Information Notice 1992-06, Reliability of ATWS Mitigation System and Other NRC Required Equipment Not Controlled by Plant Technical Specifications

Reliability of ATWS Mitigation System and Other NRC Required Equipment Not Controlled by Plant Technical Specifications

ML031200738
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:	01/15/1992
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-92-006, NUDOCS 9201080305
Download: ML031200738 (7)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 January 15, 1992 NRC INFORMATION NOTICE 92-06: RELIABILITY OF ATWS MITIGATION SYSTEM AND

OTHER NRC REQUIRED EQUIPMENT NOT CONTROLLED

BY PLANT TECHNICAL SPECIFICATIONS

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 of the importance of maintaining the reliability of

equipment required by NRC regulations but not addressed in plant technical

specifications. It is expected that recipients will review this 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.

Background

In 1983, the Salem Nuclear Generating Station experienced an anticipated

transient without scram (ATWS) event. Following this event, efforts then

in progress to establish requirements to address ATWS events were completed, and the NRC issued, on June 1, 1984, Section 50.62 of Title 10 of the

Code of Federal Regulations (10 CFR 50.62), "Requirements for reduction of risk

from anticipated transients without scram (ATWS) events for light-water-cooled

nuclear power plants." This regulation required that each reactor have equip- ment, diverse from the reactor trip system, that would automatically initiate

actions to mitigate the consequences of an ATWS. The regulation also required

that the equipment for this system be independent from the existing reactor

trip system and be designed to perform its function in a reliable manner. The

NRC did not require licensees to address the operability of this equipment in

plant technical specifications nor did the NRC require that this equipment be

designated as safety-related.

Description of Circumstances

To meet the requirements of 10 CFR 50.62, the Houston Lighting and Power

Company, the licensee for the South Texas Project (STP), installed ATWS

mitigation system actuation circuitry (AMSAC). In May and June of 1991, a\\\O3O5Z/

IN 92-06 January 15, 1992 the NRC inspected the implementation of this system at STP, Units 1 and 2, and

identified three situations in which the reliability of the ATWS mitigation

system had been compromised.

While inspecting Unit 2, the NRC found that the licensee had left open

the

switches for the interface circuit between the AMSAC system and the auxiliary

feedwater (AFW) system. These open switches disabled the automatic AFW

Initiation feature of the AMSAC, an important part of the ATWS mitigationflow

system. The NRC also found that the licensee had bypassed the automatic

initiation feature of the AMSAC system, causing the system to be inoperable, least 15 percent of the time that the system was designed to be operable. at

While inspecting Unit 1, the NRC found that the licensee had bypassed

automatic initiation feature of the AMSAC system 36 percent of the timethe

the system was designed to be operable. The NRC issued the licensee that

a Severity

Level III violation and assessed a civil penalty.

The NRC also issued the licensee for Comanche Peak a Severity Level

because the ATWS mitigation system was bypassed for approximately 10 IV violation

days while

the reactor was operating at full power.

Discussion

In April 1985, the staff issued Generic Letter 85-06, "Quality Assurance

Guidance For ATWS Equipment That Is Not Safety-Related," to provide explicit

quality assurance guidance for the nonsafety-related equipment encompassed

the ATWS rule_ Although-much of the equipment- required-by-10-cR-50.62-is by

designated safety-related, it does perform an important safety function not- -

plant's primary reactor protection system fails. The regulation was if the

issued to

reduce the risk posed by such an event. The NRC considers the failure

licensees to comply with this regulation and to ensure that the ATWS of

mitigation

system and equipment function reliably to be a significant regulatory

concern.

The events described above indicate that licensees may not place an appropriate

level of priority on resolving problems with the ATWS mitigation system

it is not a safety-related system and because the plant's technical because

ations do not govern its operability. However, maintenance of this specific- of high priority and appropriate because such action assures the system is

safety function of the system and satisfies the requirements of important

for the system to function reliably. Actions taken by licensees 10 CFR 50.62 reliability of the ATWS mitigation system have included performingto ensure the

timely

surveillance testing, completing repairs and preventive maintenance

implementing necessary modifications, and updating procedures to promptly, changes. reflect system

Plant technical specifications only address the minimum personnel

and

requirements for the various modes of plant operations. However, it equipment

is important

that licensees maintain equipment and systems required by NRC regulations, ensure their reliability, even though they are not addressed by a plant's to

technical specifications.

IN 92-06 January 15, 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 (NRR) project manager.

arls't. Rossi, Director /

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contacts: R. Evans, RIV

(512) 972-2507 C. Paulk, RIV

(817) 860-8236 J. Mauck, NRR

(301) 504-3248 Attachment: List of Recently Issued NRC Information Notices

Attciment

11 92-06 January IS. 1992 LIST OF RECCEITLY

ISS1ED

SRC INFOWATIOR WTICES

Information Date of

Notice no. Subject Issuance Issued to

92-45 Potential Coil Insuletion 02/08/92 All holders of OLs or CPs

Breakdown 1 ABBRJDH2Relays for nuclear power reactors.

