ML19329F667

Second Interim Deficiency Rept Re Undersize Welds Per ASME Code & Drawing Requirements

ML19329F667
Person / Time
Site:	Midland
Issue date:	12/22/1977
From:	Howell S CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:
References
HOWE-214-77, NUDOCS 8007100587
Download: ML19329F667 (9)

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o.a.,.,ome..:si2 w.. uice..e u .em...,.c .oe.uicn...e. 2ei December 22, 1977 Howe-214-77 -?%

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Mr J. G. Keppler, Regional Director /

Office of Inspection and Enforcement L _

Region III ' -

US Nuclear Regulatory Commission -

799 Roosevelt Road '

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Glen Ellyn, IL 60137

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p.w MIDLAND NUCLEAR PLAND -

UNIT NO.1, DOCITI NO. 50-329 UNIT NO. 2, DOCKET NO. 50-330 PIPE SUPPORP FILLHf WELDS

Reference:

Letter, S. H. Howell to J. G. Keppler, Midland Nuclear Plant -

Unit No.1, Docket No. 50-329; Unit No. 2, Docket No. 50-330; Pipe Support Fillet Welds, Serial Hove-197-77, dated November 21, 1977 The referenced letter was an interim report which provided corrective action plans relative to the undersized fillet velds on linear pipe supports.

Attachments 1 and 2 provide Bechtel Associates' Second Interim Reports in response to the Management Corrective Action Reports (MCAR-1 Report No.18 and MCAR-1 Report No. 19). These reports cover velds which are undersized to the requirements of the ASME Code and shop velds which are undersized to drawing requirements. The investigation of the two problems to date has been separated. It is recognized that the two conditions could exist con-currently on an individual pipe support and this possibility is being investigated.

Attachment 3 is the ASME response to the Code inquiry (Attachment 4 to the referenced letter) . This response states that the minimum size requirements of Table XVII-2452.1-1 are applicable and the minimum size is independent of calculations indicating that smaller velds vould be acceptable.

In response to Consumers Power Company's Nonconformance Report QF-201, which reported four undersized field welds out of a sample of h4, Bechtel has reinspected an additional sample of 112 field velds and all were found to be acceptable. Evidence to date indicates that the nonconformances reported in QF-201 are not representative of a generic problem. The hardware disposition to this Nonconformance Report vill follow the final disposition of the under-sized shop velds reported in MCAR-19

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r e Att:chment 1 Howe-211+-77

SUBJECT:

MCAR # 18 (Issued io_7s_77 )

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INTERIM REPORT # 2 DATE: 12-16-77 PROJECT: Consumers Power Company Midland Plant Units 1 & 2 Bechtel Job 7220 Description of Discrepancy Some fillet veld sizes designated on Grinnell hanger sketches are at variance with tha minimum ~ weld size requirements of ASME Section III-NF 3392, NF-3400, and Appendix XVII-NA 2452 .

. Potential Safety Implication

! Crinnell's physical tests of two of the " worst case" weld size deviant welds conducted on December 12 and 13, 1977, indicate that these " worst

, case" welds were capable of load many times their design load requirements.

Bechtel engineering analysis of 80 randomly sampled hanger sketches having

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under*specified weld callouts indicated that all the deviant weld stresses i were less than 68% of Code allowables. The physical tests and the analysis l'

continue to affirm that there is no safety problem due to underspecified weld size callouts.

Corrective Action and Investigation Bechtel has requested Grinnell, as required by MCAR-18 Item 1, to provide justification of their position on the deviation from the Code, and for their program and approach for presenting their justification to the ASME code committee and other jurisdictional authorities. To date, a response has not been received. Crinnell acknowledges the deviation from'the minimum fillet veld size aspect of the Code, but also contends that all these deviant weld callouts are very conservatively designed in terms of the-allowable weld stress aspect of the Code, which is the real intent of_the Code, and which they have met.

, Per'MCAR-18 Item 2, Bechtel requested an informal code interpretation at the ASME Code committee meeting November 1,-1977. The code committee

~ chairman' stated,-if a formal inquiry were presented, he would support a Code interp'etation r that minimum fillet veld size must be at least the

- thickness of 'the thinnest member joined where the Code minimum weld _ size table calls for a weld equal to or greater _than the thickness of the

' thinner member.

