Information Notice 1986-80, Unit Startup with Degraded High Pressure Safety Injection System

Unit Startup with Degraded High Pressure Safety Injection System

ML031250214
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, 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, Skagit, Marble Hill, Crane
Issue date:	09/12/1986
From:	Jordan E NRC/IE
To:
References
IN-86-080, NUDOCS 8609100228
Download: ML031250214 (4)

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SSINS No.:

6835 IN 86-80

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C.

20555

September 12, 1986

IE INFORMATION NOTICE NO. 86-80:

UNIT STARTUP WITH DEGRADED HIGH

PRESSURE SAFETY INJECTION SYSTEM

Addressees

All nuclear power reactor facilities holding an operating license or a

construction permit.

Purpose

The purpose of this notice is to inform recipients of an event where unit

startup involved improper interpretation of the terms "OPERABLE" and

"OPERABILITY" in the technical specifications.

It is expected that recipients

will review the information for applicability to their facilities and consider

actions, if appropriate, to preclude a similar problem occurring at their

facilities.

However, suggestions contained in this information notice do not

constitute NRC requirements; therefore, no specific action or written response

is required.

Description of Circumstances

At the McGuire Station on November 2, 1985, a single failure in a shared

instrument air system caused a trip of both units from 100% power and a safety

injection in Unit-1. A detailed sequence of events is provided for information

in attachment 1. The isolation valves between the volume control tank (VCT)

and the charging pumps closed as designed when the SI signal initiated a trans- fer of the charging pump suction to the refueling water storage tank from the

VCT.

Later, when the SI was reset, it was discovered that the VCT isolation

valve motor operators had burned-up due to overload.

Although work requests were written to repair both of the valves, operations

personnel made the erroneous decision to start-up based on the determination

that these VCT isolation valves are not in the direct ECCS flow path required

by technical specifications.

They believed that the HPSI system was still

capable of performing its design requirement.

The unit entered the start-up

mode (mode 2) at about 6:15 a.m. the following day, (November 3, 1985), but

only stayed in this mode until 12:55 p.m. when mode 3 was re-entered to repair

a severed instrument fitting on the secondary side of a steam generator.

Discussion:

The safety significance of this event is that the VCT isolation valves would

not have automatically closed if an SI signal were received.

The charging pumps

8609100228

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IN 86-80

September 12, 1986 would then be taking suction from both the VCT and the RWST with the following

possible consequences:

(1) the VCT could be drained allowing hydrogen gas to

be entrained in the charging pump suction, possibly leading to gas binding of

the charging pumps and (2) the water injected into the reactor vessel would

have a lower boron concentration than it would in the required line-up.

Duke Power personnel made their decision to start-up the unit on the basis that

neither of the two valves in question is specifically identified in Technical

Specification 3.5.2 as being a part of the required ECCS flow path.

The tech- nical specification requires "an OPERABLE flow path capable of taking suction

from the RWST on an SI signal and automatically transferring suction to the

containment sump during the recirculation phase of operation."

However, the

standard definition of OPERABLE requires that all necessary attendant instru- mentation, controls, normal and emergency power sources, cooling or seal water, lubrication or other auxiliary equipment that are required for the system, sub- system, train, component or device to perform its function(s) are also capable

of performing their related support function(s). A generic letter was issued by

the NRC Office of Nuclear Reactor Regulation on April 10, 1980 to clarify the

meaning of the term OPERABLE and to request licensees to take specific actions

to assure that the term is appropriately applied at their facilities.

This

definition of operability was also part of the McGuire technical specifications

at the time of the event.

IE Information Notice (IN) 86-38, entitled "Deficient Operator Actions Following

Dual Function Valve Failures" also addresses operator actions with regard to

valves that serve more than one function.

The valves addressed in IN 86-38 not

only accommodate emergency core cooling flow, but also provide a containment

isolation function.

The information notice also refers to the generic letter

dated April 10, 1980 that requests licensees to adopt the standard definition of

OPERABLE in their technical specifications.

No specific action or written response is required by this information notice.

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

Administrator of the appropriate regional office or this office.

war/. k*df rect or

Division

Emergency Preparedness

and Eng neering Response

Office of Inspection and Enforcement

Technical Contacts:

Joe Giitter, IE

(301) 492-9001

William T. Orders, RII

(704) 875-1681 Attachments:

1.

