Information Notice 1989-49, Failure to Close Service Water Cross-Connect Isolation Valves

Failure to Close Service Water Cross-Connect Isolation Valves

ML031180653
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:	05/22/1989
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-89-049, NUDOCS 8905160204
Download: ML031180653 (12)

'4-1 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 May 22, 1989 NRC'INFORMATION NOTICE NO. 89-49: FAILURE TO CLOSE SERVICE WATER CROSS-

CONNECT ISOLATION 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 potential

problems that may result from failure to close isolation valves in service

water system loop cross-connect piping during certain scenarios. It is

expected that recipients will review the information for applicability to

their facilities an'd 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

While. Nine Mile Point Unit 2 was shutdown in October 1988 for refueling, the licensee reviewed the control logic which actuates certain service

water valves which are used to isolate redundant loopsof service water.

It'was determined that a loss-of-offsite power with a single failure. (i.e.,

failure to start one of two diesel generators), could lead to loss of the

operating diesel generator, due to inadequate cooling water flow from the

service water system.

The service water system at Nine Mile Point Unit 2 consists of two cross- connected and redundant cooling loops (divisions), each with service water

pumps and various loads, including a diesel generator. (A third diesel

generator dedicated to high-pressure core spray takes cooling water from

either loop, but it does not provide emergency ac power for any other

function.) During normal operation, the isolation valves in the cross- connect piping are open so that any combination of service water pumps

may be used to provide cooling water to all loads. In response to a

loss-of-offsite power, the isolation valves should close so that each

loop will operate independently of the other. With a loss-of-offsite

8905160204'

-

IN 89-49 May 22, 1989 power, the control logic would ensure that closure of-the isolation valves- would occur after power is restored from either offstte-sources or the;

diesel generators.' However, if one of the diesel generators fails to

operate, power would be supplied to only one ESF division. -

The design deficiency in the control logic involved the need for power to

actually exist on ESF buses,.in both divisions for either of two isolation

valves to close. Therefore, the isolation valves would not close when there

was a loss-of-offsite power and the failure of one diesel generator. With the

valves open the cooling water flow provided by a single service water pump.

associated with the operable diesel generator would be distributed to-all

loads in both loops. As .aresult, itwas postulated that with open valves

in the cross-connect piping, there would be inadequate cooling water flow---

inthe service water loop with the operable diesel generator, and that diesel

generator would probably fail due to overheating. The control logic design

deficiency has existed since the plant was initially constructed and the:';

licensee's pre-operational routine surveillance and post.maintenance/

modification testing did not detect the design deficiency. The licensee

subsequently made changes' to the control logic that eliminated the single

failure deficiency. '

The licensee for the Cooper Nuclear Station was concerned about having an ade- quate flow of servitcewater to essential loads following a loss-of-coolant

-accident 'iven-a loss-of-offsite- power and -the-failure-of-the- number-l1-iesal

-

generator to start. Without power from this diesel generator, the single

motor operated block valve which would automatically close to isolate non- essential loads from the essential loads would fafl'to close. Without valve

closure, there may be inadequate.flow to the essential service water loads

and a 'Single service water pump could Se operating in a runout condition.

This problem was identified during the construction and licensing phase, but station-procedures we're not modified adeqouately to mitigate the concern

over pump-runout with a potential'for loss of flow. The licensee modified

procedures to assure that reactor operators take steps to close another valve

in the cross-connect piping that would isolate the nonessential loads, there- by assuring adequate cooling water flow to essential loads, including the

operating diesel generator.

Discussion:

With the service water system 'cross-connect valve-closure problems as des cribed

above, the 'loss-of-offsite power and a single failure could result ina station

blackout. Because the potential consequences are significant, licensees have

evaluated possible improvements such as'reducing cooling water flow to non- essential components following a loss-of-offsite power event, changing the

control logic so that loop isolation occurs with power available to only one

division 'and clarifying procedures that specify corrective operator actions

to ensure that adequate service water flow to the essential components is

maintained.

IN 89-49 May 22, 1989 No specific action or written response is required by this information

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

technical contact listed below or the Regional Administrator of the

appropriate regional office.

I t . I

aeles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

J. Carter, NRR

(301) 492-1194 Attachment: List of Recently Issued NRC Information Notices

- . ..