92-04 Potter S Bruefitld Model 01/06/92 All holders of OLs or CPs

MtDR Rotary Relay Failures for miclear power reactors.

92-03 R ote Trip Function 01/06/92 All holders of OLs or CPs

Failures in General Electric for nuclear power reactors.

F-Frae Molded-Case Circuit

Breakers

92-02 Relp5/NWo3 tComuter Code 01/03/92 All holders of OLs or CPs

Error Associated with the for nuclear power reactors.

Conservation of Energy

Equation

92-01 Cable DamageCaused by 01/03/92 All holders of 0Ls or CPs

Inadequate Cable Installa- for nuclear power reactors.

tion Procedures and Controls

91-87 Hydrogen Embrittlement of 12/27/91 All holders of OL or cps

Raychee Cryofit Couplings for nuclear power reactors.

91486 kw Reporting Requireents 12/27/91 All licensees authorized

for Contauination Events at to use byproduct materials

Medical Fecilities for humus use.

(10 tFR 30.10)

9145 Potential Failures of 12/26/91 All holders of OLc or CPs

Thermostatic Control valves for nuclear power reactors.

for Diesel generator Jacket

Cooling Water

9144 Problems uith Criticality 12/26/91 All Muclear Regulatory

Alarm Cot onents/Systems Commission (NRC)fuel

cycle licensees. interim

spent fuel atorage licens- ees and critical mass

licnsees.

OL

• Operating License

CP

• Construction Permit

IN 92-06 January 15, 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 (NRR) project manager.

Orig /s/'d by CERossi

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contacts: R. Evans, RIV

(512) 972-2507 C. Paulk, RIV

(817) 860-8236 J. Mauck, NRR

(301) 504-3248 Attachment: List of Recently Issued NRC Information Notices

D/ OE~rtR51 *C/OGCB:DOEA:NRR*RPB:ADM *C/SICB:IYST:NRR *SC/SICB:DST:NRR

CHBerlinger TechEd SNewberry JMauck

01/06/92 11/26/91 12/20/91 12/20/91

• OGCBI.DOEA:NRR *RESINSP:RIV *DRS:RIy *SC/DRS:RIV *D/DRS:RIV

JLBirmingham REvans CPaulk TWesterman SCollins

12/17/91 12/17/91 12/17/91 12/18/91 12/18/91 DOCUMENT NAME: IN 92-06

IN 91-XX

December xx, 1991 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: R. Evans, RIV

(512) 972-2507 C. Paulk, RIV

(817) 860-8236 J. Mauck, NRR

(301) 504-3248 Attachment: List of Recently Issued NRC Information Notices

Document Name: ATWS-IN.RFT

• SEE PREVIOUS CONCURRENCES/

D/DOEA:NRR C/OGC 1fldLA:NRR*RPB:ADM *C/SICB:DST:NRR *SC/SICB:DST:NRR

CERossi W'-' CHBerlinger TechEd SNewberry JMauck

01/ /92 4 01/VP/92 11/26/91 12/20/91 12/20/91

• OGCB:DOEA:NRR *RESINSP:RIV *DRS:RIV *SC/DRS:RIV *D/DRS:RIV

JLBirmingham REvans CPaulk TWesterman SCollins

12/17/91 12/17/91 12/17/91 12/18/91 12/18/91

IN 91-XX

December xx, 1991 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: R. Evans, RIV

(512) 972-2507 C. Paulk, RIV

(817) 860-8236

/A

L.t tIc NRCInorati ion Not

Attachment: List of R ecent W Issuel NRC Information Notices

Document Name: ATWS-IN.RFT

• SEE PREVIOUS CONCURRENCES

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

CERossi CHBerlinger TechEd SNe fry&sk45 J

12/ /91 12/ /91 11/26/91 12 /91 C12 12/ /91

• OGCB:DOEA:NRR *RESINSP:RIV *DRS:RIV *SC S:RIV *D/DRS:RIV

JLBirmingham REvans CPaulk TWesterman SCollins

12/17/91 12/17/91 12/17/91 12/18/91 12/18/91

IN 91-XX

December xx, 1991 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: R. Evans, RIV

(512) 972-2507 C. Paulk, RIV

64'J a4--CL

(817) 860-8236 Attachment: List of Recently Issued NRC Information Notices

Document Name: ATWS-IN.RFT

• SEE PREVIOUS CONCURRENCES

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

CERossi CHBerlinger TechEd

12/ /91 12/ /91 11/26/91 OGCB:DOEA:NRR RESINSP:RIY DRS:RIV SC/DRS:RIV D/DRS:RIV

Jirming ym REvans,, f CPaulkiJd TWesterman V SCollins

12/17/91 12/17/1e /DPl

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