ML20141A201
| ML20141A201 | |
| Person / Time | |
|---|---|
| Site: | 05000231 |
| Issue date: | 09/27/1971 |
| From: | Woodruff R US ATOMIC ENERGY COMMISSION (AEC) |
| To: | US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20140G249 | List:
|
| References | |
| FOIA-97-34 NUDOCS 9705140180 | |
| Download: ML20141A201 (2) | |
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0 *** UNITED STATES
! ATOMIC ENERGY COMMISSION D
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5 WASWNGTON, D.C. 20545 September 27, 1971 s
l File (SEFOR, Do ket No. 50-231)
THRU: .
.h [, Chief, ORB #1, DRL EVALUATION O PROPOSED CHANGE NO. 5 (HEAD BOLTS)
By 'IWX on March 15, 1971, GE informed DRL that the outer ring of bolts in the head of the reactor vessel had yielded. After reviewing GE's l report (1) which followed the TWX, we requested additional information(2) which GE is submittingin three parts. Two parts have been received.
The first part is a report (3) dealing with bolt stresses, the second part is a proposed change (4) to the Technical Specifications, and the third part will be a repcrt of an independent analysis of the stress at the vessel wall to flange transition.
l The report on bolt stresses summarizes analyses of strain measurements l
which demonstrate that the stresses in the bolts will be within code allowables if the prestress in the bolts is limited to 4000 psi and if the average rate of change of outlet temperature is limited to 10 F/hr
! or less. Limiting the rate of change of temperature limits the relative rotation of the flanges and the stress superposed on the prestress. At DRL's request, the report was reviewed by DRS and found to provide reasonable assurance that the bolting problem has been solved.(5)
The proposed change to the Technical Specifications would limit bolt prestress, limit the rate of change of outlet ter:perature and require surveillance of the bolts. The pro,osed change is adequately supported by the stress report. However, the proposed surveillance requirement references dye penetrant code criteria for forgings and bars instead of i
the criteria for bolts. Further, GE has omitted a reference to the code criteria for visual examination of bolts. GE has agreed (6) to appro-priate changes in their proposal.
(1) K. Cohen, letter to P. A. Morris, May 17, 1971.
(2) P. A. Morris, letter to K. Cohen, April 19, 1971.
(3) K. Cohen, letter to P. A. Morris, May 28, 1971.
1 (4) K. Cohen, letter to P. A. Morris, April 28, 1971.
(5) D. F. Lange and R. R. Maccary, memo to D. J. Skovholt and R. W.
Woodruff, August 20, 1971.
(6) R. A. Meyer, telecon with R. W. Woodruff, September 7,1971.
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Our request for the independent stress analysis of the vessel wall to flange transition stated that the information was required within six J months. GE has assured (3)-us that the information will be submitted
'within that time. The 'information is expected to be confirmatory and
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is.not essential for action on Proposed Change No. 5.
Based on our evaluation of the proposed change, we -conclude that it does not present significant hazards considerations'not described or implicit in the safety analysis report and that there is reasonable assurance that the health and safety of the public will not be endangered.
(1
-% ,h?> . c I
R. W. Woodruff l Operating Reactors Branch #1
)
Division of Reactor Licensing '
cc: D. J. Skovholt ,
i R. H. Vollmer ;
R. J. Schemel ;
R. W. Woodruff (2) !
S. A. Teets ,
M. Jinks (2) )
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