ML20078F437
| ML20078F437 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 01/27/1995 |
| From: | Horn G NEBRASKA PUBLIC POWER DISTRICT |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NLS950050, NUDOCS 9502020107 | |
| Download: ML20078F437 (5) | |
Text
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NEBRASKA PUBUC POWER DISTRICT
'W P. O. BOX 499
- P %
Nebraska Public Power District co2eus"u" EEL w a m =r n
GUY lt. HORN Yke-President. Nuclest
( 0 2) 563-5518 NLS950050 January 27,1995 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555
Subject:
Supplement to Proposed Change No.135 to Technical Specifications and Request for Emergency Consideration, Comrol Room Emergency Filter System Cooper Nuclear Station, NRC Docket No. 50-298, DPR-46
Reference:
Letter from G. R. IIorn (NPPD) to NRC dated January 26,1995, same subject (NLS950042).
Gentlemen:
The Nebraska Public Power District (District) is hereby supplementing its previously submitted Proposed Change No.135 to the Cooper Nuclear Station (CNS) Technical S pecifications. This letter supersedes in its entirety, the referenced letter, which was inadvertent:y submitted to the NRC due to an administrative error. The District apologizes for any inconvenience which this may have caused you.
Following a series of teleconferences held with the NRC Staff, and submittal of the District's Control Room dose calculation, the NRC took exception to certain assumptions used by the District in calculating Control Room operator post-accident integrated dose. As an interim measure, the District commits to implement a procedure to provide Control Room operators with potassium iodide (KI) thyroid-blocking tablets upon indications of a Loss of Coolant Accident (LOCA) which results in core damage. The purpose of the K1 is to reduce thyroid doses below General Design Criteria (GDC) 19 criteria as calcu!ated using NRC Staff assumptions. The commitment to use KI thyroid-blocking tablets has been agreed to by the District as an interim mensure until the NRC's concern with this issue can be resolved.
The District requests that the NRC consider this supplemental transmittal as an emergency request for approval of Proposed Change No.135, to support the performance of the CNS vessel hydrotest on January 29, 1995, which is required prior to startup from the current outage. As discussed below, the District only recently became aware of the NRC Staff's concerns with the District's Control Room dose assumptions. Failure to grant this technical specift ation promptly could result in preventing restart of CNS as scheduled. Therefore, e
emergency treatment of the amendment, including this supplement, could not have been avoided.
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U.S. Nuclear Regulatory Commission January 27,1995 Page 2 of 4 F he District requested that the CNS Technical Specifications By letter dated July 26,1994 t
Limiting Condition for Operation (LCO) 3.12.A.2.c be revised to allow for increased flow capacity of the Control Room Emerger.cy Filter System (CREFS). By increasing the maximum allowed makeup capacity of this system, additional margin is provided for maintaining the positive pressurization of the Control Room envelope. The proposed change also specified a new surveillance requirement in order to periodically verify that the subject LCO has been satisfied. This proposed change resulted from investigations which determined that increased flow capacity for the CREFb was desirable to improve pressurization margins for the Control Room Envelope under accident conditions.
Following NRC Staff review of Proposed Change No.135 and discussions with District personnel during a December 20,1994 conference call, the District agreed to revise its proposal to delineate a specific design flowrate for the CREFS and make additional clarifications. This revision was submitted on December 27,1994.E On January 19,1995, the District submitted its Control Room dose calculation to the NRC as requested by the NRC Staff.1 Based on NRC Staff review of the calculation, and during a series of teleconferences held with NRC Staff members during the peried January 20 - 25, 1995, it was determined that the District and the NRC Staff were not in complete agreement over various assumptions used in the District's dose calculation. The District believes that the assumptions used in its dose calculations (which demonstrate that the GDC 19 limits are met for Control Room operator integrated dose) are reasonable.
