ML20012G545

Updates 920730 Response to NRC 920417 Ltr,Transmitting SER & TER of Inservice Testing Program for Pumps & Valves.Listed Relief Requests Re Boric Acid Transfer Pumps & Check Valves Withdrawn

ML20012G545
Person / Time
Site:	Point Beach
Issue date:	03/02/1993
From:	Link B WISCONSIN ELECTRIC POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
CON-NRC-93-031, CON-NRC-93-31 VPNPD-93-054, VPNPD-93-54, NUDOCS 9303090044
Download: ML20012G545 (10)

Text

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. Wisconsin 1 Bectnc .

POWER COMPATH 231 w Meman po sax 2cas.wwasea u 5320s g<a) 229-2345 ,

VPNPD-93-054  !

NRC 031 t March 2, 1993  ;

Document Control Desk U.S. NUCLEAR REGULATORY COMMISSION Mail Station P1-137 Washington, DC 20555 '

L Gentlemen:  :

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

THIRD 10-YEAR PROGRAM SAFETY EVALUATION REPORT POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 I Your letter _ dated April 17, 1992, transmitted a Safety Evaluation Report (SER) by the Office of Nuclear Reactor Regulation and an attached Technical Evaluation Report (TER) concerning our Inservice Test (IST) Program, Third 10-Year Interval. Our initial respanse f

actions to this SER were transmitted to you in our July 30, 1992, letter (VPNPD-92-271/NRC-92-085). The' purpose of this letter is to provide you with an update to our July 30, 1992, response. ,

In our letter of July 30, 1992, we discussed the initiation of modifications to the boric acid transfer system which would enable us to withdraw several relief requests associated with that system.

Modifications to Unit 2 were completed during our Fall 1992 refueling outage. Modifications to Unit 1 are scheduled for completion during our Spring 1993 refueling outage, which will  ;

start in late March. As a result, we are withdrawing the following relief requests:

PRR-11, " Boric Acid Transfer Pumps" PRR-12, " Boric Acid Transfer Pumps" VRR-26, " Boric Acid Transfer Pump Discharge Check Valves" Modifications to the ESF HVAC system discussed in our letter of July 30, 1992, have been completed. The modifications provide instrumentation enabling measurement of Code required test 9303090044 930302 22 0n[

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l Document Control Desk March 2, 1993 ,

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parameters. Since the following relief requests related to the l ESF HVAC system are no longer applicable, we are withdrawing them ,

at this time:  :

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PRR-15, " Cable Spreading Room Chilled Water Pumps l and Control Room Chilled Water Pumps"  ;

VRR-31, " Chilled Water Pump Discharge Check Valves" l 5

As discussed in our letter of July 30, 1992, we are pursuing  !

modifications to all 4 auxiliary feedwater pump minimum flow valve l control systems to enable Code required testing. Modifications to  ;

2AF-04002 have been completed. Modifications to 1AF-04002 and j

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, non-unit specific valves, AF-04007 and AF-04014, are scheduled for completion by the end of our Spring 1993 refueling outage. Conse-quently at this time, we are formally withdrawing the following )

associated relief request: j VRR-28, " Auxiliary Feedwater Pump Mini-Recirc Valves" We have reevaluated Relief Request VRR-19 based on information in .

TER Sections 3.3.3 and 5.26. Contrary to the information stated in  !

VRR-19, CV-00300 A&B (Units 1&2) are neither tested nor required to l be tested under 10 CFR 50, Appendix J (Type C Local Leak Rate j Test). These are normally open (throttled) ranual valves which j are not relied upon to perform any safety function. Under ASME'  !

Section XI (1986), IWV-1000, " Scope and Responsibility," these i valves are not required to be tested. Consequently, they have been l removed from our IST Program and we are withdrawing the following  !

associated relief request:

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VRR-19, " Reactor Coolant Pump Seal Injection Throttle Valves" l

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In response to TER Sections 3.11.2 and 5.36, we have initiated modifications to replace the current auxiliary feedwater pump  ;

cooling water solenoid valves, MS-02090 (Units 1&2), with valves l that have position indication. The new valves will permit stroke l time testing in accordance with the Code and eliminate the need for l Relief Request VRR-20. As a result, we are withdrawing the following relief request:

VRR-20, " Auxiliary Feedwater Pump Cooling Water .

