View source for Information Notice 1994-08, Potential for Surveillance Testing to Fail to Detect an Inoperable Main Steam Isolation Valve

{{Adams
| number = ML031070034
| issue date = 02/01/1994
| title = Potential for Surveillance Testing to Fail to Detect an Inoperable Main Steam Isolation Valve
| author name = Grimes B
| author affiliation = NRC/NRR
| addressee name = 
| addressee affiliation = 
| docket = 05000003, 05000010, 05000029, 05000133, 05000155, 05000171, 05000206, 05000213, 05000219, 05000220, 05000237, 05000244, 05000245, 05000247, 05000249, 05000250, 05000251, 05000254, 05000255, 05000259, 05000260, 05000261, 05000263, 05000265, 05000266, 05000267, 05000269, 05000270, 05000271, 05000272, 05000275, 05000277, 05000278, 05000280, 05000281, 05000282, 05000285, 05000286, 05000287, 05000289, 05000293, 05000295, 05000296, 05000298, 05000301, 05000302, 05000304, 05000305, 05000306, 05000309, 05000311, 05000312, 05000313, 05000315, 05000316, 05000317, 05000318, 05000320, 05000321, 05000322, 05000323, 05000324, 05000325, 05000327, 05000328, 05000329, 05000330, 05000331, 05000333, 05000334, 05000335, 05000336, 05000338, 05000339, 05000341, 05000344, 05000346, 05000348, 05000352, 05000353, 05000354, 05000361, 05000362, 05000364, 05000366, 05000368, 05000369, 05000370, 05000373, 05000374, 05000382, 05000387, 05000388, 05000389, 05000390, 05000391, 05000395, 05000397, 05000400, 05000409, 05000410, 05000412, 05000413, 05000414, 05000416, 05000423, 05000424, 05000425, 05000437, 05000438, 05000439, 05000440, 05000441, 05000443, 05000444, 05000445, 05000446, 05000454, 05000455, 05000456, 05000457, 05000458, 05000461, 05000482, 05000483, 05000498, 05000499, 05000508, 05000528, 05000529, 05000530
| license number = 
| contact person = 
| document report number = IN-94-008, NUDOCS 9401260242
| document type = NRC Information Notice
| page count = 10
}}
{{#Wiki_filter:UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 February 1, 1994 NRC INFORMATION NOTICE 94-08:    POTENTIAL FOR SURVEILLANCE TESTING TO FAIL

TO DETECT AN INOPERABLE MAIN STEAM ISOLATION

VALVE

==Addressees==
All holders of operating licenses or construction permits for nuclear power

reactors.

PurDose

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

notice (IN)to alert addressees to a potential for surveillance testing to

fail to detect that a main steam isolation valve is mechanically bound and

will not close. 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.

DescriDtion of Circumstances

On April 19, 1993, while performing maintenance to repair a presumed faulty

limit switch on a main steam isolation valve, the licensee for the River Bend

Station (River Bend) found that the valve was mechanically bound and would not

close as required. The valve is a 24-inch-diameter (nominal), spring and

pneumatic closing, pneumatic-opening, internally balanced, poppet-type globe

valve manufactured by the Atwood & Morrill Company Inc. Plant operators had

previously performed partial stroke surveillance testing of the valve on

February 27 and April 1, 1993, but did not detect that the valve would not

close. The licensee later determined that the testing failed to detect that

the valve was inoperable because the test did not adequately consider the

design of the valve and the positioning of the limit switch arm in relation to

the valve poppet travel.

The licensee determined that the valve would not close because improper

clearances between the valve poppet and the valve body had caused excessive

wear of the guide ribs and resulted in the valve poppet becoming mechanically

bound. The excessive wear may have been avoided had the licensee installed an

anti-rotation modification recommended by the manufacturer in 1989.

Subsequent to this event, the manufacturer reported the failure to close to

the NRC under Part 21 to Title 10 of the Code of Federal Regulations and

informed affected licensees of the failure mechanism and recommended actions

to prevent recurrence. NRC Inspection Report 50-458/93-18 and Licensee Event

Report.93-006 provide additional details on the valve failure.

