ML20002C729
| ML20002C729 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point, Palisades File:Consumers Energy icon.png |
| Issue date: | 11/09/1972 |
| From: | Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Grier B US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20002C721 | List: |
| References | |
| NUDOCS 8101100797 | |
| Download: ML20002C729 (2) | |
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Campny General Offices: 912 West unchigan Avenue, Jackson. Machigan 49201. Area Coce 517 788 0550 November 9,1972 Mr. Boyce H. Grier, Regional Director Re: Docket No 50-155 Directorate of Regulatory Operations and US Atomic Energy Commission 799 Roosevelt Road Docket No 50-255 Glen Ellyn, Illinois 60137
Dear Mr. Grier:
Since receiving your letter of June 29, 1972 concerning minimum valve vall thickness verification, Consumers Power Company has investi-gated the possible alternatives available to demonstrate acceptable valve vall thicknesses at the Palisades and Big Rock Point Plants.
This letter vill inform you of our future plans.
Valves located within the reactor pressure boundary (as defined in your June 29, 1972 letter) at the Palisades Plant shall be inspected to establish vall thickness, using ultrasonic examination techniques.
The inspect, ion program vill consist of one valve of each type (check, gate, globe, etc) size and rating for each valve manufacturer.
If in-spection reveals a valve having a vall thickness deficiency, all valves of that manufacturer within the reactor pressure boundary will be cAamined.
The accuracy of ultrasonic measurements vill be that determined from calibration blocks.
The material used as a calibration block vill be representative of the valve material being measured.
Best efforts vill be extended to insure that equipment, techniques and procedures are capable of producing a measurement error of 2% or less with respect to the actual calibration block dimensions.
It is possible that some stainless steel valves vill have a metallurgical structura such that acoustic measurement to a high de-gree of precision is impossible to achieve. In such cases, vall thick-ness measurements will not be performed.
Minimum vall thickness requirements vill be established based on the followin6 codes as they are applicable to the specific installation:
ASA B31.1 (1955), USAS B31.1.0 (1967), USAS B16.5 and FSS-SP-66.
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D9chet No 50-155 and Docket No 50-255-November 9, 1972 The inspections described above can only be performed during a prolonged reactor shutdown. These inspections vill commence during the first scheduled Palisades refueling outage, Septenber 1973, and vill be completed by November 1975 Vall thickness examination of vc1ves installed in the Big Rock Point Plant is deemed unnecessary. Approximately 10 years of operating the primary system at pressures of 1350 psia and above plus numerous operating pressure (cold) hydrostatic tests have not revealed any indi-cation of valve leakage or failure caused or contributed to by inn.dequate valve vall thickness.
Since Big Rock was designed for reactor operation at 1500 psia, valve procurement specifications frequently provided for valves rated substantially higher than the service conditions actually imposed.
Recordr, indicative of this fact vill be available for your review at Big Rock Point subsequent to Decent r 1, 1972.
Yours very truly,
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RBS/ map Ralph B. Seve11 Nuclear Licensing Ad=inistrator O
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