ML20045B397
| ML20045B397 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 06/10/1993 |
| From: | Horn G NEBRASKA PUBLIC POWER DISTRICT |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-93-002, IEB-93-2, NSD930738, NUDOCS 9306170299 | |
| Download: ML20045B397 (3) | |
Text
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GENERAL OFFICE y
Ep3 P O. DOX 499. COLUMBUS, NEDRASKA 686024499 9 Nebraska Public Power District
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G NSD930738 June 10, 1993 U.S. Nuclear Regulatory Commission Attention:
Document Control Desk Washington, D.C.
20555 Subj ect :
Response to NRC Bulletin 93-02 Cooper Nuclear Station NRC Docket 50-298, DPR-46
Reference:
NRC Bulletin No. 93-02, " Debris Plugging of Emergency Core Cooling Suction Strainers," dated May 11, 1993 Gentlemen:
As directed by NRC Bulletin 93-02, the Nebraska Public Power District (District) provides the following response regarding debris plugging of Emergency Core Cooling System (ECCS) suction strainers at Cooper Nuclear Station.
NRC Bulletin 93-02 requests licensees to identify and remove fibrous air filters or other temporary sources of fibrous material installed or stored in primary containment, that are not designed to withstand the effects of a LOCA.Bulletin 93-02 also requires licensees to submit a response within 30 days identifying actions taken or planned to address these concerns.
The following discussion provides the requested information.
No immediate compensatory measures were required upon receipt of this bulletin, as the reactor was in cold shutdown with the core unloaded.
However, the District is carrying out actions necessary to address the concerns of the referenced bulletin before restart.
Extensive drywell walkdowns have been performed which identified two sources of fibrous materials within the scope of the bulletin.
These sources are temporary air filters used in the drywell fan coil units, and Kaowool blankets installed over various lengths of piping in the drywell.
No temporary fibrous material was found stored in the drywell.
Temporary inlet air filters are used in the fan coil units during extended cold shutdowns of the plant.
The CNS Preventive Maintenance program is used to install these filters and to ensure their removal from the fan coil units and drywell when work is completed (before startup). The CNS operating procedures for the drywell ventilation system and for primary containment closeout also include verification of fan coil air filter element removal. Approximately 320 sqtare feet of this material is utilized in the drywell fan coil units during shtadowns.
Use of these air filters during future refueling outages will be reconsidered in light of the information given in the reference and Information Notice 93-34.
The District also identified Kaowool insulating blankets inside primary f
containment, which were not designed to withstand a LOCA.
These blankets were installed in 18 locations replacing reflective (Mirror) insulation. Removal of l
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the Kaowool blankets was completed June 3,1993. The District will fabricate and install new sections of permanent reflective or metal-jacketed fiberglass insulation in these locations before startup from the current refueling outage.
The amounts and locations of the Kaowool blankets identified were as follows:
Approximately 113 square feet on 24 - inch Residual Heat Removal ii P P ng Approximately 80 square feet on 12 inch Reactor Feedwater piping Approximately 12 square feet on Core Spray check valves 18 and 19 Approximately 5 square feet on 6 inch Reactor Water Cleanup piping.
Approximately 25 square feet on Main Steam relief valve 71A The District also identified approximately 25 square feet of unj acketed fiberglass insulation installed on Main Steam Relief Valve 71A. Prior to startup from the 1993 outage, either metal jacketing will be installed around the fiberglass or it will be replaced with an acceptable product.
The District will complete all actions requested in Bulletin 93-02 prior to plant startup from the ongoing refueling outage, currently scheduled for June 22, 1993.
As directed by Bulletin 93-02, a report confirming completion of the requested actions will be submitted within 30 days of completion.
The District is also evaluating, in accordance with available NRC and industry guidance, LOCA effects on the permanent metal-jacketed fiberglass insulation installed in the dryvell.
This evaluation is being pursued to further ensure that ECCS pump performance will not be degraded due to accumulation of insulation material debris on ECCS suction strainers during such events.
In accordance with 10 CFR 50.54(f), this response is submitted under oath.
If you have any questions regarding this response, or require any additional
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information, please contact my office.
l Sin,perely, l cw I
G(
. Horn Nuclear Power Croup Manager
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NRC Regional Administrator Region IV Arlington, TX NRC Resident Inspector Cooper Nuclear Station
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'~ June 10,.1993 Page 3 of 3 STkTEOFNEBRASKA) j
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PLATTE COUNTY
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G. R. Horn,'being first duly sworn, deposes and says that he is an authorized l
representative of the Nebraska Public Power District, a public corporation and 4
political subdivision of the State of Nebraska; that he is duly authorized to j
submit this response on behalf of Nebraska Public Power District; and that the statements contained herein are true to the best of his knowledge and belief.
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G. R.' Horn i
Subscribed in my presence and' sworn to before me this
/O day of ri tt nb 1993.
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NOTARY PUBLIC ~
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