ML18064A582

Tech Specs Change Request to License DPR-20 Addressing Required Settings & Allowable as Found & as Left Tolerances for Primary & Secondary Safety Valves

ML18064A582
Person / Time
Site:	Palisades
Issue date:	01/13/1995
From:	Haas K CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML18064A583	List: ML18064A582 ML18064A584 ML18064A590
References
NUDOCS 9501300185
Download: ML18064A582 (12)

Text

t !--, r consumers Power KurtM. Haas Plant Safety and Licensing Director l'OWERINli MICHlliAN'S l'ROliRESS Palisades Nuclear Plant: 27780 Blue Star Memorial Highway, Covert, Ml 49043 January 13, 1995 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT - TECHNICAL SPECIFICATIONS CHANGE REQUEST - SAFETY VALVE SETTING LIMITS A request for a change to the Palisades Technical Specifications (TS} is enclosed. The attachment contains the proposed pages and the existing page which they would replace. This Technical Specifications change request (TSCR) addresses the required settings, and allowable "as found" and "as left" tolerances for the primary and secondary safety valves.

The proposed limits would allow installed primary and secondary valve settings to be within a 3% tolerance of their nominal settings, but would require returning the valve settings to within 1% of the nominal settings if the valves are removed from the piping for maintenance or testing.

The following attachments are included:

1) Proposed Technical Specifications pages

2) Existing page which is to be replaced by proposed pages

3) Palisades Loss of Load Analysis, EMF-93-086(P) [Proprietary]

4) Palisades Loss of Load Analysis, EMF-93-086(NP) [Non-Proprietary]

5) Siemens Power Corp. letter, July 26, 1993.

6) Siemens Power Corp. Affidavit Siemens Power Corporation considers some of the information in the Palisades Loss of Load Analysis, Attachment 3, to be proprietary, as stated in the affidavit included as Attachment 6. Therefore, it is requested that Attachment 3 be withheld from public disclosure. A non proprietary version of Attachment 3 is included as Attachment 4.

r.;,_~) n. n.D D 9501300185 950113 PDR ADOCK 05000255 p PDR A CMS ENER6Y COMPANY

2 It is requested that the associated Technical Specifications amendment be approved prior to the upcoming refueling outage, currently scheduled to start about May 20, 1995, and become effective upon approval.

Summary of Commitments:

This letter does not create, modify, or close any NRC commitments.

I Kurt M. Haas Director, Plant Safety &Licensing CC Administrator, Region III, USNRC Resident Inspector, Palisades State of Michigan Attachment

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ATTACHMENT 6 Consumers Power Company Pali sades Pl ant Docket 50-255 SAFETY VALVE SETTING LIMITS TECHNICAL SPECIFICATIONS CHANGE REQUEST SIEMENS POWER CORPORATION AFFIDAVIT

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.-1 AFFIDAVIT STATE OF WASHINGTON SS.

COUNTY OF BENTON I, R. A. Copeland being duly sworn, hereby say and depose:

1. I am Manager, Product Licensing, for Siemens Power Corporation ("SPC"),

and as such I am authorized to execute this Affidavit.

2. I am familiar with SPC's detailed document control system and policies which govern the protection and control of information.

3. I am familiar with the topical report EMF-93-086(P) entitled "Palisades Loss of Load Analysis," referred to as "Document." Information contained in this Document has been classified by SPC as proprietary in accordance with the control system and policies established by SPC for the control and protection of information.

4. The Document contains information of a proprietary and confidential nature and is of the type customarily held in confidence by SPC and not made available to the public. Based on my experience, I am aware that other companies regard information of the kind contained in the Document as proprietary and confidential.

5. The Document has been made available to the U.S. Nuclear Regulatory Commission in confidence, with the request that the information contained in the Document will not be disclosed or divulged.

6. The Document contains information which is vital to a competitive advantage of SPC and would be helpful to competitors of SPC when competing with SPC.

7. The information contained in the Document is considered to be proprietary by SPC because it reveals certain distinguishing aspects of SPC licensing methodology which secure competitive advantage to SPC for fuel design optimization and marketability, and includes information utilized by SPC in its business which affords SPC an opportunity to obtain a competitive advantage over its competitors who do not or may not know or use the information contained in the Document.

8. The disclosure of the proprietary information contained in the Document to a competitor would permit the competitor to reduce its expenditure of money and manpower and to improve its competitive position by giving it valuable insights into SPC licensing methodology and would result in substantial harm to the competitive position of SPC.

9. The Document contains proprietary information which is held in confidence by SPC and is not available in public sources.

10. In accordance with SPC's policies governing the protection and control of information, proprietary information contained in the Document has been made available, on a

• limited basis, to others outside SPC only as required and under suitable agreement providing for nondisclosure and limited use of the information.

11. SPC policy requires that proprietary information be kept in a secured file or area and distributed on a need-to-know basis.

12. Information in this Document provides insight into SPC licensing methodology developed by SPC. SPC has invested significant resources in developing the methodology as well as the strategy for this application. Assuming a competitor had available the same background data and incentives as SPC, the competitor might, at a minimum, develop the information for the same expenditure of manpower and money as SPC.

