NG-99-1327, Forwards IST Relief Request VR-24 Re Excess Flow Check Valve Test Frequency,Per 10CFR50.55a(a)(3)(i),for NRC Approval

Forwards IST Relief Request VR-24 Re Excess Flow Check Valve Test Frequency,Per 10CFR50.55a(a)(3)(i),for NRC Approval

ML20217B130
Person / Time
Site:	Duane Arnold
Issue date:	10/04/1999
From:	Peveler K IES UTILITIES INC., (FORMERLY IOWA ELECTRIC LIGHT
To:	NRC (Affiliation Not Assigned), NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NG-99-1327, NUDOCS 9910120162
Download: ML20217B130 (4)

Text

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l ALLIANT ENERGY- iEs utaies inc.

l Duane Arnold Energy Center 3277 DAEC Fload Palo, IA 52324-97R5 October 4,1999 g,,;c,; 3i, ,33.7,ii NG-99-1327 Fax: 319.851.7986 www.alliant-energy com OfTice of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission .

Attn: Document Control Desk Mail Station 0-PI-17 Washington, DC 20555-0001

Subject:

Duane Arnold Energy Center Docket No: 50-331 Op. License No: DPR-49 Inservice Testing (IST) Relief Request VR-24, Excess Flow Check Valve Test Frequency

Reference:

NG-99-0308, Letter from J. Franz (IES O'tilities) to NRC, {

dated April 12,1999, Technical Specification Change I Request (TSCR-010): Relaxation of Excess Flow Check Valve Surveillance Testing" File: A-105 By the referenced letter, IES Utilities Inc. requested a revision to the Technical i

Specifications (TS) for the Duane Arnold Energy Center (DAEC). Surveillance Requirement (SR) 3.6.1.3.7 currently requires verification of the actuation capability of each reactor instrumentation line er.:ess flow check valve (EFCV) I every 24 months. The proposed revision will 7.: lax the SR frequency by allowing a representative sample of EFCVs to be tested every 24 months, such that each EFCV will be tested at least o.- :very 10 years (nominal).

These EFCVs are contained within the scope of the DAEC inservice testing (IST) I program. Since the proposed SR frequency is not in accordance with ASME l Code requirements, implementation of the proposed TS revision will require NRC [l

' approval of a conforming IST relief request. This relief request (VR-24) is l attached. l d

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> -* October 4,1999 9- NG-99-1327 Page 2 10CFR50.55a(a)(3)(i) states that proposed alternatives may be used when authorized by the Director of the Office of Nuclear Reactor Regulation provided that the proposed alternatives provide an acceptable level of quality and safety.

I The proposed relief request does so, as discussed in the attachment.

IES Utilities Inc. requests approval of this conforming relief request concurrent with the approval of TSCR-010. Should you have any questions regarding this matter, please contact this office.

Sincerely, f && f Kenneth E. Peveler Manager, Regulatory Performance

Attachment cc

C. Rushworth E. Protsch (w/o)

D. Wilson (w/o) l B. lWozafari (NRC-NRR) "i J. Dyer (Region III)  !

NRC Resident Office l Docu j i

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Attachment to NG-99-1327 Page 1 of 2 RELIEF REQUEST NO. VR-24 SYSTEMS:

Nuclear Boiler, Reactor Recirculation, Reactor Core Isolation Cooling, Core Spray, liigh Pressure Coolant Injection, and Reactor Vessel Instrumentation COMPONENTS:

I XFV-xxxx, Excess Flow Check Valves J I

CATEGORY:

A/C FUNCTION:

l Excess flow check valves specifically designed for the DAEC are provided in each  !

instrument process line that penetrates the drywell and is part of the reactor coolant )

pressure boundary. The excess flow check valve is desigr.ed so that it will not close accidentally during normal operation, will close if a rupture of the instrument line is  ;

indicated downstream of the valve, can be reopened den appropriate, and has its status indicated in the control room.

An orifice is installed just inside the drywell on each of these instrument lines. The orifice limits leakage to a level where the integrity and functional perfomiance of secondary containment and associated safety systems are maintained, the coolant loss is within the capability of the reactor coolant makeup system, and the potential offsite exposure is substantially below the guidelines of 10 CFR 100. Regulatory Guide 1.11 requested that an additional isolation valve capable of automatic operation be located outside containment on these instrument process lines. At the DAEC, these are the excess flow check valves.

TEST REQUIREMENTS:

Check valves shall be exercised to the positions in which they perform their safety functions or examined at least once every reactor refueling outage. (Part 10, Para.

4.3.2.2 and 4.3.2.4 ( c ))

Category A valves shall be seat leakage tested to verify their leak-tight integrity at least once every 2 years. (Part 10 Para. 4.2.2.3) l Valves with remote position indicators shall be observed locally at least once every 2 l years to verify that valve operation is accurately indicated. (Part 10 Para. 4.1)

, Attachment to (

NG-99-1327 l Page 2 of 2 j i

BASIS FOR RELIEF:

1 The excess flow check valve is a simple device: the major components are a poppet and spring. The spring holds the poppet open under static conditions; the valve will close upon sufficient difierential pressure across the poppet. Functional testing of the valve is accomplished by venting the in::t:ument side of the tube; the resultant increase in flow imposes a differential pressure across the poppet which compresses the spring and closes off flow through the valve. i l

Excess flow check valves have been extrranely reliable throughout the industry'. In the j first 25 years of operation, no excess flow check valve has failed to close at the DAEC.

The DAEC Technical Specifications (TS) detail what frequency is required to maintain a high degree of reliability and availability, and provide an acceptable level of quality and safety. Therefore, the DAEC requests relief pursuant to 10 CFR 50.55a (a)(3)(i) to test excess flow check valves at the frequency specified in DAEC TS Surveillance Requirement (SR) 3.6.1.3.7. As discussed in the Bases for this SR, this test verifies that i 5e valve causes a marked decrease in flow rate on a simulated instrument line break. In l addition, a verification that remote position indication is accurate in the Control Room is performed during this test. j ALTERNATE TESTING: l EFCVs will be tested at the frequency specified in Technical Specification Surveillance Requirement 3.6.1.3.7.

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'NG 99-0308, Letter from J. Franz (IES Utilities) to NRC, dated April 12,1999, i Technical Specification Change Request (TSCR-010): Relaxation of Excess Flow Check i Valve Surveillanct isting j i

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