ML20106H411

Discusses NRC Concern That Util Engineers May Not Fully Appreciate NRC Position on Generation of 50.59s Re Util 50.59 NOV Response

ML20106H411
Person / Time
Site:	San Onofre
Issue date:	03/11/1996
From:	Gibson G SOUTHERN CALIFORNIA EDISON CO.
To:	Vandenburgh C NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20106H399	List: ML20106H411
References
NUDOCS 9603210055
Download: ML20106H411 (3)

Text

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SOUTHERN CALIFORNIA EDISON  :

San Onofre Nuclear Generating Station l l

Compliance l l

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, , 03/11/96 11:17 17714 368 1996 ONL @ 002/002 e

Author WALTER MARSH at NESL6 Date: 03/11/96 09:34 AM Priority: Normal TO: MIFI WHARTON at G48 To: PAUL MYERS at W48 To: DANIEL BREIG at AWS CC: ROSS KRIEGER at ANS CC: DWlGHT NUNN at G4B BCC: GREGORY GIBSON at WEST

Subject:

NRC concern - 50.59 NOV response ------- -----

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=- ------------- Message Contents ----------- i RE: NRC/ Edison discussion on 50.59 NOV Response NRC Engineering management (Chris Vandenburgh), and NRR management ]

(Nel Fields) have expressed concern with Edison's 50.59 NOV response (which we have used as a required reading assignment to engineering personnel). The NRC is concerned that Edison engineers may not fully appreciate the NRC's position on the generation of 50.59s. Compliance assured the NRC that Edison will communicate this NRC concern to the engineering division managers, and ensure they convey the lessons learned from the NRC's citation. Please forward this email as a required reading assingment to all your engineering personnel.

To recap the issue:

Edison did, in fact, incorporate the NSAC-125 guidance on performing 50.59s into procedures. NSAC-125 provides for an initial screening  ;

criteria for determining whether to perform a " full, documented" 50.59 <

analysis. )

1 For the TCN on the reactor head vent flow oriface, Edison personnel (engineers and supervision / management) carefully reviewed the proposed change and after lengthy discussions, determined the FCN failed the l screening criteria and did NOT need a full, docenented 50.59 - this was based on still meeting the function, even though the system was actually carefully, reconfigured from a flange to a valve.

The NRC, however, believes that the change in the method of achieving the fanction (going from a flange to a valve with a special oriface) was sufficiently different so that the screening test should have resulted in a full, documented 50.59 being performed.

The bottom line is that Engineering actually did the safety analysis in convincing themselves that the FCN failed the 50.59 screen; however, as it did fail the screen, the safety analysis was not deemmented. 10CER50.59 requires an analysis to be done (we did that) and documented (we did not do that) in the records of the change demonstrating the change was not an unresolved safety question. We would have expended a lot less in energy and resources to simply document the safety analysis we did, than we have expended in trying to explain why we didn't need to do so.

The lesson to be learned from all of this is that the NRC's threshold for documenting a safety evaluation is slightly lower than ours was in this instance. In retrospect, the effort we went to in order to convince ourselves that a formal safety analysis was not required is a pretty good indicator that we were close to a threshold and a conservative engineering decision would have been to document a formal safety evaluation.

ENCLOSURE 2 Summary of Licensee Response to Violation 50-361/95-26: 50-362/95-26 Based upon our review of the licensee letter dated February 20. 1996 from Mr. Dwight Nunn and discussions with the Licensing Manager. Mr. Greg Gibson, on March 8. 1996, it is our understanding that the reason for Part A of the violation was that engineering judgement incorrectly determined the modification did not constitute a change to the design function or design bases. Thus, your staff concluded that a documented 10 CFR 50.59 safety evaluation was not required. In addition, your immediate corrective action was to document a 10 CFR 50.59 safety evaluation. Your corrective action to avoid further violations was to make the details of this event required reading for all engineering personnel. The date when full compliance was achieved was February 12. 1996.

It is also our understanding that the reason for Part 8 of the violation was engineering personnel error in the review of the Updated Final Safety Analysis Report. Your immediate corrective action was to complete a change recuest to the Updated Safety Analysis Report. Your corrective action to precluce further violations was to make this issue required reading for appropriate engineering personnel. In addition, the date when full compliance was achieved was January 24. 1996.

