ML20095L195

License Amend Request 91-11 to License NPF-86 for Code Safety Valve Setpoint Tolerance Relaxation

ML20095L195
Person / Time
Site:	Seabrook
Issue date:	05/05/1992
From:	Drawbridge B PUBLIC SERVICE CO. OF NEW HAMPSHIRE
To:
Shared Package
ML20095L191	List: ML20095L184 ML20095L195 ML20095L197 ML20095L208
References
NUDOCS 9205060272
Download: ML20095L195 (4)

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- A SEABROOK STATION UNIT 1 i l

New Hampshire  !

Yankee l 4

l Facility Operating License NPF-86 )

Docket No. 50-443 l License Amendment Request No. 91-11 l Code Safety Valve-Setpoint' 1 Tolerance Relaxation I I

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This License Amendment Request is submitted by New Hampshire Yankee

pursuant to 10CFR50.90. The following information is enclosed in support of j this License Amendment Request

.Section I -

Introduction and Description of Proposed Changes

. Section ll -

Markup of Proposed Changes

. Section lli -

Retype of Proposed Changes l l l

.Section IV -

Safety Assessment of Proposed Changes

.Section V -

Determination of Significant Hazards for Proposed ChangesSection VI -

Proposed Schedule for License Amendment issuance and j Effectiveness i l

. Section Vil -

Environmental Impact Assessment 1 n M gg . Section Vill -

Other Supporting Information 4

SO' oo  %-

@@ Sworn and Subscribed ~, I to before me this '

R$ d2A . day of '64tv ,1992 ,

?hS ,4Lx I

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1. Bruce L. Drawbr, g6

! O$ v' Notary Public Executive DirectohNucles Production IRACY A. DcCn:CiC3 thmry Futue 3 My Ccram.nca Opics OzLu 0,1993

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1. Introduction und Descripilon of Proposed Chnnees A. Introduction The Seabrook Station overpressure protection design incorporates three Code safety valves on the primary system pressurizer and a total of twenty Code safety valves on the four main steam lines (five per line) in the secondary system. The pressurizer safety valves (PSVs) were designed and manufactured to meet the 1971 Edition, including the Winter 1972 Addenda, of the ASME Code, Section 111. The main steam safety valves (MSSVs) were designed and manufactured to meet the 1974 Edition, including the Summer 1975 Addenda, of the ASME Code, Section liL An ASME Code, Section til requirement for both the PSVs and- the MSSVs is that they be designed to open within 1% of their set pressure. The current Technical Specification Limiting Conditions for Operation (LCO)_ for the PSVs and MSSVs also impose the tolerance of 1% on their set pressure.

The Technical Specification Surveillance Requirements for the PSVs and the MSSVs-require that testing be performed in accordance with Section XI of the ASME Boiler and Pressure Vessel Code and applicable Addenda as required by 10CFR50.55a(g),

except where specific written relief has been granted by the Commission. The PSVs and the MSSVs are tested to verify that their lift pressures and seat leakages are acceptable pursuant to the New Hampshire Yankee Inservice Test (IST) Program -

which complies with the ASME Boiler and' Pressure Vessel Code,Section XI,1983 Edition through the Summer 1983 Addenda. The NRC evaluation of the NHY IST Program is doct.mented in NUREG-0896, Supplement No. 6, " Safety Evaluation Report Related to the Operation of Seabrook Station, Units 1 and 2", dated October 1986.

The 1983 Edition of ASME Section XI does not specify a tolerance to be applied _ to safety valve lift pressure verification; therefore the tolerance ( 1%) prescribed in the LCO for the PSVs and MSSVs is utilized as the acceptance criteria for ASME Section XI testing. ASME Section XI, Article IWV-3513, requires additional safety valve testing when a safety val e " fails to function properly". Currently, a. PSV . or MSSV which has a tested lift pressure outside the ' 1% tolerance specified in the L.CO is determined to have failed to function properly, thereby requiring te or replacement per IWV-3514 and testing of additional valves in the sys t c. -. per-IWV-3513.

The 1989 Edition of the ASME Code,Section XI, requires that -the PSVs and MSSVs l he tested pursuant to the ASME/ ANSI OM-1987, Part 1, " Requirements for Inservice -

Performance Testing of Nuclear Power Plant Pressure Relief Devices." _ This standard allows the tested lift pressure to exceed the stamped set pressure by up to 3% before declaring a test failure. It also provides a guideline for testing additional valves when a valve exceeds the 3% tolerance. Therefore, increasing the _ PSV and MS5V setpoint tolerance to x 3% for testing acceptance criteria is in compliance with the I later ASME Code,Section XI requirements. New Hampshire Yankee is-proposing to -

revise the Seabrook -Station Technical Specifications as discussed below to allow a-relaxation in the PSV and MSSV setpoint tolerance to 3% for testing acceptance criteria.

