ML20077H159

Forwards Relief Request VR-4 for Inservice Testing Program Plan for Valves

ML20077H159
Person / Time
Site:	Byron
Issue date:	07/01/1991
From:	Schuster T COMMONWEALTH EDISON CO.
To:	Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
NUDOCS 9107050256
Download: ML20077H159 (4)

Text

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Ccmm:nw:alth Edisen v

1400 Opus Place Downers Grove, Illinois 60515 g

July 1,1991 -

Dr. Thomas E. Murley, Director Office Of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555 Attn: Document Control Desk

Subject:

Byron Station Units 1 and 2 Inservice Testing (I Program Plan for Valves Valve _B9HolBequas R-4. ReyisioIL10b

Reference:

(a) May 23,1991 letter to Dr. T.E. Murley - l regarding submittal of IST Valve Program Plan .

Relief Request VR 4 *

(b) June 12,1991 teleconference between A. Hsia, K. Dempsey and T. Schuster regardi NRC Staff  !

, comments pertaining to Valve Relief equest VR 4 (c) June 14,1991 teleconference between NRC staff -

personnel, Byron Station personnel and T. Schuster regarding Byron Station's response to NRC staff comments '

Dear Dr. Murley:

Attached is the IST Program Plan for Valves Relief Request VR-4. This relief request, submitted for NRC staff review per reference (a), has been revised to incorporate NRC staff comments durin the teleconference of reference (b).- The changes made in this revision were discussed duri the teleconference of reference (c). Revision lines in the right hand margin identify each change. Specifically, the following NRC staff concems have been addressed:

'f

1. Modification of Section 4 to include reference to all pertinent ASME Code Sections, p

2. Reorganization of the inspection grou valves comprico each cample group. p table of Section 6 to clearly delineate Since the relief request has the potential of significantly impacting the September,1991

- refueling outage for Byron Station, review completion by August 15,1991 is requested. Please direct any questions you may have to this office. ,

Respectfully,

/)V4k

• T.K. Schuster Nuclear Licensing Administrator f

cc: A. Hsla, Project Manager-NRR W. Kropp, Senior Resident inspector-Byron JA A. Bert Davis, Regional Administrator Rill (M rg/867:32 - -

9107050256 910701- I

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PDR ADOCK.05000454 P PDR- l

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< RELIEEBEQUEST VR 4 7

1. Valve 14 umber: 1CS003A 2CS003A 1CS003B 2CS003B 1CS008A 2CS008A 10S008B 2CS008B

2. Number _outems: 8

3. ASME Code _ Category: AC & C

4. ASME_GodeuSection_XLBequirements:

a. Exercise check valves to the position required to fulfill their function (open-Ct; closed-Bt), unless such operation is not practical during plant operation, per IWV-3522.

b. Exercise check valves at least once every 3 months, per IWV-3521.

c. Exercise check valves at least once every 3 months to the position required to fulfill their function, unless such operation is not practical during plant operation, per IWV-3412 (for 1/2CS008A, B only).

d. When a valve has been repaired, replaced, or has undergone maintenance that could affect its performance and prior to the time it is returned to service, it shall be tested to demonstrate that the performance parameters, which could have been affected by the replacement, repair, or maintenance, are within acceptable limits, per IWV 3200.

5. Basis fodehef:

These valves cannot be full flow tested as a matter of course during unit oaeration or cold shutdown as water from the CS pumps would be d scharged through the CS ring headers causing undesirable effects on system components ins!de containment.

Additionally, the full flow testing of these check valves during periods of cold shutdown, using the CS pumps, would fill the reactor rofuellrig cavity with contaminated water from the refueling water storage tank. The filling of the cavity, via temporarily installed large bore alping, would require the removal of the reactor vessel head so as to 3recluc e oc uipment damage from borated water. The erection of temporary p ping from 11e CS line to the reactor cavity would take an estimated nine to twelve shifts, or longer compared to one to two shifts for valve inspection. This estimate foes not take into account the time required to drain and remove the piping from containment.

Currently, full flow recirculation flow paths do not exist from the discharge of the CS aumps through these check valves to the refueling water storage tank. T1e addition of such flow paths would require extensive plant modifications to existing plant designs; including penetration of containment integrity.

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BEL.lEEBEQUESLVB iconi.

Partial stroking of the 1/2CS008A, B valves using air does not provide j adequate assurance of valve operability and may be detrimental for the j following reasons: j A. There is no correlation between air flow and angle of disc movement. I B. Venting and draining the appropriate piping quarterly may cause  !

deposition of boric acid residue which could in turn promote binding of -

the check valve internals.

6. Allematelesting: ,

The A and 8 train valves are of the same design (manufacturer, size, model number, and materials construction) and have the same service conditions, including orientation, therefore they form a sample disassembly group.  ;

Group 1 Group I 1CS003A 2CS003A 1CS003B 2CS003B- ,

Group 2 Group 2 IC5008A 2C5008A 1C5008B 2CS008B One valve from each two valve group, on a per unit basis, will be tested each refueling outage, if the disassembled valve is not capable of being full stroke exercised or if there is binding or failure of valve intert.als, the remaining valve on the'affected unit will be inspected.

7. Justification:

The 1/2CS008A,B and 1/2CS003A,B valves are removed from the system and visually examined per the strict detailed inspection requirements of the

! Station Check Valve Program. This inspection adequately verifies that the valves are maintained in a state of operational readiness. The valves are verified to be functional by performing a thorough visual inspection of the L valve internals and by performing a full stroke test exercise of each disc.

E Previous inspections of these particular valves at both Byron and Braidwood L have repeatedly shown them to be in good condition. ,

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t 4 BELIEEBEQUESLVRiconi, The wafer type design of the valve body for these valves make their removal a simple process, with little chance of damage to their internals. Also, there is no disassembly of internal carts required; all wear surfaces are accessible by v!sual examination. After nspection and stfoke testing, the valve is reinstalled into the line and post maintenance testing is performed. The

'l/2CS008A, B valves receive a containment leakage test, and the 1/2CS003A, B valves are partiall'ow tested. These tests verify proper installation of the check valves, and the valve inspection procedure requires post inspection visual examination of the check valve to insure that the pin is oriented properly and that the flow direction is correct.

The alternate test frequency is justifiable in that maintenance history and previous inspections of these valves at Byron and Draidwood stations has shown no evidence of degradation or impairment. Industry experience, as documented in NPRDS, showed no history of problems with these valves. A com aany wide check valve evaluation addressing the "EPRI Applications Guic elines for Check Valves in Nuclear Power Plants" revealed that the location, orientation and application of these valves are not conducive to the type of wear or degradation correlated with SOER 88 03 type problems.

However, they requ!re some level of monitoring to detect hidden problems.

8. Applicable _Timaferiod:

This relief is requested once per quarter during the first inspection interval.

9. AppavaLStatus:

a. Relief to disassemte in place of full flow testing granted per SER 9/15/88 for 1/2CS003A, B; relief denied per SER 9/15/88 for 1/2CS008A.

b. Revised to address NRC concerns in Byron SER response 12/16/88 (Byron Station Letter 88-1321),

c. Relief to disassemble in place of full flown testing granted per Generic Letter 89 04.

d. Revised to address NRC concerns in Byron SER 9/14/90 and to include both full flow (Ct) and backflow (8t) test; relief granted per Generic Letter 89-04, i 4.6-page 9 of 39 1

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