ML20064H401

Forwards Braidwood Station Response to Anomalies Identified in Safety Evaluation of IST Program Plan for Pumps & Valves & Rev 6 IST Program Plan for Pumps & Valves Braidwood Nuclear Power Station Units 1 & 2

ML20064H401
Person / Time
Site:	Braidwood
Issue date:	03/10/1994
From:	Saccomando D COMMONWEALTH EDISON CO.
To:	Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
Shared Package
ML20064H403	List: ML20064H401 ML20064H417
References
NUDOCS 9403170291
Download: ML20064H401 (5)

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/ " } jm$onNth Edison March 10,1994 y } J . Downers Grove, !!!inois 60515 1

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1DE Thomas EJMurley, Director LOffice of Nuclear Reactor Regulation

. U.S. Nuclear Regulatory Commission

-Washington, D.C. 20555 J-Attn: ~ Document Control Desk

Subject:

Braidwood Station Units 1 and 2 Inservice Testing Program Plan for Pumps and Valves Revision 6 and Transmittal of Response to SER dated September 14, 1993, NRC Docket Nos. 50-456 and 50-457

References:

(a) D. Saccomando letter to T. E. Murley transmitting Safety  ;

Evaluation Response dated December 13,1993 1 (b) J. Dyer letter to D. Farrar transmitting Safety Evaluation for Revision 5/5A IST Program dated September 14,1993 -

l Attachment A is Braidwood Station's reponse to certain anomalies that were identified in  !

th(Safety Evalnat'io:n of the Inservice Testing Program Plan for Pumps and Valves

'(IST) as transmitted in reference B. Also included in reference B was the Technical d Evdiuation Report which lieed a total of eight anomalies. Items 3,6, and 8 are addresed in Attachment A: Items 1,2,4,5, and 7 were previously addressed ol T transmhted in reference A.

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. I 1 Also attatbed is a complete copy of the Inservice Testing Program P:an for Pumps, Revision 6 nr Braidwood Station Units 1 and 2.

i Please address <any questions you may have regarding this matter to Denise Saccomando t at 908) 663-6484.

Sincerely, f}

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l~ Ify.Jo Denise M. Sd6comando i Nuclear Licensing Administrator

' Attachments cc: R. R. Assa, Braidwood Project Manager - NRR S. G. Dupont, Senior Resident Inspector - Braidwood J. B. Martin,- Regional Administrator - Region III g {i Office of Nuclear Facility Safety.- IDNS I

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Y Attachment A Page 1 of 4 IMIll (3) Many of the licensee's relief requests (VR-8, VR-9, VR-15, VR-24, VR-25, VR-26, and VR-27) indicate that the closure of the affected check valves can only be verified by performing an LLRT.

The requests demonstrate the impracticality of performing the LLRT quarterly and during cold shutdown. While this was a commonly accepted approach in the past, several testing techniques have recently been shown to be capable of providing reliable indication of check valve closure without disturbing the valve or the associated system. Some examples of these techniques are magnetics, ultrasonics, thermography, and radiography. The licensee should evaluate the use of non-intrusive techniques to determine if it is feasible to use one or more of them to verify the closure of the affected check valves quarterly or during cold shutdown. If it is feasible to perform this testing at the Code frequency, this testing should be performed as required. If the licensee determines that performing this testing at the Code frequency is impractical or a hardship without a compensating increase in safety, this should be documented in the IST program. The licensee should respond to this staff concern within 6 months of receiving the SER. (Refer to Sections 3.3.2.1, 3.4.1.1, 3.5.1.1, 3.8.1.1, 3.9.1.1, 3.10.1.1, and 3.11.1.1 of this report)

Response

The check valve program developed at Braidwood uses acoustics for non-intrusive testing (NIT) of check valve internals. This program requires the following special considerations for IST valves:

Containment Isolation Check Valves (CIV's) and Pressure Isolation Check Valves (PlV's) are typically categorized as "AC" under ASME Section XI. These valves are leak rate tested in accordance with 10CFR50.55a, Appendix J, plant Technical Specifications or an appropriate ASME Code test.

Leak rate testing is a viable test method to detect degradation of seating surfaces in lieu of performing check valve program preventive maintenance if seat degradation is the predominant degradation mode.

Leak rate testing will not predict degradation of seating surfaces or other check valve internal parts in advance of failure as indicated by an increase in leakage. Therefore, performance of preventive maintenance can serve to compliment IST testing activities to detect check valve degradation other than seat degradation in advance of failure.

Check valves used as CIV's and PIV's that are required to be leak tested and full stroke exercised in accordance with ASME Section XI as dictated by 10CFR50.55a which are included (all IST valves are included) in the check valve program should be handled as follows:

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1) For CIV's and PIV's designated as Level A valves, inspections should be coordinated with IST testing activities. Any inspection performed shall be considered as meeting the requirements of this program.

2) For CIV's and PlV's designated as Level B valves, diagnostic tests should be coordinated with IST testing activities. Any diagnostic tests performed shall be considered as meeting the

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requirements of this program.

