ML20215B446

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Rev 0 to Clarification of Impell Cth Design Verification Criteria/Methods for Resolution of Cygna Audit Concerns, Effect of Measurement Tolerances Used for Collection of As- Built Data
ML20215B446
Person / Time
Site: Comanche Peak  Luminant icon.png
Issue date: 05/15/1987
From: Ashley G
ABB IMPELL CORP. (FORMERLY IMPELL CORP.)
To:
Shared Package
ML20215B058 List:
References
IM-P-009, IM-P-009-R00, IM-P-9, IM-P-9-R, NUDOCS 8706170333
Download: ML20215B446 (4)
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' CLARIFICATION OF.IMPELL CTH DESIGN VERIFICATION CRITERIA / METHODS FOR RESOLUTION OF CYGNA AUDIT CONCERNS l

l Effect of Measuremnt Tolerances used for Collection of As-Built Data i

Prepared for:

Texas Utilities Electric Company Prepared by:

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'Impe. .' Corporation '

0210-040/041-IM-P-009 Revision 0 Prepared by: (. ///./C A l o s_a ([f/B/

Approved by: 8[44/, J- Ar- 37 v

hbk DO K f

IM-P-009 1 l

CONCERN:

Measurement' tolerances are defined (Reference 1) for-~ use in the collection of cable tray as-built data. CYGNA has raised issues which' pertain to the lack of consideration of installation tolerances in the design calculations. i o

BACKGROUND: Measurement tolerances used for piping systems have been subjected to much greater scrutiny by the nuclear power industry than have cable tray systems. 'This is true, in part, because the dimensional accuracy used for the evaluation of pressure-retaining components is more critical. Thus, the more detailed standards available i

for piping have been referenced to address measurement '

deviations from as-built drawings.

DISCUSSION: Impell Calculation M-69 (Reference 9) has performed a i detailed review of TU Electric cable tray walkdown tolerances. The review includes a comparison of TU Electric tolerances (ReferMee 1) to (1) installation and walkdown tolerances app 14 8 by other utilities, (11)

PVRC/WRC task group publimed tolerances, and (iii) code fabrication tolerances, (References 2 through 6). The details of this comparison and pertinent comments are presented in the table attached to M-69.

A summary of the review is as follows:

Tolerances for the location of hangers with respect to cable tray layout are comparable to or more accurate than those specified in other documents referenced above.

Tolerances for the lengths, widths, thicknesses and relative locations of cable tray hanger members and I for weld attributes are comparable to or more accurate than those specified in other documents. 'f Tolerances for the location of bolts are, in some cases, comparable to those specified in other y documents. In other cases, for expansion anchors in particular, they are somewhat more liberal.

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IMJ-009 j

Industrial practice 'for the qualification of-concrete anchor bolts is to recommend a minimum  ;

spacing, a' minimum embedment, and a~ minimum edge ~ j

. distance'in order to warrant that allowable loads j remain applicable to a particular installation.- '

Wherever the minimum dimensions are violated,

' allowable bolt' loads are reduced according to project-specified criteria. TU Electric tolerances will'have no impact on design consideration where a recommended dimensions are respected. . '

Impell has assessed the-impact of TV Electric I anchor bolt tolerances on design' verification i re sul ts.- Anchor bolt allowable load reductions were :l considered for minimum dimension violations of bolt spacing, bolt embedments,. and edge distances in - 1 accordance with' applicable project procedures 1 (Reference 8). The assesment indicates that  !

deviations are'of the same order of magnitude as those presented in the PVRC study (Refuence 4).

The TU Electric anchor bolt tolerances 'are accordingly deemed to be acceptable, even thou'gh'-

they are somewhat more liberal than the other.

industrial standards reviewed.-

CONCLUSION: .The TU Electric tolerances applied during the collection of as-built data for cable tray design verification are adequate for design and analysis purposes. In fact, they.

are more specific in applicatien and frequently more . '

i conservative than are those developed for piping by other utilities and the PVRC task _ group.-- Thus, in agreement -

with current industrial positions, the subject tolerances should have insignificant effect on the integrity of Comanche Peak cable tray systems and supports, i

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-IM-P-009-l l

REFERENCES:

- 1. Specification No. TNE-FVM-CS-001, Rev. 5, " Comanche Peak Steam Electric Station, Unit 1 - Field 3 Verification Method, Unit 1 Cable Tray Hanger j As-Builting and Design Adequacy Yerification-

, Program", dated July 1,1986 by Texas Utilities .]

i Generating Company, Nuclear Engineering, j

2. Specification No. CS-P207, Rev. 2, " Specification for Safety and Non-safety Related Pipe Support Field i Fabrication and Installation",' Southern California l Edison Company, San Onofre Nuclear Generating i Station, Unit 1, dated October 30,-1984 by Bechtel '

Power Corporation.

3 Manual of Steel Construction, Seventh Edition, dated 4/79 by the American-Institute of Steel Construction, Inc.  !

i 4 " Technical Position on Piping System Installation I Tolerances", Draf t-6 (Approved by Steering Committee 1 for issuance as a WRC Bulletin), dated September 10,- ]

1985 by the Task Group on Industry Practice of the j PVRC Technical Committee on Piping Systems.. -j

5. Document No. ESD 223, " Installation and Inspection of Pipe Supports", Diablo Canyon Nuclear Power  !

Plant, Revision dated 4/9/82 by Pullman Power Products.

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6. Specification No. CS-C8, Rev.13. " Design,- (

Installation and Testing of Concrete Expansion j Anchors", Southern California Edison Co., San Onofre Nuclear Generating Station Units 2 & 3, dated 4/18/84 by Bechtel Power Corporation.

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CYGNA letter 84056.095 to W.G. Counsil from N.H.

Williams, " Review Issues List, TUGC0 Comanche Peak Steam Electric Station, Independent-Assessment Program - All Phases", dated November 26, 1985, 8 Impe11 Project Instruction PI-07, Rev. 3 "TUGCO' CPSES Unit 1 Design Verification of Base Plates, Base Angles and Embedment Plates", Job No. 0210-040, j

. dated September 16, 1986

9. Impe11 Calculation M-69, " Cable Tray As-built Measurement Tolerances", Rev. O.

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