BVY-96-163, Forwards Rev 18 to Inservice Testing Program Plan for Vermont Yankee Nuclear Power Station

Forwards Rev 18 to Inservice Testing Program Plan for Vermont Yankee Nuclear Power Station

ML20132G563
Person / Time
Site:	Vermont Yankee
Issue date:	12/19/1996
From:	Sojka R VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20132G567	List: BVY-96-163, Forwards Rev 18 to Inservice Testing Program Plan for Vermont Yankee Nuclear Power Station ML20132G578
References
RTR-NUREG-1482 BVY-96-163, GL-88-04, GL-88-4, TAC-M82229, TAC-M85067, TAC-M91450, TAC-M92018, NUDOCS 9612260296
Download: ML20132G563 (13)

Text

_. ._ . _ - _ - . _ _ _ - .

VERMONT YANKEE NUCLEAR POWER CORPORATION 7, Ferry Road, Brattleboro, VT 05301-7002

,, m ENGINEERING OFFICE 580 MAIN STREET BOLTON, MA 01740

($v8) 7794711 December 19,1996 BVY 96-163 United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 t

References:

See Attachment A Subjact: Vermont Yankee Inservice Test Program Plan - Revision 18 With this letter Vermont Yankee is providing the following documents:

(1) Revision 18 of the Vermont Yankee Inservice Test Program Plan (Attachment B)

(2) Relief Requests RR-V12 Rev 1, RR-V13 Rev 0 and RR-V14 Rev 0 (Attachment C) l Vermont Yankee is providing Revision 18 of the Inservice Test (IST) Program Plan for your information. It is a complete program re-write which incorporates scope additions and deletions based upon: Vermont Yankee's IST self assessment, recent NRC inspections, plant design changes, NUREG- 1482 recommendations and correction of j t, oographical errors.  ;

Vermont Yankee is seeking NRC review and approval for Relief Requests RR-V12, RR-V13 and RR-V14. We are currently performing quarterly radiography and outage i disassembly on these components and will only use these proposed alternative tests after receipt of your approval. Once approved, these alternative tests will be '

incorporated into our IST Program Plan as Revision 19. We request your evaluation of Relief Requests RR-V12, RR-V13 and RR-V14 by August 1997. 4 '

Relief Request RR-V12 Revision 0, was originally submitted with Revision 17.of the IST k

Program Plan per Reference (p). NRC provided a Safety Evaluation (Reference m) for

\

9612260296 961219 ,

PDR ADOCK 05000271 0 PDR i

UcS. Nuclear Regulatsry Commission VERMONT YANKEE NUCLEAR POWER CORPORATION December 19,1996 Page 2 l

l l

Relief Request RR V12 which requested that Vermont Yankee expand the basis in this request to clearly show that closure verification of each valve is impractical during l refueling outages, and address the possible use of non-intrusive testing methods.

Relief Request RR-V12 has been revised to expand on the basis for this relief and to include the use of non-intrusive testing methods on a sampling basis during refueling )

outages.

We trust that the information provided is acceptable; however, should you have any questions or desire additional information, please contact this office.

Sincerely, VERMONT YANKEE NUCLEAR POWER CORPORATION

/

p.

Robert E. Sojka Operations Support Manager Attachments l cc: USNRC Director, Office of Nuclear Reactor Regulation USNRC Regional Administrator, Region i USNRC Project Manager, VYNPS USNRC Resident inspector, VYNPS i

i Attachment A i References  !

