Information Notice 1986-92, Pressurizer Safety Valve Reliability

Pressurizer Safety Valve Reliability

ML031250138
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill, Crane
Issue date:	11/04/1986
From:	Jordan E NRC/IE
To:
References
IN-86-092, NUDOCS 8610300067
Download: ML031250138 (4)

SSINS No.: 6835 IN 86-92-

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C.

20555

November 4, 1986

IE INFORMATION NOTICE NO. 86-92: PRESSURIZER SAFETY VALVE RELIABILITY

Addressees

All pressurized-water reactor (PWR) facilities holding an operating license or

a construction permit.

Purpose

This notice is provided to inform recipients of potentially significant problems

pertaining to the reliability, of pressurizer safety valves.

It is expected that

recipients will review the information for applicability to their facilities and

consider actions, if appropriate, to preclude a similar problem from occurring

at their facilities.

However, suggestions contained in this information notice

do not constitute NRC requirements; therefore, no specific action or written

response is required.

Description of Circumstances

St. Lucie 2:

On April 17, 1986 while shut down for refueling, St. Lucie 2 personnel bench

tested three pressurizer safety valves that have a technical specification (TS)

set point of 2515 +/- 1x psig.

Valve V-1200 lifted at 2554 psig (14 psi above the

maximum TS set point, valve V-1201 lifted at 2893 psig (353 psi above the

maximum TS set point), and valve V-1202 was leaking too much to test.

The

problem with V-1201 was attributed to a hole in the bellows which allowed boric

acid to contaminate and corrode the valve internals causing them to bind.

The

seat of V-1202 was badly steam cut.

The minor set point drift of V-1200 was

considered normal for 18 months operation.

All valves were repaired before

replacing them in service.

McGuire 1:

On September 2, 1986, McGuire 1 reported that a pressurizer safety valve had

lifted at 2375 psig, 85 psi below the 2485 +/- 1% TS required set point.

The

primary system depressurized to 1800 psig before the valve fully closed.

This

event occurred during pressurization for an inservice leak test.

During

subsequent bench testing of that valve, the as-found set point was determined

to be 2320 psig.

Analysis showed that the three lifts used to determine the

valve set point at the last test were trending downward.

Cocking of the spring, probably because of debris under the spring or a burr, was considered to be the

cause of the set point "drift." When the spring was properly seated, the set

point stabilized.

8610300067

IN 86-92 November 4, 1986 The low pressure at which the valve reclosed is attributed by the licensee to

the setting of the blowdown adjusting ring, which deviated from the vendor's

recommended setting by 137 notches.

The remaining pressurizer safety valves on

unit 1 were inspected and one other had misadjusted ring settings.

The

misadjustment was attributed to on-site readjustment by maintenance personnel.

The correctly set rings on the third valve were set by the vendor's representa- tive.

Unit 1 valves will be repaired and reset.

Unit 2 had two pressurizer safety valves set by the vendor's representative and

one set by plant maintenance personnel.

The plant technician had recorded the

ring settings, which were the same as the vendor's recommendation.

Therefore, Unit 2 valves were determined to be operable.

Arkansas Nuclear One, Unit 2:

On September 15, 1986 while at 29% power, ANO 2 experienced a spurious opening

and rapid reseating of two pressurizer safety valves, which resulted in an

increase in level and pressure in the quench tank and a 4 psig drop in reactor

coolant pressure.

On September 25, 1986 following a reactor trip, quench tank

parameters and tail pipe temperatures indicated that one or both pressurizer

safety valves had lifted.

Licensee tests showed that the setpoints of the valves

were lower than the TS required 2485 psig +/- 1%.

One valve lifted at 2365 psig

and the other between 2430 and 2455 psig.

It was determined that the wrong test

equipment had been used to set the lift pressure of the valves at the outage

prior to these events. The valve manufacturer sent a representative to the site

with the correct equipment.

The valves have been correctly reset.

A search of licensee event reports from January 1, 1983 to the present shows

that 20 other evepts involving 32 valves occurred.

The problems were: 18 valves

with set point drift, 12 valves with seat leakage, 1 valve with set pressure

high and 1 valve designated as inoperable.

Attachment 1 contains the details

of this compilation. Other information on the subject of safety valve

performance and reliability may be found in information notices 86-05;

86-05, Supplement 1; and 86-56, the subject of which are main steam safety

valves.

No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact the Regional

Administrator of the appropriate regional office or this office.

4,)!& 5 ector

Oivisiji of Emergency Preparedness

and Ehgineering Response

Mary S. Wegner, IE

(301) 492-4511 Attachments:

1. Other Pressurizer Safety Valve Problems

2.

Attachment 1

IN 86-92 OTHER PRESSURIZER SAFETY VALVE PROBLEMS FROM 01/01/83 TO PRESENT

PLANT

NO. VALVES

INOPERABLE

SEQUOYAH 1

1 LEAKING

SALEM 2

3 SALEM 1

3 MILLSTONE 2

1 SEQUOYAH 2

1 SEQUOYAH 2

1 BEAVER VALLEY 1

1 SUMMER

1 SEQUOYAH 2

1

SET POINT DRIFT

CALVERT CLIFFS 2

1 BEAVER VALLEY 1

1

SET POINT DRIFT HIGH

FT CALHOUN

1 SALEM 2

3 SALEM 1

3 MILLSTONE 2

1 PALISADES

1 SUMMER

1 YANKEE-ROWE

1

SET POINT DRIFT LOW

ANO 1

1 SEQUOYAH 1

1 SEQUOYAH 2

3

SET PRESSURE HIGH

YANKEE-ROWE

1

Attactment 2

IN 96-92

November 4. 1986

UI

UUb

, I'

I

Nootice No.

68-91

LIST OF RECENTLY ISSUED

IE INFObMATION NOTICES

Date of

'55 IV3/86 nns

Subiject

Limiting Acc

Autherizat1o

Issued to

All power reactor

facilities holding

in OL or CP; fuel

fabrication and

processing facilities

K6-90

t6-e9 t6-05 Sup. 1 e6-25 Sup. 1

86-t8

"-tJ

t6-U6

86-85 Requests To Dispose Of Very

11/3/66 Low-Level Radioactive Waste

Pursuant to 10 CFR 20 302

Uncontrolled Rod Vlthdrawel

10/16/t6

Because Of A Single Failure

Rain Ste

Safety Valve Test

10/16/86

Failures And Ring Setting

Adjustments

Traceability And Material

10/15/U6

Control of Material And

Equipment, Particularly

Fasteners

Compensatory measures For

10/15/U6

Prolonged Periods Of Security

System Failures

Loss Ot Offsite Power Upon An 10/10/86

Automatic tus Transfer

Clarification Of Requirements 10/10/t6

For Fabrication And Export Of

Certain Previously Approved

Type t Packages

Enforcement Actions Against

10/3/86

Medical Licensees For

Willfull Failure To Report

i satdmisistrations

All power reactor

facilities holding

an OL or CP

All WR facilities

holding an OL or CP

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP; fuel

fabrication and

processing facilities

All power reactor

fpcilities holding

an OL or CP

All registered users

of NRC certif ied

packages

All NRC medical

IIcensees

OL a Operating License

CP a Construction Permit

UNITED STATES

NUCLEAR REGULATORY COMMISSION

WASHINGTON, D.C. 20555

OFFICIAL BUSINESS

PENALTY FOR PRIVATE USE. *300

FIRST CLASS MAIL

POSTAGE 6 FEES PASO

USNRC

WASH O.C.

PERMIT No G47

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