyS:
Stello Taylor o,,
Hoyle August 12, 1988 Murley, NRR OFFICE OF THE Thompson, NMSS SECRETARY -
LShotkin, RES Scroggins, ARM MEMORANDUM FOR:
Victor Stello, Jr.
Shelton, ARM Executive Director for Operations JBeeson, ARM William C.
Parler, General Counsel pt U.6 FROM:
Samuel J.
Chilk, Secretary
SUBJECT:
STAFF REQUIREMENTS - AFFIRMAT70N/ DISCUSSION AND VOTE, 3:30 P.M.,
THURSDAY, AUGUST 4, 1988, COMMISSIONERS' CONFERENCE ROOM, ONE WHITE FLINT NORTH, ROCKVILLE, MARYLAND (OPEN TO PUBLIC ATTENDANCE)
I.
SECY-88-164-- ALLOCATION BETWEEN COMMISSION AND ILLINOIS OF REGULATORY AUTHORITY OVER WEST CHICAGO FASTE MATERIALS The Commission by a 4 O vote, approved an order which resolved the uncertainty whether Illinois has jurisdiction over certain materials in Kress Creek and other locations at or near the West Chicago Facility.
The order held that the NRC retains jurisdiction over the Kress Creek materials and that the Commission has relinquished jurisdiction over the other materials in dispute.
In addition the Commission approved an order denying the NRC staff's July 13, 1987 petition for review of ALAB-867.
(Subsequently, on August 5, 1988 the Secretary signed the order.)
II.
SECY-88-184 - LICENSING BOARD DECISION ON SENIOR REACTOR OPERATOR LICENSE FOR DAVID W.
HELD l
The Commission by a 4-0 vote approved an order which completed its consideration of January 11 and February 2, 1988 decisions of the Administrative Judge presiding over the request of Mr. David W. Held for a hearing on the denial of a senior reactor operator license.
The order remands the case to the Administrative Judge for a proceeding on the specific issue of whether Mr. Held should have been found to have passed or failed the simulator examination.
Chairman Zech had additional views which were attached to the order.
(Subsequently, on August 8, 1988 the Secretary signed the order.)
Rec'd Off. EDO Date 'P' I EY l
q&
f0b>
~1me l0: IV 8800346
2_
III. SECY-88-162 - REVISION OF THE ECCS RULE CONTAINED IN APPENDIX K AND SECTION 50.46 OF 10 CFR PART 50 The Commission by a 4-0 vote approved revisions of the ECCS Rule contained in Appendix K and Section 50.46 of.10 CFR Part 50, subject to the: attached modifications.
The Federal Register notice should be modified as noted and returned for signature and publication.
("OC) d66 (SECY Suspense: 9/9/88) cc:
Chairman Zech Commissioner Roberts j
Commissioner Carr i
Commissioner Rogers GPA ACRS ACNW ASLBP ASLAP-DCS - P1-124 PDR - Advance copy 1
i
crrors are discos ad in cvaluation models, reque s are m:de to revise plant technical specific'itions, er som] other questions
\\
regarding th'e analyses are raised. The NRC believes that shared tyv responsibility for evaluation models would not be in the best interest of the public health and safety and therefore has not implemented the suggestion of this commenter.
The NRC received two requests for an extension of the comment period to allow time for review of NUREG-1230, which describes the research supporting the proposed rule revision.
The NRC believes the comment period was sufficient since most of the research is not new and has been extensively reviewed in the past. Both commenters were contacted and told that comments received after the comment period would be considered if time.
permitted.
Comments from both parties were received late and were indeed considered b'y the NRC.
6.
Reporting Requirements.
Some comenters viewed the proposed
~
reporting procedures as new requirements needing consideration in the backfit analysis while others stated that they are a major relaxation and clarification of existing reporting requirements.
The NRC position is that the reporting requirements are new in the sense that they will now appear in the Code of Federal Regulations.Ed therefer. l.avo Leen : = idered in u.= Le dfit
=1 yd e.fewew-rIn practice, these reporting requirements are indeed a clarification and relaxation over the current interpretation of the existing requirements and therefore the net,effect of these requirements will be to reduce the frequency for reporting an'd reanalysis.
i l
A number of commenters requested that only significant errors or l
changes in the non-conservative direction or only those that f
result in exceeding the 2200 F limit be required to 6e reported.
(
In addition, a number of commenters suggested that the NRC require only annual reporting of significant errors or changes.
)
Page 8 ENCI.05URE E l
l L-
REGULATORY. ANALYSIS
\\
9 The Commission has prepared a regulatory analysis for this final
(
regulation which examines the costs and benefits of the alternatives considered and is available for inspection and copying at the NRC Public Document Room, 1717 H Street NW, Washington, DC.
Single copies of the analysis may be obtained from L. M. Shotkin,' Office of Nuclear Regula-tory Research, Washington, DC. 20555, telephone (301) 492-3530.
REGULATORY FLEXIBILITY CERTIFICATION As required by the Regulatory Flexibility Act of 1980, 5 U.S.C.
605(b), the Comission certifies that t,his rule will not have a significant economic i= pact upon a substantial number of small entities.-
This rule affects only the licensing and operation of nuclear power plants. The companies that own these plantis do not fall within the scope of the definition of 'small ent,1, ties." set forth in the Regulatory Flexibility Act or the Small Business Size Standards set out in regu-lations issued by the Small Business Administration in 13 CFR Part 121.
Since these compcnies are dominant in their service areas, this rule does not fall within the purvie'w of the Act.,
BACKFIT ANALYSIS Grept far tha ern.g reaun...;r,Q g backfit analysis is not required by 10 CFR 50.109 because the rule does not require applicants or licensees to make a change but only offers additional option Nonetheless, the factors in 10 CFR b:1.109(c)havebeenanalyzedfjorOkikE*
the' entire rule.
fd'#Nm [ 80 laf l s
N 7M,,
L 1.
Statement of the specific objectives' that the backfit is designed to achieve.
The objective of the rule 1s to modify 10 CFR SU.46 and Appendix K to permit the use of realistic ECCS evaluation models.
More realistic estimates of ECCS performance, based on the improved knowledge gained from recent research on ECCS Page 24 ENCLOSURE E
_____-