Information Notice 1989-66, Qualification Life of Solenoid Valves

Qualification Life of Solenoid Valves

ML031180742
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, Three Mile Island, 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
Issue date:	09/11/1989
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-89-066, NUDOCS 8909060284
Download: ML031180742 (6)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 September 11, 1989 NRC INFORMATION NOTICE NO. 89-66: QUALIFICATION LIFE OF SOLENOID VALVES

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

This information notice is being provided to alert addressees to a potential

problem, resulting from a common-mode failure, that may affect the operability

of main steam line isolation valves or similarly designed components. The

problem relates to control solenoid valves whose elastomer discs (seats) are

exposed to temperatures higher than originally assumed in calculating their

qualified life and which may be presently in service beyond their actual

qualified service life. It is expected that recipients will review the

information for applicability to their facilities and consider actions, as

appropriate, to avoid similar problems. However, suggestions contained in

this information notice do not constitute NRC requirements; therefore, no

-specific action-or written response is required.

Description of Circumstances

Following a reactor trip in August 1989, the operators of Grand Gulf Unit 1 closed the main steam line isolation valves (MSIVs) manually. However, they

observed that one outboard MSIV did not close until more than 15 minutes after

a subsequent automatic closure set point (low vacuum) was reached. Upon

investigating the event, the licensee found a piece of the elastomer seat

from the solenoid valve used for control of that MSIV on an outlet screen.

The licensee concluded that the piece had been lodged in the solenoid valve

internals, thereby keeping the solenoid valve from venting control air and

hence keeping the MSIV from closing. It is believed that after the piece of

elastomer became dislodged from the internals, the MSIV closed.

Subsequent inspections by the licensee of all eight dual-coil solenoid valves

piloting the MSIVs disclosed that all eight solenoid valves had degraded seats.

Initial visual inspection did not reveal the degradations. However, the degra- dations became apparent under microscopic examination. The EPDM (ethylene

propylene dimer) seats of all eight solenoid operated valves had cracking.

However, on six of them, the raised portion of the seat formed by the annular

8909060284 ZAo

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IN 89-66 September 11, 1989 impression made in the seat by the exhaust port was missing. Thus, it appears

as if six of the eight solenoid valves had experienced similar sloughing of

material from the seat. This had been sufficient to prevent one of the solenoid

valves from operating properly, thereby preventing the MSIV from operating

properly.

The solenoid valves in question are dual-coil solenoid valves manufactured by

Automatic Switch Co. (ASCO Model NP8323). In 1985, the Grand Gulf licensee

calculated the qualified life of these valves with EPDM seats using single-coil

heatup data. The resultant qualified life was calculated at 5.9 years on

inboard MSIVs. After the recent event, the licensee repeated the qualification

calculations using heatup data for dual-coil solenoids (which became available

in 1987) and estimated the life to be about 2.9 years. These solenoid valves

had been in service for about 4.5 years.

Recent qualification calculations by the Perry licensee for their solenoid

valves, which have operating conditions similar to those at Grand Gulf, found

that NP8323 solenoid valves with Viton seats on the inboard MSIVs have an

estimated service life of about two years. These solenoid operated valves

are routinely changed every refueling outage at Perry.

Discussion:

A number-of operab1+-ty-problems-have-been-associated-with-the-dual-coi- solenoid- valve Model NP8323 manufactured by ASCO. Information Notice No. 88-43, "Solenoid

Valve Problems," dated June 23, 1988, identifies older generic communications and

describes potential common-mode failure mechanisms, for example, contamination, thermal degradation of the elastomer, sticky material, and deficient maintenance.

ASCO issued a service bulletin dated May 23, 1989, which stated that rebuilding

kits for the NNPN series valves were being discontinued. ASCO has also recently

indicated that it plans to phase out the NP8323 solenoid valve and that two NP8320

nuclear qualified single-coil solenoid operated valves connected in series may be

an acceptable substitute.

Since better and more recent temperature information is now available, it is

important to note that the calculated maximum service period data supplied with

solenoid valves used at both boiling water reactors and pressurized water reactors

may be based on temperatures at the elastomer seat that are too low. Therefore, the calculated service life may be in error. Temperatures in the vicinity of

the elastomer seat are dependent upon the plant-specific ambient temperatures, localized hot spot heat sources, and heat input from the solenoid coils during

the time the solenoids are energized. A temperature rise of about 100 0 F above

ambient temperature could be expected in the vicinity of the seat with the dual

solenoid coils energized. ASCO has temperature profile data available for various

solenoid valve designs. The temperature profile data vary for different solenoid

valves under different operating conditions.

IN 89-66 September 11, 1989 In a service bulletin dated April 12, 1988, ASCO stated that it had no evidence

of elastomer degradation when Viton was used. General Electric Company issued

SIL No. 481, dated February 14, 1989, which recommended that the elastomer be

changed from EPDM to Viton. Regardless of the material used, the qualified

life will be adversely affected by higher temperatures and may be significantly

less than the initially determined qualified life and possibly even less than

the actual operating time.

MSIVs are subject to different testing and surveillance requirements. Some

licensees test MSIYs for operability once each quarter and others may use special

slow-closing testing techniques such as that described in IN 88-43. Regardless

of the testing or frequency, the MSIVs may be susceptible to a common mode of

failure which could disable both MSIVs in a steam line. This failure, in itself, would not cause a significant accident; however, should the MSIV failures occur

in conjunction with a steam line break, radioactivity released to the public

could result in doses in excess of the guidelines of 10 CFR Part 100.

