ML20210P127
| ML20210P127 | |
| Person / Time | |
|---|---|
| Issue date: | 06/24/1999 |
| From: | Lyons J NRC (Affiliation Not Assigned) |
| To: | |
| References | |
| GL-83-11, NUDOCS 9908120076 | |
| Download: ML20210P127 (14) | |
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7590-01 P Nuclear Regulatory Commission LICENSEE QUALIFICATION FOR PERFORMING SAFETY ANALYSES; ISSUE
(
AGENCY: Nuclear Regulatory Commission.
ACT) #L Notice of Issuance.
PUBLIC DOCUMENT ft00M
SUMMARY
- The Nuclear Regulatory Commission (NRC) has issued Supplement 1 to Generic Letter (GL) 83-11, Licensee Quali$atio o Pe or ing Safety Analyses, to all holders of I
l operating licenses for nuclear power reactors. This GL supplement presents criteria that ',
licensees may choose to comply with to verify to the NRC their qualifications to use approved codes and methods for performing safety analyses.
DATES: The GL supplement was issued on June 24,1999.
ADDRESSES: Not applicable.
FOR FURTHER INFORMATION CONTACT: Laurence I. Kopp, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, telephone 301-415-2879, e-mail lik@nrc. gov.
j SUPPLEMENTARY INFORMATION: In 1995, the Nuclear Regulatory Commission (NRC) prepared a draft of a supplement to Generic Letter 83-11, Licensee Qualification for Performing l
Safety Analyses, for the purpose of presenting criteria that licensees may choose to comply I
with to verify to the NRC their qualifications to use approved codes and methods for performing j
safety analyses. By complyin with these criteria, a licensee would eliminate the need to submit a topical report for qualifying their use of a previously approved methodology. A notice of opportunity for public comment including a draft of the supplement were published in the Federal Register on October 25,1995 (60 FR 54712). NRC staff responses to the comments 7
received are presented below under the heading " Discussion of Comments."
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l The NRC subsequently decided to cancel the issuance of the generic letter supplement primarily because of issues that had arisen at a nuclear power facility (Maine Yankee) regarding the improper application of approved methods. At that time, the NRC concluded that the potential reduction in staff oversight which would result from its issuance was not justified. A notice of cancellation was published in the Federal Register on October 30,1996 (61 FR 56069). The specific issue that arose concerned the licensee's failure to comply with all of the restrictions and conditions stated in the staff's safety evaluation report (SER) for proper I
application of a loss-of-coolant-accident (LOCA) code.
A review of the lessons learned from Maine Yankee has indicated that the issue involved was adequately addressed in the generic letter supplement as published for public comrnent on October 25,1995, because the supplement requires that licensees adhere to all limitations and restrictions in the staff's SER. Further, this supplement to GL 83-11 does not apply to LOCA codes. Therefore, the NRC determined that there would be no reduction in staff oversight and decided to proceed with issuance of the supplement.
The GL supplement is available in the NRC Public Document Room under accession number 9906210103.
Discussion of Comments i
I Comments were received from 13 licensees,3 fuel vendors, and 3 industry interest groups, in response to the notice of opportunity for public comment noted above. Following are the staff responses to comments received on the proposed GL 83-11 supplement:
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.. Studsvik of America. Inc.
Comment:
Clarify that " safety analysis" includes the physics parameters and codes used to generate them.
Response
Clarification has been made in both the Purpose section and 2.0 Guidelines section.
Comment:
For physics codes, approval of code should be separate from the application method.
Response
Section 2.2 has been modified to clarify that in some instances the approval of the code is separate from the application method.
Comment:
Clarification of what constitutes NRC approval of a code and/or method would be helpful.
Response
Section 2.1 has been modified to clarify the eligibility of codes and methods for this process.
Comment:
Clarify what constitutes a significant code and/or methodology update that must be reviewed by the NRC.
Response
What constitutes a significant code or methodology update that must be I
reviewed by the NRC is too complex a topic to fully address in a generic manner at this time. However, as mentioned in the Federal Register notice (October 25, l
1995 (60 FR 54712)), the NRC is also investigating modified procedures for reducing the resource effort for acceptance of new or revised licensee or vendor
4 analysis methods.: Therefore, it is anticipated that this topic will be addressed at
= a future date.
Westinahouse Electric Corooration
' Comment:
Reemphasize that NRC's experience has shown that a large percentage of all errors or discrepancies discovered in safety analyses can be traced to the user rather than the code itself.
Response
The fact that NRC's experience has shown that many times errors or discrepancies discovered in safety analyses can be traced to the user rather than the code itself is stated in the Description of Circumstances section.
Florida Power & Liaht Comoany Comment:
NRC should allow licensees to modify the Core Operating Limit Report (COLR) without specific NRC review so long as the methods and codes have already been approved by the NRC.