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q p Grinnell submitted the Test Procedure T-S-91990-2 " Full Size Destructive Loading Test of.Three llanger Assemblies, Midland Units 1 & 2 Bechtel 7220-M-106-AC," on December 9, 1977. The tests were performed at Grinnell's test facilities in Providence R.I. on December 12 and 13, 1977, with observers from both Consumers Power Co. and Bechtel. Pre-liminary indications of the tests confirm Grinnoll's contention that these " worst case" designs were very conservatively designed.

Grinnell has affirmed that all new designs of fillet welds since April 1977 are in compliance with the minimum weld size Code cricaria.

Drawings reviewed by Bechtel confirm this.

Bechtel's random sample check (1% per MCAR-18 Item 3) of 650 earlier hanger sketches yielded 110 fillet veld callouts that did not comply with the Code Appendix XVII-NA 2452.1 criteria for such welds. The noncompliant veld callouts were underspecified as follows: 59% by 1/16", 43% by 1/8", and 2% by 3/16".

An engineering analysis by Bechtel of 80 of the 110 noncompliant weld callouts indicated that all weld stresses were 12.3 ksi or less, ucl1 below the 18 ksi maximum designated by the Code. (Completes MCAR-18 Item 3) .

To comply with MCAR-18 Item 4, Bechtel QA/QC personnel inspected 23 installed hangers and hangers in the warehouse representing 112 welds.

The results of the inspection were: 76% met or exceeded the designated weld callout, 15% were under the designated wcld size by 1/16 inch or less over less than 15% of the weld length, 5% were under the designated weld size by 1/16 inch or 1 css for more than 15% of the veld length, and 4% were under the~ designated weld size by 1/8 inch for more than 15% of the wcld length. The resolution of the "as-built" undersized welds will be addressed in MCAR 19. (Completes MCAR-18 Item 4)

Forecast Date on Corrective Action The interim reports will be issued on a 30-day basis until the final Crinnell report justifying their position on the deviation from the Code in February 1978 is issued. Program results will then have to be accepted by the Owner and the Code jurisdictional authority. A final report would then follow.

Submitted by: r Approved by L M b G'R[T h A.

Concurrence by: Mrd // /h

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,,- Howe-214-77

SUBJECT:

MCAR # 19 (Issued 11-7-73 4

INTERIM REPORT # 2 DATE: 12-16-77 PROJECT: Consumers Power Company Midland Plant Units 1 & 2 Bechtel Job 7220 Description of Discrepancy

' A random sample of 32 hangers was inspected at the jobsite, using a veld fillet gauge, to determine the actual shop weld sizes compared to the design weld sizes identified on Grinnell drawings. 22% of the 112 welds 4

, on the sample hangers were found to be under the specified nominal size

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required by Grinnell drawings'.

Potential Safety Implications To date, Grinnell's analytical analysis of the reported deviant welds continues to reaffirm Grinnell's original position that no safety

-problem exists.

Status of Corrective Action and Investigation The cause of the deviation was an insufficient level of internal weld inspection by Grinnell QA/QC personnel. (Completes MCAR-19 la)~

Grinnell utilized a visual inspection technique per their Quality Control Procedure 02A006 dated 3/14/74, which allows fillet welds in any single

continuous weld to underrun the nominal fillet size required by 1/16 inch l without correction provided that the undersized weld does not exceed 10%

of the length of the weld. Grinnell has stated that all shop welds are i inspected; however, only welds that appear suspect are actually checked with a gauge. ~(Completes MCAR-19 lb)

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Grinnell'has. submitted for approval their " Visual and Dimensional Acceptance Criteria for Welds" per their revised Quality Assurance / Quality Control Procedures 02A006 dated 12/8/77 to allow tolerances on fillet velds:

Undersize is permitted, provided it does not exceed 1/16 inch for 10% of the weld length or an equivalent volume.

Oversize welds are permitted as follows:

a) Nominal weld size up to and include 1/4 in. +1/8 in.

b) ,_ Nominal weld size over 1/4 in. and up to

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+3/16 in.

and including 1/2 in.

c) All welds over 1/2 inch +1/4 in.

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. F Grinnell is committed to revise the weld inspection procedure to include both under and over tolerances, reference the inspection procedure on the permanent record QC checklist (one for each hanger), and provide additional training to the inspection team upon Bechtel's approval of Grinnell's revised procedures.

Qualification of existing weld sizes will be by Grinnell's analysis in lieu of MCAR Items 2a, 2b, and'2c.

