ML19274F808

Interim Deficiency Rept 2 Re impact-testing of Main Feedwater Pipe.Bechtel Corp Is Presently Pursuing Acceptability of Matl Associated W/Heats N-32762 & L-20479. Reportable Condition Remains Uncertain

ML19274F808
Person / Time
Site:	Midland
Issue date:	07/26/1979
From:	BECHTEL GROUP, INC., BECHTEL POWER CORP.
To:
Shared Package
ML19274F807	List: ML19274F806 ML19274F808
References
MCAR-29, NUDOCS 7908060410
Download: ML19274F808 (6)

Text

Attachment 2 Howe-215-79 Bechtel Associates Professional Corporation Attachment to BLC-7942 ,

SUBJECT:

MCAR 29 (issued 7/13/791 Impact Testing of Mafn Feedwater Pipe INTERIM REPORT 2, DATE: July 26, 1979 PROJECT: Consumers Power Company Midland Plant Units 1 & 2 Bechtel Job 7220 Status of Corrective Action and Investigation The status of actions in progress f or resolution of the subject MCAR is as follows.

1) Bechtel has reviewed, at Grinnell, 70 spool data packages for impact test properties on certified material test reports in the following size range: 14-inch, 18-inch, 26-inch, and 36-inch diameter pipe. This review covered all material requiring Charpy impact testing. This action vas taken to determine whether additional material, other than that identified in MCAR 29, cet specification and ASME Section III, Class 2 code requirements.

The spools were fabricated from a total of 16 heats. Of these heats, two material test reports for Heats N-32762 and L-20479 contained questionable data. Heat N-32762 was considered questionable because Grinnell performed more than one retest, which is not allowed by ASME Section III, Class 2 code.

Crinnell has agreed that the original Charpy test results (+30F) submitted for Heat N-32762 are not valid under ASME III, Class 2 requirements in the as-received condition. Grinnell had performed a Charpy test (+30F) for the material of this heat in the stress-relieved condition but it had failed.

Grinnell was requested to furnish its rationale for acceptance of the impact test results on Heat L-20479 in the stress-relieved ccndition. Grinnell's rationale was based on its experience that a subcritical (1100-1200F) henc treatment has the effect of reducing the spread of toughness values (smaller variances) and slightly improving lateral expansion valuas through a sof tening mechanism (a slightly reduced yield point). The retest of Heat L-20479, after stress-relieving, met the code impact test requirements. However, 79 08 0 G 01449 " '

Bechtel Associates ProfessionalCorporation Attachment to BLC-7942 MCAR 29 Interim Report 2 July 26, 1979 Page 2 Grinnell concedes that its rationale, as demonstrated by the results of Heat N-32762 is not 100% consistent, and as a result, it believes that other stress-relieved heats may also be suspect in relation to the repeatability of the impact properties on cach piece of equip-ment.

Grinnell has rationalized that because it did not obtain improved Charpy test results for Heat N-32762 stress-relieving, Heat L-20479 cannot be considered to have the desired impact properties (+30F).

2) In Fby 1979, Grinnell tested three samples of Heat N-32762. These samples were from a f abricated spool which consisted of a straight piece of pipe which was hot-bent, air-cooled, and then full furnace stress-relieved. These samples yielded results of 9, 6, and 17 mil lateral expansion. Because the samples were taken near the area of the bend, it was thought that they may have been from a heat-affected zone (an area which had received an intermediate heating and cooling cycle because of its proximity to the hot bend area).

Grinnell has indicated that measurement of the actual sample location relative to the area which was heated and bent, shows that it was not significantly heated during the bending cycle. Grinnell is preparing a graph of the temperature versus distance to show what these samples would have been subject to during the bending cycle.

The graph will be used to determine whether the samples could have been affected by the bending operation.

