Information Notice 1993-34, Potential for Loss of Emergency Cooling Function Due to a Combination of Operational and Post-LOCA Debris in Containment

Potential for Loss of Emergency Cooling Function Due to a Combination of Operational and Post-LOCA Debris in Containment

ML031210149
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, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Crane
Issue date:	05/06/1993
From:	Grimes B Office of Nuclear Reactor Regulation
To:
References
IN-93-034, Suppl 1, NUDOCS 9305050002
Download: ML031210149 (6)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C.

20555 May 6, 1993 NRC INFORMATION NOTICE 93-34, SUPPLEMENT 1:

POTENTIAL FOR LOSS OF EMERGENCY

COOLING FUNCTION DUE TO A

COMBINATION OF OPERATIONAL AND

POST-LOCA DEBRIS IN CONTAINMENT

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) issued Information Notice

(IN)

93-34 because of the possible problems that could'occur with operational

and post-accident debris blocking emergency core cooling pump strainers in a

boiling-water reactor (BWR) or containment sump screens in a pressurized-water

reactor (PWR). The IN was based, in part, on an event that occurred at the

Perry Nuclear Plant. The NRC is issuing this supplement to IN 93-34 to alert

addressees to additional information relating to that event. 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 are not NRC

requirements; therefore, no specific action or written response is required.

Description of Circumstances

IN 93-34 described clogging of emergency core cooling (ECC) pump suction

strainers at the Perry Nuclear Plant, a BWR-6. The latest strainer clogging

event occurred in March 1993, 2 months after the licensee had replaced the

strainers and thoroughly cleaned the suppression pool.

After the IN was

issued, the licensee chemically analyzed the debris on the strainer. The

debris consisted of fibers from air filter material that had been

inadvertently introduced into the suppression pool and corrosion products that

had been filtered from the pool by the fibers adhering to the surface of the

strainer. A small amount of the fibrous filter material also was found in the

suppression pool near the weir wall.

The licensee uses the fibrous material in the drywell in three air filters

that each have a surface area of about 5.57 square meters C60 square feet].

In addition, there are six similar air filters in containment. The purpose of

the filters is to provide filtered air in containment and the drywell during

reactor outages. It has been the licensee's practice to replace the filter

material at the end of each outage and to leave the material in the drywell

and containment during operation of the.plant at power. As a result of the

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IN 93-34, Supplement 1 May 6, 1993 March 1993 event, the licensee intends to remove the filter material from the

drywell before startup to eliminate this source of fibrous material from the

drywell.

Discussion

NUREG-0897, Rev. 1, "Containment Emergency Sump Performance," which was

written in conjunction with resolution of Unresolved Safety Issue (USI) A-43, addresses transport of fibrous thermal insulation from the containment to the

strainers during a loss-of-coolant accident (LOCA).

Resolution of USI A-43, in part, was based on strainer head loss tests with fibrous thermal insulation

obstructing flow.

USI A-43 did not address the consequences on head loss of

the filtering action of the fibrous material on the strainer.

The Perry event

showed that filtering corrosion products, dust, and other debris from the

drywell during a LOCA may cause an unexpectedly rapid loss of net positive

suction head for the ECC pumps when they are needed to perform their intended

function.

Related Generic Communications

°

NRC Information Notice 92-71:

"Partial Plugging of Suppression

Pool Strainers at a Foreign BWR"

o

NRC Information Notice 88-28:

"Potenttalfor-to-s-of 1-os-t-10DC

Recirculation Capability Due to Insulation Debris Blockage'

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:

Roger W. Woodruff, NRR

(301) 504-2917 Attachment:

List of Recently Issued NRC Information Notices

i

.-

I

Attachment

IN 93-34, Supplement 1

May 6, 1993 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information

Date of

Notice No.

Subject

Issuance

Issued to

93-34

93-33

Potential for Loss of

Emergency Cooling

Function Due to A

Combination of

Operational and Post- Loca Debris in Contain- ment

Potential Deficiency

of Certain Class IE

Instrumentation and

Control Cables

04/26/93

04/28/93

All holders of OLs or CPs

for nuclear power reactors.

All holders of OLs or CPs

for nuclear power reactors.

93-32

Nonconservative Inputs

for Boron Dtlution

Event Analysis

04/21/93

All holders of OLs or CPs

->for pressurized water

reactors (PWRs).

93-31

93-30

93-29

93-28

Training of Nurses

Responsible for the

Care of Patients with

Brachytherapy Implants

NRC Requirements for

Evaluation of Wipe

Test Results; Cali- bration of Count Rate

Survey Instruments

Problems with the Use

of Unshielded Test Leads

in Reactor Protection

System Circuitry

Failure to Consider

Loss of DC Bus in the

Emergency Core Cooling

System Evaluation May

Lead to Nonconservative

Analysis

04/13/93

04/12/93

04/12/93

04/09/93

All U.S. Nuclear Regulatory

Commission medical

licensees.

All U.S. Nuclear Regulatory

Commission medical

licensees.

All holders of OLs or CPs

for nuclear power reactors.

All holders of OLs or CPs

for nuclear power reactors.

OL - Operating License

CP - Construction Permit

IN 9%,J4, Supplement 1 May 6, 1993 March 1993 event, the licensee intends to remove the filter material from the

drywell before startup to eliminate this source of fibrous material from the

drywell.

Discussion

NUREG-0897, Rev. 1, "Containment Emergency Sump Performance,' which was

written in conjunction with resolution of Unresolved Safety Issue (USI) A-43, addresses transport of fibrous thermal insulation from the containment to the

strainers during a loss-of-coolant accident (LOCA). Resolution of USI A-43, in part, was based on strainer head loss tests with fibrous thermal insulation

obstructing flow. USI A-43 did not address the consequences on head loss of

the filtering action of the fibrous material on the strainer. The Perry event

showed that filtering corrosion products, dust, and other debris from the

drywell during a LOCA may cause an unexpectedly rapid loss of net positive

suction head for the ECC pumps when they are needed to perform their intended

function.

Related Generic Communications

NRC Information Notice 92-71:

"Partial Plugging of Suppression

Pool Strainers at a Foreign BWR"

NRC Information Notice 88-28: 'Potential for Loss of Post LOCA

Recirculation Capability Due to Insulation Debris Blockage'

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: Roger W. Woodruff, NRR

(301) 504-2917 Attachment:

List of Recently Issued NRC Information Notices

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IN "_.34, Supplement 1 May 6, 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:

Roger W. Woodruff, NRR

(301) 504-2917 Attachment:

List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCE

• SCSB:DSSA

• OGCB:DORS *BC:SCSB:DSSA

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IN 93-34, Supplement 1 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:

Roger W. Woodruff, NRR

(301) 504-2917 Attachment:

List of Recently Issued NRC Information Notices

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