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THAT the statements made hereinabove are, to the best of my knowledge, information, and belief, truthful and complete.

FURTHER AFFIANT SAYETH NOT.

SUBSCRIBED before me this J t(

day of CJ~b ,g_ L, 1994.--

"J II 11:.

CONSUMERS POWER COMPANY Docket 50-255 Request for Change to the Technical Specifications License DPR-20 It is requested that the Technical Specifications contained in the Facility Operating License DPR-20, Docket 50-255, issued to Consumers Power Company on February 21, 1991, for the Palisades Plant be changed as described below:

I. Changes It is proposed that specification 3.1.7 be changed to allow an as found tolerance of +/-3% for the pressurizer safety valves and to clarify the individual setpoints of the primary and secondary safety valves. In addition, it is proposed that a +/-1% as left tolerance be imposed for primary and secondary ~afety valves following reinstallation after removal for valve maintenance or testing.

To implement these proposed changes, Specification 3.1.7 and its basis have been completely rewritten. It is proposed that the existing page 3-25 be replaced with new pages 3-24a, 3-24b, and 3-25.

II. Discussion Existing specifications 3.1.7a and 3.l.7b would be replaced by proposed specification 3.1.7.1 and existing specification 3.1.7c would be replaced by proposed 3.1.7.2.

The existing 3.l.7a is applicable only when the reactor is critical; the proposed 3.1.7.1 is applicable above cold shutdown (>210°F). The existing 3.l.7c is applicable during power operation; the proposed 3.1.7.2 is applicable above cold shutdown. In each of these cases, the proposed applicability encompasses the existing applicability.

Existing 3.l.7b is applicable when the reactor head is on the vessel; the proposed 3.1.7.1 is applicable above Cold Shutdown. The proposed revision removes the requirement for one operable pressurizer safety valve to be installed whenever the reactor head is on the vessel. Instead, proposed Specification 3.1.7.1 requires all of the pressurizer safety valves to be operable above cold shutdown, and overpressure protection during cold shutdown is provided by the Power Operated Relief Valves required by an existing specification, 3.1.8.

The pressurizer safety valves provide overpressure protection for the primary coolant system. The main steam safety valves provide overpressure protection for the secondary system. *The setpoints and relief capacities of the pressurizer and main steam safety valves are sufficient to limit primary and secondary system pressures to less than 110% of the design pressure following a complete loss of external load without the reactor trip on turbine trip. A loss of external load is the bounding event for challenges to pressurization acceptance criteria.

The existing Technical Specification criteria for the pressurizer safety valve lift setpoint tolerance (+/-1% of the as-found value) was derived from ASME Section III, Division 1, NB-7524.3. This code, however, applies to original construction only. We consider the +/-1% as-found criterion imposed on these valves too restrictive and feel it may promote valve

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degradation caused by too frequent testing. ASME B&PV Code, 1986 edition,Section XI, subsection IWV-3500, specifies ANSI/ASME OM-1-1981 requirements which allow the specified tolerances in the lift pressures of safety valves. Following the as-found testing, the pressurizer safety valve setpoints are calibrated to less than +/-1% of the nominal setpoint.

Since setpoint adjustments can only be made through trial and error, it is necessary to "pop" the valve several times before the proper setpoint is achieved.

Excessive actuation of the valves may result in poor setpoint repeatability and unpredictable valve performance caused by steam cutting the nozzle and disk or by changes in the valve spring characteristics.

Throughout the history of testing of the pressurizer safety valves it has been common for at least one valve to exceed the +/-1% criterion, however there have only been two occasions when the as-found setting exceeded the

+/-3% criterion. If a safety valve is tested and found to be outside of the allowable setpoint tolerance, an additional safety valve (or valves) must

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be tested in accordance with ASME section XI requirements. Increasing the i as-found setpoint tolerance will reduce the frequency of requiring more I

I than one valve to be tested during a refueling outage and will correspondingly result in a decrease in the number of test actuations of the valves which should increase reliability.

The proposed changes for the pressurizer safety valves clarify the individual valve setpoints, changes the operability requirement to when

• the plant is above cold shutdown, increases the acceptable setpoint tolerance to+/- 3% as-found, and eliminates the requirement of one installed operable pressurizer safety valve when the reactor head is on the vessel. Following reinstallation after removal for testing or maintenance, the safety valve lift settings shall be within +/-1%.

Clarification of the individual pressurizer safety valve setpoints does not affect the safety function of the valves.

Analysis of the loss of external load (the event which bounds the challenges for the primary safety valves) supports the upper limit on the pressurizer safety valve setpoints with a + 3% tolerance. The loss of load analysis included the safety valve setpoint tolerance and accumulation and was performed with parameters selected to maximize system pressures to bound the results for overpressurization. For the lower limit with a -3% tolerance on the pressurizer safety valve setpoints, the transient analyses were reviewed and found to result in peak pressurizer pressures less than 2200 psia which would not challenge the pressurizer safety valves. Thus, the change would not decrease the available thermal margin for the reactor core during transients. A departure from nucleate boiling (DNB) analysis also exists to bound the consequences of inadvertent opening of a pressurizer safety valve (Standard Review Plan 15.6.1).

