Information Notice 1988-92, Potential for Spent Fuel Pool Draindwon

Potential for Spent Fuel Pool Draindwon

ML031150046
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, Crane
Issue date:	11/22/1988
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-88-092, NUDOCS 8811160470
Download: ML031150046 (8)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C.

20555

November 22, 1988

NRC INFORMATION NOTICE NO. 88-92: POTENTIAL FOR SPENT FUEL POOL DRAINDOWN

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 resulting from the failure of the fuel transfer canal door seal.

It is expected that recipients will review the information for applicability

to their facilities and 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

On October 2, 1988, with Surry Unit 1 in cold shutdown, the licensee was pre- paring to test the fuel transfer system (see attached figure) before fuel

off-load. The transfer canal door was in place and the single door seal was

inflated.

The fuel transfer canal was dry.

The fuel transfer tube was open, the blind flange was removed on the containment side, and the gate valve was

open on the spent fuel pool side. The refueling cavity seal was not in place.

An accidental pinhole puncture of the single air supply line to the transfer

canal door pneumatic seal was promptly detected and the air leak quickly

stopped before it could lead to a loss of seal integrity.

Discussion:

A review of this event by the licensee showed that, given the configuration of

the transfer canal, the transfer tube, and the refueling cavity existing at the

time of the event, an inadvertent draindown of the spent fuel pool could occur

to a height of only 13" above the top of the fuel assemblies (see attached

figure). This postulated draindown assumes no operator action and a loss

of instrument air or pneumatic seal failure.

Increased radiation levels in

the spent fuel pool building would have limited stay time in the building and

impeded recovery.

The licensee estimated that the dose rate, based on the

spent fuel inventory at the time of the event, could have reached 50 R/hour

on the operating deck. The licensee also calculated that with the refueling

cavity seal assembly in place, the spent fuel pool could only draindown to

14 feet above the top of the fuel assemblies.

In 88-92 November 22, 1988 If newly discharged fuel had been placed in the spent fuel pool, a postulated

draindown of the spent fuel pool could have led to even higher radiation levels

in the spent fuel pool building than the radiation levels postulated by the

licensee.

If a seal failed and spent fuel pool water were lost while a fuel

assembly was lifted, fuel could be uncovered and fuel cladding could fail.

The licensee is considering several actions based on the review of this event.

The short-term actions include: (1) revising procedures to require that the

refueling cavity seal assembly be installed before opening the transfer tube

gate valve for dry testing the fuel transfer system, (2) reviewing and up- grading a procedure for the loss of spent fuel pool inventory, (3) upgrading

the material of the plastic air hose in which the pinhole occurred and (4)

providing an emergency escape system for personnel in the transfer canal.

The

long-term actions include: (1) evaluating the canal door and seal design in- cluding the need for a backup air supply, a low air pressure alarm, and a

backup seal, (2) evaluating other pneumatic seals used at Surry, (3) developing

a procedure for installing, inspecting, and testing the seals in accordance

with the manufacturer's recommendations, (4) revising procedures to ensure

the transfer tube blind flange is installed whenever the transfer canal is

drained for maintenance on the transfer tube gate valve, and (5) reviewing

further the procedures for loss of spent fuel pool and refueling cavity water

level, after the short-term modifications to these procedures.

In 1981, a related event occurred at Arkansas Nuclear One, Unit 2. At the

end of a refueling outage with the transfer canal door closed and the door

seal inflated, the transfer canal was drained in preparation for performing

maintenance on the fuel upender.

Concurrent maintenance on the air system

resulted in a loss of air pressure to the seal, and water leaked from the

spent fuel pool into the fuel upender pit.

The transfer gate valve was closed

and acted as a barrier to the flow. The leakage stopped when the water levels

equalized. The spent fuel pool level had decreased by 7 feet.

If the seal

had leaked while the maintenance on the upender was in progress with the fuel

transfer tube gate valve open and the fuel transfer tube blind flange removed, the spent fuel pool could have drained down to a level just above the top of

the fuel assemblies.