(a) License No. DPR 28 (Docket No. 50-271)  !

l (b) Code of Federal Regulations, Title 10 Chapter I, Part 50, Section 50.55a 56 Fed. Reg. 4666, dated 8/6/92  ;

(c) ASME Boiler and Pressure Vessel Code, Section XI,1980 Edition, " Rules for Inservice Inspection of Nuclear Power Plant Components" l

f (d) ASME Boiler and Pressure Vessel Code, Section XI,1989 Edition, " Rules for laservice Inspection of Nuclear i Power Plant Components" (e) ASME/ ANSI Standard OMa-1988 Addenda to ASME/ ANSI OM-1987, " Operation and Maintenance of Nuclear ,

Power Plants" l

l (f) Letter, USNRC to VYNPC, " Vermont Yankee Nuclear Power Station, Approval of the Use of ASME/ ANSI l Standard OMa-1988 With Clarification". NVY 92-161, dated 9/2/92  !

(g) Letter, VYNPC to USNRC, " Vermont Yankee Nuclear Power Corporation Inservico festing Program Update", ,

BVY 92-98, dated 8/13/92 l

l (h) Letter, USNRC to VYNPC, ' Safety Evaluation - Inservice Testing (IST) Program Relief Requests - Vermont ,

Yankee Nuclear Power Corporation, Vermont Yankee Nuclear Power Station (TAC No. M82229)", NVY 92-  ;

I 79, dated 5/13/92  !

(i) Letter, VYNPC to USNRC, ' Response to USNRC Generic letter 89-04: Guidance on Developing Acceptable Inservice Testing Programs", BVY 89-90, dated 10/3/89 l l

(j) Letter, USNRC to All Holders of Light Water Reactor Operating Licenses and Construction Permits, ' Guidance I on Developing Acceptable Inservice Testing Programs (Generic Letter 89-04)", NVY 39-75, dated 4/3/89 l

(k) Letter, USNRC to VYNPC, " Safety Evaluation of the laservice Test Program Relief Requests for Pumps and Valves, Vermont Yankee Nuclear Power Station (TAC No. M85067)", NVY 93-151, dued 9/3/93 (1) Letter, USNRC to VYNPC, ' Safety Evaluation of Relief Requests and Action item Responses for the Third Interval Pump and Valve Inservice Testing Program - Vermont Yankee Nuclear Power Station (TAC No.

M91450)", NVY 95-88, dated 6/12/95 (m) 1.etter, USNRC to VYNPC, " Safety Evaluation of Relief Request RR-V12 for the Third Interval Pump and Valve laservice Testing Program - Vermont Yankee Nuclear Power Station (TAC No. M92018)", NVY 95-100, dated 7/27/95 (n) USNRC NUREG-1482, ' Guidelines for IST at Nuclear Power Plants", dated April 1995 l (o) USNRC NUREG/CR-6396, " Examples, Clarifications, and Guidance on Preparing Requests for Relief from Pump and Valve Innervice Testing Requirements', dated February 1996 (p) Letter, VYNPC to USNRC, " Vermont Yankee laservice Test Program Plan Revision 17", BVY 95-40, dated 3/31/95 i

f l

! 1 l .

l f

Attachment B Inservice Testing Program Plan Revision 18 I

i I

l l

t l

l Attachment C Proposed Alternate Test Methods RR-V12, Rev.1 Alternate Cooling Check Valve V70-43A,B testing i

RR-V13, Rev.0 Keeptill check valve testing RR-V14, Rev.0 Core Spray / Condensate transfer check valve testing !

l-  ;

l i

l f

I 1

I I

Verm:nt Ycnkee Nucle:r Pcwer Stati:n Inservice Testing Prcgram l

RELIEF REOUEST Number: RR-V12, Revision 1 (Sheet 1 of 3)

SYSTEM: Service Water System COMPONENTS:

, Valve Number OM Cat. Safcty Class Drawing Number Dwg. Coord. ,

l V70-43A C 3 G-191159 Sh I J-12 V70-43B C 3 G-191159 Sh 1 B-12  !

l These valves are the Service Water System header discharge check valves. These valves have a safety function to close to prevent the backflow of RHRSW pump discharge to the suction of the l pumps when operating in the Alternate Cooling mode of operation.