(9401260242)                                                            TJ'O

02 w>        44M'j                       J7JD#V&//c/S

*                                                              '(I

YJ                              Kx/ IN 94-08 February 1, 1994 Discussion

The original design positioning of the limit switches was such that, during

partial stroke testing, the limit switches could be actuated and indicate

movement of the main valve poppet even though the valve poppet had not

actually moved. Thus, a failure of the valve to properly stroke may go

undetected by partial stroke testing.

Under normal operation, the valve stem travels 28 centimeters [11 inches] to

fully stroke in either direction. As the valve strokes open, the first

2.5 centimeters [1 inch) of stem travel moves an internal poppet which opens

an equalizing port allowing the pressure on both sides of the main poppet to

equalize. During the remainder of the open stroke, the internal poppet lifts

the main poppet and retracts it to the fully open position. During a partial

stroke test in the close direction, as the stem (and the internal poppet)
begins to close, the main poppet also begins to close because of gravity.

However, during the event, with the main poppet stuck in the open position, the stem travelled about 2.5 centimeters [I inch] and stopped when the

internal poppet seated in the equalizing port.

There are three limit switches on the valve that are of concern in this event.

The first two switches provide a safety-related signal to the reactor

protection system that the valve is 92 percent open. The third switch sends a

nonsafety-related signal to position indicating lights in the control room

indicating that the valve is 90 percent open. The licensee had set the

90-percent-open limit switch such that stem movement of about 2.8 centimeters

[1.1 inch] was required to actuate the switch and indicate that the main valve

poppet had moved to the 90-percent-open position. However, because the limit

switches are set with a + 2 percent tolerance, actual stem travel to actuate

the 90-percent-open limit switch may be only 2.25 centimeters [0.88 inch]. In

a worst-case scenario both the 92- and the 90-percent-open limit switches

could be actuated without the main valve poppet moving.

During the partial stroke testing conducted on February 7 and April 1, the

first two limit switches (92-percent-open indication) actuated, the third

limit switch (90-percent-open indication) did not actuate. Although the

procedural step called for receipt of the 90-percent-open indication, the

operators did not declare the valve inoperable because the first two limit

switches had actuated and they assumed that the third limit switch (nonsafety)
had failed. Later, on April 17, during maintenance on the presumed faulty

limit switch, the licensee found that the main valve poppet was mechanically

bound and that the valve would not close.

The licensee for River Bend changed the third limit switch setting to actuate

at 85 percent of the open position to ensure that its actuation during partial

stroke testing would give positive indication of poppet movement. Pending

further evaluation of these valves during the next refueling outage, the

licensee is performing full stroke testing of the valves on a quarterly basis

and intends to install the anti-rotation modification recommended by the

vendor to prevent recurrence of the excessive wear of the valve guides. Also, operations personnel have been trained on the operation and function of the

limit switches.

--- IN 94-08 February 1, 1994 The valve described in this notice is used in safety-related applications at

nuclear facilities. One such application is as a main steam isolation valve.

At River Bend and most domestic boiling water reactors, there are two main

steam isolation valves for each main steam line; an inboard valve, located

inside the drywell, and an outboard valve, located Just outside the primary

containment. After a design-basis accident, these valves are required to

close and remain closed for 1 hour. Should these valves fail to close, offsite dose limits could be exceeded. A similar failure of a main steam

isolation valve to close had occurred at a foreign boiling water reactor.

The potential for limit switch positioning to adversely affect surveillance

test accuracy may exist for valves other than that described in this notice.

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 persons listed below or the appropriate Office of Nuclear Reactor

Regulation (NRR) project manager.                                      by

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts:  Thomas F. Westerman, RIV      Patricia Campbell, NRR

(817) 860-8145                (301) 504-1311 David P. Loveless, RIV        William M. McNeill, RIV

(512) 972-2507                (817) 860-8174 Attachment:

===List of Recently Issued NRC Information Notices===

v-" IN 94-08 February 1, 1994 The valve described in this notice is used in safety-related applications at

nuclear facilities. One such application is as a main steam isolation valve.

