ML20081F534

Forwards Response to SER Request for plant-specific Info on NUREG-0737,Items II.D.1.A & II.D.1.B, Reliability Engineering Re Operability of Pressurizer Safety Valves, PORVs & PORV Block Valves

ML20081F534
Person / Time
Site:	Catawba
Issue date:	10/26/1983
From:	Tucker H DUKE POWER CO.
To:	Adensam E, Harold Denton Office of Nuclear Reactor Regulation
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-2.D.1, TASK-TM TAC-65753, TAC-65754, NUDOCS 8311030121
Download: ML20081F534 (11)

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DuxE Powen GOMIENY 18.0. ISOx 33180 CifAHLOTTE. N.O. 28242 HAL H.TUCKEN Tr. _ renown

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October 26, I983 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.-S. Nuclear Regulatory Commission Washington, D. C. 20555 Attention:

Ms. E. G. Adensam, Chief Licensing Branch No. 4 Re: Catawba Nuclear Station Docket Nos. 50-413 and 50-414

Dear Mr. Denton:

Section 3.9 3 2 of the Catawba Safety Evaluation Report discusses License Condition 3, Relief and Safety Valve Testing. Therein the Staff requested plant-specific Information concerning the operability of the Catawba pressurizer safety valves, power operated relief valves (PORVs) and PORV block valves.

This information is attached.

Very truly yours,

%J Walk /

Hal B. Tucker ROS/php Attachment cc:

Mr. James P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Commission Region 11 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30303 NRC Resident inspector Catawba Nuclear Station Mr. Robert Guild, Esq.

Attorney-at-Law P. O. Box 12097 Charleston, South Carolina 29412 p./A Palmetto Alliance

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'21351 Devine Street Columbia, South-Carolina 29205 8311030121 831026

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I Mr. Harold R. Denton, Director October 26, 1983 Page 2-I

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cc:- Mr. Jesse L. RIley Carolina Environmental Study Group 854 Henley Place Charlotte, North Carolina '28207 e

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Catawba. Nuclear Station Safety Valve Operability Report NUREG 0737, item II.D.I.A.

This ' report' is in response to. the requi rements of NUREG 0737, item I I.D.I. A.

to demonstrate Pressurizer Safety Valve operability for Catawba Nuclear Sta'tlon.

The hasis for this report is the generic safety / relief valve test program that was developed on behalf of participating utIIIties by the Electric Power Research Institute"(EPRI),

in addition to this test program, a plant specific analysis was performed by EPRI for the Catawba safety valves.

VALVE DESCRIPTION Dresser Industries MANUFACTURER Spring Loaded Safety Valve TYPE 31749A MODEL-3NC-019 MANUFACTURERS DRAWING 3

VALVES PER UNIT Each safety valve is. connected to a separate pressurizer nozzle with the valve inlet piping run to prevent formation of a water loop seal.

EPRI TEST PROGRAM Duke Power has been a full' participant in the EPRI test program, and.the Catawba

- s'afety valve is represented by ~ the four program outputs ' listed below:

1) Valve Selection / Justification Report

2) Test Condition Justification Report 3)

Safety and Relief Valve Test Report

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4) Valve inlet Fluid Conditions Tor Pressurizer Safety and Relief Valves in llestinghouse Designed Plants.

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' Catawba Nuclear Station -is also represented by Westinghouse's evaluation of valve <opirability presented in WCAP 10105, " Safety valve operability-Report."

APPLICABILITY OF EPRI TEST RESULTS

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The EPR'l test results are applicable to Catawba Nuclear Station as follows:

Test Valve-----------Catawha safety valves, Dresser Model 31749A are enveloped by the Dresser test valves, models 31739A and 31709HA.

These test valves are of the same design and model series-and are geometrically similar (nozzle, seat chamber, rings, bellows, body bowl, etc.) to;the Catawba safety valves.

'TheI 31739A. valve 'Is smaller. and the 31709NA is larger than the Catawb'a valve.

Fluid Conditions-----TheLtested conditions covered all-the design basis tran-s.

sient events for th'e Catawba ' pressurizer relief system.

3 in addition, the test back pressures of the model 31739A valve envelope.those at Catawba.

TestLFacil!.ty--------The test facility -(wi th long inlet pipe configuration) -and

-the Catawba pressurizer relief system in the safety valve-region-are similar with respect to piping length and pipe size.

~ VALVE.0PERABILITY

'The Dresser model 31739A and 31709NA valves successfully~ opened and closed for all design' basis test transients.

In addition, rated flow was exceeded for those tests with. proper ring settings.

Stable va'Ive performance and full flow were achieved when testing the model

. 31739A safety valve- (at high back pressure and long inlet pipe configuration) with blowdown in the 12.2% range. This data was the basis for an EPRI plant

'(Catawba)' specific analytical correlation to determine the ring settings for the Catawba model 31739A safety valves.