EXAM OR TEST CATEGORY:

r Category C 1

CODE REOUIREMENT: Part 10 i

j Para. 4.3.2.1 " Exercising Tests for Check Valves" '

? " Check valves shall be exercised nominally every 3 months, except as provided by paras. 4.3.2.2, i 4.3.2.3, 4.3.2.4 and 4.3.2.5.  !

i

! REOUEST FOR RELIEF: l S ,

j Relief is requested on the basis that compliance with the Code requirements is impracticable and that the proposed alternatives would provide an acceptable level of quality and safety, i

It is impracticable to full or pan-stroke exercise these valves in the closed direction on a quanerly, cold shutdown or refueling outage basis unless the Service Water System is operated in the Alternate i Cooling mode of operation.

d i

t 5

Vernunt Ycnkee Nuclear Power Stati:n Inservice Testing Program RELIEF REOUEST Number: RR-V12, Revision 1 (Sheet 2 of 3)

REOUEST FOR RELIEF (CONT.):

Closure testing of these valves utilizing the Residual Heat Removal Service Water Pump (RHRSW) with the Service Water system configured in its normal alignment is not practical. The RHRSW pumps rely on the operation of the Service Water pumps to supply the equired suction while in the normal SW alignment. Closum verification of these valves is not practical since RHRSW pump pressure is reduced by throttling RHR Heat Exchanger outlet valve V10-89A(B) to maintain sufficient differential pressum across the heat exchanger to support RHR system operation and to limit RHRSW pump flow. Since RHRSW pump discharge pmssure is throttled to support system operating requirements, the differential pressure acmss V70-43A(B) is low and gross leakage past the valve could be masked by the constant upstream pressure supplied by the Service Water Pumps.

Themfore, this method of verifying valve closum for V70-43A(B) would not be technically valid l under any conditions where Service Water Pump flow is provided to support RHRSW pump operation.

. The flow path through PCV-69A is not available for use during normal system operation. This flow

path is used only during the Alternate Cooling mode of operation to supply cooling water to the emergency diesel generator heat exchangers. This flow path is administratively contmiled by the closure of V70-42A during normal system operation to prevent the overpressurization of the emergency diesel generator heat exchangers. Themfore, this method of testing V70-43A(B) is not practical under any conditions.

Closure verification of these valves would require that the Service Water System be aligned in the Alternate Cooling mode of operation. The Alternate Cooling mode of operation is designed as an alternate means of providing service water to safety systems in the event (1) a fire in the Intake Structure, (2) loss of the Vemon Dam coincident with a loss of site electrical power and (3) flooding of the Service Water Intake Stmeture. Swap over of the Service. Water System to the Alternate Cooling mode of operation requires that each of the Service Water pumps in their individual trains be shutdown, the Service Water system be manually re-aligned to take suction off of the cooling tower deep basin and an Residual Heat Removal Service Water Pump be started to verify proper valve closure.

1 i

d Vcrm:nt Yankee Nucl:ar Pow:r Stati::n Inservice Testing Program RELIEF REOUEST Number: RR-V12, Revision 1 (Sheet 3 of 3)

REOUEST FOR RELIEF (CONT.h In accordance with station procedures, some the actions that are required before the Alternate Cooling Subsystem can be started are as follows:

1) The reactor must be manually scrammed or be shutdown.

2) The operating Contml Rod Drive Pump must le secured. (during power operations)

3) All Residual Heat Removal Pumps must be p ul in the Pull-to-Lock position.

4) All Service Water Pumps in 4 subject tre ;nust be secured. (during power operations)

Them has been no specific frequency for placing the alternate cooling system into service due to the heat exchanger capability testing requirements of USNRC Generic Letter 89-13 " Service Water System Problems Affecting Safety Related Equipment". Therefsm, periodic verification of valve closure utilizing RHRSW pump pressure in the Alternate Cooling flow mode of operation is not' practical on a quarterly, cold shutdown or every refueling outage basis.