Attachment A Page 2 of 4 kein (3)

Response (Continued) i

3) For CIV's and PlV's of either Level A or B where seat degradation has been shown to be the predominant degradation mode, currently performed IST leak rate testing and full stroke exercising activities may be used as a substitute for performing preventive maintenance, if any change to the valve design has been made so that valve performance during leak rate testing has been improved, the check valve should be re-evaluated for other predominant degradation modes. ,

The check valves identified in VR-8, VR-9, VR-15, VR-24, VR-25, VR-26, and VR-27 are all part of the check valve program and are tested accordingly per the above considerations. It is not practical at this time to use NIT quarterly (quarterly testing would require entry into containment) or in cold shutdown for these valves using acoustics, magnetics, ultrasonics, thermography, or radiography to prove closure. NUREG-1482, Guidelines for Inservice Testing at Nuclear Power Plants, Section 4.1.3 has also determined that leak rate testing check valves at refueling is acceptable when the Code frequency is impractical. This would be in the form of a refueling outage justification versus the current relief request format and is acceptable per 10 CFR 50.55a(f)(4)(iv).

Magnetics are currently being investigated by CECO. Braidwood's current acoustic testing system would require a $50K investment to upgrade to the magnetic portion. We have had demonstrations from two other different vendors offering a magnetic system, but were not satisfied with the results. Most versions were in their testing (beta) stages and the data was not suitable for analysis of check valve position, which would be used to compliment the acoustic data.

Ultrasonics are only good for water valves, but will not provide any indication of seat condition, therefore, leak rate testing is superior to this test method for proving seat integrity (i.e. closure function of these salves).

Thermography is presently utilized at Praidwood for condition monitoring of both electrical and mechanical type equipment. Over the past two years, a considerable amount of experience has been acquired on valve condition assessments utilizing thermography. However, based on review of the subject systems and components, thermography, is not deemed suitable for condition assessment of the subject components due to a lack of an appropriate temperature differential between process fluids and ambient.

Radiography, while an acceptable test method, can only be performed by outside contractors. This represents )

a considerable drawback to the station in scheduling valve testing during a forced outage to cold shutdown  !

conditions. Again, this method would not provide any indication of seat condition, therefore, leak rate testing -j is superior to this test method for proving seat integrity (i.e. closure function of these valves).

As new NIT techniques are reviewed and incorporated into the check valve program, these relief requests will be reviewed and amended if it is determined not to be impractical during cold shutdowns. Using NIT for proving closure per the Section XI Code requirements at refueling, in lieu ofleak rate testing, is considered to be redundant and impractical because it cannot identify seat condition. Also, CECO. is closely following the Nuclear Industry Check Valve (NIC) Group's efforts currently underway to evaluate ultrasonic, magnetic, and acoustic techniques for CECO.'s own program enhancement regarding NIT techniques, c

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I Attachment A l Page 3 of 4 hem (6) VR-5 requests relief from the test frequency requirements of Section XI for the safety injection accumulator discharge and combined injection header check valves. The licensee proposes to exercise these valves open by performing a reduced pressure accumulator discharge during refueling outages and verifying a full-stroke by flow calculations and acoustic testing. ASME/ ANSI OMa-1988, Part 10, Subsection 4.3.2.2 permits deferral of full-stroke exercising until refueling outages when this exercising is not practical during plant operation of cold shutdowns. The licensee demonstrated that it is impracticable to full or part-stroke exercise these valves quarterly during power operations.' The licensee also provided several reasons why it is impracticable to full-stroke exercise these valves during cold shutdowns. However, the licensee has not discussed part-stroke exercising these valves during cold shutdowns. Part 10,14.3.2.2(d), requires a part-stroke during cold shutdowns if exercising is not practicable during plant operation and full-stroke during cold shutdowns is also not practicable. It appears that part-stroke exercising of 1(2)SI8948A through D (the combined injection header valves) is practical during RHR cooling operations at cold shutdowns. A part-stroke of 1(2)S18956A threugh D (accumulator discharge valves) may be practical by burping the accumulators when going into cold shutdowns. Part-stroke exercising should be performed on these valves if practicable or the basis for not performing this test should be documented in the licensee IST program. (Refer to Section 3,7.1.1 of this report)

Resnonse The 1(2)S18948A through D (the combined injection header valves) will be partial-stroked in cold shutdowns.

However, the 1(2)S18956A through D (accumulator discharge valves) cannot be practically partial-stroked exercised in cold shutdown for the same reasons given in the VR-5 relief request for refueling. The proposed testing described above regarding burping the accumulators in cold shutdown would provide no commensurate increase in plant safety for the burden imposed, if partial-stroking were imposed. Draft NUREG-1482, Guidlines for Inservice Testing at Nuclear Power Plants, Section 4.1.2, requires that licensee's only perform . l non-intrusive testing on a sampling basis once baseline data is established. ' VR-5 uses non-intrusive testing for all four usins (passive mode of safety injection) during accumulator injection each refueling outage. Once l approved, braidwood plans to resubmit VR-5 to adopt the NRC position of one train per outage to save ALARA (40) to 600 mrem). ,

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1 Attachment A l Page 4 of 4 j D  !

(8) Valves 1(2)S18818A through D were added to Relief Request VR-15 to defer their exercise test to the closed position until refueling outages (refer to Item 47 of the Summary of Changes for Revision 5/Sa of the Braidwood IST Program). However, the IST program plan specifies that these valves are full-stroke exercised open at cold shutdowns. These valves are also identified as Event V check valves that are required by TS to be leak rate tested within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following actuation. Because they are exercised open during cold shutdowns and required to be leak rate tested following actuation, it does not appear that relief is required for these valves and their inclusion in VR-15 may not be appropriate.

The licensee should address this concern and make any necessary changes to the IST program within 6  !

months of receiving the SER.

Responsg The 1(2)S18818A through D valves were removed from VR-15 and Note 9 was revised to indicate that both open and close directions will be tested in cold shutdowns.

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