Pneumatic seals are also used in the refueling cavity seal assembly. In many

cases, the failure modes of the refueling cavity seals (IE Bulletin 84-03,

"Refueling Cavity Water Sealn and Information Notice 84-93, "Potential for

Loss of Water From the Refueling Cavity") apply to the spent fuel pool gate

seals.

These events show that a door equipped with a single seal and/or a single air

supply is subject to complete loss of function from a single failure.

There- fore, the seal must be properly installed, and the seal and air supply system

must be carefully maintained. The scenarios discussed also point out the need

for carefully coordinating such activities as maintenance and testing to avoid

undesirable interactions between systems which could result in fuel uncovery, personnel injury, and personnel contamination.

IN 88-92 November 22, 1988 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.

arleh E. Rsgs , DDi recto r

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Daniele Oudinot, NRR

(301) 492-1174 Attachments:

1. Figure of Fuel Transfer System

2. List of Recently Issued NRC Information Notices

Normal Water

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Spent Fuel

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Attachment 2

IN 88-92

November 22, 1988 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information

Date of

Notice No.

Subject

Issuance

Issued to

88-91

88-90

88-89

Improper Admini stration

and Control of

Psychological Tests

Unauthorized Removal of

Industrial Nuclear Gauges

Degradation of Kapton

Electrical Insulation

Degradation of Westinghouse

ARD Relays

Pump Wear and Foreign

Objects in Plant Piping

Systems

Feedwater Line Break

Operating with Multiple

Grounds in Direct Current

Distribution Systems

Broken Retaining Block

Studs on Anchor Darling

Check Valves

11/22/88

11/22/88

11/21/88

11/16/88

11/16/88

11/10/88

10/21/88

10/14/88

All holders of OLs

or CPs for nuclear

power reactors and

all fuel cycle facility

licensees who possess, use, import, export, or transport formula

quantities of strategic

special nuclear material.

All NRC licensees

authorized to possess, use, manufacture, or

distribute industrial

nuclear gauges.

All holders of OLs

or CPs for nuclear

power reactors.

All holders of OLs

or CPs for nuclear

power reactors.

All holders of OLs

or CPs for nuclear

power reactors.

All holders of OLs

or CPs for nuclear

power reactors.

All holders of OLs

or CPs for nuclear

power reactors.

All holders of OLs

or CPs for nuclear

power reactors.

88-88

88-87

86-106, Supp. 3

88-86

88-85 OL = Operating License

CP = Construction Permit

IN 88-92 November 22, 1988 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

Daniele Oudinot, NRR

(301) 492-1174 Attachments:

1. Figure of Fuel Transfer

2. List of Recently Issued

System

NRC Information Notices

• SEE PREVIOUS PAGE FOR CONCURRENCE

• Tech Ed

11/7/88 Q~dinot:db

1ll/1Y88 EAB:NRR k

RLobelCL

115/7/88

• C:EAB:NRR

WLanning

11/10/88

• C:OGCB:NRR

CHBerlinger

11/10/88

11D-a8

IN 88- November

, 1988 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

Daniele Oudinot, NRR

(301) 492-1174 Attachments:

1. Figure of Fuel Transfer

2. List of Recently Issued

System

NRC Information Notices

• SEE PREVIOUS PAGE FOR CONCURRENCE

• Tech Ed

11/7/88 ARR

udinot:db

11/1 /88 QL

EAB:NRR

RLobel

11/ID/88 Lan ng

11//1 /88 C:

B:NRR

CHBerlinger

11/tV/88 D:DOEA:NRR

CERossi

11/ /88

IN 88- November

. 1988 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

Daniele Oudinot

(301) 492-1174 Attachments:

Figure of Fuel Transfer System

List of Recently Issued NRC Information Notices

Ekt;NR

W'u-dinot:db

// /9t/88 EAB:NRR

RLobel

/

/88

4110~1112 C:EAB:NRR

WLanning

/

/88 C:OGCB:NRR

CHBerlinger

/ /88 D:DOEA:NRR

CERossi

/ /88