At River Bend and most domestic boiling water reactors, there are two main

steam isolation valves for each main steam line; an inboard valve, located

inside the drywell, and an outboard valve, located Just outside the primary

containment. After a design-basis accident, these valves are required to

close and remain closed for 1 hour. Should these valves fail to close, offsite dose limits could be exceeded. A similar failure of a main steam

isolation valve to close had occurred at a foreign boiling water reactor.

The potential for limit switch positioning to adversely affect surveillance

test accuracy may exist for valves other than that described in this notice.

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 persons listed below or the appropriate Office of Nuclear Reactor

Regulation (NRR) project manager.                      Original t1gnad b

Brian K. Grimes

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts:    Thomas F. Westerman, RIV        Patricia Campbell, NRR

(817) 860-8145                  (301) 504-1311 David P. Loveless, RIV          William M. McNeill, RIV

(512) 972-2507                   (817) 860-8174 Attachment:

===List of Recently Issued NRC Information Notices===
*SEE PREVIOUS CONCURRENCE

OFFICE       RPB:ADM     EMEB:DE:NRR    C/EMEB:DE:NRR     PDIV-2 NAME         RSanders*   PCampbell*     JNorberg*         EBaker*
  DATE         11/18/93    12/21/93       12/22/93          12/27/93 REGION IV    REGION IV     C/ES:RIV        DD/DRS:RIV     D/DRS:RIV

WMcNeill*    DLoveless*    TWesterman*     AHowell*       SCollins*
  12/27/93    01/03/94      01/03/94        01/03/94       01/04/94 of

OIP/NA/Per _ OGCB:DORS:NRR        C/OGCB:DORS:NRR     D

KHenderson*     JBirmingham*      GHMarcus*                  Wg9
01/06/94        01/10/94          01/10/94            01/Z7/94 OFFICIAL DOCUMENT NAME:    94-08. IN

IN 94-xx

January xx, 1994 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 persons listed below or the appropriate Office of Nuclear Reactor

Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts:
Thomas F. Westerman, Region IV         Patricia Campbell, NRR

(817) 860-8145                         (301) 504-1311 David P. Loveless, Region IV           William M. McNeill, Region IV

(512) 972-2507                         (817) 860-8174 Attachment:

===List of Recently Issued NRC Information Notices===
*SEE PREVIOUS CONCURRENCE

OFFICE      RPB:ADM      EMEB:DE:NRR lC/EMEB:DE:NRR      PDIV-2 NAME        RSanders*    PCampbell*      JNorberg*       EBaker*
  DATE         11/18/93    12/21/93      l12/22/93         12/27/93 REGION IV [REGION IV       C/ES:RIV         DD/DRS:RIV lD/DRS:RIV

WMcNeill*   DLoveless*     TWesterman*      AHowell*     SCollins*
12/27/93    01/03/94       01/03/94         01/03/94     01/04/94 OIP/NA/Per

KHenderson*
01/06/94 OGCB:DORS:NRR

JBirmingham*
                 01/10/94 IC/OGCB:DORS:NRR

GHMarcus

01/10/94 D/DORS:NRR (
                                                        BKGrimes

01/ /94 I

OFFICIAL DOCUMENT NAME:   ATWOODIN.JLBA

IN 94-xx

January xx, 1994 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 persons listed below or the appropriate Office of Nuclear Reactor

Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts:
Thomas F. Westerman, Region IV        Patricia Campbell, NRR

(817) 860-8145                        (301) 504-1311 David P. Loveless, Region IV          William M. McNeill, Region IV

(512) 972-2507                        (817) 860-8174 Attachment:

