ML19274F806
| ML19274F806 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 08/01/1979 |
| From: | Howell S CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| Shared Package | |
| ML19274F807 | List: |
| References | |
| HOWE-215-79, NUDOCS 7908060405 | |
| Download: ML19274F806 (4) | |
Text
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(A )s ceneumers fc power gg Stephen H. Howell g
Sennor Vice Ivesident y,
General Of fices: 1945 West Parnall Road, Jackson, Michigan 49201 + (517) 788-0453 August 1, 1979 Hove-215-79 Mr J G Keppler, Regional Director Office of Inspection and Enforcement Region III US Huclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137 MIDLAUD NUCLEAR PLANT UTIT No 1, DOCKET NO 50-329 UNIT NO 2, DOCKET No 50-330 IMPACT TESTED - ITT GRINNELL SUPPLIED MAIN FEED PIPE
Reference:
S H Howell letter to J G Keppler; Midland Nuclear Plant; Unit No 1, Docket No 50-329; Unit no 2, Docket no 50-330; Impact Tested - ITT Grinnell Supplied Main Feed Pipe; The referenced letter and this letter are interim 50 55(e) reports on the status of Main Feed Pipe Spools which have questionable impact test results.
Attachment (1) ic Consumers Power Company's statement of the status of activities associated with the spools which was derived from the referenced letter and from the additional basic data given in Ecchtel's MCAR Interim Report, provided as Attachment (2).
Another report, either interim or final, will be provided by September 7, 1979 em D
~
Attachment s:
(1) Consumers Pcver Company's Statement of the Status of Action Associated With ITT-Grinnell Supplied Main Feedvater Pipe Spools (2) MCAR-29, Interim Report no 2, dated July 26, 1979 CC: Director of Office of Incpection & Enforcement Att: Mr Victor Stello, USNBC (15)
D12ec^or, Office of Management Information and Program Control, USImc (1)
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Page 1 Howe 215-79 CONSUMERS POWER COMPANY'S STATEMEIC OF THE STATUS OF ACTION ASSOCIATED WITH ITT-GRI!TNELL SUPPLIED MAIM FEEDWATER PIPE SPOOLS The purpose.of this attachment is to provide a summary of the sequence of events that are associated with each of the heats of piping spools.
Thic data is taken from Attachment No 2 and Con,sumers Power Company's previously referenced letter.
A. - Heat N-32762 1.
One set of Charpy impact specimens were taken, but were not valid because they were obtained from an incorrect location.
9 The first set of valid test specimens were obtained.
For the material under consideration, the ASME acceptance criteria required three full-sized specimens be tested and that each specimen have a minimum test result of 25 mils lateral expansion.
The test results were 21, h0 and h5 mils lateral expansion (at the required +30 F temperature) and the test was unacceptable.
3.
The ASME Code allows one retest at the same test temperature to be performed, if the initial test results met the following criteria:
a.
the average result of all three initial test specimens meets the minimum requirement b.
not more than one of the original specimens was below the minimum requirement c.
the specimen, which failed, was not more than 5 mils below the specified requirement.
Based on the results of the original test (see A.2) one retest, consisting of two additional specimens taken as near as possible to the failed specincn, was allowed. To be acceptable, both of the additional specimens nust meet the original minimum requirement.
The retest results were 18 and 25; therefore, the retest was unacceptable.
h.
Subsequent to the tests described in A.2 and A.3, ITT Grinnell performed Charpy impact testing on another set of specimens at its own laboratory. The results obtained were 29, 30 and 32 mils lateral expansion and the heat of material was accepted by ITT Grinnell on the basis of this test.
The ASME Code does not allow this third test and the material is still unacceptable to Code requirements. It is Consumers Power Company's interpretation that a third set of impact specimens would be acceptable (per SA-106/
SA-530) if a thermal heat treatment was first perforned to improve the fracture properties of the as-rolled material.
Page 2 Hove-215-79 5
One '. pool of material from this heat later required hot bending and vat subsequently stress-relieved.
Charpy-impact specimens obtained from this spool vere 6, 9, and 17 mils lateral expansion, which is unacceptable.
B.
Heat L-20h79 1.
An initial set of Charpy impact specimens were tested to the same ASME acceptance criteria given in A.2.
The test results were 13, lh and 32 mils lateral expansion and the test was unacceptable.
2.
Based on the test results of B.1 and the criteria given in A.3, no retest should have been allowed because the original specimens failed to meet all three criteria needed to allov 'a retest.
ITT performed a second Charpy impact test (with three specimens similar to an initial test versus two specimens required in a retest).
The results of the second set of tests were 23, 31 and h3 mils lateral expansion and this test was also unacceptable.
3 This heat was nubsequently stress-relieved to improve fracture properties of the as-rolled material and retested with a new set of three Charpy impact specimens.
The test results after stress-relieving vere 29, 29 and 30 mils lateral expansion. These test resu2ts were above the minimum requirement and the heat was then considered acceptable in the stress-relieved condition.
h.
The results of the post stress relief tests described in A.5 indicates that stress-relieving does not always improve the Charpy impact results.
Because of this, ITT Grinnell no longer believes that material stress-relieved and tested per B.3 can be considered acceptable.
C.
Other Pine Scools With Hot Bent Sections Because of the unacceptable results obtained from hot bent and stress-relieved spool described in A.5, the acceptability of all other spools which were hot bent and stress-relieved is being investigated.
D.
Status of Identification of Material Under Investication 1.
Five piping spools with material from heat U-32762 have been identified.
2.
Five piping spools with material from heat L-20h79 have been identified.
3 Tbree additional piping spools with material from b.ith heat N-32762 and L-20h79 have been identified.
Page :
Howe-215-79 1
An investigation is being r.ade to identify piping spools, from 4
1 heats other than U-32762 and L-20 479, which were hot bent and stress-relieved.
Tnis attachment attempts to present the raw data presently available and is not neant to offer any conclusions at this time.
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