ML20207K596

Rev 1 to, Pipe Stress Calculations:Acceptance Criteria for Overlap Areas of Calculations

ML20207K596
Person / Time
Site:	Sequoyah
Issue date:	12/02/1986
From:	Malkam M TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20207K578	List: ML20207K577 ML20207K596 ML20207K617 ML20207K626 ML20207K646 ML20207K680 ML20207K697 ML20207K727 ML20207K748 ML20207K776 ML20207K795 ML20207K838 ML20207K854 ML20207K887
References
218.7(B), 218.7(B)-R01, 218.7(B)-R1, NUDOCS 8701090462
Download: ML20207K596 (11)

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t TVA EMPLOYEE CONCERNS REPORT NUMBER: 218.7 (B)

SPECIAL PROGRAM

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REPORT TYPE: SEQUOYAH ELEMENT REVISION NUMBER: 1 TITLE: PIPE STRESS CALCULATIONS Acceptance Criteria for Overlap Areas of Calculations PAGE 10F 10 m

REASON FOR REVISION:

TVA comments incorporated.

PREPARATION PREPARED BY:

% .M. W A_N e M g 'h 11- 24-1986 SIGNATURE / ' " DATE REVIEWS

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SIGNATURE DATE

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SIGNATURE DATE CONCURRENCES A. L !s!& /2-2-12 CEG-H: W J 2. - t-V6 SRP:

SIGNATURE DATE SIGNATURE DATE APPROVED BY:

M ECSP MANAGER DATE MANAGER OF NUCLEAR POWER DATE

• + CONCURRENCE (FINAL REPORT ONLY)

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TVA ENPLOYEE CONCERNS REPORT NUN 8ER: 218.7 (B) e SPECIAL PROGRAN REVISION NUN 8ER: 1

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PAGE 2 0F 10

1. CHARACTERIZATION OF ISSUE (S):

Concern: Issues:

IN-85-039-003 a. There was no consistent policy on "There are various ' alternately what constituted an acceptable lapped analyzed' problems on Watts 8ar region at alternate analysis Unit 1 and Unit 2, which have boundaries.

lapped region boundaries rather than anchor terminations. The b. The methods actually implemented for concern is 'there was no con- interfacing alternate analysis sistant policy on what consti- problems may not have been sufficient.

tuted an acceptable lapped region'. The following method and/or combinations were employed: a). Terminate at a 3-way support between problems.

b). Establish a rigid region between problems c). Eliminate torsion & bending by introducing

, f e,h additional supports. Problem yf area example: Root line N3-26-A42A, branch line 26238, 26234, 26227, 26007, 26228.

l There are many more examples

, available in file."

2. NAVE ISSUE (S) BEEN IDENTIFIED IN ANOTHER SYSTENATIC ANALYSIS 7 YES x NO Identified by_ TVA. Sequoyah Date See Below i

Documentation Identifiers:

4 a. TVA, Sequoyah Nuclear Plant, Generic Concern Task Force, Employee Concern No IN-85-039-003, Rev. 1 (05/29/86)

b. TVA, Nonconformance Report SQNCE88303 (08/29/86) j I 1074d - 10/26/86 a

TVA EMPLOYEE CONCERNS REPORT NUM8ER: 218.7 (B)

SPECIAL PROGRAM REVISION NUMBER: 1 PAGE 3 0F 10

3. DQCUMENT NOS. TAG NOS.. LOCATIONS. OR OTHER SPECIFIC DESCRIPTIVE IDENTIFICATIONS STATED IN ELEMENT:

Root Line: N3-26-A42A Branch Lines: 26238, 26234, 26227, 26007, 26228 3-way Support

4. INTERVIEW FILES REVIEWED:

QTC File Review for Employee Concern IN-85-039-003, Element 218.1, 218.7, 222.1, (review notes by Gordon Parkinson, Bechtel), 06/18/86.

5. DOCUMENTS REVIEWED RELATED TO THE ELEMENT:

See Appendix A.

6. WAT REGULATIONS. LICENSING COMITMENTS. DESIGN REQUIREMENTS. OR OTHER

[]

kJ APPLY OR CONTROL IN THIS AREA?

See Appendix A.

7. LIST REOUESTS FOR INFORMATION. MEETINGS. TELEPHONE CALLS. AND OTHER

. DISCUSSIONS RELATED TO ELEMENT.

See Appendix A.

8. , EVALUATION PROCESS:

a. Review past and present procedures for interfacing / terminating alternate analysis piping.

! b. Evaluate rigidity of alternate analysis pipe spans.

c. Review the cited examples for applicability to the Sequoyah plant.