However, the NRC Staff's evaluation indicated that additional protective measures are needed to ensure that GDC 19 limits are met for CNS Control Room operator dose for certain LOCAs. Specifically, the NRC stated that their evaluation indicated that Control Room operator use of K1 thyroid-blocking tablets during a LOCA which results in core damage would be required to reduce thyroid dose below GDC 19 limits. Therefore, as an interim measure for resolving this issue, the District commits to implement a procedure which provides KI tablets to the Control Room operators in accordance with the recommended dosage if plant conditions indicate that a LOCA is occurring coincident with core damage. This interim compensatory measure will ensure that GDC 19 limits are met far both the District's and the NRC Staff's evaluation and will remain in effect until the NRC's concerns are resolved.
This interim measure was determined to be necessary based on differences between the District's and the NRC Staff's evaluations of the Control Room operator dose consequences for this accident. These differences are unrelated to the changes to the CNS Technical Specifications in Proposed Change No.135. Accordingly, the significant hazards determination submitted previously remains unchanged, as the existing significant hazards determination 1.
Letter from G. R. llorn (NPPD) to NRC dated July 26,1994, " Proposed Change No.135 to Technical Specifications," (NLS940006).
2.
Letter from G. R. Ilorn (NPPD) to NRC dated December 27,1994, " Revision to Proposed Change No.135 to Technical Specifications," (NLS940143).
3.
Letter from J.11. Mueller to NRC dated January 19,1995, " Transmittal ofInformation in Support of Proposed Ch:mge No.135 to the CNS Technical Specifications," (NLS950032).
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'D U.S. Nuclear Regulatory Commission January 27,1995 Page 3 of 4 adequately addresses the increased CREFS design flowrate, which has limited impact on Control Room operator dose. Further, based on the interim commitment to utilize K1 thyroid-blocking tablets as a Control Room operator dose reduction measure, the NRC agrees that GDC 19 limits will be met for the Loss-of-Coolant Accident. Therefore, NRC approval of Proposed Change 'No.135 will not rest.lt in the introduction of a significant hazard as defined by the criteria given in 10 CFR 50.92(c).
As discussed above, the District will continue to work with the NRC te achieve final resolution of this issue. This resolution may involve additional requests to modify the CNS Technical Specification Limiting Condition for Operation 3.12.A.2.c.
This emergency supplement to Proposed Change No.135 has been reviewed by the necessary District safety review committees. Ily copy of this letter and the attached, the appropriate State of Nebraska official is being notified in accordance with 10 CFR 50.91(b)(1). Copies to the NRC Region IV Office and the CNS Resident Inspector are also being sent in accordance with 10 CFR 50.4(b)(2).
Please contact me if you have any questions or require any further information concerning this issue.
Sine ely, c>w G
forn resident - Nuclear V
GRil:MJil/mjb cc:
- 11. R. Borchert Department of llealth State of Nebraska NRC Regional Office Region IV Arlington, TX NRC Resident inspector Cooper Nuc! car Station NPG Distribution
D.S. Nuclear Regulatory Commission o
January 27,1995 Page 4 of 4 STATE OF NEBRASKA )
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i NEMAllA COUNTY
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G. R. llorn, being first duly sworn, deposes and says that he is an authorized represen+ative of the Nebraska Public Power District, a public corporation and political subdivision of the State of Nebraska; that he is duly authorized to submit this request on behalf of Nebraska Public Power District; and that the statements contained herein are true to the best of his knowled.e and belief.
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i R.IIorn Subscribed in my presence and sworn to before me this 2 9 day of Idtt
, 1995.
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l LIST OF NRC COMMITMENTS l ATTACHMENT 3 l Correspondence No: NLS950050 The following table identifies those actions committed to by the District in this document. Any other actions discussed in the submittal represent intended or planned actions by the District. They are described to the NRC for the NRC's information and are not regulatory commitments.
Please notify the Licensing Manager at Cooper Nuclear Station of any questions regarding this document or any associated regulatory commitments.
COMMITTED DATE COMMITMENT OR OUTAGE Implement administrative controls for administering of Prior to startup potassium iodide thryroid blocking tablets to control room operators during a LOCA with core damage.
PROCEDURE NUMBER 0.42 l
REVISION NUMBER 0 l
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