ML20235M376
| ML20235M376 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, 05000000 |
| Issue date: | 02/21/1989 |
| From: | Richter M COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 5550K, IEB-88-004, IEB-88-4, NUDOCS 8902280231 | |
| Download: ML20235M376 (2) | |
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a One First National Plaza. Chicago, Illinois
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. ' / Address Reply to: Post Office Box 767
/ Chicago, Illinois 60690 - 0767 February 21, 1989
.U.S. Nuclear Regulatory Commission Attn Document Control Desk Washington, D.C.
20555
Subject:
Byron Station Units 1 and 2 Braidwood Station Units 1 and 2 Supplemental Response to NRC Bulletin 88-04 Docket Nos. 50-454/4554_50-456/457
References:
(a) NRC Bulletin No. 88-04, dated May 5, 1988.
(b) W.E. Morgan letter to U.S. NRC, dated July 11, 1988.
Dear Sirs Reference (a) requested that-licensees investigate and correct as applicable two miniflow design concerns. The first concern involves the potential for the dead-heading of one or more pumps in safety-related systems that have a miniflow line common to two or more pumps or other piping configurations that do not preclude pump-to-pump interaction during miniflow operation.
'A second concern is whether or not the installed miniflow capacity is adequate for even a single pump in operation.
In deference (b), when addressing the adequacy of the minimum flow bypass lines for safety-related centrifugal pumps at Byron and Braidwood Stations, Commonwealth Edison (Edison) indicated that pump suppliers would be contacted to verify that current miniflow rates are sufficient to ensure that there will be no pump damage from low flow operation.
Edison contacted Pacific Pumps, the manufacturer of the Safety Injection (SI), Chemical and Volume Control.(CVC), and Auxiliary Feedwater (AF) pumps at Byron and Braidwood Stations.
Pacific Pumps, in a letter to Edison dated September 16, 1988, indicated that based on originally provided minimum flow values, a catastrophic type failure is not a concern.
Pacific Pumps also indicated that damage caused by low flow operation is not immediate but cwiulative in nature, and recommended that the duration of operation at the minlaum flow values be limited to approximately ten (10) hours per month.
Operation at Byron and Braidwood Stations at minimum flow rates is well under 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> eacn month.
Edison also contacted Ingersoll-Rand, the manufacturer of the ResiduO. Heat Removal (RHR) pumps at Byron and Braidwood Stations.
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l IngerFell-Pand, in a letter to Edison dated September 20, 1988, indicated that l;
a minimum flow rate of 500 gallons per minute (GPM) is adequate to prevent l
short-term damage. Test tesulto from Byron and Braidwood Stations indicate that the RHR pumps operate at minimum flow rates greater than 500 GPM.
It is Edisen's understanding that Ingernoll-Rand is conducting a study for relating flow rates to service life. Any new vendor information on this subject will be evaluated appropriately by Edison.
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.d The responses from the pump suppliers, coupled with the. review of 1
I pump vibration data ~previously discussed in Reference (b), provide assurance that operation of the Byron and Braidwood safety-related pumps at low flow conditions will not cause pump damage.
To the.best of my knowledge and belief, the statements contained p
above are true and correct.
In some respect these statements are not based on' l
8 my personal' knowledge, but obtained Information furnished by other Commonw^alth Edison employees, contractor employees, and consultants. Such information has been reviewed in accordance with company. practice, and I I
believe it to be reliable.
i Please address any questions that you or your staff may have concerning this response to this office.
Respectfully, aA H. Aar~
M.H. Richter Nuclear Licensing Administrator
-rf 5550K cc A.B. Davis Resident Inspectors - BY/BW i
Subscrfi ed and to g day beford o this (L4A W 1909 a s b u't k l Y, doA Notary Public f
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