Information Notice 1993-44, Operational Challenges During a Dual-Unit Transient

Operational Challenges During a Dual-Unit Transient

ML031070483
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, 05000355, 05000204, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	06/15/1993
From:	Grimes B Office of Nuclear Reactor Regulation
To:
References
IN-93-044, NUDOCS 9306080170
Download: ML031070483 (8)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON D.C. 20555 June 15, 1993 NRC INFORMATION NOTICE 93-44: OPERATIONAL CHALLENGES DURING A DUAL-UNIT

TRANSIENT

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 shift

notice to inform addressees of an event during which an atypical in that

staffing level and lack of familiarity with the tasks to be performed

control room operating shift

shift configuration affected the ability of the review the

to respond to the event. It is expected that recipients will

information for applicability to their facilities and consider contained actions, as

suggestions in

appropriate, to avoid similar problems. However, no specific

this information notice are not NRC requirements; therefore, action or written response is required.

DescriDtion of Circumstances

On December 31, 1992, a dual-unit reactor trip initiated by an electrical Units 1 and 2 fault in the switchyard occurred at the Sequoyah Nuclear Plant, event the control

at Sequoyah share a common control room. At the time of the

room reactor operator staffing was the minimum allowed by the plant Technical

Specifications (TS); shift staffing consisted of five licensed senior

operators (the shift operations supervisor, one assistant shift operations

supervisor for each unit, the shift technical advisor, and an additional

senior operator) and three reactor operators - two assigned to Unit 1 and one

assigned to Unit 2. The NRC inspection team investigating the event concluded

that the Unit 2 response to the event, with one reactor operator, was hampered

by lack of adherence to procedures, operator errors, and an unnecessary

cooldown of the reactor coolant system (RCS) after the reactor trip. The

event, with two reactor operators, was normal.

Unit 1 response to the same

Discussion

An NRC inspection team reviewed the effects of the Unit 2 staffing level

during the event with regard to the crew's ability to stabilize the unit after

2 the reactor trip occurred. The inspection team concluded that the toUnit erroneous

staffing level delayed the recovery of plant systems, contributed

decisions made by the assistant shift operations supervisor (ASOS), and

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IN 93-44 June 15, 1993 overburdened and challenged the crew's ability to perform tasks in the manner

in which it was trained. Control room simulator training scenarios had not

been conducted using only one reactor operator.

Although the normal shift staffing and training consisted of two

reactor operators for each unit, licensee operational staffing practices

resulted in the frequent use of one reactor operator for one of the units.

The licensee used this reduced staffing configuration 12 times in

December 1992. In this configuration, with the dual-unit transient, the

single reactor operator performed all of the recovery evolutions for the unit

as directed by the ASOS in charge of the unit.

Because of delays caused by the one reactor operator performing primary and

secondary system recovery evolutions, as required by the applicable recovery

procedures, an RCS cooldown resulted. This was a direct result of the crew

not adequately controlling auxiliary feedwater after the reactor

atypical staffing level also contributed to problems involving thetrip. The

decision

the assistant shift operations supervisor to use the normal-batch borate of

process in response to the cooldown rather than the emergency borate process

as required by the emergency procedure. The decision not to use the emergency

borate process was made, in part, because of the reluctance of the assistant

shift operations supervisor to commit the one reactor operator to the

emergency borate process, which restricts the operator's attention to

monitoring only that activity.

As a corrective action to prevent recurrence, the licensee implemented revised

administrative controls to ensure that the control room staffing

maintained at two reactor operators for each operating unit. The will

need

be

additional training at minimum staffing levels is being evaluated by thefor

licensee.

Related Generic Communications

1. IN 85-80, "Timely Declaration of an Emergency Class, Implementation of

an Emergency Plan, and Emergency Notifications," dated October 15, 1985

2. IN 91-77, "Shift Staffing at Nuclear Power Plants," dated November 26,

1991

IN 93-44 June 15, 1993 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.

Brian K. Grimes, Director

Division of Operating Reactor-Support

Office of Nuclear Reactor Regulation

Technical contacts: S. M. Shaeffer, RII

(615) 842-8001 D. R. Desaulniers, NRR

(301) 504-1043 Attachment: a dgtil0l5

List of Recently Issued NRC Information Notices

LIST OFRECENTLY ISSUED \_2 NRCINFORMATION NOTICES I' a

---

--

Notice Ib. Subject Issua ssued to I

93-43 Use of Inappro te 06/10/93 All holders of OLsor CPs

Lubrication OI s in for nuclear power reactors.

