ML20024G456
| ML20024G456 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 08/08/1972 |
| From: | Wachter L NORTHERN STATES POWER CO. |
| To: | Grier B US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20024G451 | List: |
| References | |
| NUDOCS 9102120499 | |
| Download: ML20024G456 (2) | |
Text
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COOED NORTHERN STATES POWER COMPANY 1
weNNs Apou e. umus eovA se4oi August 8, 1972 L
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Mr Boyce H Grier, Regional Director U S Atomic Energy Commission Directorate of Regulatory Op(rations, Region III l
799 Roosevelt Road l
Glen Ellyn, Illinois 60137 i
Daar Mr Grier i
MONTICEllo NUCLFAR GENEPATING PIANT AEC Ibeket No. 50-263 Valve Wall Wickness Verification In response to your letter of June 29, 1972 concerning the vall thickness of valves within the reactor coolant system boundary of our Monticello Nuclear Generating Plant, the following information summarizes our efforts to date I
and our future direction of endesvor.
i The valves within the reactor coolant pressure boundary, as defined in subsection l
50 55 (a) of 10 CFR 50, that are over lh inch and 2h inch nominal pipe size in water lines and in steam lines, respectively, have been identified and listed by system, manufacturer, and valve size, class, and type.
Knowledge of any valve in our system with inadequate vall thickness would, of course, be of great concern to us.
We have had some assurance in the fact that through hydrostatic tests at pressures well above operating pressures that these valves in the primary system are at the present capable of providing integrity to our pressure boundary system.
In addition, we are unaware of any valve failures in either fossil or nuclear plants due to inadequate vall thickness. Nevertheless, we are concerned with any question or doubt in our plant's, safety.
A program is being developed which will assure that the valves within the reactor coolant system boundary have adequate vall thickness. A definite plan vill be submitted when investigation of several relevant factors are completed.
Some of these factors are AUG 10 WL 9102120499 730913 gDR ADOCK O M 263 e
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- RN OTATEO POWER CON ANY 2-Augus t 8,1972 Mr li H Grier 1.
Entimtion of radiation levelo, including escalated levels over the three year period.
2.
Development of ultrasonic techniques to measure vall. thickness within a wtximum error of repentability.and accuracy mutually agreed to.
3 Estination of time' per valve and for entire program, which includes all accociated activities.
4.
Factoring the program into the Monticello's Incervice Inslection Program.
It appears that the most practien1 method of meacuring valve vall thickness in an operational plant is by ultraconic techniques.
It is our intention these techniques vill be developed and adequate tecting performed to verify mutually agreed to accuracy.
We vill inform you on the details of the program and schedule within ninety days, and vill meet comp 1,etion of the program in your specified three year limit.
We trust that the above is recponsive to your letter and are prepared to discuss this uitter at your convenience.
Yours very truly, Yeh L J hachter, Vice President Power Pitduction &' System Operation IJW/ca e
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