ALTERNATE TEST METIIOD:

As identified in Vermont Yankee SER dated 07/27/95 (NVY 95-100), it is practical to verify the condition of these valves by the use of non-intrusive techniques (radiography). Since these valves are 8 inch swing check valves of the same design, manufacturer, size, model, materials of construction and are both oriented in the horizontal position and see similar service conditions, the closure capability of these valves shall be verified utilizing either a non-intrusive technique (preferable if practical) or disassembly on a sampling basis (one valve in each train) during refueling outages. If indications are found which affect the operational readineas of the sample valve, the subject valve shall be disassembled, inspected, and (if necessary) repaired and the sample size will be expanded to. include examination of the other valve utilizing either a non-intrusive technique (preferable if practical) or disassembly.

These valves are partial-stroke opened during quarterly DG testing. When non-intrusive techniques are used, both full open and full close verification will be performed.

The commitment made by Vermont Yankee in LER 89-017 in corrective action #2 to exclusively disassemble and inspect one valve each refueling will be superseded upon approval of this relief request.

USNRC EVALUATION STATUS Relief was granted in the July,1995 SER [ Reference (m)] for Relief Request RR-V12, Revision 0.

Revisim- 1 incorporated NRC comments from this SER.

Verm:nt Yankee Nuclear Power Stati:n Inservice Testing Program RELIEF REOUEST Number: RR-V13, Revision 0 (Sheet 1 of 3)

SYSTEhfi Residual Heat Removal Core Spray System RCIC HPCI COMPONENTS: ,

Valve Number OM Cat. Safety Class Drawing Number Dwg. Coord.

V10-36A C 2 G-191172 J-03 V10-368 C 2 G-191172 J-14 i V14-33A C 2 G-191168 H 11 l V14-33B C 2 G-191168 H-15 V23-20B C 2 G-191169 Sh 1 G-07

~

V13-20B C 2 G-191174 Sh 1 G-11 l These valves are the RHR, Core Spray, RCIC and HPCI system Keep-Fill Check Valves. The safety function of these valves is to close to prevent back-flow of water into the lower pressure non- l l

safety grade condensate transfer system.

EXAM OR TEST CATEGORY:

Category C CODE REOUIREMENT: Part 10 Para. 4.3.2.1 " Exercising Test Frequency"

" Check valves shall be exercised nominally every 3 months, except as provided by paras. 4.3.2.2, 4.3.2.3, 4.3.2.4 and 4.3.2.5.

REOUEST FOR RELIEF:

It is impracticable to individually verify a full-stroke exercise of these valves in the closed direction on 3 month, cold shutdown or mfueling outage basis in accordance with the requirements of Paragraph 4.3.2.1 of the Code.

.. . . - . _ - _ _ . _- =.

Verm:nt Yankee Nuclear P wer Stati:n Inservice Testing Prcgram RELIEF REOUEST Number: RR-V13, Revision 0 (Sheet 2 of 3)

REOUEST FOR RELIEF (CONT.):

These valves are one inch lift check valves in the keep-fill pmssurization lines for the residual heat removal, core spmy, high pressum coolant injection and reactor core isolation cooling systems. ]'

These valves am each arranged in series with a non-nuclear safety (NNS) check valve (V64-20) with no test connections or test taps. The lack of test connections or test taps does not enable each of j

the subject valves to be individually verified closed using flow.  !

1 1

The safety ftmetion of these check valves is to close to isolate Safety Class 2 Core Spray, RHR, ,

RCIC or HPCI piping from NNS Condensate Transfer System piping in the event of a system actuation. The Vermont Yankee plant design also incorporates the use of one NNS check valve (V64-20) upstream of each of these valves. The Vermont Yankee safety analy;is does not rely on j the upstream check valve V64-20 to perform a safety related function to suppon the operation of the core spray, RHR, HPCI or RCIC systems. However, since these valves are in parallel to each other with a common NNS check valve upstream, the testing of these valves as a series pair as suggested in NUREG-1482, subsection 4.1.1 (" Closure VeriGcation for Series Check Valves without It termediate Test Connections") would not provide positive verification of closure for either the subject valve or V64-20.

