ML19224A121
| ML19224A121 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 08/18/1978 |
| From: | Herbein J Metropolitan Edison Co |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| GQL-1390, NUDOCS 7809150498 | |
| Download: ML19224A121 (2) | |
Text
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UNITED STATES
'e NUCLEAR REGULATORi' COMMisslON
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j WASHINGTON, D. C. 20555 YOJ; s, w y Docket No. :
0
't ADDRESSEES Gentlemen :
RE: REACTOR VESSEL ATYPICAL HELD MATERIAL This letter confirms our telephone conversation with your staff of August 14, 1978.
The NRC was advised by Bab:ock & Wilcox (B&W) on August 4,1978, that a chemical analysis of an archive weldment performed as part of the program for evaluation of reactor vessel material properties indicated that the nickel and silicon content of the weld material were outside the specified
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range.
It has been determined.that the weld filler wire used for that particular weld was atypical.
As of this date, it is not known whether or not this atypical weld wire was used in the manufacture of your reactor vessel.
Therefore, we request that you provide the following information to us by Friday, August 18, 1978 (a telecopy of your response is adequate):
1.
What interim measures, such as revised pressure / temperature limits, you are taking to ensure reactor vessel integrity in the event that the atypical weld wire was used, i
2.
Your assessment as to the continued safe operation of your facility based on these interim measures, and 3
Your commitment that these measures will continue in force pending the resolution of this issue.
Your submittal should be three signed originals plus 37 additional copies.
Sincerely, i
i i
Branch Chief 7"
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A f a f lf. m.a,. J fg-na. -au w
i METROPOLITAN EDISON COMPANY suestoisarascenenat puoticuritiriescoaroaaricn POST OFFICE BOX 542 READINC. PENNSYLVANIA 19603 TELEPHONE 215 - 929 ':601 GQL 1390 Director of Nuclear Reactor Regulation C
Attn:
R. W. Reid, Chief Operating Reactor Branch No. h U. S. Nuclear Regulatory Cc= mission Washington, D. C. 20555
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Dear Sir:
Three Mile Island Nuclear Station, Unit 2 ( M -2)
Operating License No. DPR-73 Docket No. 50-320 in response to your letter of August 14, 1978 (concerning the possible use of veld filler vire which was atypical of the sub=erged are veld filler wires used by Babecck & Wilcox (3&W), in DC-2 Reactor Vessel velds), please be advised that 3&W has deter =ined that the cnly possible uses of the atypical material in the DE-2 Reacter Yessel vere:
- 1) as filler =aterial for the buildup of lov areas on the ID and CD of the Upper Shell (h" ID: not of sufficient depth to affect operating limits or structural integrity), and
- 2) as veld material en tne Duteb m to Lover Head weld (low flux, lov stress location).
3&W has analyced these possible applications c f the atypical vel:1 =aterial, and has found that; "The structural integrity of the reactor vessel has net been ecsprc=ised by the pcssible presence of the atypical material".
3&W has also cencluded, based on their analysis that: "There is no effect en the reactor vessel operatien for DE-2".
As ycu may be avare, the possible use of this atypical veld material (i.e.,
material having a greater percentage concentration of silicon (1.0% vs 0.5%)
and a snar er percentage cencentration of nickel (0.1% vs 0.6%) than specified by 3&'41in critical veld 1ccations =ay require sete plants to cperate under more stringent pressure-temperature heatup and eccldcyn rate 1 N taticns.
"his is not the case for TMI-2.
3&W has deternined that the heatup and ccoldown rate l u tations are calculated for a " critical uld".
This critical veld is neither of the tvo velds tentioned above in which the atypical veld =aterial
=ay have been used.
(All other velds including the two velds centioned abcve, require less stringent heatup an:1 cooldevn 1"tations than dcea the " critical veld".)
2&W has reanalyced the velds in which the atypie d caterial may have been used, and has determined that the " critical veld" has not changed.
~he current heatup and cooliovn lhitaticns have been, therefore, fcund to be ac-ceptable for all velds in the DE-2 reactor vessel (even for those velds in which the atypical veld mater-ial may have been used).
1'0 m Ew 7~,120047 0
W. Reid, Chief August 18, 1978
,Rt GQL 1390 1
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Therefore, please be advised that Met-Ed is not contemplating taking any interim measures to ensure reactor vessel integrity, for TMI-2 because, as indicated above, such measures are not necessary.
We also believe that, despite the possible use of atypical weld material, the continued safe operation of TMI-2 is assured.
This is because the current heat up and cooldown rates, ac well as the structural integrity of the TMI-2 Reactor Vessel have been analyzed and found to be acceptable.
Sincerely, jv J. G. Herbein Vice President JGH:RAL:tas cc:
Mr. S. A. Varga Mr. H. Silver 1.0?B 6%%
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