Detailed Sequence of Events

2.

Attachment 1

IN 86-80

September 12, 1986 11/2/85 A fatigue-induced failure of the discharge line from one of three

'0640

instrument air compressors, which comprise a shared instrument air

system, resulted in the loss of instrument air pressure to all loads

on both units.

The main feedwater flow control valves on both units

closed as designed as a result of the loss of instrument air.

Due to

low-low steam generator levels, both units tripped from 100% power.

The auxiliary feedwater systems auto-started and provided feedwater

to the team generators.

A safety injection (SI) signal was received on Unit 1 when the reactor

coolant system pressure dropped below the SI set point of 1845 psig.

Injection occurred for about 10 minutes.

The pressure decrease was

caused by several factors:

(1) post-trip steam loads were higher

than normal because the main steam drains opened on loss of instru- ment air; (2) three steam generator power operated relief valves and

code safeties opened to relieve the initial pressure transient; (3)

pressurizer heaters failed to energize as required; and (4) steam

generators were overfed because flow control valves in the auxiliary

feedwater system went open as a result of the loss of instrument air;

and (5) Unit 1 was providing house load auxiliary steam.

When the SI signal was received, the high-pressure safety injection

(HPSI) charging pump suction transferred from the volume control tank

(VCT) to the refueling water storage tank (RWST) as designed.

This

requires that the valves between the RWST and the charging pumps open

and the two motor operated isolation valves between the VCT and the

charging pumps closed.

The isolation valves between the VCT and the

charging pumps closed (i.e., the required safe position).

SI was reset, the isolation valves could not be opened from the

control room.

An equipment operator was dispatched to manually open

the valves.

The valves were subsequently determined to be electri- cally inoperable because the valve motors had burned-up due to over- load.

Work requests were written to repair both of the valves.

Operations personnel made the erroneous decision to start-up based

on the determination that these VCT isolation valves are not in the

direct ECCS flow path required by technical specifications.

They

believed that the HPSI system was still capable of performing its

design requirement.

11/3/85 Unit entered the start-up mode (mode 2) with the VCT isolation valves

-0615 open and electrically inoperable.

The unit did not exceed 2% reactor

power while in mode 2.

11/3/85 Mode 3 was re-entered to repair a severed instrument fitting on the

-1255 secondary side of a steam generator.

IN 86-80

September 12. 1986

LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information

Date of

Notice No.

Subject

Issue

Issued to

86-79 Degradation Or Loss Of

9/2/86

All power reactor

Charging Systems At PYR

facilities holding

Nuclear Power Plants Using

an OL or CP

Swing-Pump Designs

86-78 Scram Solenoid Pilot Valve

9/2/86

All BWR facilities

(SSPV)

Rebuild Kit Problems

holding an OL or CP

86-77 Computer Program Error Report 8/28/86

All power reactor

Handling

facilities holding

an OL or CP and

nuclear fuel man- ufacturing facilities

86-76 Problems Noted In Control

8/28/86

All power reactor

Room Emergency Ventilation

facilities holding

Systems

an OL or CP

86-75 Incorrect Maintenance

8/21/86

All power reactor

Procedure On Traversing

facilities holding

Incore Probe Lines

an OL or CP

86-74 Reduction Of Reactor Coolant

8/20/86

All BWR facilities

Inventory Because Of Misalign- holding an OL or CP

ment Of RHR Valves

86-73 Recent Emergency Diesel

8/20/86

All power reactor

Generator Problems

facilities holding

an OL or CP

86-72 Failure 17-7 PH Stainless

8/19/86

All power reactor

Steel Springs In Valcor

facilities holding

Valves Due to Hydrogen

an OL or CP

Embritt lement

86-71 Recent Identified Problems

8/19/86

All power reactor

With Limitorque Motor

facilities holding

Operators

an OL or CP

86-70

Spurious System Isolation

8/18/86

All GE 8WR facilities

Caused By The Panalarm Model

holding an OL or CP

86 Thermocouple Monitor

OL = Operating License

CP = Construction Permit

UNITED STATES

NUCLEAR REGULATORY COMMISSION

WASHINGTON. D.C. 20565

FIRST CLASS MAIL

POSTAGE & FEES PAIO

USN RC

WASH 0 C

PERMIT No GL67

OSFICIALt BUSINESS

PEMAITV fOX PRIVATE USE

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