ML19294B703
| ML19294B703 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 02/28/1980 |
| From: | Biemiller E Maine Yankee |
| To: | Snaider R Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0577, RTR-NUREG-577 MEG-128-80, NUDOCS 8003050365 | |
| Download: ML19294B703 (2) | |
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ENGINEERING OFFICE WESTBORO, MASS ACHUSETTS 01581 617-366-9011 N%
_Q February 28, 1980 MEG 128/80 MY G 1.8.9 Division of Operating Reactors Of fice of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Attention:
R. P. Snaider
Subject:
NUREG-0577, " Potential for Low Fracture Toughness and Lamellar Tearing on PWR Steam Generator and Reactor Coolant Pump Supports".
Dear Mr. Snaider:
NUREG-0577 ranked nuclear power plant, heavy component supports as to their susceptibility to brittle failure (having low f racture toughness p rope rties).
Because the heat treatment of Maine Yankee's steam generator sliding bases was unknown, Maine Yankee was placed into the Group I ranking (highest susceptibility). This ranking would require additional studies to be made.
Since the issuance of NUREG-0577, it has been determined that Maine Yankee steam generator sliding bases (Cp Drawing #220-020) fabricated from A27 Grade 70-40 casting material were heat treated at 16500F.,for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. This normalization heat treatment, according to NUREG-0577, Page C-40, will allow Maine Yankee's ranking to be reduced to the Grotip II category.
Attached is a copy of C-E's letter indicating the heat treatment and the fact that recorder traces of the heat treatment are available if necessary.
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Page 2 of 2 Feb rua ry 28, 1980 R. P. Snaider We t rus t that the above information causes Maine Yankee to be placed in the Group II category with respect to support material f racture toughness and that no further information will be required.
Should you have any questions, please contact us.
Sincerely, MAINE YANKEE ATOMIC POWER COMPANY f'
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^~~~ p E. C. Biemiller Mechanical Engineering Group ECB/aja CC:
R. H. Groce E. C. Wood /MY Enclosure