Information Notice 1992-15, Failure of Primary Systems Compression Fitting

Failure of Primary Systems Compression Fitting

ML031200596
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, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	02/24/1992
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-92-015, NUDOCS 9202190038
Download: ML031200596 (9)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 February 24, 1992 NRC INFORMATION NOTICE 92-15: FAILURE OF PRIMARY SYSTEM COMPRESSION FITTING

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice

to alert addressees to problems that could result from the inadequate installa- tion of compression fittings. 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 are not NRC requirements; therefore, no specific action or

written response is required.

Description of Circumstances

On November 23, 1991, operators at the Oconee Nuclear Station, Unit 3, detected

unidentified leakage of approximately 70 gallons per minute (gpm) from the

reactor coolant system (see licensee event report 50-287/91-008). The licensee

shut down the reactor in an orderly manner. The licensee observed a maximum

leak rate of approximately 130 gpm.and found that a total of 87,000 gallons of

reactor coolant was discharged to the containment before the reactor coolant

system could be depressurized. On November 25,1991, personnel entered the

Unit 3 containment building and determined that the source of the leak was a

separated compression fitting on a 3/4-inch diameter instrument line. The

instrument line is part of the reactor vessel level indication system (RYLIS).

The leak occurred where the line connects to the top of the "An steam generator

hot leg. The tubing separated from the fitting next to a 3/4-inch flow

restriction valve.

The licensee inspected the fitting and determined that the probable cause of

the tubing separating (or pulling out) was that the nut had not been suffi- ciently tightened onto the compression fitting. The nut on the fitting

appeared to have been tightened approximately 1/2 turn less than was recom- mended by the fitting manufacturer, the Parker-Hannifin Corporation. The gap

between the nut and the fitting was greater than the maximum nominal value

furnished by the vendor. The licensee inspected the tubing at the failed

fitting and determined that the diameter reduction at that location was much

less than the diameter reduction for the tubing in another fitting that had not

failed. Based on these inspections the licensee determined that the ferrule

9202190038 2).

t I/,:

IN 92-15 February 24, 1992 was not adequately compressed into the tubing. The licensee reconfigured the

instrument line and replaced the valve, the 3/4-inch instrument tubing, and the

fittings on the hot legs of both steam generators.

The licensee inspected all of the fittings on instrument tubing connected to

the Unit 3 primary system. The licensee examined the 264 Parker-Hannifin

fittings in the primary system using nominal expected gap values furnished by

Parker-Hannifin as an acceptance criteria. However, Parker-Hannifin does not

consider the gap to be a critical dimension. The licensee also inspected the

191 Swagelock fittings in the primary system using gap inspection gages fur- nished by Swagelock. The licensee found that approximately 27 percent of both

types of fittings appeared to have gaps outside of the nominal range. The

licensee attempted to tighten these fittings to reduce the gaps to the values

recommended by the manufacturers. However, a small percentage of the

Parker-Hannifin fittings could not be tightened to meet the vendor's nominal

gap values. The licensee accepted these fittings as-is based on the judgement

of the instrument technicians that the connections could not be tightened

further without damaging the tubing or connections, and on an engineering

evaluation made after disassembling and inspecting one of the questionable

fittings.

Discussion

This event reemphasizes the importance of making successful connections in

instrument tube lines. Fitting-nuts-on compression-fittings-must-be tightened- sufficiently to ensure that the fitting has been adequately seated. According

to the licensee, they have previously experienced problems with inadequate

assembly of 3/4-inch fittings due to the high torque required to properly seat

the fittings. The licensee's modifications to the RVLIS eliminated the use of

3/4-inch fittings on these lines.