Response
The issuance of this supplement would allow this modification as long as the approved methodology is referenced in the technical specifications. The Introduction and Section 2.0 have been modified to address this, j
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. Duke Power Comoanv -
Comment:
NRC should generically lift restrictions included in topical report SERs that restricted application of the methodology to the plants operated or supported by the licensee of the methodology.
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Response
- The issuance of this supplement would generically lift these restrictions.
However, any other limitations stated in the SERs should be adhered to.
Comment:
The introduction should state that the codes are developed by vendors, utilities, national labs, or organizations like EPRI.
Response
The proposed statement has been added to the Introduction.
1 Comment:
The scope of safety analyses should be defined to cover any analytical areas including reload physics design, core thermal-hydraulics, fuel mechanical i
analysis, transient analysis, dose analysis, setpoint analysis, containment analysis, criticality analysis, statistical methods, and any other analytical area for which topical reports have been approved by the NRC.
Response
The suggested clarification has been incorporated in the Purpose and 2.0 Guidelines sections, with the exception of LOCA analysis codes.
Nuclear Enerav Institute
' Comment:
Recommends deletion of last two items in Section 2.5.
Response
The NRC believes that the two items emphasized are of sufficient significance to be explicitly stated.
f Comment:
Recommends rewording of Section 2.4 so as not to imply all of the suggested set of benchmark data is required.
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' Response:
- The wording in Section 2.4 has been modified to clarify that these are examples of appropriate benchmark data and are not all required.
Commonwealth Edison Company i
Comment:
Terminology and criteria are open to interpretation. For example, in Section 2.4, what the licensee may think is appropriate justification for an observed deviation in comparison calculations may satisfy one reviewer but not another.
Response
Suggested rewording for benchmark deviations has been added to Section 2.4 to eliminate ambiguity, 1
l Comment:
~The intent of the term " application procedure" in Section 2.2 could be misinterpreted.
Response
Section 2.2 has been revised for clarification.
Comment:
Section 2.4 should be revised to read "Significant, unexpected, or unusual deviations should be..."
Response
The suggested rewording has been added to Section 2.4.
Comment:
Vendor updatesimplementation in Section 2.5 should be clarified so as not to 1
imply that all changes that vendor makes must be implemented.
Response:'
Section 2.5 Item (1) has been modified to allow an evaluation of updates to determine if implementation is required.
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.. Electric Power Research Institute Comment:
Questions whether a licensee must base the methodology on a previously approved plant SER or can develop a "new" topical based only on the generic code SER?
Response
By adhering to the guidelines in the supplement, a licensee can perform its own analyses using any approved code or method.
Comment:
For clarity, the words " application of the" should be deleted from Section 2.2.
Response
The in-house application procedures should be consistent with the code qualification and approved application of the methodology. Therefore, this has been retained in Section 2.2.
Comment:
Training should be performed by either the developer or someone who has been previously qualified.
Response
The proposed wording has been added to Section 2.3.
Comment:
" Vendor" analysis should be changed to " analysis of record."
Response
The proposed rewording has been added to Section 2.4.
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Comment:
An appropriate set of benchmark data should include analysis of events, using higher order codes or published numerical benchmarks.
Response
The proposed wording has been added to Section 2.4.
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Comment:
In Section 2.4, "Any deviations" should be explained.
Response
A revision has been made to Section 2.4 to more clearly define deviations that must be explained.
Southern Nuclear Operatino Comoany Concurs with NEl comments.
GPU Nuclear Corporation Comment:
It seems appropriate to identify existing codes and methodologies that have been developed by national labs for the NRC that can be considered NRC approved codes and methods.
Response
The identification of existing codes and methodologies developed by national
- labs that can be considered as NRC approved codes and methods, even though formal NRC review and approval has never been performed, is beyond the scope of this proposed supplement.
Comment:
Suggests that the terms " codes", " methods", and " applications" be clearly defined.
Response
A definition of codes, methods, and applications has been added to the 1
introduction.
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Siemens Power Corooration Supports the approaches described in the proposed supplement.
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i ' Viroin'ia Power-End$rses the proposed supplement.
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~ Pacific Gas and Electric ' Company l
Comment:
Concept should not be limited to core analysis.
Response
The specific analytical areas that the GL refers to have been added to the Purpose Section.
l Comment:'
NRC should allow the training requirement to be met by on-the-job training.
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- Response:
A new user can be qualified by on-the-job training as well as by formal classroom L
instruction. In many cases, user qualification will be accomplished by a t.
combination of both -
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. Yankee Atomic Electric Comoany (VAEC)
Comment:
It is YAEC's understanding that the supplement will only apply to licensees who use another organization's methods and codes, and not to an organization that
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l receives approval for its own codes and methods, and conducts safety analyses using those c' odes and methods.
Response
- YAEC's interpretation is correct.
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. Comment:'
Recommends that the supplement also note that other organizations such as t
I utilities and engineering service companies have developed codes and methods.
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.. Response:
The example of possible code developers has been modified to include utilities and nationallabs.
indiana Michiaan Power Company Comment:
Suggests that different versions of previously approved codes should be applicable as long as the calculational methodology is not changed.