This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact one

of the technical contacts listed below or the appropriate NRR project manager.

- ~- -.-

A  ; ~t,'t- 7..- ~ -

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: J. Carter, NRR

(301) 492-1194 H. Ornstein, AEOD

(301) 492-4439 Attachment: List of Recently Issued NRC Information Notices

""Attschmsnt

IN 89-66 September 11, 1989 Pago I of I

LIST OF RECENTLY ISSUED

NRCINFORMATION NOTICES

InTor05atlon uate oT

Notice No. Subject Issuance Issued to

88-46. Licensee Report of 9/11/89 All holders of OLs

Supp. 4 Defective Refurbished or CPs for nuclear

Circuit Breakers power reactors.

89-65 Potential for Stress 9/8/89 All holders of OLs

Corrosion Cracking in or CPs for PWRs.

Steam Generator Tube

Plugs Supplied by

Babcock and Wilcox

89-64 Electrical Bus Bar Failures 9/7/89 All holders of OLs

or CPs for nuclear

power reactors.

89-63 Possible Submergence of 9/5/89 All holders of OLs

Electrical Circuits Located or CPs for nuclear

Above the Flood Level Because power reactors.

of Water Intrusion and Lack

of Drainage

89-62 Malfunction of Borg-Warner 8/31/89 All holders of OLs

Pressure Seal Bonnet Check or CPs for nuclear

Valves Caused By Vertical power reactors.

Misalignment of Disk

89-61 Failure of Borg-Warner Gate 8/30/89 All holders of OLs

Valves to Close Against or CPs for nuclear

Differential Pressure power reactors.

88-48, Licensee Report of Defective 8/22/89 All holders of OLs

Supp. 2 Refurbished Valves or CPs for nuclear

power reactors.

89-60 Maintenance of Teletherapy 8/18/89 All NRCMedical

Units Teletherapy Licensees.

89-59 Suppliers of Potentially 8/16/89 All holders of OLs

Misrepresented Fasteners or CPs for nuclear

powerreiactors.

OL - Operating License

CP* Construction Permit

UNITED STATES

NUCLEAR REGULATORY COMMISSION FIRST CLASS MAIL

POSTAGE & FEES PAID

WASHINGTON, D.C. 20555 USMNC

PERMIT No. con7 OFFICIAL BUSINESS

PENALTY FOR PRIVATE USE, $300

- =

IN 89-66 September 11, 1989 In a service bulletin dated April 12, 1988, ASCO stated that it had no evidence

of elastomer degradation when Viton was used. General Electric Company issued

SIL No. 481, dated February 14, 1989, which recommended that the elastomer be

changed from EPDM to Viton. Regardless of the material used, the qualified

life will be adversely affected by higher temperatures and may be significantly

less than the initially determined qualified life and possibly even less than

the actual operating time.

MSIVs are subject to different testing and surveillance requirements. Some

licensees test MSIVs for operability once each quarter and others may use special

slow-closing testing techniques such as that described in IN 88-43. Regardless

of the testing or frequency, the MSIVs may be susceptible to a common mode of

failure which could disable both MSIVs in a steam line. This failure, in itself, would not cause a significant accident; however, should the MSIV failures occur

in conjunction with a steam line break, radioactivity released to the public

could result in doses in excess of the guidelines of 10 CFR Part 100.

This information notice requires no specific action or written response. If

you have any questions about the information inthis notice, please contact one

of the technical contacts listed below or the appropriate NRR project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: J. Carter, NRR

(301) 492-1194 H. Ornstein, AEOD

(301) 492-4439 Attachment: List of Recently Issued NRC Information Notices

• SEE PREVIOUS PAGE FOR CONCURRENCE

• Tech Ed

RSanders

8/30/89

• EAB:DOEA:NRR *EAB:DOEA:NRR *C:EAB:DOEA:NRR*C:OGCB:DOEA:NRR *AEOD

TJCarter PBaranowsky CHaughney CHBerlinger HOrnstein gss A,-

CERos

9/5/89 9/5/89 9/6/89 9/6/89 9/5/89 9/4 /89

IN 89- September , 1989 Page 3 of

In a service bulletin dated April 12, 1988, ASCO stated that it had no evidence

of elastomer degradation when Viton was used. General Electric Company issued

SIL No. 481, dated February 14, 1989, which recommended that the elastomer be

changed from EPDf4 to Viton. Regardless of the material used, the qualified

life will be adversely affected by higher temperatures and may be significantly

less than the initially determined qualified life and possibly even less than

the actual operating time.

MSIVs are subject to different testing and surveillance requirements. Some

licensees test MSIVs for operability once each quarter and others may use special

slow-closing testing techniques such as that described in IN 88-43. Regardless

of the testing or frequency, the MSIVs may be susceptible to a common mode of

failure which could disable both MSIVs in a steam line. This failure, in itself, would not cause a significant accident; however, should the MSIV failures occur

in conjunction with a steam line break, radioactivity released to the public

could result in doses in excess of the guidelines of 10 CFR Part 100.

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

If you have any questions about this matter, please contact one of the technical

contacts listed below or the Regional Administrator of the appropriate regional

office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: J. Carter, NRR

(301) 492-1194 H. Ornstein, AEOD

(301) 492-4439 Attachment: List of Recently Issued NRC Information Notices

EA:OEA:NRR EAADOEA:NRR C:E EAC: NRR D:DOEA:NRR

TJCa ter PBaranowsky CHaughney CERossi

9/7 /89 9/ 1/89 9/( /89 9/ /89