ML20198K508

Part 21 Rept Re Transient Analyses at Exposures Prior to End of Cycle.Caused by Component Defect.Notified Commonwealth Edison of Defect & Provided Revised Limits by Siemens Power Corp

ML20198K508
Person / Time
Site:	LaSalle
Issue date:	01/06/1998
From:	Maas L SIEMENS POWER CORP. (FORMERLY SIEMENS NUCLEAR POWER
To:	NRC, NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
REF-PT21-97 LJM:98:001, LJM:98:1, NUDOCS 9801150020
Download: ML20198K508 (3)

Text

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SIEMENS 1

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January 6,1998 ,

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j LJM:98:001 .

- U.S. Nuclear Regulatory Commission j Document Control Desk Attn: Chief, Planning, Program and Managemsnt Support Branch Washington, D.C. 20555 j f

' DJar Gentlemen:-

Subject:

10 CFR 21 Notification Regarding Transient Analyses at Exposures Prior to End of Cycle -  ;

This letter and its attachment provide written notification of a reportable defect per 10 CFR Part 21 reported to the NRC Operations Center by facsimile on Decern'oer 10,1997. Report No.

33377 was assigned to the notification by the Duty Officer.

Very truly yours,-

d O CYQ &#W '

. L. J. Maas, Manager Regulatory Compliance

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Attachment cc: E. Y. Wang (NRR/DRPM/PECB)

E. W.Merschoff, Administrator, NRC Region ~lV E l1 ',

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- Siemens Power Corporationi Nuclear DMaion 2101 Horn Rapids Road - Tet; (509) 375 8100

- Engineering & Manufacturing - . P.o. Box 130 . Fax: 1509) 376-8402 RicNand, WA - 99302-0130

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REPORTABLE DEFECT i

(i.) Name and address of the IndividualInforming the Commission. l L.J. Maas, Manager, Regulatory Compliance, Siemens Power Corporation, 2101 Horn Rapids Road, Richland, WA 99352.

(ii.) Identification of the facility, the activity, or the basic component supplied for such facility or such activity within the United States which fails to comply or contains a defect.

Operating limits based upon transient analyses for LaSalle Unit 2 Cycle 8.

(iii.) Identification of the firm constructing the facility or supplying the basic component which fails to comply or contains a defect.

Siemens Power Corporation, Richland, WA.

(iv.) - . Nature of the defect or failure to comply and the safety hazard which is created or could be created by such a defect or failure to comply.

INPO operating experience report (OE 8422) indicated that transient analysis results at end of cycle (EOC) might not always be limiting for the entire cycle. SPC had performed analyses at EOC which were expected to bound analyses at other exposures.

An evaluation of the impact of cycle exposure on transient analyses for both normal operation (no equipment out-of-service) and equipment out of-service (EOOS) conditions ,

was performed. Under normal operating (NO EOOS) conditions, transient results at EOC are bounding at power levels greater than Pbypass (direct scram on valve position operable). Although results at exposures prior to EOC can be more severe at power

- levels below Pbypass (non-direct scram), current operating limits for all plante remained protected during normal operation. Similar analyses performed under various EOOS conditions indicate that current operating limits remain applicable in all cases with the exception of.LaSalle Unit 2 Cycle 8.

More specifically, the evaluation concluded that for LaSalle Unit 2 Cycle 8, thermal limits previously provided would not be adequate when operating with all of the following conditions: 1. Turbine bypass valves out of service (TBVOOS) or feedwater heaters out-of service (FMOOS),L2. Reactor power less than 30% of rated (Pbypass), and 3. Core flow greater shan 50% of rated.

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i I-1 (v.), , The,date on which the Information of such defect or failure to comply was obtained.

The deviation was initially identified in the SPC Nonconformance Report (NCR) 6230 which was prepared on August 18,1997. An interim report (SPC Interim Report No.97-009) of an evaluation of a deviation pursuant to 10 CFR 21.21(a)(2) was provided to the NRC on October 16,1997 (Letter, J. 5. Holm (SPC) tc Document Control Desk, " interim Report of Evaluatian of a Deviation Pursuant to 10 CFR 21.21(a)(2)," dated October 16, 1997). A 10 CFR 21 notification was conveyed to the NRC Operations Center on December 10,1997 and was assigned Report No. 33377.

(vi.) In the case of a basic component which contains a defect or fails to comply, the number and the location of all such components in use at, supplied for, or being supplied for one or more facilities or activities subject to the regulations in this part.

The impact of the deviation is restricted to operating limits for Commonwealth Edison, LaSalle Unit 2 Cycle 8.

(vii.) The corrective action which has been, is being, er willbe taken; the name of the individual or organization responsible for the action; and the length of time that has been or willbe taken to complete the action.

Commonwealth Edison has been notified of this defect and has been provided with revised limits by SPC on December 12,1996.

Four additional corrective actions are planned:

1) include a recommendation in the BWR core wide transient analysis guideline that analyses at power levels where direct scram is inoperable be performed assuming the high flux scram is also inoperable.

2) Develop an interim process to set MCPRp limits and LHGRFACp values until Corrective Actions 3 and 4 can be completed.

3) Investigate the mechanisms that cause transiert ana!ysis results at exposures prior to EOC to he more limiting than results at EOC.

4) Developlldentify a process or processes that can be used to ensure truit MCPRp lir s and LHGRFACp values are established that provide the necessary protection across the entire exposure domain for which they are intended.

These additional corrective actions will be completed by March 1998.

(viii.) Any advice related to the defect or failure to comply about the facility, activity, or basic component that has been, is being, or willbe given to purchasers or licensees.

This notification is being provided to SPC BWR customers.

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