Attachrtrt

IN 89-49 May 22, 1989 Page I of I

LIST OF RECENTLY ISSUED

NRCINFORIATION NOTICES

Information

NOtice No. Subject Date of

Issuance Issued 'to

89-4E Design Deficiency in the 5/22/89' All holders of OLs

Turbine-Driver. Auxiliary -or CPs for. nuclear

Feedwater Pump Coolinc

power reactors.

Water System

Potential Problems With 5/18/89 All holders of OLs

Worn or Distorted hose or CPs for nuclear

Clamps on Self-Contained power reactors and

Breathing Apparatus

fuel facilities.

Confidentiality cf 5/11/89 All holders of licenses

Exercise Scenarios

for fuel cycle facilities

and byproduct material

licensees having an

approved emergency

response plan.

89-45 Metalclad, Low-Voltage 5/8/89 All holders of OLs

Power Circuit Breakers or CPs-for nuclear

Refurbished with Sub- power reactors.

standard Parts

89-44 Hydrogen Storace on the 4/27/89 All holders of OLs

Roof of the Control Room 'Or CPs for' nuclear

power reactors.

88-82, Torus Shells with Corrosion 5/2/89 Supp. I All holders of OLs

and Degraded Coatings in or CPs for BWRs.

BWRContainments

B9-4 Permanent DWformation of 5/1/89 All holders of OLs

Torque Switch Helical or CPs for nuclear

Springs in Limitorque power reactors.

SMA-Type Motor Operators

88-97. Potentially Substandard 4/28/89 All holders of OLs

Supp. I Valve-Replacement Parts or CPs-for-nuclear

power reactors.

89-42 Failure of Rosemount 4/21/89 All holders of OLs

Models 1153 and 1154 or CPs for nuclear

Transmitters power reactors.

power reactors.

OL

• Operating License

CP

• Construction Pern;it

UNITED STATES

'NUCLEAR REGULATORY COMMISSION FIRST CLASS MAIL

POSTAGE & FEES PAID

WASHINGTON, D.C. 20555 USNRC

PERMIT No. 047 OFFICIAL BUSINESS

PENALTY FOR PRIVATE USE, $300

IN 89-49 May 22, 1989 No specific action or written response is required by this information

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

technical contact 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

J. Carter, NRR

(301) 492-1194 Attachment: List of Recently Issued NRC Information Notices

-

I

• SEE PREVIOUS CONCURRENCE

• EAB:NRR *EAB: NRR *TECH:ED *C:EAB:NRR *C:OGCB:NRR

JCarter:db PBaranowsky WDLanning CHBerlinger

5/12/89 5/2/89 / /89 5/8/89 5/12/89 5 //89

1989 No specific action or written response is required by this information

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

technical contact 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

J. Carter, NRR

(301) 492-1194 Attachment: List of Recently Issued NRC Information Notices

-

• SEE PREVIOUS CONCURRENCE

• bR *EAB:NRR *TECH:ED *C:EAB:NRR C:OGCB:NRR D:DOEA:NRR

J rter:db PBaranowsky WDLanning CHBerlinger CERossi

.C//2/89 / /89 / /89 / /89 .j1i.;q9 / /89

IN 89- May , 1989 The design deficiency in the control logic was that for either isolation

valve to close, power must actually exist on ESF buses in both divisions.

Therefore, the isolation valves would not close upon loss of offsite power and

the failure of one diesel generator. With the valves open the coolingdiesel water

flow provided by the service water pump associated with the operable

generator would be distributed to all loads in both loops. As a result, it

was postulated that with open valves in the cross-connect piping, there would

be inadequate cooling water flow in the service water loop with the operable

diesel generator, and that diesel generator would probably fail due to

overheating.

Discussion:

With the service water system cross-connect valve isolation logic as described

above, the loss of offsite power and a single failure could result in a

station blackout. Because the potential consequences of this design deficiency

are significant, the licensee is evaluating possible corrections, such as

reducing, cooling water flow to non-vitil components following a loss-of-power

event and changing the control logic so that loop isolation occurs with power

available to only one division. The control logic deficiency was present

since the plant was initially constructed. The licensee's pre-operational

routine surveillance and post maintenance/modification testing did not detect

the design deficiency.