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The correlation'was based on~the" analytical results provided in the-paper, "A

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l correlation for Safety ~ Valve Blowdown,and Ring Settings", presented at the ASME Winter Annual' Meeting, November16, 1982.

Since the-Catawba safety valve, model-31749A,' is"dimensionally closer'to the EPRI tested model 31709HA

' safety' valve, this valve was used to scale ring' settings for the Catawba safety valves'. 'The' rings on'the Catawba safety valves will be set in accordance with tha EPRI analytical--correlation, and pop tested'at Wylie Laboratories.

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CONCLUSION

~ Based on the test data for.the Dresser Model 31739A and 31709NA safety Valves

.I and the-analytical. correlation for ring,sett'ings of the Catawba-safety valves, operability of.'the Catawba safety valves has.been demonstrated for expected

. operating and : accident.condi tions as requi red ' by NUREG ' 0737, i tem l l.D. I. A.'

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CATAWBA NUCLEAR STATION PRESSURIZER POWER OPERATED RELIEF VALVE QUALIFICATION REPORT NUREG 0737, ITEM 11. D.I.A.

/This report is in response.to the requirements of NUREG 0737, item II.D.I.A. to demonstrate Pressurizer Power Operated Relief Valve (PORV) operability for Catawba Nuclear Station. The basis for this report is the generic safety / relief valve test program that was developed on behalf of participating' utilities by the Electric Power Research Institute (EPRI) combined with in-house and in-plant testing performed-by Duke Power'.

Duke Power has been a participant in the EPRI program, and the results of this program were submitted to the NRC on April 1,1982

.on behalf of'the utilities by David Hoffman of Consumers Power.

PRESSURIZER PORV SYSTEM DESCRIPTION The pressurizer is equipped with three power operated relief valves which limit system pressure for a large power mismatch condition. The Pressurizer Power Operated Relief Valves are operated at a high setpoint either automatically or by remote manual control. The operation of these valves also limits the unde-

!sirable opening of the spring-loaded Pressurizer Safety Valves.

The Pressurizer Power Operated Relief Valves are also used for overpressure protection during periods of water solid operation.. Protection against such over pressurization events is provided through the addition of low pressure setpoints to two Pressurizer PORV's.-

Since this protection is required only during low temperature water solid' operation,-the' low pressure setpoint, 400

-psig,.is~ enabled by the operator at reactor coolant loop temperatures below 3200F. The low pressure setpoint is Interlocked with reactor coolant loop temperature to minimize the possibility of inadvertent actuation.

VALVE DESCRIPTION Control Components international Manufacturer Type-3 inch Air Operated Globe Valve Self Drag Element

'Hodel 1

Manufacturer Drawing 921101010

. Operator Air Piston (air to open; spring / air to f

close)

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-The CCl; PORV'uses an air operated piston type actuator. Normal operation uses

-air to open and.close the valve. A closure spring is also_provided in the actuator:tolautomatica11y' close the valve in the. event of loss of air pressure.

.8ACKGROUND' As a result of Pressurizer PORV problems in-the Initial McGuire hot functional test,zDuke performed full scale in-house PORV. testing at Marshall Steam Station. A 1

Pressurizer PORV from Catawba Nuclear Station was used as a test valve.. in-

' conjunction with the valve manufacturer, a. series of modifications and proof tests were performed to improve valve performance. The modifications included:

1): revising bonnet design from pressure seal to bolted bonnet

2) -increasing operator size to provide additional spring closure force in

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- event of loss of air supply.

l3) elimination of the upstream water loop seal _ to reduce thermal transient loading on valve disc stack 14) revising'alr' supply' system to decrease valve operator stroke. time After completion of all modifications, a series of proof tests were performed

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,and the. valve met a11' operating requirements..The tests were documented in a Duke report, " Report of Pressurizer PORV Operability Test", dated February 5

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and 6,,1980.

The above modifica'tions were then made to all six (6) Catawba Pressurizer PORVs.

EPRI TEST. PROGRAM

Duke. Power has been a full participant in the EPRI. test program. The Catawba Pressurizer PORV testing is represented in the following EPRI reports submitted

-to'the NRC on April 1, 1982:'

-1) Value Selection Justification Report E "

2) Valve inlet Fluid Conditions' for Pressurizer Safety and Relief Valves in Westinghouse Designed Plants

3) ' Test Condition Justification Report 4)

Safety and Relief Valve Test Report items of a' plant specific nature not covered'in the above reports are addressed below.

- TESTVALV'EAPPblCABILITY, The EPRI test _ valve,Is the Catawba Pressurizer' PORVs.

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VA'LVE FLUID CONDITIONS

.The cold overpressure ~ conditions in the Westinghouse Fluid. inlet. Condition Report.do notL specifically address Catawba, since the-valves and controls were

-, purchased by Duke Power.

However, the Catawba system is based on the Westinghouse design..

~ -TheiPORV high setpoint is 2335 psig, with IIquid 'ischarge temperatures ranging d

~from'3200F to-6500F,' The low setpoint.is 400 psig with IIquid discharge tempera-0 tu'res ranging from'100 F to 450 F.