===List of Recently Issued NRC Information Notices===
*SEE PREVIOUS CONCURRENCE

OFFICE      RPB:ADM     EMEB:DE:NRR    C/EMEB:DE:NRR    PDIV-2 NAME        RSanders*   PCampbell*     JNorberg*        EBaker*
  DATE        11/18/93    12/21/93        12/22/93        12/27/93 REGIONY,      EG10   YVI C/ES:RI ee       DD/DR       ' D/DRS:R    ' ,,20d

'7--
WM6N                      Tte 'ste a     nAH &i'        SColl I i 12+
  12/27/93   01/03/94      01/03/94        01/03/94      01/04/94 OIP/NA er      OGCB: DORS:NK,    C/OGCB:DORS:NRR     D/DORS:NRR

KHen6'ri&#xb6;"'1 JBI rminghar       GHMarcus            BKGrimes

01/06/94      101//0/94          01/   /94           01/    /94 OFFICIAL DOCUMENT NAME:   ATWOODIN.JLB

IN 93-xx

January x, 1993 stroke testing would give positive indication of poppet movement. Pending

further evaluation of these valves during the next refueling outage, the

licensee is performing full stroke testing of the valves on a quarterly basis

and is considering installing the anti-rotation modification recommended by

the vendor to prevent recurrence of the excessive wear of the valve guides.

Also, operations personnel have been trained on the operation and function of

the limit switches.

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 persons listed below or the appropriate Office of Nuclear Reactor

Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts:
Thomas F. Westerman, Region IV                   Patricia Campbell, NRR

(817) 860-8145                                   (301) 504-1311 David P. Loveless, Region IV                     William M. McNeill, Region IV

(512) 972-2507                                   (817) 860-8174 Attachment:

===List of Recently Issued NRC Information Notices===
*SEE PREVIOUS CONCURRENCES

OFFICE     EMEB:DE:NRR          C100AWR               PDIV-2 NAME       PCampbel

__JN___rg__       _ I

DATE       12/AI/93             12/1ZI93              12/27/93         I

OFFICE   }jGIONI                REGION IV           [REGION IV         F

NAME

_McNeil                f'       DLoveless            TWesterman

DATE      12A_7/93____          12/   /93            12/ /93            12/   /93 OFFICE     RPB:ADM              OGCB:DORS:NRR         C/OGCB:DORS:NRR    D/DORS:NRR

NAME       RSanders*            JBirmingham           GHMarcus           BKGrimes

DATE       11/18/93             12/ /93               12/ /93            12/  /93 A.F IC A _U U L l NAME:  .' R                  LI._.^
                              L ,A~wu v r. . .J_.

===M FIGIAL DOUMEN                  AMUMOIN.JLB===

IN 93-xx

January x, 1993 stroke testing would give positive indication of poppet movement. Pending

further evaluation of these valves during the next refueling outage, the

licensee is performing full stroke testing of the valves on a quarterly basis

and is considering installing the anti-rotation modification recommended by

the vendor to prevent recurrence of the excessive wear of the valve guides.

Also, operations personnel have been trained on the operation and function of

the limit switches.

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 persons listed below or the appropriate Office of Nuclear Reactor

Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts:
Thomas F. Westerman, Region IV       Patricia Campbell, NRR

(817) 860-8145                       (301) 504-1311 David P. Loveless, Region IV         William M. McNeill, Region IV

(512) 972-2507                       (817) 860-8174 Attachment:

===List of Recently Issued NRC Information Notices===
*SEE PREVIOUS CONCURRENCES

OFFICE     EMEB:DE:NRR   C/EMEB:DE:NRR    PDIV-2 NAME       PCampbell     JNorberg       I

DATE       12/   /93     12/  /93       I 12/   /93 OFFICE    REGION IV      REGION IV       REGION IV

NAME      WMcNeill       DLoveless       TWesterman

DATE      12/   /93      12/  /93        12/   /93        12/   /93 OFFICE     R1B:Ap    L   OGCB:DORS:NRR    C/OGCB:DORS:NRR  D/DORS:NRR

NAME       RSanders      JBirmingham      GHMarcus         BKGrimes

DATE       11/18/93      12/  /93         12/   /93        12/  /93 OFFICIAL DOCUMENT NAME:  ATWOODIN.JLH

Atta -ement, IN 94-08 February 1, 1994 Page I of 1 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information                                   Date of

Notice No.              Subject                Issuance   Issued to

93-26,          Grease Solidification          01/31/94   All holders of OLs or CPs

Supp. 1         Causes Molded-Case                        for nuclear power reactors.