Supp1f Valves" {

Our earlier letter of July 30, 1992, formally withdrew several  ;

relief requests no longer required after completion of physical <

modifications to various systems. In addition to the requests

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r previously withdrawn, our review of Relief Requests PRR-17 and [

PRR-18 in response to TER Section 5.07_ finds that these relief t requests may also be withdrawn now that the necessary modifications  !

to permit testing have been-completed. As a result, we are  !

withdrawing the following two relief requests: -

PRR-17, " Safety Injection and Residual Heat Removal Pumps" '

PRR-18, " Auxiliary Feedwater Pumps" lt The SER and TER evaluated several relief requests as not being required, and neither granted nor denied these requests. Our F review of these relief requests concurs with the SER and TER  ;

evaluations that they are not required. As a result we are '

withdrawing the following relief requests t

PRR-16, " Measurement of Differential Pressure; All Pumps" l VRR-32, " Instrument Air Supply Check Valves to i PORVs" i VRR-33, " Fuel Oil Transfer Pump Pressure Regulating i Valves" '

Interim relief for a period of 1 year was granted by the SER f

for Relief Request VRR-21, " Main Feedwater Check Valves." In j response to TER Sections 3.10.1 and 5.31, we have revised relief  :

request VRR-21 to provide additional information justifying why  !

unconditional relief should be granted. This revised request i (Enclosure 1) addresses those concerns identified in TER Sections 3.10.1 and 5.31.

Relief Request VRR-24, " Emergency Boration Check Valves," has i been listed as an "open item" by the SER. In response to TER i Sections 3.3.4 and 5.27, we have revised Relief Request VRR-24 i (Enclosure 2) to provide additional justification for relief. We believe that the additional information provided in this request is j sufficient to now enable the granting of full relief.  :

i Recent discussions between representatives of Edward Valves, t Incorporated (formerly Rockwell-Edwards) and our engineering staff, have caused us to reevaluate Relief Request VRR-27, " Safety Injection Pump Mini-Recirc Check Valves." This request, granted j with provisions by the SER, established a disassembly and inspection program for Valves 1&2 SI-00891 A&B (4 valves) in  !

lieu of Code required stroke testing.

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i Document Control Desk March 2, 1993  ;

Page 4 Our experience with lift check valves of this manufacturer, type, I and style indicates that there is a high probability that the threads on these valves will be destroyed by the disassembly process. The body to bonnet threads on these valves are fine, non-tapered, stainless steel, and highly susceptible to galling.

The risk of thread damage associated with disassembly has been confirmed by the manufacturer, and this thread style is no longer used on their newer valves. Since the disassembly and inspection program prorosed in VRR-27 may result in destroying these valves by damaging body to bonnet threads, we are withdrawing the following relief request: i VRR-27, " Safety Injection Pump Mini-Recirc Check Valves" ,

In lieu of disassembly and inspection as described in NRC Generic Letter (GL) 89-04, Attachment 1, Position 2, Check 5 Valves 1&2 SI-00891 A&B will be full stroke exercised quarterly  ;

during safety injection pump tests, in accordance with the criteria in GL 89-04, Attachment 1, Position 1. A new relief request, VRR-37 (Enclosure 3), is being submitted to account for this test method. i Should there be any questions regarding this matter, please do not hesitate to contact us.

Sincerely, j' " l- .

Bob Link Vice President Nuclear Power i

DEK/jg Attachments cc: NRC Resident Inspector NRC Regional Administrator, Region III Adele DiBiasio, Brookhaven National Laboratory I

Enclosum 1 ,

RELIEF REQUEST VRRr21 j i

COMPONENTS: UNIT I (Drawing M-202 Sh. 2): CS-00466 AA&BB.

CS-00476 AA&BB. .

UNIT 2 (Drawing M-2202 Sh. 2): CS-00466 AA&BB.

CS-00476 AA&BB.  ;

CATEGORY: A/C. l t

FUNCTION:  !

The main feedwater line to each steam generator has two, normally open, in line, series check valves. The function of these valves is to close upon reversal of flow to ensure that ,

auxiliary feedwater flow is unimpaired to at least one of the two steam generators while main feedwater is not available. The series check valves also prevent simultaneous blowdown of .!

both steam generators in the event of a main feed pipe failum.  ;

f SECTION XI REOUIREMENT:  !

