ML20059D206

Discusses Technique to Be Utilized to Demonstrate That Check Valve 1SI-00876B Has Been Full Stroke Exercised,In Response to NRC Transmitting SER Re Several Outstanding Relief Requests for Ist.Relief Request VRR-4 Encl

ML20059D206
Person / Time
Site:	Point Beach
Issue date:	12/28/1993
From:	Link B WISCONSIN ELECTRIC POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
CON-NRC-93-139 VPNPD-93-223, NUDOCS 9401070062
Download: ML20059D206 (6)

Text

'

Wisconsin Electnc POWER COMPANY 231 w Mchgort PO fion 2046. Mdwoihee WI 53201-2046 (M4) 22t 2345 VPNPD-93-223 NRC-93-139 December 28, 1993 Document Control Desk U.S. NUCLEAR REGULATORY COMMISSION Mail Station P1-137 Washington, DC 20555 Gentlemen:

DOCKETS 50-266 AND 50-301 ASME SECTION XI PUMP AND VALVE INSERVICE TESTING PROGRAM ,

OCTOBER 28, 1993, NRC SAFETY EVALUATION REPORT POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 Your letter dated October 28, 1993, transmitted a Safety Evaluation (SE) by the Office of Nuclear Reactor Regulation (NRR) concerning several outstanding relief requests for our Inservice Test (.ST)

Program. Section 3.1 of the SE granted approval for our Relief Request No. VRR-4 (copy attached), bu' recommendes that we pursue-development of nonintrusive techniquet for exercising the check valves in question. As stated in the L3, employment of a nonintrusive technique which demonstrates that a check valve disc has br- ,

fully stroked under flow would eliminate the necessity to disast the valve for IST purposes.

For Check Valves SI-00867 A and B~(Units 1 and 2), we believe it is possible to demonstrate that the valve disc has undergone a full stroke using radiography. SI-00867 A'and B are currently partial stroked in the open direction under flow from the safety injection-(SI) pumps and/or residual heat removal (RHR) pumps during refueling outages. We believe that the flow rates-utilized during these evolutions are sufficient to full strcke exercise the valve discs.- A successful demonstration of a valve full stroke using radiography would consist of obtaining conclusive evidence that the.

valve disc had reacned its backstop, as evaluated by an RT Level II or III certified individual in conjunction with engineering personnel.

The disassembly'and inspection program we have developed to' satisfy the provisions of Relief Request No. VRR-4 identifies 1SI-00867B as  ;

the check s ve scheduled for disast embly during our upcoming '

Spring 1994 'efueling outage (Unit 1) if a full core offload is performeu. It~is our intention to utilize the nonintrusive i w

9401070062 931228 M DR ADOCK05000gg6 gp

, Asak&.y(HisamsinDngOpvathm _

' 4 .,

• g i Document Control Desk ,

December 28, 1993 Page 2 technique discussed above (radiography) to demonstrate that [

ISI-00867B has been full stroke exercised. Flow from the RHR pumps:  ;

will be used.

]

As discussed in Section 3.1 of your SE, success of this nonintrusive technique precludes the need for future disassembly and inspection of this valve. Consequently, it is our intention to disassemble and inspect 1SI-00876B during our Spring-1994 Unit i refueling outage only if the attemot to demonstrate full stroke utilizina the nonintrusive method fails and a core offload is-  !

performed.

If the nonintrusive technique discussed above is successful, we will revise Relief Request No. VnR-4 prior to our Fall 1994 Unit 2 refueling outage to formally incorporate the technique into our IST Program.

Unfortunately, the remaining check valves covered by Relief Request No. VRR-4 (1&2 SI-00842 A&B) will still require periodic disassembly and inspection per Generic Letter 89-04, Position'2.

• The physical configuration of the piping and the location of the valves within the system does not allow sufficient flow to be passed through the valves for full stroke exercising.

To properly plan and schedule activities for our Spring 1994 Unit 1 ,

refueling outage, requires that any questions you may have be submitted promptly. Please contact us within the next 30 days should there bc are any questions regarding this matter.

Sincerely,

d. aI Bob Link n ot -

Vice President >

nuclear Power DEK/jg. ,

Attachment cc: NRC. Resident Inspector NRC Regional Administr4 tor, Region III Adele DiBiasio, Broo)~. haven National Laboratory

. j

.s.

. i RELIEF REQUEST NO. VRR-4 l

SYSTEM: Safety Injection (110E017, Sh 1/110E035, Sh 1)

COMPONENTS: SI-00842 A and B (Units 1 and 2)

SI-00867 A and B (Units 1 and 2)

CATEGORY: A/C FUNCTION:

These valves open with differential pressure to provide flow paths from the safety injection (SI) pumps and SI accumulators to the reactor coolant system (RCS) cold legs during an accident. They are normally closed. In the closed position, they~ serve as RCS pressure isolation valves.

SECTION XI REOUIREMENT: 1 Check valves shall be exercised at least once every 3 months, except as provided by IWV-3522. (IWV-3521)

BASIS FOR RELIEF:

During normal operation, neither SI pump discharge pressure of 1500 psi nor SI accumulator pressure of 760 psig, is sufficient to overcome RCS pressure. Full or partial stroke testing therefore is  ;

not possible.

