ML19254D605
| ML19254D605 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 10/18/1979 |
| From: | Conner E Office of Nuclear Reactor Regulation |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7910290157 | |
| Download: ML19254D605 (2) | |
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION p
WASHINGTON. D. C. 20555
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October 18, 1979 c
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Docket No. 50-336 MEMORANDUM FOR:
Robert W. Reid, Chief Operating Reactors Branch #4 Division of Operating Reactors FROM:
E. L. Conner, Project Manager Operating Reactors Branch #4 Division of Operating Reactors
SUBJECT:
FORTHCOMING MEETING WITH NORTHEAST ENERGY COMPANY ON FEEDWATER LINE CRACKS Time & Date:
10:00 a.m.
Friday, October 19, 1979 Location:
Phillips Building, P-110 Bethesda, Maryland (Extention 27700)
Purpose:
To discuss the second inspection of feedwater line crack indications observed at Millstone 2 and the attached questions related to the inspection and repair.
Participants:
NRC NNECO B. Grimes E. DeBarba W. Gammill R. Kacich V. Noonan M. Kupinski R. Reid R. Rothgeb W. Hazelton E. Conner W. Hermann E. Jordan W. Sanders T. Shediosky
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E. L. Conner, Project Manager Operating Reactors Branch #4 Division of Operating Reactors Attachment 1221 133 791029015 7
MEETIt4G fl0TICE DISTRIBUTION ORB #4 Docket File W. Gammill NRC PDR L. Shao LPDk J. Miller ORB #4 Rdq NRR P,dg H. Denton E. G. Case D. Eisenhut R. Vollmer W. Russell B. Grimes T. J. Carter A. Schwencer D. Ziemann T. Ippolito R. Reid V. Noonan P. Check G. Lainas G. Knighton Project fianager OELD 01&E(3)
R. Ingram Receptionist, Bethesda R. Sley, ACRS (16)
Projram Support Branch i
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,l J. R. Buchanan f
Meeting flotice File NRC Participants W. Hazelton k22\\
}J74 W. Hermann E. Jordan W. Sanders T. Shedlosky s,
MILLSTONE NUCLEAR POWER STATION UNIT 2 ADDITIONAL. INFORMATION REQUIRED h
TO ASCERTAIN ACTIONS NECESSAky u1 UN il REGARDING THE FEEDWATER SYSTEM PIPING 1.
In your letter of September 28, 1979 you stated that thermal variations (stratification) was observed during low flow conditions. Address the potential for crack propagation during these low flow conditions (low cycle fatigue).
Provide a quanitative analysis regarding crack growth rates during the thermal transient cycle.
2.
Assuming the analysis requested above predicts crack growth at a sufficiently low rate to ensure adequate safety margins can be maintained until a perm-anent repair can be made at the June 1980 refueling outace, provide the details of an augmented inspection program which verifies that crack growth has not occurred at a rate faster than predicted by the analysis.
3.
In the proposed repair / replacement program you submitted, you stated that the removal of the shield wall section can be made within design bases limitations.
a.
Provide the technical information supporting your conclusion, b.
Provide assurance that the method of removing part of the concrete wall by drilling and chipping will not damage the concrete left in place and the existing reinforcing bars. Describe the quality assurance procedures which will be used during the concrete removal operation, c.
Describe the procedure which will be used if the reinforcing bars must be removed.
d.
If replacement on the removed shield wall segment is required, address the following:
(i)
Define the concrete mix which will be used to fill the recess in the shield wall.
(2) Describe the procedure for reinforcing bar. replacement.
(3)
Define the method to be used tc ensure compatibility of the new and old concrete, especially the measures planned to limit shrinkage of the new concrete.
Discuss the degree of working together that can be expected from the new concrete and existing wall.
4 Provice the details for material removal as discussed in repair Option B.
Also, provide the detailed procedures for the weld repair on the ID of the pipe should the wall thickness be reduced below Code limits. Address the mock-u: used to qualify the welding procedures,for training and to qualify the helders/weiding machine operators.
5.
Descrite the simulation for welder training and qualification to account for the li-ited access between the shield wall and steam generatcr in Option A.
Provide.ny details regarding the consideration of autcmated welding to make the nozzle to pipe repair.
6.
State if a UT baseline examination will be performed for the nozzle to piping weld if Option A is used.
1221 135