While conducting inspections at other facilities, the NRC and licensees have

noted other problems with the installation of compression fittings, including

the following:

° Interchanging hardware from different manufacturers

o Installing the ferrules backwards in fittings, or omitting the ferrules

• Failing to bottom the tubing on the shoulder of the fitting

o Using tubing that is not cut square or that is burred, scratched, deformed, or contaminated with dirt, oil, or other contaminants

o Failing to adequately tighten the fitting to the finger-tight position

before making additional turns from the finger-tight position

o Failing to ensure that the tubing has not moved back out of the fitting

when the nut is tightened

These problems indicate that licensees' procedures for installing compression

fittings may not provide adequate guidance to avoid improper assembly of the

IN 92-15 February 24, 1992 fittings. Procedures may also fail to address the vendor's installation

recommendations, not only for the initial installation of connections, but also

for disconnecting and retightening fittings during normal maintenance activities.

In addition, personnel who make compression fitting connections may not be

adequately trained.

Related Generic Communications

The NRC staff has previously issued Information Notice 84-55 (including Supple- ment 1), "Seal Table Leaks at PMRs," to address problems associated with

compression fitting failures.

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 Office of Nuclear

Reactor Regulation (NRR) project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contacts: Joseph J. Lenahan, RII

(404) 331-4190

John R. Fair, NRR

(301) 504-2759 Attachment: List of Recently Issued NRC Information Notices

\ch ent

-'11192-15 February 24. 1992 Page I of I

LIST OF RECENTLYISSUED

NRCINFORMATION NOTICES

Information Date of

Notice ho. Subject Issuance Issued to

92-14 Uranium oxide Fires at Fuel 02/21/92 All fuel cycle and uranium

Cycle Facilities fuel research and development.

licensees.

92-02, Relap5/1od3 Computer Code 02/18/92 All holders of OLs or CPs

Supp. 1 Error Associated with the for nuclear power reactors.

Conservation of Energy

Equation

92-13 Inadequate Control Over 02/18/92 All holders of OLs or CPs

Vehicular Traffic at for nuclear power reactors.

Nuclear Power Plant Sites

92-12 Effects of Cable Leakage 02/10/92 All holders of OLs or CPs

Currents on Instrument TCArucatar power reactors.

Settings and Indications

92-11 Soil and Water Contamina- 02/05/92 All uranium fuel fabrica- tion at Fuel Cycle Facil- tion and conversion facil- ities ities..

92-10 Irachytherapy Incidents 01/31/92 All Nuclear Regulatory Cco.

Involving Iridium-192 Wire mission (NRC)licensees

Used In Endobronchial authorized to use

Treatments Iridium-192 for brachy- therapyl manufacturers and

distributors of irldium-192 wire for use in brachy- therapy.

92-09 Overloading and Subsequent 01/30/92 All holders of OLs or CPs

Lock Out of Electrical for nuclear power reactors.

Buses During Accident

Conditions

CL

• Operating License

CP

• Construction Permit

UNITED STATES

NUCLEAR REGULATORY COMMISSION MAGS D MUSPAID

WASHINGTON, D.C. 2055 USNRC

PERMIT No. 047 OFFICIAL BUSINESS

PENALTY FOR PRIVATE USE, $300

IN 92-15 February 24, 1992 fittings. Procedures may also fail to address the vendor's installation

recommendations, not only for the initial installation of connections, but also

for disconnecting and retightening fittings during normal maintenance activities.

In addition, personnel who make compression fitting connections may not be

adequately trained.

Related Generic Communications

The NRC staff has previously issued Information Notice 84-55 (including Supple- ment 1), "Seal Table Leaks at PWRs," to address problems associated with

compression fitting failures.

This information notice requires no specd fic action or written response. If

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

of the technical contacts listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contacts: Joseph J. Lenahan, RII

(404) 331-4190

John R. Fair, NRR

(301) 504-2759 Attachment: List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCES

D/,P.y4R *C/OGCB:DOEA:NRR *RPB:ADM *D/DET: NRR *C/EMEB:DET:NRR

C0 o5s,') CHBerlinger TechEd JERichardson JANorberg

0277491 02/13/92 01/30/92 02/12/92 02/11/92

• OCBtDOEA:N R*RII *RII *EMEB:DET:NRR *EMEB:DET:NRR

AJKugler JJLenahan AFGibson JRFair TLChan

01/31/92 02/06/92 02/06/92 02/11/92 02/11/92 DOCUMENT NAME: IN 92-15

IN 92-XX

February XX, 1992 fittings. These procedures may also fail to address the vendor's installation

recommendations, not only for the initial installation of connections, but also

the limitations in disconnecting and retightening fittings during normal

maintenance activities. In addition, the personnel who make the compression

fitting connections may not be adequately trained.

