Information Notice 1990-07, New Information Regarding Insulation Material Performance and Debris Blockage of PWR Containment Sumps

New Information Regarding Insulation Material Performance and Debris Blockage of PWR Containment Sumps

ML031210601
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, 05000000, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	01/30/1990
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-90-007, NUDOCS 9001240190
Download: ML031210601 (3)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 January 30, 1990

NRC INFORMATION NOTICE NO. 90-07: NEW INFORMATION REGARDING INSULATION

MATERIAL PERFORMANCE AND DEBRIS

BLOCKAGE OF PWR CONTAINMENT SUMPS

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

This Information notice is intendedto alert addressees to new information con- cerning performance of Insulating materials in post-loss-of-coolant-accident

(LOCA) environments within pressurized water reactor (PWR) containment sumps

when such materials become debris which may block the sump. It is expected

that recipients will review the information for applicability to their facili- ties and consider actions, as appropriate, toaavoid similar problems. However, suggestions contained in this information notice do not constitute NRC require- ments; therefore, no specific action or written response is required.

Description of Circumstances

By letter (Attachment 1) dated October 19, 1989, the NRC staff was informed by

Performance Contracting, Inc. of the results of recently conducted tests on

Owens-Corning NUKON fiberglass insulating material. The tests were conducted

by Performance Contracting, Inc. at the request of a European customer in order

to further investigate the potential for containment sump blockage due to insu- lating material debris in the "long-term' following a LOCA. "Long-term" was

defined as one day to 30 days duration following LOCA initiation. Similar

tests were previously conducted by the Swedish Nuclear Power Inspectorate on

NUKON and M.I.T. insulating materials. The results obtained were comparable

to those discussed in the attached letter.

The NRC staff previously considered containment sump performance including

debris blockage concerns under Unresolved Safety Issue (USI) A-43. USI A-43 was resolved in 1985 with the issuance of several NUREGs and Revision 1 to

Regulatory Guide 1.82. However, no specific actions were required by licensees.

The NRC staff focus was on the short-term effects of containment sump blockage

assuming chemically neutral cooling water at room temperature.

Performance Contracting, Inc. reported that the recent tests were conducted on

NUKON insulation material with water at a temperature of 1800 F and pH of 9.1 for a 7-day period. The results indicated that head loss across the insulation

9001240190

IN 90-07 January 30, 1990 material increases significantly after about 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> due to a reduction in flow

area caused by compaction of the fiberglass material at elevated pH conditions.

On the basis of discussions with Owens-Corning, this is consistent with what

would be anticipated, because devitrification of fiberglass occurs under alkaline

conditions.

Assuming that full cooling water (residual heat removal) flow is necessary to

ensure adequate post-LOCA heat removal capacity for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and beyond after

accident initiation, the effect of the increased pressure loss and associated

flow reduction, caused by compaction of insulation material debris, may have an

effect on the post-LOCA cooling performance. Additional tests conducted with

water at the same temperature but with a chemically neutral pH as is the case

in boiling water reactor (BWR.$ plants, did not result in an increase in head

loss. Thus, the phenomenon observed during these tests appears to be relevant

to plants with alkaline sump conditions.

Discussion:

Because some plants may potentially have alkaline post-LOCA sump conditions, addressees are being made aware of this new information regarding the potential

for increased containment sump blockage caused by compaction of fiberglass

insulation debris under high pH conditions so that they may assess the impact

on their plant-specific licensing basis post-LOCA sump performance and reactor

cooling analyses. Performance Contracting, Inc. indicated that a test report

of the newly performed tests is available for use by interested licensees.

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 NRR project manager.

Charles E.Ross, eirector

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: J. Wermiel, NRR

(301) 492-0870

F. Witt, NRR

(301) 492-0823 Attachments:

1. Letter from Gordon H. Hart (Performance Contracting, Inc.)

to Dr. Thomas E. Murley (NRC) dated October 19, 1989

2. List of Recently Issued NRC Information Notices

Attachment 2 IN 90-07 January 30, 1990 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

IntRUaRon Date of

Notice No. SubJect Issuance - Issued to

90-06. Potential for Loss of 1/29/90 All holders of OLs

Shutdown Cooling While or CPs for nuclear

at Low Reactor Coolant power reactors.

Levels

90-05 Inter-System Discharge of 1/29/90 All holders of OLs

Reactor Coolant or CPs for nuclear

power reactors.

90-04 Cracking of the Upper Shell- 1/26/90 All holders of OLs

to-Transition Cone Girth or CPs for Westinghouse- Welds in Steam Generators designed and Combustion

Engineering-designed

nuclear power reactors.

90-03 Malfunction of Borg-Warner 1/23/90 All holders of OLs

Bolted Bonnet Check Valves or CPs for nuclear

Caused by Failure of the power reactors.

Swing Arm

90-02 Potential Degradation of 1/22/90 All holders of OLs

Secondary Containment or CPs for BWRs.

90-01 Importance of Proper 1/12/90 All holders of NRC

Response to Self-Identified materials licenses.

Violations by Licensees

89-90 Pressurizer Safety Valve 12/28/89 All holders of OLs

Lift Setpoint Shift or CPs for PWRs.

89-89 Event Notification 12/26/89 All holders of OLs

Worksheets or CPs for nuclear

power reactors.

89-88 Recent NRC-Sponsored 12/26/89 All holders of OLs

Testing of Motor-Operated or CPs for nuclear

Valves power reactors.

89-87 Disabling of Emergency 12/19/89 All holders of OLs

Diesel Generators by or CPs for nuclear

Their Neutral Ground-Fault power reactors.

Protection Circuitry

OL = Operating License

CP = Construction Permit