Information Notice 1993-38, Inadequate Testing of Engineered Safety Features Actuation Systems

Inadequate Testing of Engineered Safety Features Actuation Systems
	ML031080046
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:	05/24/1993
From:	Grimes B; Office of Nuclear Reactor Regulation
To:	;
References
	IN-93-038, NUDOCS 9305180426
	Download: ML031080046 (7)
	v • d • e

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 May 24, 1993 NRC INFORMATION NOTICE 93-38: INADEQUATE TESTING OF ENGINEERED

SAFETY FEATURES ACTUATION SYSTEMS

Addressees

for nuclear power

All holders of operating licenses or construction permits

reactors.

Purpose

this information

The U.S. Nuclear Regulatory Commission (NRC) is issuing testing of

in which inadequate

notice to alert addressees to situations It is expected

engineered safety features actuation systems was performed. to their

that recipients will review the information for applicability

avoid similar problems.

facilities and consider actions, as appropriate, to notice are not NRC

However, suggestions contained in this information response is required.

requirements; therefore, no specific action or written

Description of Circumstances

South Texas Units 1 and 2

Nuclear Plant

On September 15, 1992, personnel at the South Texas spray channels

(South Texas) determined that a portion of the containment and logic circuitry was

between the process instrumentation and the actuation engineered safety

not being tested. The containment spray system is an

to be verified

feature (ESF) and is required by technical specifications

operable for plant operation.

is part of the

The controlling logic for the containment spray systemThe purpose of the ESFAS

engineered safety features actuation system (ESFAS). signals to actuate ESF

is to sense plant conditions and, if required, transmit During plant

accidents.

equipment to mitigate the consequences of postulated the ESFAS circuitry is

operation, a set of overlapping tests verifies that

at which process

operable. These tests are performed from the point

of the logic relays. When the

conditions are sensed through the signal output the contacts for the logic

containment spray portion of the system is tested, of the containment spray

relays are opened to prevent inadvertent actuation complete, the

logic is

system. After testing of the containment spray closed position.

contacts for the logic relays are returned to the normal

to verify that

However, the test procedure does not require the test personnel The licensee

the contacts are closed and that the circuits are continuous.

could render the

has determined that a failure of these contacts to close

circuitry inoperable.

9305180426 I: tE NotI CR_ q3-°23

IN 93-38 May 24, 1993 discrepancy. Later, this condition was also found in the same test circuits

at the Braidwood Nuclear Power Station (Braidwood) and at McGuire.

Discussion

In three of the events described above, the testing of normally energized

ESFAS circuits was found to be inadequate because the licensee did not

that the contacts which were opened for the test were closed and the verify

circuits

continuous after completing the test. Failure to close these contacts

result in the failure of ESF equipment to actuate as required. Because could

indication of continuity for this type of circuit may not be available

same manner as for normally energized circuits, other methods may be in the

used

verify that the contacts are closed and that the circuits are continuous. to

Although these three events occurred at pressurized water reactors, potential exists for similar conditions at boiling water reactors. the

The wiring discrepancy found in the test circuitry at Byron, Braidwood

McGuire may also exist in test circuits supplied by Westinghouse at and

sites. At these three facilities, the discrepancy resulted in a failureother

the licensee to perform a required technical specification surveillance by

of the containment isolation phase B logic. test

This information notice requires no specific action or written response.

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

the technical contact listed below or the appropriate Office of Nuclearcontact

Reactor-Regulation-(NRR}-projecttmanagei%.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: P. Kim VanDoorn, RII

(704) 875-1681 Attachment:

List of Recently Issued NRC Information Notices

IN 93-38 May 24, 1993 For most of the circuits in the ESFAS, the bistables are normally energized.

The status of these circuits can readily be monitored and displayed on a

bistable status monitoring panel. However, to prevent spurious actuation of

containment spray, the bistables for the containment spray circuits are

normally deenergized and the status of the circuits cannot be monitored in the

same manner as the normally energized circuits. At South Texas, a test

circuit was provided in the containment spray circuitry to allow verification

of circuit continuity between the process instrumentation and the ESF

actuation and logic circuitry without actuating the containment spray system.

The test personnel were not aware that it was necessary to use this test

circuit to verify circuit continuity after closing the contacts.

After making the above discovery, the licensee tested the containment spray

circuitry and found the circuits acceptable. The licensee revised the

applicable procedures to ensure that these circuits would be tested during

future surveillances.