The proposed relaxation of the setpoint tolerances for the PSVs and the MSSVs has been determined to be in compliance with the 1989 Edition of the ASME _ Code,Section III, Subarticle NB-7410/NC 7410, which states that: "The set pressure of at 1

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y a 4 n 4 least one of the pressure relief devices connected to the system not be great'r than the Design Pressure of any component within the pressure retaining boundary of the protected system". The Reactor Coolant System ' design pressure is- 2485 psig (reference UFSAR Table 5.31) which corresponds to the setpoint-of the PSVs. The Main Steam Supply System design pressure is 1185 psig (reference. UFSAR -Section -

+ 10.3.2.1) which corresponds to the Group 1 htSSVs which have the' lowest opening; setpoint.

4 The impact of the relaxed PSV and htSSV setpoint tolerance on the licensing basis analysis documented in the Seabrook Station Updated Final Safety Analysis ' Report

( U FS A R), Chapter 15, has been reviewed by Yankee. Atomic Electric Company

(YAEC) and documented in iopical report YAEC-1847 "Seabrook Station Code Safety i

Valve Setpoint Tolerance Relaxation". A copy of YAEC-1847 is enclosed in Section Vill, herein. YAEC 1847 demonstrates that the licensing basis criteria are still met when the relaxed Code safety valve tolerance of 2 3% is assumed.

it is important to note that NHY proposes to- utilize the 3% tolerance for the ,

"as-found" acceptance criteria for additional valve testing required by ASME Section-XI, Subsection IWV-3513. The proposed Technical Specification revisions require that the PSV and MSSV setpoints be restored to within 1% of their nominal setpoints following testing.

D. Description of Proposed Changes New Ilampshire Yankee is proposing to revise the Seabrook Station Technical Specifications to allow a relaxation in the PSV and htSSV. setpoint tolerances .to:

3% for testing acceptance criteria. The proposed Technical Specification changes

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, also require that the PSV and M55V setpoints be restored to within 2 1% of their nominal setpoints following testing. New Hampshire Yankee is also proposing to revise the BASES for Technical Specification 3/4.7.1.1 to specify the correct Edition of the ASME Boiler and Pressure Vesss! Code, Section til; applicable to the MSSVs.

l The affected Technical Specifica*. ions and ' BASES are identified below:

, Technical Specification 3/4.4.2 SAFETY VALVES SHUTDOWN Technical Specification Limiting Condition -for Operation - (LCO) 3.4.2.1 curren!!y

requires that "A minimum of one pressurizer Code safety valve shall be OPERABLE with a lift setting of 2485 psig 1W in MODES 4 and 5. New Hampshire Yankee .

i is proposing to revise LCO 3,4.2.1 to allow a relaxation in the PSV lift setting

[ tolerance to z 3% for testing acceptance criteria. -The proposed change to LCO

! - 3.4.2.1 also incorporates a footnote which will specify'that the setpoint tolerance is .

"within 1 1% following pressurizer Code safety- valve testing".

. Technical Soecification 3/4.4.2 S AFETY VALVES OPER ATING Technical Specification LCO 3.4.2.2 currently requires that 'All pressurizer Code

, safety valves shall be OPERABLE with a lift setting of 2485 psig 1%" in MODES I, 2, and 3. New 1lampshire Yankee is proposing to revise LCO 3.4.2.2 to allow a 4

relaxation in the PSV lift setting tolerance to 2 3% for~ testing acceptance criteria.

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The proposed change to LCO 3.4.2.2 also incorporates a footnot'e which:will specify that the setpoint tolerance is "within . 2 '1% following pressurizer . Code safety valve

, testing" J

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Technical Specification Table 3.7-2 Steam 1.ine Safety Valves Per I.oon Technical Specification Table 3.7-2 identifies the twenty main steam line code safety valves which are located in the four main steam lines. The five safety valves in cach main steam line have increasing lift settings of 1185 psig,1203 psig, .1220 psig,1238 psig and 1253 psig. Table 3.7-2 currently identifies the litt setting tolerance for each of the main steam line Code safety valves as 1%. New llampshire Yankee is prorosing to revise Table 3.7 2 to allow a relaxation in the MSSV lift setting tolerance to 2 3% for testing acceptance criteria. The proposed change to Table l

3.7-2 also incorporates a footnote which will specify that the setpoint tolerance is

" wit hin 1% following main steam line Code safety valve testing".

II ASES for Technical Specification 3/4.7.1.1 S AFETY val,VES OPER ATING Currently the BASES for. Technical Specification 3/4.7.1.1 which addresses the main steam line Code safety valves states that "The specified valve lift settings and relieving capacities are in accordance with the requirements of Section III of the ASME Boiler and pressure Vessel Code,1971 Edition' New Hampshire Yankee is proposing to revise the HASES for Techaical Specification 3/4.7.1.1 to specify the correct Edition of ASME Section Ill which is applicable to the main steam line-Code safety valves.

The proposed change will specify the 1974 Edition, including the'1975 Addenda of ASME Section Ill.

Additionally, NHY is proposing to correct a typographical error in the BASES for Technical Specification 3/4.7.1.1. The BASES currently contain an incorrect reference to Technical Specification Table 347-2, whereas the correct reference is to Table 3.71.

A markup of the proposed Technical Specification changes is enclosed in Section il.

l A retype of the proposed Technical Specification changes is enclosed in Section Ill.

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