In order to verify individual valve closure capability on an interim basis, the subject valves have been non-intmsively tested quanerly, using radiography. Indication of valve closure has been conclusive. However, continued testing more than once per cycle of the subject valves has preven i to be impracticable and burdensome due to the potential hazards to plant personnel, and potential l for unexpected challenges to plant safety systems due to high radiation actuations associated with I this test method. From an ALARA standpoint, it is most desirab!c .o perform RTs when a minimum number of people are within the impacted area, and a minimum number of activities am ongoing.  !

This configuration typically occurs off shift during the operating cycle, but sometimes occurs during  ;

cenain outage windows.

Vennont Yankee has investigated the possible use of other non-intmsive techniques such as acoustics. However, due to valve size, valve type and low flow rates through the keep-fill lines, 1 it is not expected that this method would provide conclusive indication of valve closum.

Additionally, Vermont Yankee has investigated the potential use of performing sample non-intmsive testing with flow as described in NUREG-1482, subsection 4.1.2 (" Exercising Check Valves with Flow and Nonintmsive Techniques") for the subject valves but has detennined that it is not applicable for these valves since safety function of these valves is to close on cessation or reversal of flow.

s Vernunt Yankee Nuclear Power Station Inservice Testing Progrant i

i RELIEF REOUEST l l

Number: RR-V13, Revision 0 (Sheet 3 of 3)

REOUEST FOR RELIEF (CONT.):

l Vermont Yankee has also investigated the use of perfonning a disassembly and inspection of each )

of these valves on a refueling outage basis in accordance with subsection 4.3.2.4(c) of Part 10 of l

the Code. However, in recent NRC guidance identified in Appendix A of NUREG 1482 (question group 15) and in a previously resolved Vermont Yankee IST Program Safety Evaluation anomaly, the NRC discouraged the use of the disassembly and inspection technique on the basis that disassembly is not a tme substitute for an operability test using flow.

ALTERNATE TEST METIIOD: l i

l l Since subject valves are of simple design and operate in mild service conditions and since a myiew '

of the maintenance history of these valves indicates that the valves have not been susceptible to service induced failures or significant wear, Vermont Yankee proposes to implement a sample non-intrusive testing plan for these valves.  !

i l Based on the valve size, model number and function, it is proposed that two groups of valves be i fonned. I Group #1 Grouc #2 V10-36A V23-20B V10-36B V13-20B V14-33A V14-33B It is proposed that one valve in each group be tested each operating cycle on a mtating basis utilizing a non-intmsive test method. In the event that the sampled valve fails to meet its closum l criteria, all of the remaining valves in the mspective group will be tested.

USNRC EVALUATION STATUS

Vermont Yankee Nuclear Pow:r Stati:n Inservice Testing Program '

l RELIEF REOUEST i

l

Number

RR-V14, Revision 0 (Sheet 1 of 3) ,

SYSTEM: Core Spray System

COMPONENTS:

Valve Number OM Cat. Safety Class Drawing Number Dwg. Coord.

f V14-22A C 2 G-191168 I-09 j

{ V14-22B C 2 G-191168 C-10 ,

V14-23A C 2 G-191168 I-09

_ V14-23B C 2 G-191168 C-10 These valves are the Core Spray System Flushing Line Check Valves. The safety function of these l valves is to close to pmvent back-flow of water into the lower pressure non-safety grade condensate transfer system.

EXAM OR TEST CATEGORY:

I Category C j CODE REOUIREMENT: Part 10 Para. 4.3.2.1 "Exemising Test Frequency"  !

" Check valves shall be exercised nominally every 3 months, except as provided by paras. 4.3.2.2, 4.3.2.3, 4.3.2.4 and 4.3.2.5.