Grinnell concluded that because the samples were far enough from the furnace not to be affected by its heat, the poor results are because of the material inconsistency associated with this particular heat. ,

3) Bechtel aas performed a documentation survey at the jobsite to identify all spools Charpy test qualified in heat treatment condition and to confirm that those spools identified were in fact heat-treated. The results of this survey, as related to Heats N-32762 and L-20479, are tabulated in the attached appendix.

Bechtel is still pursuing the acceptability of material associated with IIcats N-32762 and L-20479 as well as any spools with hot bend sections. Therefore, the reportable condition of the pipe remains uncertain at this time.

Bechtel Associates Professional Corporation Attachment to ELC-7942 MCAR 29 Interim Report 2 July 26, 1979 Page 3 Forecast Data for Investination and Corrective Action The next interim report is scheduled for August 23, 1979.

i Submitted by:

Approved by:c dd<+1 Concurrence by:

RBI/js 7/12/9

Page 1 of 3 APPENDIX -

SUMMARY

OF FIELD DOCUMENTATION SURVEY FOR HEATS N-32762 AND L-20479 Charpy Test Results Heat N-32762 Spools Register CMTR Heat-Treated 1 lELB2S638134 MP413 P142 ' No 2 2ELBlS639133 MR416 P142 Yes 2ELB1S639133A MR416AX P142 Yes 2ELB2S639133 MR424 P142 Yes .

2ELB2S639134 MR425 P142 Yes Test Result @ +30F e As-Received Condition 1st 2nd 3rd 21 :25 29 40 18 30 45 32 Passed No No Yes

1. Heat treatment verification was based on review of actual documen-tation at the jobsite. Heat treatment consisted of post weld stress-relieving.

2. This spool is currently on hold at Grinnell Shop.

Because the third test at 30F is considered invalid, disposition of material is undetarmined at this time. (See Code Acceptance Criteria for Charpy Impact Test Results.)

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Appendix -

. . Page 2 of 3 Charpy Test Results Heat L-20479 .

. Spools Register CMTR Heat-Treated 1 lELBlS638134 MP44 , P142 Yes lELBlS638136 MP46 P142 Yes 2ELBlS639135 MR418 P142 Yes 2ELB2S639135 MR426 P142 Yes 2ELBS639136 MR427 P142 Yes Test Results +30F As-Received Condition Stress-Relieved 1175F 1st 2nd 1st Test 32 31 -

30 14 , 43 29 13 23 29 Passed No No 'Yes

1. Heat treatment verification was based on review of actual documen-tation at the jobsite. Heat treatment consisted of post weld stress-relieving.

In accordance with code regulations material, this heat is considered acceptable in the stress-relieved condition. However, because of incon-sistent results with other heats after stress-relieving, Grinnell considers these results questionable. Disposition of this material is considered undetermined at this time.

Spools Consisting of a Combination of Heats N-32762 and L-20479 Spools Register. CMTR Heat-Treated lELBlS638133 MP43 P142 Yes-

~

lELB2S638133 MP412 P142 Yes lELB2S638136 MP414 P142 Yes Because these spools are combinations of unacceptable heats, they are not-acceptabic.

7/12/9 ,

Appendix At t aciment to !!!.C 790 Pag (* 3 of 3

!! CAR 2') 1!;TI~.1;IV 1mPORT 2 July 26, 1979 Page 6 Code Acceptance Cr'iteria for Charpy Impact Results in Accordance with ASME Code,Section III,1971 Faition Through Sum =cr 1973 Addenda

1) Acceptance tests consist of a set of three full-size specimens.

2) Specimens shall have a minimum of 25 mil lateral expansion.

3) Retests (Summer Addenda,1973)

One retest permitted at the same temperature provided:

a) Average values of the test results meet the minimum requirements b) Not more than one specimen per test is below the minimum require-ment c) Specimen not meeting the minimum requirements is not lower than 10 ft/lbs or 5 mils lateral below specified requirement d) A ret'est consists of two additional specimens taken as close as practical to the failed specimens. For acceptance of the retest, both specimens shall meet the minimum requirements.

O 7/12/9