During cold shutdown, partial or full stroke testing via the use of SI pumps or SI accumulators is not permitted so as to prevent the possibility of a low-temperature over-pressurization event.

A full stroke test to the ICS could be possible during refueling when the reactor vessel head is removed, but the volume and flow rate required for the test could result in damage to-the core internals. There is air s the potential of forcing .a nitrogen bubble-into the PCS piping and refueling cavity resulting in ,

possible safety implications, which makes this testing concept ~

inadvisable.

Page 1 of 4

)

.e ,

ALTERNATE TESTING:

The following alternate testing will be performed:

1 At a minimum for these valves, partial.open and shut stroke tests will be done at each refueling outage. In addition, partial open and shut stroke tests will be conducted at.each' >

cold shutdown which requires an Event V test.- (See Technical-Specification 15.3.16)

2. Seat leakage tests of SI-00867 A and B will be performed in accordance with Point Beach Technical-Specification 15.3.16,

" Reactor Coolant System Pressure Isolation Valve Leakage Tests."

3. Seat leakage tests of SI-00842 A and B will be performed quarterly coincident with SI pump tests. A seat leakage rate of 5 gpm or less will be considered acceptable. .

4. Valves SI-00842A and SI-00867A will each be disassembled, inspected, and manually stroked once every 6 years; rotating the sequence of valves being inspected such that a different one is completed each time until all have been inspected and the sequence repeats. Should a failure be detected, the other '

valve for that unit shall be disassembled and proper operation verified prior to completion of that outage. The opposite unit's two valves will be disassembled and' inspected during that unit's next scheduled refueling outage.

5. Valves SI-00842B and SI-00867B require a complete core offload in order to disassemble and inspect. One valve of the four will be disassembled, insp;cted, and manually stroked each outage in which a completc core offload is scheduled.

Typically this will be done concurrently with reactor vessel inspections. The disassembly schedule will be arranged such that a different valve is disassembled, inspected, and mt'ually stroked during each core offload and all valves are completed at least once every 120 months.- Should a failure be detected, the other valve for that unit will be. disassembled and proper operation verified. prior to the completion of the outage.

6. In the inspections which result from the detection of a failure, should an additional failure be detected, all remaining six valves will be disassembled, inspected, and manually stroked. -Valves associated with the unit in outage will be completed prior to the return of that unit to service, .

even if it requires an unscheduled core offload to be l performed. Valves associated with the opposite unit will be completed during the next scheduled refueling outage,.even-if a complete core offload was not previously planned.

I Page 2 of 4 i

i w

e HASIS FOR EXTENDED INSPECTION INTERVAL:

The NRC,' in Generic' Letter (GL) 89-04, Position 2, requested information to support extension of valve disassembly and .

inspection' intervals of greater than once every 6 years. Within  !

the last 3 years, each valve of the eight identified in this request has been disassembled, inspected, and manually stroked per the criteria in GL 89-04, Position 2. This maintenance was performed in conjunction with retaining block stud replacement done in response to NRC Information Notice 88-05. To date, no degradation of valve operability or performance has been noted in any disassembly and inspection performed on these valves. The 1 following table lists each specific valve,-the individual  ;

maintenance work request (MWR) under which the inspection was  !

performed, and the completion date:

i UNIT 1 SI-00842A MWR 872759 April 14, 1988 MWR 890172 April 11, 1990 SI-00842B MWR 890174 April 21, 1990" .

SI-00867A MWR 872755 April 15, 1988 MWR 890176 April 24, 1990 ,

SI-00867B. MWR 890178 April 21, 1990 URIT 2 SI-00842A MWR 872760 October 18, 1987 MWR 890173 October 05, 1989  ;

SI-00842B MWR 890175 November 04, 1989 -

SI-00867A MWR 872753 October 20, 1987

• MWR 890177 October 05, 1989 SI-00867B MWR 890179 November 03, 1989 i The request to provide basis for extended inspection interval only applies to SI-00842B and SI-00867B, as these are the only valrea which will go beyond the 6-year period specified in GL 89-04, Position 2. The maintenance history of all eight valves ir, .

provided for completeness when attempting to show the trooble-free l history of the valves in general.

t Add:itional justification for the extended inspection interval '

may be found in the NRC Safety Evaluation Report (SER) on the In-Service Test Program at Point Beach dated April 17, 1992. The Technical Evaluation Report'(TER), Section 3.14.3.4,~ attached to-the SER states, " ...it would be an extreme hardship to require the  ;

licensee to comply with the 6-year inspection interval for_the two valves which require the reactor to be defueled and drained in order to be tested (SI-00842B)." '

Page 3 of 4 t

h

'4 @

2 The drawings referenced by this request will show that the conditions which must exist to permit the' disassembly of SI-00842B-must also' exist to' permit the disassembly of SI-00867B. Thus,-the-extended period for inspection should. apply to both (four valves

- total, two-per unit).

STATUS:

Relief granted per NRC SE of October 28, 1993.

I a

E k

?

Page 4.of 4-

,