ML20151H691
| ML20151H691 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 07/21/1988 |
| From: | Mroczka E NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| Shared Package | |
| ML20151H694 | List: |
| References | |
| REF-GTECI-A-43, REF-GTECI-ES, RTR-REGGD-01.082, RTR-REGGD-1.082, TASK-A-43, TASK-OR B12965, NUDOCS 8808020006 | |
| Download: ML20151H691 (2) | |
Text
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General Offices e Sewn Street. Bedin. Coonetticut t
J 2 ) 5 July 21, 1988
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Docket No. 50-245
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B12965 Re:
ISAP Topic 1.47 U.S. Nuclear Regulatory Commission Attn: Document Control Desk l'ashington, D.C. 20555 Gentlemen.
Millstone Nuclear Power Station, Unit No. I h
Maximum Averace Planar Linear Heat Generation Rate i
l Pursuant to 10Cg0.90, Northeast Nuclear Energy Company (NNECO) submitted a i
proposed change to the Technical Specifications of Millstone Unit No. I which would reduce the Maximum Average Planar Linear Heat Generation Rate (MAPLHGR) limit by 2 percent.
The change would compensate for potentially l
degraded emergency core cooling system flow due to debris induced strainer plugging following a loss of cool (ECCS) ant accident (LOCA), which has been 4
postulated as a result of a study performed under the ?ntegrated Safety I
Assessment Project (ISAP)
Topic 1.47, "Containment Emergency Sump Performance."
This study was undertaken to evaluate the acceptability of l
fibrous insulation in Millstone Unit No.
I's drywell with respect to i
degradation of long term ECCS recirculation.
As part of NNECO's proactive efforts to utilize ISAP to address unresolved safety issues (USIs) and generic issues, ISAP Topic 1.47 was initiated to address USl A 43, "Containment
[
Emergency Sump Performance."
The study included a review of the criteria in t
Regulatory Guide 1.82, Revision 1, "Water Sources for Long Term Recirculation Cooling following a LOCA."
j in a subsequent telephone conversation with members of the NRC Staff on June 28, 1988, NNECO was requested to provide additional information concerning the j
results of the study and our conclusions that ECCS pump net positive suction head (NPSH) margin and operability could potentially be compromised.
Specifi-cally, NNECO was requested to submit additional information concerning the drywell insulation study.
The attached document explains our corrective actions and bases, and was previously provided to the Millstone Unit No.1 j
Senior Resident inspector.
j With respect to the requested license amendment resulting from the 2 percent I
reduction in the MAPLHGR limit, we emphasize that our request is a conserva.
i tive action to update our Technical Specifications to accurately reflect i
l i
J l
(1)
E. J. Hroczka letter to U. S. Nuclear Regulatory Comission, ' Maximum I
Average Planar Linear Heat Generation Rate," dated June 3, 1988, i
' VI l
esoeoroco6 eso722 DR ADOCK o5o00245 p
U.S. Nuclear Regulatory Commission B12965/Page 2 July 21, 1988 actual lin.its that we have already administratively imposed. As was Indicated in Reference (1), the MAPLHGR thermal limit has previously been implemented administratively, and issuance of the amendment would yield no substantive changes.
The 2 percent reduction in MAPLHGR limit will only be required until the ECCS suction strainers are replaced with larger area strainers, which is currently scheduted to be completed by the end of the 1989 refueling outage.
(Preliminary results of our ongoing efforts to develop a revised Integrated Irplementation Schtdule support this schedule.)
Since our administrative controls already in effect preclude exceeding the reduced thermal limit, the issuance (or absence thereof) of the requested license amendment will not affect plant operation.
If you have any furtl,er questiors on this matter, please feel free to contact my staff.
Very truly yours, NORTHEAST NUCLEAR ENERCY COMPANY aDr
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Senio Vice President Enclosure ec:
W. T. Russell, Region 1 Administrator M. L. Boyle, NRC Project Manager, Millstone Unit No. 1 W. J. Raymond, Senior Residant inspector, Millstone Unit Hos 1, 2, and 3 L. Kolownauski, Resident inspector, Millstone Unit No. 1 A