ML19257D873
| ML19257D873 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities  |
| Issue date: | 01/18/1980 |
| From: | Peoples D COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| IEB-80-01, IEB-80-1, NUDOCS 8002060667 | |
| Download: ML19257D873 (2) | |
Text
Commonwealth Edison e
One First National Plaza, Chicago. litinois Address Reply to: Post Office Box 767 Chicago, Illinois 60690 6
January 18, 1980 Mr. James G. Keppler, Director Directorate of Inspection and Enforcement - Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137
Subject:
Dresden Station Units 1, 2, & 3 Quad Cities Station Units 1 & 2 Response to IE Bulletin No. 80-01 NRC Docket Nos. 50-10/237/249 and 50-254/265
Dear Mr. Keppler:
In response to IE Bulletin 80-01, Commonwealth Edison Company has developed a program for confirming the seismic capability and leakage rates for the ADS valve pneumatic supply systems at Dresden Units 2 and 3 and Quad Cities Units 1 and 2.
This program is based on an analysis which shows that, for reduced maximum average planar linear heat generation rate (MAPLHGR) limits, the single pneumatically controlled ADS valve on each of thest units is not required to meet the licensing basis ECCS requirements.
This analysis is discussed in more detail in the following paragraphs.
Since these pneumatically controlled valves are not required to provide full ADS function, the pneumatic supply system review will be performed no later than the next refueling outage for each unit.
This program will assure plant safety margins consistent with the intent of the Technical Specifications and your IE Bulletin 80-01.
The subject bulletin requires confirmation of the adequacy of the ADS as affected by postulated failures on the Target-Rock valve pneumatic supply system.
These postulated failures affect only one of the five valves comprising our ADS; the other four valves are operated electrically from DC power supplies.
The aforementioned ECCS analysis (including ADS) was performed to confirm ECCS adequacy with regard to power supply failures.
Specifically, a case involving a small break area loss-of coolant accident and a failure oi one DC pcwer supply was analyzed.
For this case, only four ADS valves, two LPCI pumps and one core spray pump were considered operable.
The results of this analysis indicates chat peak clad temperatures remain below the Appendix K limit (22000F) for the 7 educed NAPLHGR values used.
The lower MAPLHGR values are expre ssed as reduction factors to existing limits based on the most limiting fuel type / exposure.
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Commonwealth Edison Mr. James G. Keppler NRC Docket Nos. 50-10/237/249 January 18, 1980 and 254/265 Page 2
Since the reduction factor for the most limiting fuel type / exposure is used for all other fuel types, the analysis remains conservative for all other fuel types and exposures.
Based on these analyses, ADS operability for the subject bulletin is assured, regardless of the loss of the pneumatic supply system to the Target-Rock valve if the units are operated within the reduced MAPLHGR limits.
Accordingly, we will submit Technical Specification changes requiring operability of four ADS valves and defining appropriate actions in the event that an additional valve becomes inoperable and reducing the MAPLHGR limits.
These reduced MAPLHGR limits will be administrative 1y in force at the stations until the Technical Specifictilon changes become approved.
We will inspect and modify as applicable the Target-Rock valve pneumatic supply system during scheduled refueling outages to assure seismic capability.
Additionally, the isolation check valves will be tested for excessive leakage and modified if appropriate.
These actions will be completed on Quad Cities Unit 2 prior to startup from the current refueling outage.
Dresden Unit 1 design does not include an ADS of any kind.
The bulletin is, therefore, not applicable and no further action on Dresden 1 is required.
Please address any questions you may have concerning this matter to this office.
Very truly yours, D. L. Peoples Director of Nuclear Licensing cc:
Director, Division of Reactor Operations Inspection 1927 228 1485^
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