ML20010C089

From kanterella
Jump to navigation Jump to search
Provides Supplemental Response to Violations Noted in IE Insp Repts 50-454/80-09,50-455/80-08,50-456/80-04 & 50-457/80-04.Review Indicated That,In All Cases,Max Load Was Less than Reduced Allowable
ML20010C089
Person / Time
Site: Byron, Braidwood  Constellation icon.png
Issue date: 03/26/1981
From: Abel J
COMMONWEALTH EDISON CO.
To: James Keppler
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20010C082 List:
References
NUDOCS 8108190107
Download: ML20010C089 (2)


Text

,_

q' .

.' ' 'D Commonwealth Edison

^

) On3 First National Plan, Chicago, Illinois

, O' Address Reply to: Post Office Box 767 s

( Chicago, tilinois 60690 March 26, 1981 Mr. James G. Keppler, Director Directorate of Inspection and Enforcement.- Region III U.S. Nuclear Regulatory Commission-799 Roosevelt Road Glen Ellyn, IL 60137

Subject:

Byron Station Units 1 and 2 Braidwood Station Units 1 and 2 Supplemental Response to IE Inspection Report Nos.

50-454/80-09, 50-455/80-08 50-456/80-04, and 50-457/80-04 NRC Docket Nos. 50-454, 50-455, 50-456 and 50-457-References (a): July 11, 1980 letter from D. L. Peoples to James G. Keppler.-

(b): July 18, 1980 letter from D. L. Peoples to James G. Keppler.

(c): October 15, 1980 letter from J. S. Abel to James G. Keppler.

(d): December 11, 1980 letter from J. S. Abel to James G. Keppler.

(e): March 4, 1981 letter from J. S. Abel to James G. Keppler.

Dear Mr. Keppler:

This is to provide the technical assessment of coating requirements for repair of spot welds on UNISTRUT hangers which was discussed in references (a) and (b).

We have reviewed the effect of corroded welds to determine if this weld deterioration could significantly reduce the load-carrying ability of a cable tray support over its 40-year design life, and have concluded that this corrosion is an acceptable condition and that touch-up painting will not be required. This conclusion is based on the following information.

An extensive literature search was performed to establish a l corrosion rate for pregalvalized material over a 40 year period. We conservatively assumed 8.5 mils as the corrosion allowance based upon the published literature for uncoated carbon steel in a rural exposure.

8108190107 810814 $PR _ 2 jgg)

PDR ADDCK 05000454 0 PDR.

( .-

  • t s UNISTRUT provided actual shear test results from tests performed during the time period in which strut was being produced for Byron and Braidwood. These test results were used to establish the average ultimate shear strength of the spot welds. A reduced allowable shear load was established on the basis of this test data and the 8.5 mil corrosion allowance.

The maximum shear load per spot weld was established from the cable tray support design. Each of the three types of double strut members, P1001, P5501, and P5001 (as manufactured by UNISTRUT) were considered. In all cases the maximum load was found to be less than the reduced allowable.

Please address any questions that you might have concerning this matter to this office.

Very truly yours,

/

. . Abel Director of Nuclear Licensing 16018 C'