ML19206A746
| ML19206A746 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 03/26/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Herbein J METROPOLITAN EDISON CO. |
| References | |
| NUDOCS 7904200449 | |
| Download: ML19206A746 (1) | |
Text
v8 "fCog UNITED STATES NUCLEAR REGULATORY COMMisslON
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REGION I 3.'
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KING OF PRUS$1 A, PENNSYLV ANI A 19406 March 26,1979 Docket Nos. 50-289 50-320 Metropolitan Edison Company ATTN: Mr. J. G. Herbein Vice President - Generation P. O. Box 542 Reading, Pennsylvania 19640 Gentlemen:
This Information Notice is provided as an early notification of a possibly significant matter.
It is expected that recipients will review the information for possible applicability to their facilities. No specific action or response is requested at this time.
If further NRC evaluations so indicate, an IE Circular, Bulletin or NRR Generic Letter will be issued to recommend or request specific licensee actions.
If you have questions regarding the matter, please contact this office.
Sincerely,
/ coyce H. 9rier Directcr
Enclosures:
1.
IE Information Notice No. 79-07 2.
List of Information Notices Issued in 1979 7904200441 60-323 b
Metropolitan Edison Company 2
cc w/encis:
E. G. Wallace, Licensing Manager J. J. Barton, Project Manager R. C. Arnold, Vice President - Generation L. L. Lawyer, Manager - Generation Operations G. P. Miller, Manager - Generating Strtion - Nuclear J. L. Seelinger, Unit 1 Superintendent W. E. Potts, Unit 1 Superintendent - Technical Support J. B. Logan, Unit 2 Superintendent G. A. Kunder, Unit 2 Superintendent - Technical Support I. R. Finfrock, Jr.
Mr. R. Conrad C. F. Trowbridge, Esquire Miss Mary V. Southard, Chairman. Citizens for a Safe Environment 60-324
UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 IE Informatior Notice No. 79-07 Date:
March 26, 1979 Page 1 of 2 RUPTURE OF R.iDWASTE TANKS Description of Circumstances:
In November, 1977 a radwaste tank ruptured at the Millstone Nuclear Power Station.
Two problems led to the tank failure.
First, the tank vent, which was intended to relieve excessive pressure in the radwaste tank, had been plugged by accumulated solidified concentrates.
- Second, corrosion had weakened the capability of the radwaste tank to withstand pressure.
Individually, or in combination, these problems were causa-tive factors in the rupture of the radwaste tank due to overpressurization.
The Licensee Event R, ort states that an aerated waste concentrates tank was overpressurized and ruptured.
The tank contained radwaste evapo-rator concentrates with a 10-12 percent boric acid concentration.
These concentrates, when cooled to ambient temperatures, formed a solid crystaline structure.
Apparently, concentrate had entered the vent line by previous tank overflows or purging of air through the tank so that a solid buildup occurred in the vent line.
This buildup eventually led t a flow blockage in the vent line.
The licensee, in an attempt to blow out or clear a radwaste pipe, applied 100 PSI air pressure to the tank.
The tank was designed for 15 PSI and the plugged vent could not relieve pressure.
Therefore, the tank overpressurized and ruptured.
This tank had a history of corrosion problems such that the corrosion p*obably caused some weakness which contributed to the rupture.
The tank war, constructed of type 304 stainless steel.
The plant was a sea-coast site such that significant amounts of chlorides were present in the aerated waste system and, consequently, in the waste concentrate tank.
The presence of significant amounts of chlorides, coupled with residual welding stresses in the type 304 stainless steel, resulted in chloride stress corrosion.
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