Liquid tests representative of th'e obove conditions were performed. Tests number 38' and:43 of table:3-13 in the Test Condition Justification Report are representative =of.the high set point IIquid conditions.

For the reduced pressure condition, tests 39 and 40 are representative. The valve opened and closed as required :for each test.

Based on the above tests, the fluid. conditions for which the CCI valve was tested represent the range of conditions for Catawba Cold Overpressurization events.

4 VALVE OPERABILITY' The criteria for _ successful operation is.that the valve opens and closes for all. fluid conditions and passes the specified flow. The CCI valve successfully met this ' criteria for every. test.

For.the abnormal operating mode of unassisted spring closure on loss of all air, several delays in valve closing were observed'in.the Wylie EPRI' testing that were not observed in the Marshall (EPRI) steam testing.

Five (5) steam tests

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"were run at W lle with closure on spring only. The valve had delays of l'to 3 y

seconds on 3 of <the tests. After the Marshall testing, the valve was disassembled cleaned, reassembled, and_ repacked.

Delays in the Wylie testing were attributed to the tightness to which the valve was assembled prior to testing. Valve opera-

. tion afterl reassembly was not as smooth as.In.the Harsha11 testing.

Six?(6)_ water tests:were.also run with spring only closure.- The-valve closed with'no delay on four tests and had delays'of.20 and 40 seconds-on the other two.

The last two water tests were high pressure water at saturated temperature conditions ( 2'650 F).; Valve closure.did occur when~ intet pressure decreased to.2035 psia.

Evaluations with the valve manufacturer determined that high temperature sater flashing across the drag element creates' higher pressure in the valve throat than expected. Under. spring only closure, this throat pressure is sufficient to prevent valve closure until inlet pressure falls to approximately 2035 psia. This condition occurs only for high pressure saturated water in the

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This was verified by_a 6400F high pressure water test, in which no -valve delay-occurred on spring only closure.

Duke considersLthe above valve performance as acceptable for the following

. reasons:

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1). the occurrence of 650 F. water at the valve inlet is a degraded event of low-probability.-

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. 2) the valve has been shown to close on spring force alone by test at an

Inlet pressure'of ? 2035 psia for this case. This closure pressure is above' reactor' trip and safety injection setpoints.

3) the' delay will only occur on the improbable set of circumstances that

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the. valve has opened with air, had a transistion to high temperature water, and then had a complete loss of air prior to receiving a close signal. Any air remaining in the air lines will assist in normal closure.

CONCLUSION Based on the.above testing, operability of_the CCI Pressurizer Power Operated

-Relief Valves.have been demonstrated for expected operating and accident conditions as required by NUREG 0737 Item II.D.I.A.

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j CATAWBA NUCLEAR STATION PRESSURIZER PORV BLOCK VALVE QUALIFICATION REPORT NUREG 0737 ITEM'll.'D.l.B.

This_ report is in response to the_ requirements of NUREG 0737, item II. D.I.B

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, pertaining ~ to qualifications of Pzr PORV block ~ valves for Catawba Nuclear Station.

Duke Power'has met this' requirement through a combination of full scale in-house (testing,and: participation in the~. Electric. Power Research Institute PORV Block

-Valve Test Program.

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-Valve Description Rockwell International Manufacturer 3" Gate 1717 lb Std. Int. pressure class

, Type Fig. 12511 (CF8M) FJMNPQTY-

,Model' 080-23264-01

' Manufacturer Drawing Limitorque SMB-00-10 Operator Valves Per Unit 3

Background

Duke first performed.. full-scale testing of the Pressurizer PORV Block Valve in conjunction with in-house testing of the PORV at Marshall Steam Station.

The test valve used was a.Ro' kwell Valve similar to the installed Catawba c

valves.

The Rockwell testi valve successfully tested in a 21 cycle evaluation test at full pressure and temperature. Successful completion of this test was documented in, an in-house report,." Report of EMO Valve. Operability Test", dated January 30,-1980.

'EPRI Test Program Duke.has been a full participant-in the EPRI safety / relief valve test program, including the Block Valve Program.;. Duke's Rockwell test valve was also used

. in. the EPRI Block Valve Test Program. The valve was cycled an' additional 21 times against flow at full pressure and temperature and operated successfully for=each' cycle.

.The results of this' program has been documented in a report entitled "EPRI PWR Safety. and Relief Valve Test Program PORV Block Valve -Information Package."

-This report was' _ transmitted to the NRC by Mr. David Hoffman on behalf of Duke Power and the other participating utilities on July' I,1982.

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Pcga 2 CONCLUS10NS.

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The Catawba PORV Block-Valve-has been cycled 21 times at full-pressure and temperature'under a Duke ' test program and 21 times at full pressure and temperature under ~ the EPRI. program.

These tests confirm:' Catawba PORV Block Valves operability for all fluid conditions and. meet the requirements of NUREG 0737, item 11. D.I.B.

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