The specification changes for the main steam safety valves simply clarify the individual valve setpoints and change the operability requirement to above cold shutdown. These changes do not affect the safety function of the main steam safety valves.

3 III. Analysis of No Significant Hazards Consideration Consumers Power Company finds the activities associated with this Technical Specifications {TS) change involve no significant hazards and accordingly, a no significant hazards determination per 10 CFR 50.92(c) is justified. The following evaluation supports the finding that operation of the facility in accordance with the proposed TS would not:

I. Involve a significant increase in the probability or consequences of an accident previously evaluated The proposed change to Technical Specifications increases the acceptable as found tolerance for the pressurizer safety valves.

The most limiting overpressure event, loss of external load, has been analyzed to account for this change. The loss of external load analysis was performed using a conservative 25% steam generator tube plugging and an initial pressurizer level of 67.8% (providing an approximate 10% conservative margin above programmed pressurizer level for full power). Primary and secondary safety valve accumulation was conservatively accounted for and the setpoint tolerance of +3% was assumed. Reactor trip on turbine trip was assumed to be disabled and the atmospheric dump valves were assumed unavailable. The results of the analysis demonstrated primary and secondary system pressures within 110% of design pressures.

Therefore, the consequences of overpressurization events will not be significantly increased with a +3% tolerance on the primary safety

• valve setpoints. The proposed Technical-Specifications change will not affect normal plant operation and will not increase the probability of an accident.

A review of all DNB analyses was performed to ensure that predicted pressurizer pressures for those analyses would not be affected by a

-3% tolerance on the lowest setpoint valve. The DNB analyses for which significant primary system pressure increases were predicted do not result in pressures high enough to lift the pressurizer safety valves with the proposed tolerance. A conservative DNB analysis that bounds the consequences of inadvertent opening of a pressurizer safety valve has also been previously performed with predicted acceptable results. If a pressurizer safety valve were to stick open, the consequences would be bounded by the small break LOCA analysis. Therefore, the consequences due to a -3% tolerance on the primary safety valve setpoints will not increase the consequences or probability of an accident.

The proposed revision removes the requirement for one operable pressurizer safety valve to be installed whenever the reactor head is on the vessel. Instead, proposed Specification 3.1.7.1 requires all pressurizer safety valves to be operable above cold shutdown, and overpressure protection during cold $hutdown is provided by existing Specification 3.1.8.2, Power Operated Relief Valves.

The proposed Technical Specifications change also lists the lift settings for each of the primary and secondary system safety valves .

This change will not affect the operation or function of the valves.

Therefore, the probability and consequences of previously evaluated accidents will not be increased.

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2. Create the possibility of a new or different kind of accident from any previously evaluated The proposed changes to Technical Specifications will not affect the manner in which the plant operates. The proposed increase in pressurizer safety valve lift setting tolerance could change the pressure at which the valves open in an overpressurization event, but would not create the possibility of a new or different kind of accident. Since Technical Specification 3.1.8 addresses primary system overpressurization during cold shutdown, the proposed removal of the requirement for an operable pressurizer safety valve to be installed whenever the reactor head is on the vessel will not create the possibility of an new overpressurization event during cold shutdown. The proposed change to list the lift settings for the individual primary and secondary safety valves will have no effect on the safety function of the valves. Therefore, the proposed changes will not create the possibility of a new or different kind of accident from any previously evaluated.

3. Involve a significant reduction in a margin of safety The proposed changes to Technical Specifications do not affect the DNB analyses that have been previously performed. The most limiting overpressurization event, .loss of external load, has been conservatively analyzed accounting for the proposed changes and demonstrated that the primary and secondary system pressures remain

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within 1103 of the design pressures. Overpressurization during cold shutdown is addressed by Technical Specification 3.1.8. Therefore, the proposed changes do not involve a significant reduction in a margin of safety.

Conclusion The Palisades Plant Review Committee has reviewed this Technical Specifications change request and has determined that the change involves no significant hazards consideration. This change has been reviewed by the Nuclear Performance Assessment Department. A copy of this Technical Specifications change request has been sent to the State of Michigan.

5 CONSUMERS POWER COMPANY To the best of my knowledge, the contents of this Technical Specifications change request, addressing primary and secondary safety valve settings, are truthful and complete.

Byzu~L~

Robert A. Fenech, Vice President Nuclear Operations Sworn and subscribed to before me this I JiA day of ~ 1995.

Davis, Notary Public ler, Notary Public nty, Michigan Van Buren ounty, Michigan (Acting in Buren County, Michigan) My commission expires 05/14/98 My commission exp' August 26, 1999

ATTACHMENT 1 Consumers Power Company Palisades Plant Docket 50-255 SAFETY VALVE SETTING LIMITS TECHNICAL SPECIFICATIONS CHANGE REQUEST Proposed Technical Specification Pages 4 Pages