Check v <es shall be exercised at least once every 3 months, except as provided by j IWV-3$d. (IWV-3521)

Valves that are normally open during plant operation and whose function is to prevent

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mversed flow shall be tested in a manner that pmves that the disk travels to the seat j promptly on cessation or reversal of flow. Confirmation that the disk is on its seat shall be ,

by visual observation, by an electrical signal initiated by a position indicating device, by  !

observation of pressure indications in the system, or by other positive means. (IWV-3522)

Category A valves shall be leak tested, except that valves which function in the course of j plant operation in a manner that demonstrates functionally adequate seat tightness need not be leak tested. In such cases, the valve record shall provide the basis for the conclusion that operational observations constitute satisfactory demonstration. (IWV-3421) l BASIS FOR RELIEF:

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The main feed line to each steam generator consists of two series check valves. The Point <

Beach FSAR makes no assumptions that require both series check valves to function. There  :

are no position indicators on these valves to verify disk position, nor are there any pressure I

taps between them to enable individual leak rate testing. It is physically impossible, given the present plant configuration, to verify individual valve closure. Closure and seat tightness 3 of at least one of the two series check valves can be verified by measuring the diffemntial pressure across, or the leakage past, the combination of both valves. Since the valves in i series are considered to be redundant, testing both valves as a single unit is adequate to I ensum that the safety function of the valve combination is verified and maintained.  !

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Enclosure 1 l

BASIS FOR RELIEF: (continued) ,

Prompt seating of each valve on cessation or reversal of flow cannot be verified at the instant j of closure since no direct indication of valve disk position is available.  !

Valve testing can only be conducted during cold shutdowns, since flow of main feedwater to the steam generators must be secured in order to perform the tests.

ALTERNATE TESTING:

A valve exercise test of each series combination of main feedwater check valves will be conducted during cold shutdowns, in accordance with the provisions of IWV-3412(a) and '

IWV-3522 that address the exercising of valves which have had testing deferred to cold shutdown conditions. At least one of the series valves will be verified closed after flow is secured by measuring the differential pressure across, and the leakage past, the two valves in i series.

Leak rate testing to satisfy Category A requirements will meet the criteria outlined in .

IWV-3420, except that the two valves in series shall be treated as though they were a single ,

component. ,

Additionally, once every 10 yc.ars, each main feedwater check valve shall be opened and -

inspected. The split body constmetion of valves 1&2 CS-00466 AA and 1&2 CS-00476 AA limits access to the valve internals, and permits inspection only through use of a boroscope. i Complete disassembly of these valves is not practical since it would require the movement of ,

piping and the cutting of large pipe support stmetures. Valves 1&2 CS-00466 BB and 1&2 CS-00476 BB are constmeted with no such limitations.

S_TATUS:

Active. Interim relief granted with provisions for a period of one year by NRC SER, dated Ap-il 17,1992. Request revised as this submittal to incorporate the necessary pmvisions and address regulatory concerns in an effort to obtain unconditional relief.

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Enclosure 2 j

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RELIEF REQUEST VRR-24 COMPONENTS: UNIT 1 (Drawing 684J741): CV-00351. ,

UNIT 2 (Drawing 685J175): CV-00351. l CATEGORY: C. -

FUNCTION:  ;

i These valves open to provide a flow path for emergency reactor coolant system (RCS) boration from the discharge of the boric acid tmnsfer pumps to the suctions of the charging  ;

pumps.

SECTION XI REOUIREMENT:

Check valves shall be exercised at least once every 3 months, except as pmvided by i IWV-3522. (IWV-3521)  :

i BASIS FOR RELIEF:

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Stroke testing these valves in the open direction requires the introduction of highly concentrated boric acid solution from the boric acid makeup tanks to the suctions of the charging pumps. This results in the addition of an excessive amount of boron to the RCS which will adversely affect plant power, potentially causing a reactor trip. During cold- i shutdowns of shon duration, the introduction of excessive amounts of boron into the RCS  ;

complicates the task of maintaining proper plant chemistry and creates difficulties with ,

subsequent startup, especially later in core life.

t In addition to the adverse effects on primary plant chemistry, pumping' high concentations of boric acid through the emergency boration line can cause reactor coolant pump (RCP) seal -

failure. The RCP seal water supply lines are not heat traced. Crystallization of concentrated boric acid in the RCP seal injection filters will occur and cause a loss of RCP seal water.

Consequently, it is only possible to perform stroke testing on I&2 CV-00351 when reactor coolant pumps are secured and the associated RCP seal water lines are isolated.

Crystallization of boric acid may also occur in instrumentation sensing lines as concentrated boric acid is pumped into the chemical and volume control system (CVCS) for the purpose of stroke testing 1&2 CV-00351.

The steps necessary to establish plant conditions to permit the testing of 1&2 CV-00351, and those which are required to recover from that testing, are sufficient to preclude the testing of the valves during cold shutdowns in which there is no reactor refueling. Extending a cold shutdown period for the sole purpose of providing the necessary time to allow for the test and recovery from test conditions is excessively burdensome to the licensee.