McGuire Units 1 and 2 On February 16, 1993, personnel at the William B. McGuire Nuclear Station

(McGuire) Units 1 and 2, determined that, similar to the event at South Texas, continuity checks were not performed for the containment spray logic relay

contacts and for a contact in the reactor protection circuitry that was also

opened during testing. The contact in the reactor protection circuitry was

the channel test relay contact at the bistable output to the solid-state

protection system for containment spray. The licensee revised the applicable

procedures to ensure that these contacts would be tested during future tests.

Catawba Units 1 and 2 On February 16, 1993, personnel at the Catawba Nuclear Station Units 1 and 2, determined that, similar to the condition at McGuire, continuity checks were

not performed for certain normally deenergized contacts. The licensee

verified the continuity of the circuits and revised procedures to ensure that

the contacts would be tested during future tests. In addition, the licensee

found that, for three channels in Unit I and two channels in Unit 2, the test

points on the printed circuit cards were mislabeled.

Byron Units I and 2

On February 22, 1993, personnel at the Byron Nuclear Power Station (Byron)

Unit 1, found a wiring discrepancy in a cabinet of the solid-state protection

system. The licensee determined that a test connection for containment

isolation phase B (set to actuate at 50 percent of the design pressure of the

containment) was wired to pin 5 of a terminal board instead of pin 6. Because

of this error, surveillance tests performed to verify that the containment

isolation phase B logic cicuitry was acceptable were actually performed on the

containment spray logic circuitry. As a consequence, surveillance tests of

the containment isolation phase B logic had not been performed as required.

This condition was later found to exist also in Unit 2. The licensee

consulted with the supplier, Westinghouse Electric Company, and corrected the

Attachment

IN 93-38 0

.I . May 24, 1993 Page I of I

4 y) I0

0)LU

LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Date of

Information

Notice No. Subject Issuance Issued to <U) ~

93-37 Eyebolts with Indeter- 05/19/93 All holders of OLs or CPs 0

minate Properties In- for nuclear power reactors. IL

stalled in Limitorque

Valve Operator Housing

Covers

93-36 Notifications, Reports, 05/07/93 All U.S. Nuclear Regulatory

and Records of Misadmin- *Comission medical

istrations licensees.

93-35 Insights from Common- 05/12/93 All holders of OLs or CPs

Cause Failure Events for nuclear power plants

(NPPs).

93-34, Potential for Loss of 05/06/93 All holders of OLs or CPs

Supp. 1 Emergency Cooling for nuclear power reactors.

Function Due to A

Combination of

Operational and Post- Loca Debris in Contain- ment

93-34 Potential for Loss of 04/26/93 All holders of OLs or CPs

Emergency Cooling for nuclear power reactors.

Function Due to A

Combination of

Operational and Post- Loca Debris in Contain- ment

93-33 Potential Deficiency 04/28/93 All holders of OLs or CPs

of Certain Class IE for nuclear power reactors.

2 Instrumentation and

Control Cables

0

) 93-32 Nonconservative Inputs 04/21/93 All holders of OLs or CPs 'no

for Boron Dilution for pressurized water coo0L 0.

Event Analysis reactors (PWRs). td

wUO0

DL

Operating License

CP - Construction Permit

o'o (A U.

U-

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25

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IN 93-xx

'-' May xx, 1993 Discussion

In three of the events described above, the testing of normally energized

ESFAS circuits was found to be inadequate because the licensee did not verify

that the contacts which were opened for the test were closed and the circuits

continuous after completing the test. Failure of these contacts to close

could result in the failure of ESF equipment to actuate as required. Because

indication of continuity for this type of circuit may not be available in the

same manner as for normally energized circuits, other methods may be used to

verify that the contacts are closed and that the circuits are continuous.

Although these three events occurred at pressurized water reactors, the

potential exists for a similar condition at boiling water reactors.

The wiring discrepancy found in the test circuitry at Byron, Braidwood and

McGuire may also exist in test circuits supplied by Westinghouse at other

sites. At these three facilities, the discrepancy resulted in a failure by

the licensee to perform a required technical specification surveillance test

of the containment isolation phase B logic.

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

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

the technical contact 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 contact: P. Kim VanDoorn, Region II

(704) 875-1681 Attachment: List of Recently Issued NRC Information Notices

SEE PREVIOUS CONCURRENCE

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

RSanders JBirmingham GHMarcus BKGrimes

03/29/93 05/14/93 05/14/93 05/ /93

RII *RII:DRP

PKVanDoorn WMiller

05/12/93 05/12/93 DOCUMENT NAME: ESFAS.IN2

IN 93-xx

v<-' May xx, 1993 Discussion