Response
Section 2.1 has been modified to clarify code eligibility. What constitutes a significant code or methodology update that must be reviewed by the NRC is too complex a topic to fully address in generic terms at this time. However, as mentioned in the Federal Register notice (60 FR 54712; October 25,1995), the NRC is also investigating modified procedures for reducing the resource effort i
for acceptance of new or revised licensee or vendor analysis methods.
Therefore, it is anticipated that this topic will be addressed at a future date, i
Enterav Operations. Incoroorated Comment:
The applicability of a particular method to either a specific fuel design or to a l
l core which contains a mixture of fuel types is important. Use of one vendor's hot channel analysis code with another's transient codes may not necessarily yield conservative results and may not be consistent with the NRC-approved reload i
analysis package. In-house application procedures should have proper controls to preclude such a misapplication, and should be permitted to include the flexibility to perform comparison tests between the different methodologies to show that a conservative assessment can be made.
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Response
_ Section 2.2 has been modified to incorporate this application procedure.
Comment:
NRC should consider issuing an inspection procedure concurrently with the supplement so that licensees would know what questions and documentation I
requests might be needed to support audits.
Response
The NRC willincorporate oversight of this GL supplement into the NRC inspection program following the issuance of this supplement.
Comment:
NRC should consider providlig licensees the flexibility to conduct its own assessment of a third part.v reviewer similar to what is currently allowed in NRC Inspection Module 40501.
Response
Issuance of this supplement would eliminate the need to submit a qualification topical report for NRC review and thus eliminate the need for a third party reviewer.
Comment:
The "first licensing application" is interpreted by APS as being the first proposed license amendment or other licensing basis change requiring prior NRC review and approval that was supported by safety analyses performed by the licensee 1
instead of a vendor.
Response
The "first licensing application" may not necessarily be a licensing basis change requiring NRC approval before implementation, but may be a revision to a COLR parameter, for example.
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t i Comment:
APS would interpret " eligibility"in Section 2.1 to mean that code packages previously approved in topical reports or license amendments for other plants would be generically approved.
Response
The only codes and methods that are eligible for this process are those that have been generically approved, or those that have been otherwise accepted as part of a plant's licensing basis. Section 2.1 has been modified to clarify this, i
Comment:
APS suggests that plant specific uncertainties could be used without additional NRC review, even if these uncertainties are less than the generically approved uncertainties.
Response
As a general rule, plant specific uncertainties may be used without additional NRC review provided that they are derived with previously approved methods.
I However, NRC review is required for modifications to uncertainties that were generically approved to cover uncertainties due to codes and methods, correlations, etc.
Comment:
APS states that they would control changes to methodology by design control procedures and that the changes would be subject to 10 CFR 50.59 evaluations, if appropriate. i i
Response
As stated in Section 2.1, the use of a new methodology or a change to an existing methodology is not applicable to this process. However, as mentioned in the Federa/ Register notice (60 FR 54712; October 25,1995), the NRC is also investigating modified procedures for reducing the resource effort for acceptance i
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. of new or revised licensee or vendor analysis methods. Therefore, it is anticipated that this topic will be addressed at a future date.
Comment:
APS considers an appropriate set of benchmark data to include other acknowledged industry standard data or criteria.
Response
The examples of appropriate benchmark data has been expanded to include APS' suggestions.
Comment:
APS suggests that Section 2.5 be revised to allow a provision for evaluating i
vendor updates and implementing those updates, if applicable.
Response
The proposed rewording has been incorporated into Section 2.5.
Centerior Eneroy Comment:
The guidance should be explicit enough to allow for utilities to reference topical reports submitted by non-NSSS vendors.
Response
Utilities have been added to the example of organizations that develop methods.
Comment:
The proposed guidance should be sufficiently flexible to allow substitution of computer codes within an approved analytical methodology.
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Response
The Application Procedures have been modified to allow this, but should contain proper controls to preclude misapplications or inappropriate use of an application.
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\\ Comment:
NRC should maintain a listing of the codes or methods it has approved.
Response
The NRC is currently developing a data base of approved codes as a separate action.
l Comment:
NRC should define the point at which reapproval of updates is necessary.
Response
What constitutes a significant code or methodology update that must be reviewed by the NRC is too compiex a topic to fully address in generic terms at i
this time. However, as mentioned in the FederalRegister notice (60 FR 54712; i
October 25,1995), the NRC is also investigating modified procedures for reducing the resource effort for acceptance of new or revised licensee or vendor i
analysis methods. Therefore, it is anticipated that this topic will be addressed at l
a future date.
Dated at Rockville, Maryland, this 24th day of June 1999.
FOR THE NUCLEAR REGULATORY COMMISSION.
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w Jam s E. Lyons, De ty hief Even:s Assessment, Ge ric Communications and o 1-Power Reactors Branch, Di on of Regulatory improvement Programs, s
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