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TVA ENPLOYEE CONCERNS REPORT NUN 8ER: 218.7 (B)

SPECIAL PROGRAN REVISION NUN 8ER: 1

([, PAGE 4 0F 10

9. DISCUSSION. FINDINGS. AND CONCLUSIONS:

4 , Discussion:

The overlap method has been used throughou' c the industry, to varying degrees, to justify the subdivision of large piping

, problems into smaller subproblems more amenable to computer stress analysis. Ideally, piping models include all piping between points of total fixity known as ' anchors' in pipe-stress terminology.

Where there is an insufficient number of anchors to subdivide a -

, large problem, the problem can be subdivided by use of an overlap method. In the overlap method the interfaces would not be discrete

-locations on the piping but rather, regions of piping common to each model. In other words: if hypothetical piping system 'A' were subdivided into systems 'B' and 'C', the model of 'B' would j include a portion of the piping of model 'C', and vice versa (over the same region). The portion common to both would be the

' overlap' region. Overlap methodology, when it is formally defined,

. usually specifies requirements for the extent and configuration of the overlap region. This is to ensure that analysis of the ftd) subproblems yields conservative values for pipe stress, pipe

df~st support loads, etc. Hence, by modeling the safety-related piping i systems incorrectly or in such a nenner so as to yield j nonconservative results could pose safety / code compliance concern.

l. The first of the two issues (Issue a., Section 1) is that there was

, no consistent policy on what constituted an acceptable lapped

region at alternate analysis boundaries.

In 1975, procedure DED-EP 21.10 Rev. 0 ( App. A, 6.c) was issued that provided ". . . complete definition to [11?_] the analytic techniques employed in the analysis of the Sequoyah Nuclear Plant

! piping systems prepared by TVA Civil Engineering Branch" (Section

, 1.1 of the procedure). A related criteria document (SQN-DC-V-13.3)

made reference to the procedure and a similar document concerning ,

I the analysis completed by EDS Nuclear for TVA on the Sequoyah ,

Nuclear Plant (Section 1.3 of the procedure).

[ Three alternate analysis criteria have been implemented at

! Sequoyah: CE8 80-5, CEB 74-2 and CE8 76-5 (App. A, 5.p. 3.0). One j (CEB 76-5, Section 5.5.2) provides recommendations for interfacing rigorous analysis problems with alternate analysis problems, instead of appropriately referring to the rigorous analysis procedures which govern. These recommendations, however, differ from those of DED-EP 21.10 (App. A, 6.c) and the Sequoyah Rigorous Analysis Handbook (App. A, 6.a).

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1074d - 10/26/86

1 TVA EMPLOYEE CONCERNS REPORT NUM8ER: 218.7 (8)

SPECIAL PROGRAM REVISION NUMBER: 1 eg PAGE 5 0F 10 Section 8.0 of DED-EP 21.10. "Modeling Techniques for Detailed Piping Analysis," provides instructions for overlap modeling for rigorous analysis problems (Section 2.1.1). These instructions are

!. typical of the methods generally used by the industry at the time they were issued (1975).

Section 8.2.5.2 of this procedure gives the method for interfacing the rigorous analysis computer models with alternate analysis non-computer-analyzed piping. These instructions apparently [

, remained standard until the Sequoyah Rigorous Analysis Handbook *

(SQN-RAH) was issued in 1983 as a response to NUREG/CR-1980 ( App. ,

A 5.1). The SQN-RAH, which was issued in 1983 does provide more '

instructions for interfacing rigorous analysis piping with alternate analysis piping, as well as for interfacing Rigorous to rigorous and rigorous to deadweight piping.

The second issue (Issue b., Section 1) of this report is that a i

single three-directional translational restraint, with no overlap, may be an insufficient temination of a piping computer analysis when the piping actually continues beyond the three-directional g

y.?

restraint. Concern was also expressed with termination justified by the use of three changes of piping direction to eliminate bending and torsion.

Section1.3'oftheSON-RAH-206(App.A,5.agl rigorous analysis problem may be terminated with provides that(or a 3-way a i effective 3-way) support. ,

i I This was issued in 1983 as a response to NUREG/CR-1980 ( App. A,

• 5.1). The NUREG states "It is concluded that one overlap method should not be substituted for a complete analysis of a full system. However, if a sufficiently high natural frequency is associated with the overlap section, or the overlap is a i substantial portion of the system, acceptable results could be obtained." (App. A 5.1, Abstract, iii) l l 2 "Teminated" is interpreted to mean that the rigorous analysis

! computer model need not be extended into the alternate analysis category piping. (See TVA reply to RFI #567, item #3)

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TVA EMPLOYEE CONCERNS REPORT NUMBER: 218.7 (B) i SPECIAL PROGRAM I

REVISION NUMBER: 1 l(: ,; _ PAGE 6 0F 10 The evaluation team requested that TVA-Sequoyah provide justification for the policy of terminating rigorous analysis problems at a 3-way support (App. A., 7.b). TVA replied that "If Alternate Criteria CEB 76-5 supported piping is essentially rigid, than an effective 3-way support is adequate . . ." (see TVA reply to RFI SQN-543, item #1).