Circuit Breaker Failure

to Close

94-07           Solubility Criteria for        01/28/94   All byproduct material and

Liquid Effluent Releases                  fuel cycle licensees with

to Sanitary Sewerage Under                the exception of licensees

the Revised 10 CFR Part 20                authorized solely for

sealed sources.

94-06           Potential Failure of           01/28/94   All holders of OLs or CPs

Long-Term Emergency                       for boiling water reactors.

Nitrogen Supply for the

Automatic Depressurization

System Valves

93-85,          Problems with X-Relays         01/20/94   All holders of OLs or CPs

Rev. 1          in DB- and DHP-Type                       for nuclear power reactors.

Circuit Breakers Manu- factured by Westinghouse

94-05           Potential Failure of           01/19/94   All holders of OLs or CPs

Steam Generator Tubes                     for pressurized water

with Kinetically Welded                   reactors (PWRs).

Sleeves

94-04           Digital Integrated             01/14/94   All NRC licensees except

Circuit Sockets with                      licensed operators.

Intermittent Contact

94-03           Deficiencies Identified        01/11/94   All holders of OLs or CPs

during Service Water System               for nuclear power reactors.

Operational Performance

Inspections

94-02            Inoperability of General      01/07/94   All holders of OLs or CPs

Electric Magne-Blast                      for nuclear power reactors.

Breaker Because of Mis- alignment of Close-Latch

Spring

OL  = Operating License

CP  = Construction Permit

K-'                                   xJ     IN94-08 February 1, 1994 The valve described in this notice is used in safety-related applications at

nuclear facilities. One such application is as a main steam isolation valve.

At River Bend and most domestic boiling water reactors, there are two main

steam isolation valves for each main steam line; an inboard valve, located

inside the drywell, and an outboard valve, located Just outside the primary

containment. After a design-basis accident, these valves are required to

close and remain closed for 1 hour. Should these valves fail to close, offsite dose limits could be exceeded. A similar failure of a main steam

isolation valve to close had occurred at a foreign boiling water reactor.

The potential for limit switch positioning to adversely affect surveillance

test accuracy may exist for valves other than that described in this notice.

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 persons listed below or the appropriate Office of Nuclear Reactor

Regulation (NRR) project manager.                       Original igned Iy

Brian K. Grimes

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts:    Thomas F. Westerman, RIV         Patricia Campbell, NRR

(817) 860-8145                   (301) 504-1311 David P. Loveless, RIV           William M. McNeill, RIV

(512) 972-2507                    (817) 860-8174 Attachment:

===List of Recently Issued NRC Information Notices===
*SEE PREVIOUS CONCURRENCE

OFFICE       RPB:ADM     [EMEB:DE:NRR lC/EMEB:DE:NRR l PDIV-2 NAME         RSanders*    PCampbell*     JNorberg*         EBaker*
  DATE         11/18/93     12/21/93       12/22/93          12/27/93 REGION IV   REGION IV      C/ES:RIV        DD/DRS:RIV     D/DRS:RIV

WMcNeill*   DLoveless*     TWesterman*     AHowell*       SCollins*
  12/27/93    01/03/94       01/03/94        01/03/94       01/04/94     do

OIP/NA/Per      OGCB:DORS:NRR      C/OGCB:DORS:NRR

KHenderson*    JBirmingham*       GHMarcus*
  01/06/94       01/10/94           01/10/94            0 1/Z7/94 OFFICIAL DOCUMENT NAME:     94-08.IN}}

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