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. SOUTHERN calif ORNIA Dwight E Nunn i

{ Vice President An EDISON IVTERNATIONAL Company 1

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3I February 20, 1996

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U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington D. C. 20555

Subject:

Docket Nos. 50-361 and 50-362 Reply to a Notice of Violation (IR 95-26)

San Onofre Nuclear Generating Station, Units 2 and 3

Reference:

1) Letter, Thomas P..Gwynn (NRC) to Mr. Harold B. Ray (Edison), NRC Inspection Report 50-361/95-26 and 50-362/95-26, dated January 19, 1996

2) Meeting summary from James E. Tatum, Project Manager Project Directorate V, to Edison, dated j October 11, 1989.

Reference 1 provided the results of a routine engineering inspection conducted from November 13 through December 1, 1995.

The enclosure to Reference 1 transmitted a Notice of Violation for: a) the apparent failure to perform a 10 CFR 50.59 safety evaluation when Edison substituted a valve body for a flange body holding the reactor coolant system gas vent flow-restricting  ;

orifice, and b) the' failure to update the UFSAR to reflect the replacement of the flow-limiting orifice with an orificed gate valve.

Prior to the implementation of Field Change Notice (FCN) F9329M, an operating procedure controlled the installation of the orifice plate in its flange holder. This was done to allow the orifice plate to be removed in MODE 6, yet ensure the orifice plate was reinstalled prior to entering MODE 4 where its presence is t required.

I FCN F9329M replaced the pipe flange orifice container with a gate valve containing an orificed disk identical in design

requirements to the original design flow restriction

, requirements, i.e., the disk of the gate valve was drilled with P. a M 128 Mn Clememe. CA 42672 7y yyyn p g. 94- o s o 2.

l Document Control Desk )

an identical sized orifice. Operational procedures were changed l from requiring an individual to visually verify the orifice plate '

was properly reinstalled at the head vent prior to entering MODE 5, to having an operator verify the orifice is in its proper position by checking the valve closed and locked prior to entering MODE 4. Additionally, a second independent check j (inclusion in the locked valve program) was added to ensure the valve orifice is in its proper closed and locked position.

Reference 2 documented Edison's commitment to use NSAC/125 as our method of ensuring compliance with the provisions of 10 CFR 50.59. The provisions of NSAC/125 were carried over into FCN procedure, S0123-XXIV-10.21, Rev 4, " Field Change Notice (FCN) l and Field Interim Design Change Notice (FIDCN)." The FCN procedure specifies the NSAC/125 screening criteria appropriate to reasonably determine if a 10 CFR 50.59 safety evaluation is necessary. For FCN F9329M, Edison engineers used the screening criteria contained in S0123-XXIV-10.21, Rev 4, and concluded i there was no change to the design function or design bases, and that the written discussion of the RCS gas venting system as described in the UFSAR was appropriate for the modified system '

without change.

Edison has performed a formal 50.59 safety evaluation for the l orifice body replacement. The 50.59 evaluation concluded the change did not constitute an unreviewed safety question. This 50.59 was completed February 12, 1996.

Part B of the violation, Reference 1, also identified the failure to update the UFSAR to reflect the replacement of the flow-limiting orifice with an orificed gate valve. Edison engineers erred when they reviewed the UFSAR in that they missed the sketch that depicted the original design. Edison has completed a revised UFSAR change page for submission in the next scheduled UFSAR update to properly depict the change. Edison has also issued required reading on the incident to the appropriate engineering staff to facilitate thorough reviews of future UFSAR description and figure changes. Full compliance was achieved on January 24, 1996, when NEDO initiated UFSAR change request SAR23-424 to update the UFSAR attachment Figure 9.3-15.

The referenced cover letter requested Edison evaluate whether the UFSAR was being accurately maintained. Edison is reviewing the issue of UFSAR accuracy, and will provide our conclusions and any

Document Control Desk appropriate corrective actions and schedules in a separate letter within 60 days.

If you have any questiens, please call me.

Sin erely, n \,.

cc: L. J. Callan, Regional Administrator, NRC Region IV T. P. Gwynn, Director, Division of Reactor Safety, NRC Region IV J. E. Dyer, Director, Division of Reactor Projects, NRC Region IV K. E. Perkins, Jr., Director, Walnut Creek Field Office, NRC Region IV J. A. Sloan, NRC Senior Resident Inspector, San Onofre Units 2 and 3 M. B. Fields, NRC Project Manager, San Onofre Units 2 and 3

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