ML19345G140
| ML19345G140 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 04/05/1976 |
| From: | Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| IEB-76-01, IEB-76-1, NUDOCS 8103060734 | |
| Download: ML19345G140 (2) | |
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t Mr James G. Keppler US Uuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137 DOCKET 50-155, LICENSE DPR '
BIG ROCK POINT PLANT IE Bulletin 76-01 describes problems which have occurred in the emergency condenser at the Millstone Unit 1 facility and requires a description of the steps that are being taken to (1) assure the integrity of the emergency condenser tubes during operation, (2) assure that the marg!n of emergency condenser tube integrity is maintained and (3) assure prompt detection and-operator response to an emergency conuenser tube leak.
In order to assure the integrity of the e=ergency condenser tubes during operation, we plan to conduct daily water level checks of the emergency condenser shell side, and to sample the shell side water to determine its gross beta gamma activity on a monthly basis. These checks vill be per-formed whenever the reactor is at operating pressure.
It should be noted that whenever a shell side water sample is taken, the shell side must be opened to the containment atmosphere. This means that containment integrity is provided only by the inventory of water in the emergency con-denser shell side. For this reason, we feel that more frequert sa=ples would not be prudent.
In order to assure that a margin of condenser tube integrity is maintained, the IE Bulletin proposes nondestructive testing, or as an alternative, hydro-static testing of the emergency condenser tubes. For the reasons given below, we feel that neither method is practicable.
In order to perform nondestruc-tive testing, the reactor coolant piping to the emergency condenser must be cut in order to permit access to the tube side of the condenser. This is a significant work project. Hydrostatic testing could be accomplished in conjunction with the Nuclear Steam Supply System hydrostatic test which is performed during each refueling outage; however, because of the large volume of the emergency condenser shell side, the smallest leak which could be detected is on the order of one gallon per minute. A consideration which
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obviates the need for a hydrostatic test is that during reactor operation, the emergency condenser is continuously exposed to a pressure of about 1,328 ps'2.
Since this pressure is greater than the pressure normally applied to the emergency condenser tubes during condenser operation (ex-cept for the first few minutes of operation while reactor pressure is decaying), we feel there is little to be gained by conducting a hydro-static test.
The condenser vent radiation monitors with alarms in the control room backed by the daily water level checks and monthly gross beta gamma samples will assure prompt detection of tube leakage.
Procedures are already in effect to require operator action to determine which tube bundle is leaking and to eff'ect its isolation.
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L Ralph B. Sewell Nuclear Licensing Administrator i
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Attached is licensee's reply dated April 5, 1976, to IE Bulletin 76-01.
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i Do NOT use this forrn as a RECORD of approvals. concurrences, disapprovals, clearances. and similar actions e R ou ta..... r,...r...,., s...re 3
G. Fiore111, IE:111 04/07/76
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