ML19330B982
| ML19330B982 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 08/04/1980 |
| From: | Crouse R TOLEDO EDISON CO. |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| 640, TAC-11005, NUDOCS 8008070350 | |
| Download: ML19330B982 (2) | |
Text
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R3LEDO Docket No. 50-346 Ei[3lEiC)rd License No. NPF-3 acwo P Cacuse Serial No. 640
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August 4, 1980
,.n si ass-sar Director of Nuclear Reactor Regulation Attention:
Mr. Robert W. Reid, Chief Operating Reactors Branch No. 4 Division of Licensing United States Nuclear Regulatory Commission Washington, D. C.
20555
Dear Mr. Reid:
Condition 2.C.(3)(e) of the Davis-Besse Nuclear Power Station, Unit 1 (DB-1)
Operating License (NPF-3) required the reactor coolant system flow indication to meet the single failure criterion with regard to pressure sensing lines to the flow differential pressure transoitters.
Through discussions with your staff and your letter of March 15, 1979 (Log No.375) an NRC staff position was transmitted that identified an acceptable method of compliance with similar license condition on another facility. Toledo Edison Company is modifying its current reactor coolant system (RCS) flow indication scheme in a similar manner and will complete this effort prior to startup follow-ing the current refueling outage. On July 21, 1980 Toledo Edison submitted a general description of the modification to the NRC (TECo Serial No. 633). This letter and its attachment provides specific details of the modification discussed with your staff on July 30, 1980.
In addition an error is noted in the July 21, 1980 response from Toledo Edison.
The correct minimum separation for the new sensing lines should read 3 feet.
Further clarification of the separation criteria is provided in the attachment.
Very truly yours, f
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THE TCLECO ECISCN COMPANY EDISCN PLAZA 3C0 MAC!SCN AVENUE TCLEDO, CHIO 43652 8008070 3 50
Docket No. 50-346 License No. NPF-3 Serial No. 640 August 4, 1980 ADDITIONAL INFORMATION FOR REACTOR COOLANT LOOP FLOW INDICATORS Item 1 "Is there a manual shutoff valve on each line downstream of the tee?"
RESPONSE
There are no manual shut-off valves on the new redundant sensing lines downstream of the tees.
However, the tees for the new lines are at a minimum distance (approximately 4") downstream of the isolation (root) valves on the existing sensing lines.
Item 2 "How are the independently routed redundant lines directed? Does this configura-tion meet the single failure criteria?"
RESPONSE
This follows the Bechtel generic separation criteria. The new redundant sensing lines have been routed a minimum of three feet from the existing lines to meet a single failure criteria.
Iten 3
" Identify separation or barriers between channel flow transmitters on loops A and B."
RESPONSE
The separation criteria is maintained between channels at tSe flow transmitters as follows:
For R. C. Loop "A" The existing sensing lines now serve transmitters FT-RCIA2 and FT-RCIA4, and the new sensing lines will serve FT-RCIA1, FT-RCIA3 and FF-RC01A (test transmitter).
4 Where physical separation between installed transmitters is less then three feet apart, a steel shield plate (1/2 inch thick x 36 inches long x 18 inches deep) has been installed. This is the case between transmitters FT-RCI A3 and FT-RCIA4.
For R.C. Loop "B" The existing sensing lines now serve transmitters FT-RC1B1, FT-RC1B4 and FP-RC01B (test transmitter), and the new sensing lines will serve FT-RC182 and FT-RC1B3.
Steel shield plates have also been installed at the "B" loop transmitters and associated piping to maintain channel integrity, as described above, where the three foot separation criteria has not been met.