The evaluation team has provided TVA with a calculation showing that alternate analysis piping is not all rigid (App. A., 7.b). TVA has not commented on that information.

The employee's concern related to the adequacy of establishing a

• rigid region between problems, or/and eliminating torsion and bending by introducing additional supports applies more to the interface between rigorous to rigorous and rigorous to deadweight analysis.

This aspect of the concern does not specifically apply to the interface between rigorous to alternate analysis. However, various methods of interface between problems can be used to achieve the same results.

In September of 1983, Nonconformance Report No. SQNCEB8303 was written identifying a deficiency in the way lapped regions were handled pr1or to the revision of the Rigorous Analysis Handbook. In l g%f '

May of 1984, 358 analysis problems were evaluated by TVA and 51 were determined to be affected by the revision of the Rigorous Analysis Handbook (Cited in Section III.B of App. A, 5.b). A design study (App. A, 5.d) was subsequently performed to determine which of the l analysis problems required reanalysis. Sixteen rigorous / alternate

' boundaries' were found to be unacceptable and required further review (reported in App. A, 5 b). These sixteen problems will be addressed by TVA under NCR 8215 and/or NCR 8222 per reference App. A, 5.d.

[ , The other employee concern is that improper overlapping may have been L performed for certain specific example analyses (see section 1.0).

The examples cited are Watts Bar plant examples and do not apply to

the Sequoyah plant. Therefore, these examples will not be reviewed

! under the Sequoyah Employee Concern Review Program but they will be l reviewed under the Watts Bar Employee Concern Review Program.

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TVA EMPLOYEE CONCERNS REPORT NUMBER: 218.7 (B)

SPECIAL PROGRAM REVISION NUMBER: 1

[ PAGE 7 0F 10 Findings

a. There were consistent procedures for interfacing computer-analyzed rigorous analysis piping with non-computer-analyzed alternate analysis piping (cited in Section 8.2.5.2 of App. A, 6.c). As per procedure, there is no need for lapped region at alternate analysis boundaries.

(" Terminating at points where alternate analysis begins requires less isolation, since the system will be supported rigidly from that point on" (cited in Section 8.2.5.2 App. A,

• 6.c]).

b. There is no justification for use of a 3-way restraint, without overlap, at the interface of rigorous analysis piping with ,

alternate analysis piping where the alternate analysis piping is not rigidly supported.

Conclusions

.t b a. The employee concern that there was no consistent policy on

.J6@yp lapped regions of alternate analysis boundaries is not valid.

There were written procedures for interfacing rigorous analysis with alternate analysis piping, wherein there was no need for overlapped regions.

b. The employee concern that the methods implemented for interfacing alternate analysis problems may not.have been sufficient is valid, where the alternate analysis piping is not rigidly supported.

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TVA EMPLOYEE CONCERNS. REPORT NUM8ER: 218.7 (B)

SPECIAL PROGRAM

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REVISION NUMBER: 1 gg-PAGE 8 0F 10 APPENDIX A

5. DOCUMENTS REVIEWED RELATED TO THE ELEMENT:

a. TVA, Sequoyah Nuclear Plant, Ricorous Analysis Handbook, i

Section SQN-RAH-206, Rev. O, (08/25/83)

b. TVA, Sequoyah Nuclear Plant, Generic Concern Task Force, Employee Concern No, IN-85-039-003, Rev. 1, (05/29/86)

~

c. TVA reply to Bechtel RFI 509,(08/25/86)

d. TVA, " Review of Piping Analysis for Adequate Termination",

SDR SO48, (02/27/86)

e. TVA, " Engineering Report re CAQ Report No. SQNSWP8215 Rev.

0",(06/12/86)

f. TVA, Sequoyah Nuclear Plant, Alternate Analysis Review Program, " Program Description", SQN-AA-001, (07/01/86)

g. TVA, Sequoyah Nuclear Plant, Ricorous Analysis Handbook, Section SQN-RAH-401, Rev.1, (11/15/85)

h. 8echtel, Walts 8ar Nuclear Plant Engineering Related Employee Co.icorns, Element Review Sheets, " Element 218.7",

(07/30/86)

i. U.S. NRC, NURE6/CR-1980, 8NL-NUREG 51357: " Dynamic Analysis of Piping Using the Structural Overlap Nethod", Feb.1981 '

l ,J. US NRC Standard Review Plan i k. TVA, Sequoyah Nuclear Plant, " Procedure for Detailed Analysis j of Category I Piping Performed by TVA, DED-EP 21.10, Rev. 0",