No specific action or written response is required by this information

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

technical contact 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

J. Carter, NRR

(301) 492-1194 Attachment: List of Recently Issued NRC Information Notices

• SEE PREVIOUS PAGE FOR CONCURRENCE

• EAB:URR *EAB:KRR *TECH:ED C -t C:OGCB:NRR D:DOEA:NRR

JCarter:db PBaranowsky WDLanning CHBerlinger CERossi

5/1/89 5/2/89 5/ /89 5/6/89 5/ /89 5/ /89

IN 89- May , 1989 Page 3 of

No specific action or written response is required by this information

the

notice. If you have any questions about this matter, please contact

technical contact 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

J. Carter, NRR

(301) 492-1194 Attachment: List of Recently Issued NRC Information Notices

• YPRR EAB:NRR *TECH:ED C:EAB:NRR C:OGCB:NRR D:DOEA:NRR

Carter:db PBaranowsky WMLanning CHBerlinger CERossi

. / I/89 !5/89 / /89 / /89 / /89 / /89

IN 89-49 May 22, 1989 No specific action or written response is required by this information

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

technical contact 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

J. Carter, NRR

(301) 492-1194 Attachment: List of Recently Issued NRC.Information Notices

I

• SEE PREVIOUS CONCURRENCE

• EAB: NRR *EAB:NRR *TECH:ED *C:EAB:NRR *C:OGCB:NRR

JCarter:db PBaranowsky WDLanning CHBerlinger

5/12/89 5/2/89 / /89 5/8/89 5/12/89 DO

51/6/89

J1 89- t'.o , 1989 II S

No specific action or written response is required by this information

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

technical contact 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

J. Carter, NRR

(301) 492-1194 Attachment: List of Recently Issued NRC Information Notices

I' e

• SEE PREVIOUS CONCURRENCE (f)d4 T

• 4BNRR *EAB:NRR *TECH:ED *C:EAB:NRR C:OGCB:NRR D:DOEA:NRR

J3 arter:db PBaranowsky WDManning CHBerlinger CERoss i

r I/2/89 / /89 / /89 / /89 j /i.;89 / /89

IN 89- V

May , 1989 The design deficiency in the control logic was that for either isolation

valve to close, power must actually exist on ESF buses in both divisions.

Therefore, theisolation valves would not close upon loss of offsite power and

the failure of one diesel generator. With the valves open the cooling water

flow provided by the service water pump associated with the operable diesel

generator would be distributed to all loads In both loops. As a result, it

was postulated that with open valves in the cross-connect piping, there would

be inadequate cooling water flow in the service water loop with the operable

diesel generator, and that diesel generator would probably fail due to

overheating.

Discussion:

With the service water system cross-connect valve isolation logic as described

above, the loss of offsite power and a single failure could result in a

station blackout. Because the potential consequences of this design deficiency

are significant, the licensee is evaluating possible corrections, such as

,reducing cooling water flow to non-vital components following a loss-of-power

event and changing the control logic so that loop isolation occurs with power

available to only one division. The control logic deficiency was present

since the plant was initially constructed. The licensee's pre-operational

routine surveillance and post maintenance/modification testing did not detect

the design deficiency.

No specific action or written response is required by this Information

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

technical contact 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

J. Carter, NRR

(301) 492-1194 Attachment: List of Recently Issued NRC Information Notices

• SEE PREVIOUS PAGE FOR CONCURRENCE

• EAB:NRR *EAB.NPJM *TECH:ED C ( C:OGCB:NRR D:DOEA:NRR

JCarter:db PBaranowsky W tanning CHBerlinger CERossi

5/1/89 5/2/89 5/ /89 5/6 /89 5/ /89 5/ /89

N.

IN 89- May , 1989 Page 3 of

No specific action or written response is required by this information

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

technical contact 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

J. Carter, NRR

(301) 492-1194 attachment: List of Recently Issued NRC Information Notices

• IERR EAB:NRR *TECH:ED C:EAB:NRR C:OGCB: NRR D:DOEA:NRR

Carter:db PBaranowsky WDLanning CHBerlinger CERossi

1/ (f. /89 : /89 / /89 / /89 / /89 / /89