REOUEST FOR RELIEF:

It is impracticable to individually verify a full-stroke exercise of these valves in the closed direction i on 3 month, cold shutdown or refueling outage basis in accordance with the requirements of  !

Paragraph 4.3.2.1 of the Code.

These valves are two inch lift check valves in the flushing lines for the core spray system. V14-23A and V14-22A are located downstmam of norma!!y closed valve V14-21 A. V14-23B and V14-22B are located downstream of normally closed valve V14-21B. These valves are each arranged in series with no test connections or test taps. The lack of test connections or test taps does not enable each of the subject valves to be individually verified closed using flow.

Vermtnt Ycnkee Nuclear Pcwer Stati:n Inservice Testing Program 4

RELIEF REOUFET

^

Number: RR-V14, Revision 0 (Sheet 2 of 3)

REOUEST FOR RELIEF (CONT.h The safety function of these check valves is to close to isolate Safety Class 2 Core Spray from NNS Conderisate Transfer System piping in the event of a system actuation. Since each of these valves is Safety Class 2 both of these valves are relied upon to perform their safety function. Since both valves are relied upon to perform a safety function, the ability to test these valves as a series pair ;

l as described in subsectica 4.1.1 (" Closure Verification for Series Check Valves without Intermediate

Test Connections") is not applicable.

In order to verify individual valve closure capability on an interim basis, the subject valves have been non-intmsively tested quarterly, using radiography. Indication of valve closure has been conclusive. However, continued testing more than once per cycle of the subject valves has proven to be impmeticable and burdensome due to the potential hazards to plant personne1, and potential for unexpected challenges to plant safety systems due to high radiation actuations associated with this test method. From an ALARA standpoint, it is most desirable to perfonn RTs when a minimum number of people are within the impacted area, and a minimum number of activities are ongoing. I This configuration typically occurs off shift during the operating cycle, but sometimes occurs during certain outage windows. 1

Vermont Yankee has investigated the possible use of other non-intrusive techniques such as acoustics. However, due to valve size, valve type and low flow rates thmugh these lines, it is not 4 expected that this method would provide conclusive indication of valve closure.

i Additionally, Vermont Yankee has investigated the potential use of perfonning sample non-intmsive testing with flow as described in subsection 4.1.2 (" Exercising Check Valves with Flow and j Nonintmsive Techniques") for the subject valves but has determined that it is not applicable for l these valves since the safety function of these valves is to close on cessation or reversal of flow.

Vermcat Yankee has also investigated the use of perfonning a disassembly and inspection of each  !

of these valves on a refueling outage basis in accordance with subsection 4.3.2.4(c) of Part 10 of the Code. However, in recent NRC guidance identified in Appendix A of NUREG 1482 (question group 15) and in a previously resolved Vemiont Yankee IST Program Safety Evaluation anomaly, the NRC discouraged the use of the disassembly and inspection technique on the basis that disassembly is not a tme substitute for an operability test using flow.

Vcrm:nt Yankee Nuclear Power Stati:n Inservice Testing Program RELIEF REOUEST Number: RR-V14, Revision 0 (Sheet 3 of 3)

ALTERNATE TEST METIIOD:

The subject valves are of simple design, operate in mild service conditions, are not subject to flow induced wear since the flushing line is normally isolated during plant operation. Additionally, since a review of the maintenance history of these valves indicates that the valves have not been susceptible to service induced failures or significant wear, Vermont Yankee proposes to implement a sample non-intrusive testing plan for these valves.

Bared on the fact that these valves are identical in size, model number and function, it is proposed tha; all four valves be classified in one sampling group.

It is proposed that one valve in the sampling group be tested each operating cycle on a rotating basis utibzing a non-intrusive test method. In the event that the sampled valve fails to meet its closure enteria, all of the remaining valves in the sampling group will be tested.

USNRC EVALUATION STATUS l

l 1

l