Bechtel has completed a representative field inspection sample per HIL-STD-105D of "as-built" hanger wolds as compared to the weld size specified on hanger sketches. Grinnell has analyzed 26 of the deviant welds resulting from the Bechtel field inspection. Grinnell analyzed these deviant welds on a " worst case" undersize basis and preliminary shown that all the welds were stressed less than 46% of the Code allowable stress. Grinnell's final report, expected on January 3, 1978, will include the 34 hangers which had deviant welds.

To establish control of hangers not installed or in manufacture, the following steps were taken or conditions e'stablished:

- Bechtel PSQR shop monitoring program has continued on the esta-blished quality verification daily monitoring basis with satis-factory results. Bechtel PSQR shop monitoring program indicates that Grinnell's internal shop inspection has improved which is evidenced by a smaller number of Bechtel PSQR rejections. The

. latest field receipt inspection shows no undersized welds. The evidence indicates the program is operating satisfactorily.

(Completes MCAR-19 3bl, 5)

Bechtel field QA/QC personnel have been performing 100% inspection on all incoming hangers and they have found no welds undersized from the weld sizes designated on the hanger sketches. Bechtel's incoming hanger

, inspection will continue until Grinnell's revised inspection procedures have been approved and Bechtel's PSQR verifies that the procedures have been implemenced.

Forecast Date on Corrective Action It is expected that the Grinnell summary report will be received by Bechtel in January 1978. A final report would then follow.

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Submitted by:

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Concurrence by: -

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'51 The American Society of Mechanical Engineers

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United Engineering Center / 345 E. 47th St., New York, N.Y. 10017 / 212 644-7815 g

THE 80lLER AND -

PRESSURE VESSEL ,

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212 West Michigan Avenue P' g '-y t 3,, , Jackson, MI 49201 ,

C.S.HOYT Att: W. R. Bird C.'.*!. ALLiSON

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Subject:

Section III, Division 1, R.J. sosN A K Table NF-3132.1(b)-1 and NF-3292 P.M. BRISTER

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[*CYPL Ref: Your letter of October 28, 1977 LJ. CHOCKIE ASME File #NI 77-406 ,

C.E. COOPER w.O. DOTY G.E. FR ATCH ER Gentlemen- * '

R.C. GRIF FIN S.F. H ARRISON In response to yout inquiry, it is our understanding that you are asking N. ON the following questions:

E.L KEMMi.ER E.L KIME QUESTIONS:

J.E. LATTAN J. LeCOFF J.R. MACKAY (1) If Class 1 linear supports are designed by " experimental stress R.H. MOE LLER analysis" or by " load rating," does paragraph NF-3292 apply?

T.E. NORTHUP C.f RAWLtNS C.R. SMITH. SR. (2) When paragraph NF-3292 applies, must all fillet welds comply with W.E. SOMERs the minimum size requirements of paragraph XVII-2452 and Table XVII 2452.1-1 when the analysis shows a smaller weld size to be satisfactory?

REPLY:

(1) NF-3292 is applicable to linear supports designed by any of the procedures permitted by NF-3132.1(a) and as shown on Table NF-3132.1 (b)-1.

(2) The minimum size requirements of Table XVII-2452.1-1 are applicable when the joints are connected by fillet welds only as stated in XVII-2452.1. These minumum size requirements are independent of calculations indicating that smaller welds would be acceptable from the computed stresses although larger welds shall be provided when necessary to satisfy stress calculations.

Member of Engineers Council for Professional Development and Engineers Joint Council

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. *a e (2) When fillet welds are used in combination with another type of weld configuration, such as groove velds, the minimum size requirements of Table XVII-2452.1-1 do not apply. J Very truly yours, i

ohn Millman Assistant Secretary O

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Attachments 1 & 2 - Bechtel Associates' Second Interim Reports re Pipe Support Fille- Welds-Attachment 3 - ASME response to the Code inquiry (Attachment 4 to Consumers ltr. of

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Attachments: 1) Interim Report No. 2 dated December 16, 1977, MCAR-18

2) Interim Report No. 2 dated December 16, 1977, MCAR-19

3) Letter, John M11Lnan (ASME) to W. R. Bird (CPCo),

Subject:

ASME File #NI 77-408, dated December 8,1977 CC: Dr Ernst Volgenau, USNRC (15)

Director, Office of Management Inforn:ation and Program Control, USNRC (1) l

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