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' Enclosure 2-

. BASIS FOR RELIEF: (continued)

Point Beach operates on an annual refueling cycle for each unit, and non-refueling cold ~ ,

shutdowns between cycles are rare. Deferral of testing for 1&2 CV-00351 to refueling '

outages will test each valve on an annual basis and is in keeping with ASME OMa-1988, i Pan 10, Section 4.3.2.2(e). Testing during annual refueling outages provides adequate -

assurance of the ability of these valves to perform their safety function.

l ALTERNATE TESTING:  ;

These valves will be full stroke exercised to the open position during reactor refueling outages. t STATUS: l Active. His request is an open item as evaluated by the NRC SER dated April 17, 1992.

Request revised as this submittal to address regulatory concerns in an effen to obtain  ;

unconditional relief.  ;

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Enclosure 3 RELIEF REQUEST VRR-37 COMPONENTS: UNIT 1 (Drawing Il0E017 Sh. 2): SI-00891 A&B.

UNIT 2 (Drawing 110E035 Sh. 2): SI-09891 A&B.

CATEGORY: C.

FUNCTION:

These valves open to pmvide flow paths from the safety injection (SI) pumps to the refueling water storage tank (RWST) to provide for minimum flow through the respective pumps in the event they are operating against reactor coolant system (RCS) pressures higher than pump shutoff head.

Flow through the mini-recirc lines is limited by the individual line orifices, and is small ,

enough to make the effects of bypass flow through an idle pump negligible with respect to i the running pump's ability to fulfill its safety function. During long-term recirculation, there is no path back from the RCS that would allow reverse flow through an idle pump. As a result, these check valves do not have a safety-related closure function.

SECTION XI REOUIREMENT:

Check valves shall be exercised to the position required to fulfill their function.

Confirmation that the disk moves away from the seat shall be by visual observation, by electric signal, by observation of substantially free flow through the valve, or by other .:

positive means. (IWV-3522) i If valve exercising is performed using flow through the valve as the means to verify that the disk has moved away from its seat, there must be quantitative measurement of flow which confirms that " maximum required accident condition flow" has passed through the valve. 1 Any flow rate less than this is considered a panial stroke exercise.

(GL 89-04, Attachment 1, Position 1) ,

BASIS FOR RELIEF:  ;

There is no installed flow rate instrumentation available to verify valve full stroke exercising as required by GL 89-04, Attachment 1, Position I. These valves have no means of local or remote position indication. Disassembly and inspection in accordance with GL 89-04, Attachment 1, Position 2, risk destroying the valve due to galling of the body-to-bonnet threads. i Use of ponable instruments provides a suitable means to measure flow rate in the lines

-i containing these valves and enables testing per GL 89-04, Attachment 1, Position 1.

Although the portable instruments lack the accuracy and repeatability of pennanently installed instrumentation, these difficulties can be overcome.

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' Enclosure 3 i

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. BASIS FOR RELIEF: (continued) i Use of portable instmments can be sufficiently pmcedumlized to ensure reasonable repeatability and accuracy in measurements. Inaccuracies associated with equipment can be j applied conservatively when establishing check valve flow rate acceptance criteria, such that even with the worst possible instrument accuracy, the chec1; valve must pass the " maximum  ;

required accident condition Dow" of GL 89-04, Attachme ,t 1, Position 1, if the acceptance  ;

criteria is met. j Note that these portable flow rate instruments are only being used for the full stroke ,

exercising of Check Valves 1&2 SI-00891 A&B, and not for gathering any data related to i pump perfor:iance. Consequently, the strict Code requirements penaining to instruments l used in pump testing (IWP-4000) do not apply in this instance, and relief is not required  ;

from these sections of the Code, j ALTERNATE TESTING:

During quarterly pump testing, each of these valves will be full stroked exercised via recirculation through the minimu n flow test circuits. Quantitative measurement of flow which confirms that " maximum requimd accident condition Dow" has passed through the  ;

valve shall be accomplished using ponable flow rate instruments. The manner of use of these instmments shall be sufficiently proceduralized to ensure maximum repeatability and ,

accuracy of the measuremen'.s. Acceptance criteria established based on flow rate will take- l portable instmment accuracy into account in such a manner so as to ensure that the check valve must have passed the " maximum required accident condition flow" of GL 89-04, .,

Attachment 1, Position 1, if the acceptance criteia is met.

STATUS:

Active. Request submitted to the NRC for initial review and approval.

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