Sefety-Rolat d Applications

93-42 Failure of Anti-Rotation 06/09/93 All holders of OLsor CPs

Keys in Motor-Operated for nuclear Power reactors.

FVaTes Manufactured by

93-41 One Hour Fire Endurance 05/28/93 All holders of OLsor CPs

Test Results for Thermal for nuclear power reactors.

Ceramics Kaowool3M

Ctany FS-195 and

311Company Intern E-SO

Barrier Systoes

93-40 Fire Endurance Test 0O/26/93 All holders of OLsor CPs

Results for Thereal for nuclear power reactors.

Ceramics FP-60 Fire

Barrier Material

93-39 Radiation Beas from 09/25/93 All holders of OLsor CPs

Power Reactor Dialog- for nuclear power reactors.

1csl Shields

93-38 Imedequote Testing of 05/24/3 All holders of OLsor CPs

Engineered Safety for nucleur power reactors.

Featurs Actuation

Systmn

93-31 Eyobolts with Indeter- 05/19/93 All holders of OLsor CPi

Minote Properties In- for nuclear power reactors.

stalled In tleitorque

Valve Operator Housing

Covers

93-36 Nortifications, Reports OS/07/93 All U.S. Nuclear Regulatory

andRecords of Nisd1ni- Cosmission Medical

istrations licensees.

93-3S Insights from Comon- OS/12/93 All holders of OLsor CPs

Cause Failure Events for nuclear power plants

(UPP)'.

OL* Oper Lcense

LIog

tP - Construction Per1it

UNITED STATES

NUCLEAR REGULATORY COMMISSION FIRST CLASS MAIL

WASHINGTON, D.C. 20555-0001 POSTAGE AND FEES PAID

USNRC

PERMIT NO. G-67 OFFICIAL BUSINESS

PENALTY FOR PRIVATE USE, $300

PFUNTED ON RECYCLED PAPER

IN 93-44 June 15, 1993 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.

Original Isgned by

Brian K. Grime§

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: S. M. Shaeffer, RII

(615) 842-8001 D. R. Desaulniers, NRR

(301) 504-1043 Attachment:

List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCE

• DD:DRCH *D:DRCH *PD2-4:DRPE *DRP:RII RVC

RGallo BBoger FHebdon for EMerschoff

05/21/93 05/21/93 06/02/93 05/28/93

• OGCB:DORS *TechEd *OGCB:DORS

TJKim MMejac GMarcus '9

05/28/93 05/24/93 06/04/93 06// o/93 DOCUMENT NAME: 93-44.IN

IN 93-XX

June XX, 1993 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.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts: S. M. Shaeffer, Region II

(615) 842-8001 D. R. Desaulniers, NRR

(301) 504-1043 Attachment:

List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCE

• DD:DRCH *D:DRCH *PD2-4:DRPE *DRP:RII RVC

RGallo BBoger FHebdon for EMerschoff

05/21/93 05/21/93 06/02/93 05/28/93

• OGCB:DORS *TechEd OGCB:DORS DORS:NRR

TJKim MMejac GMarcus qW4 BGrimes

05/28/93 05/24/93 06/+ /93-- 06/ /93 DOCUMENT NAME: SEQUOYAH.INF

IN 93-XX

May XX, 1993 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: S. M. Shaeffer, Region II

(615) 842-8001 D. R. Desaulniers, NRR

(301) 504-1043 Attachment: List of Recently Issued NRC Information Notices

File Name: SEJWOYAH.INF

ConcurentU

PD z:DRPE DRP: RII ARC,

eu'2~4 iip FHegion $ EMerschoff

o~fiO 9 /57L493 05/ae/93 OGCB:DQjRS TechEd OGCB:DORS DORS:NRR

TJKim'J GMarcus BGrimes

O5/;?S/9 05p//93 05/ /93 05/ /93

From: Richard V. Crlenjak (RVC)

To: TJK3 Date: Friday, May 28, 1993 1:01 pm

Subject: RII CONCURRENCE OF PROPOSED IN

Region II has completed a review of the proposed Information

Notice, OPERATIONAL CHALLENGES DURING A DUAL-UNIT TRANSIENT. We

have no further comments and concur with the proposed IN.

Should you need any additional info let me know.

Thanks, Jack

cc: WEH, PJK1, SMS, AFG, JRJ, TAP, EWM