Related Generic Communications

The NRC staff has previously issued Information Notice 84-55 (including Supple- ment 1), "Seal Table Leaks at PWRs," that addressed problems associated with

compression fitting failures.

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 Office of Nuclear

Reactor Regulation (NRR) project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contacts: Joseph J. Lenahan, RII

(404) 331-4190

John R. Fair, NRR

(301) 504-2759 Attachment: List of Recently Issued NRC Information Notices

Document Name: COMPRESSION FITTING IN/2

• SEE PREVIOUS CONCURRENCEI

D/DOEA:NRR C/OGCB/ E RR*RPB:ADM *D/DET:NRR C/EMEB:DET:NRR

CERossi CHBerl~t'dr TechEd JERichardson JANorberg

02/ /92 02/1 j92 01/30/92 02/12/92 02/11/92

• OGCB:DOEA:NRR*RII *RI I *EMEB:DET:NRR *EMEB:DET:NRR

AJKugler JJLenahan AFGibson JRFair TLChan

01/31/92 02/06/92 02/06/92 02/11/92 02/11/92

IN 92-XX

February XX, 1992 Related Generic Communications

The NRC staff has previously issued Information Notice 84-55 (including

Supplement 1), "Seal Table Leaks at PWRK' that addressed problems associated

with compression fitting failures.

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 Office of

Nuclear Reactor Regulation project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: Joseph J. Lenahan, Region II

(404) 331-4190

John R. Fair, NRR

(301) 504-2759 Attachments:

1. List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCES

D/DOEA:NRR C/OGCB:DOEA:NRR *OGCB:DOEA:NRR *RPB:ADM

CERossi CHBerlinger AJKugler TechEd

2/ /92 2/ /92 1/31/92 1/30/92 / v

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2/ l /92 2/ i /92 2/1t /92

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JJLenahan AFGibson

2/6/92 2/6/92

IN 92-XX

February XX, 1992 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 Office of

Nuclear Reactor Regulation project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: Joseph J. Lenahan, Region II

(404) 331-4190

John R. Fair, NRR

(301) 504-2759 Attachments:

1. List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCES

D/DOEA:NRR C/OGCB:DOEA:NRR OGCB:DOEA:NRR *RPB:ADM

CERossi CHBerlinger AJKug lerIAK TechEd

2/ /92 2/ /92 1/'&t /92 1/30/92 EMEB:DET:NRR EMEB:DET:NRR C/EMEB:DET:NRR D/DET:NRR

JRFair TLChan JANorberg JERichardson

2/ /92 2/ /92 2/ /92 2/ /92 RII fi i: RII

JJLenahan AFGibso k"

2/ ( /92 2/6/92

IN 92-XX

February XX, 1992 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 Office of

Nuclear Reactor Regulation project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: Joseph J. Lenahan, Region II

(404) 331-4190

John R. Fair, NRR

(301) 504-2759 Attachments:

1. List of Recently Issued NRC Information Notices

D/DOEA:NRR C/OGCB:DOEA:NRR OGCB:DOEA:NRR RPB:AEC1 CERossi CHBerlinger AJKugler TechEd 11man 97

2/ /92 2/ /92 2/ /92

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EMEB:DET:NRR EMEB:DET:NRR C/EMEB:DET:NRR D/DET:NRR

JRFair TLChan JANorberg JERicharcison

2/ /92 2/ /92 2/ /92 2/ /92 RII RII

JJLenahan AFGibson

2/ /92 2/ /92