(10/30/75) i

! 1. TVA, Sequoyah Nuclear Plant, Performance Plan. Volume 2, (07/14/86) 1

m. TVA, NCR SQNCE88303, Rev. 1, (08/29/86) l n. TVA, Engineering Report, Rev. 6/12/86, NCR SQNCE88303, Rev. O i o. TVA memo D. W. Wilson to J. A. Raulston, NCR SQNCE88303, Rev.

t 1,(09/02/86) i l U2%

l N p. TVA, " Alternate Piping Analyses and Support Criteria for l Category 1 Piping Systems, Design Criteria No. SQN-DC-V-13-7, l 4-1-73 Rev. 2", (10/04/84) 1074d - 10/26/86 i

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TVA EMPLOYEE CONCERNS REPORT NUMBER: 218.7 (B)

SPECIAL PROGRAM p y, -- -

REVISION NUMBER: 1 PAGE 9 0F 10 li 6. WHAT REGULATIONS. LICENSING COMMITMENTS. DESIGN REQUIREMENTS. OR OTHER APPLY OR CONTROL IN THIS AREA 7

a. TVA, Sequoyah Nuclear Plant, Ricorous Analysis Handbook, Section SQN-RAH-206, Rev. O, (08/25/83) i

b. TVA, Sequoyah Nuclear Plant, Ricorous Analysis Handbook, Section SQN-RAH-401, Rev.1, (11/15/85)

c. TVA, Sequoyah Nuclear Plant, " Procedure for Detailed Analysis of Category I Piping Performed by TVA, DED-EP 21.10, Rev. 0",

(10/30/75)

R

d. TVA, Sequoyah Nuclear Plant, Final Safety _ Analysis Report

e. TVA, " Alternate Piping Analysis and Support Criteria for Category I Piping Systems, Design Criteria No. SQN-DC-V-13-7, 4/1/73, Rev. 2", (10/04/84) l 7. REQUESTS FOR INFORMATION. MEETINGS. TELEPHONE CALLS. AND OTHER I k. 't DISCUSSIONS RELATED TO ELEMENT:

a. Bechtel RFI #SQN-509, (08/21/86)

I b'. Bechtel RFI #SQN-543, (09/10/86)

! c. Bechtel RFI #SQN-567, (09/17/86) l

d. Bechtel RFI #SQN-570, (09/18/86)

{

l , e. Bechtel RFI #SQN-588, (09/25/86)

f. Telecon between Bechtel and TVA, IOM #338 (10/22/86) l j g. Bechtel RFI #SQN-617, (10/03/86)

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O 1074d - 10/26/86

j TVA EMPLOYEE CONCERNS REPORT NUMBER: 218.7 (B)

SPECIAL PROGRAM REVISION NUM8ER: 1 PAGE 10 0F 10 l

CATO LIST t The following CA1D forms are included as part of this report:

21807 SQN 01 (revised 11/26/86)

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1074d - 10/26/86

7 1 e . . , .

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l ECTG C.3 -

Attachment A m Page 1 of 1 4-Revision 2 - A i ECSP CORRECTIVE Action Tracting Document (CATD)

INITIATION

1. Inusediate Corrective Action Required: ( Yes a No

2. Stop Wort Reconvaended: O Yes ( No

3. CATD No. 2.16 0'1 S Q hl O f 4 INITIATION DATE II" U" N

5. RESPONSIBLE ORGANIZATION: 1)N E,

6. PROBLEM DESCRIPTION: ( QR O NQR THERE #3 No Tp17tFICATf 9M FFA (/12 07 A 1 - kl4 Y AswAAlhfT. WITHO WT OWfdLAP. AT far INTEMAct e#

knso&OtJS "AN ALV SLt 97 Of NG ldITM ALT #dNAT& ANAL 1$LC PJ9f M k . W M S A E TW E ALTdANAff ANALYAf #####4 f.S N87 A'a d18 LY JWPPORTfD .

11 l WA A . O ATTACHMENTS

7. PREPARED BY: NAME M. bl. M ALKAblI /WLLT4 ATE: 11 - t4- 96 s

8. CONCURRENCE: CEG-H #dL- % , m R.W@ -

DATE: rt 7. -W

9.

• I (3;J'-J<l APPROVAL: ECTG PROGRAM MGR. DATE:

CORRECTIVE ACTION

10. PROPOSED CORRECTIVE ACTION PLAN:

O ATTACHMENTS

11. PROPOSED BY: DIRECTOR /MGR: DATE:

12. CONCURRENCE: CEG-H: DATE:

SRP: DATE:

ECTG PROGRAM MGR: DATE:

VERIFICATION AND CLOSEOUT

13. Approved corrective actions have been verified as satisfactorily

/ implemented.

SIGNATURE TITLE DATE l -

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