AECM-90-0072, Forwards Response to Recommendations Re Areas of Concern Noted in NRC SER & 900316 Request for Addl Info Re Design Criteria for Cable Tray Supports in Turbine Bldg

Forwards Response to Recommendations Re Areas of Concern Noted in NRC SER & 900316 Request for Addl Info Re Design Criteria for Cable Tray Supports in Turbine Bldg

ML20042G868
Person / Time
Site:	Grand Gulf
Issue date:	05/09/1990
From:	Cloninger T SYSTEM ENERGY RESOURCES, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
AECM-90-0072, AECM-90-72, NUDOCS 9005160204
Download: ML20042G868 (12)

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-May 9, 1990:

- T.H. Cloninger vce Peo" -

Nudear Entrneevng & Smport U.S. Nuclear Regulatory Commission-Mai1 Station P1-137-Washington' D.C.

.20555-Attention: LDocument Control Desk Gentlemen:

SUBJECT:

Grand' Gulf' Nuclear Station Unit 1-Docket No. 50-416 License No. NPF-29~

SERI Response to NRC SER on Audit of?

-Pipe Support Calculations AECM-90/0072 System Energy Resources, Inc. (SERI)1 received the NRC's'.Safet'y Evaluation Report (SER) dated March 16, ~ 1990. (MAEC-90/0063) regarding the NRC audits:

conducted on the.GGNS pipe supports.

The NRC's-SER finds the1 existing GGNS pipe supports to be acceptable.- Howev'er, the SER discu'sses six:~ areas of.

concern and makes recommendations on. calculation-methodologies that should be-incorporated'into the GGNS~ Pipe. Support Design Specification.

Except-for SER.

Item #1 pertaining to warping normalistress loads'on-welds, SERI: agrees in general with the NRC recommendations =and has revised-'the current GGNS Design Specification (M-300.2) to address these recommendations.

The six items-identified in the SER and-our' action'with respect to incorporating:these items into the Design Specification is described in Attachment l'.-

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In addition, the NRC cover letter of March 16, 1990 requested.that the-design criteria for the cable tray supports in the. turbine building. be -

provided for NRC review. Attachment 2 provides this. additional:information.

l Please advise, if you require additional.information on-this matter.

Yours truly,.

^l THC:mte-Attachment cc:

(See Next Page) l.,

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.A9004161/SNLICFLR - 1 9005160204 900509

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_Mr.' D.'Ci Hintz (w/a)\\

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Mr.'W T. Cottle (w/a).

Mr. R. ' B. McGehee: (w/a)-

'Mr.1N. S.:Reynolds (w/a) j

Mr. H L. Thomas ~(w/o)-

t Mr. H.-0 Christensen (w/a)

Mr. Stewart D.:Ebneter (w/a)

Regional 1 Administrator.

t U.S. Nuclear' Regulatory Commission.-

Region II; 101 Marietta St'.':N.W.,

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' Atlanta, Georgia-30323; Suite 2900:

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Mr.1L. LL Kintner, Project Manager:(w/a)

J Office of Nuclear Reactor. Regulation a

U.S. Nuclear' Regulatory Commission-Mail Stop 14B20

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= Washington, D.C.

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-ATTACHMENTil TO AECM-90/0072

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. NRC SER ITEIL1 We recommend that the j % w eri a % require the..

evaluation of normal 9t> =stics.I

.o torsion in such'

-i members and-the> evalue ten C e5ects. due to-warping =

bending on the weld wnficWFMons, particularly at, the ;

' connections to base p M a.

x; SERI RESPONSE::

'I The'recommendationto'evaluatewarpingnormal) stresses'instructuralmembers:

has been incorporated into the Design Specification.(M-300'.2).- The

additional' recommendation to include' warping normal, stress Into the weld-

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check was. discussed with the NRC'during an earlier audit of:the Alternate-1 Decay llent Removal System,(ADilRS).- In AECH-89/0028 dated February 6,fl989,-

SERI provided details of the veld calculation methodology currently being utilized. Tholnubmittal concludedxthat design process conservatisms ands stress redistribution which is a fundamental consideration in base weld-

' design. compensates for the,absenceLof warping normal stressesLin welded.

connections.

The NRC SER on ADilRS dated March 27, 1989 (MAEC-89/0099) found:

U the:GGNS ADilRS pipe support design-calculational approach ~to be acceptable.

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.SERI h'as'also researched the current industry application of warping normal-

. stresses'in piping support weld' calculations and concludes that SERI's

-existing calculational methodology.is adequate and;representsfthe current.

j approach within.the industry.

NRC SER' ITEM 12:

The response to AQF 89/004 included proposed criteria for q

the applicability of CE-050.

Wo have evaluatod these critoria and have concluded that they;are acceptable'.

ilowever, we also recommend that GGNS restrict this:

-program.to the~ovaluation of rectangular base plates.with four-anchor patterns and single. attachments only. The-licensee:has committed in Reference'l~.to use ME-035 for plates falling outside his proposed criteria and;for.

complex plates. We recommend thatithe: additional i

restrictions' stated above be-included in Reference 1,..and i

that the specified anchor tension stiffness'in:the proposed criteria-also be applicab'le to ME-035.

SERI kESPONSE:

q Design Specification (M-300.2) was revised, prior to:the' issuance of.the=

SER, to include the limitations for the use of Computer Program CE-050.

The

. additional restrictions recommended in the SER have.also been incorporated into the Design Specification including the value of anchor tension '

3 stiffness.

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ATTAC'HMENTLl'TO'AECM-90/00727

~i NRC SER ITEM _3-A~ provision has' alsolbeen included in Section 3.4.2 of 1

Reference 1 to: evaluate punching shear: per: ANSI /AWS D1.1.77. -We find this provision' acceptable.but recommend a

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.that the, evaluation be based.on' ANSI /AWS D1.1-88, or a-later edition' of. this. Code.

SERI RESPONSE:

SERI hasiupdated the GGNS Design Specification'from the! 1977 to the 1983

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Codo edition of., ANSI /AWS DI.1.- Prior to issuance of the NRC SER,'SERI.had taken the initiative'to purchase standard'Bechtel; computer software that is:

being'used'to perform pipe support punching: shear; calculations;to thefl983, edition. Changesfto the program :to incorporate th'e recommended:1988 Code edition would' require'a custom designed software package'by GGNS andLwould; require significant. additional.' expenditure. _ Sample calculations' performed t

~ with the.two. Codes (1983;vs.'1988)~show1that results are close or that.the 1983 Code predicted conservative resulta..

therefore' believes t that ' our !

iSERIi current practice. satisfies.the recommendation to upgrade from;the:1977 Code.

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.NR_C_SER ITEM 4 GGNS has performed; a: reanalysis-of.as stress problem Lin L t

which the stiffness of standard components were, included in the calculations.- Results submittedfin the response!

.to:AQF-89/002 indicate that the pipe stresses had i

apparentlysincreased -although they;were:found'to still 2i be below;the ASME: Code 1allowables.

Based on these

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results the Design Specification'wasLrevisedLto require-L consideration and inclusion of standard comp'onent c

stiffness lfor new supportst(Section 3.8 of Reference 1).

We find ~this acceptable.-

SERI RESPONSE:

d It is need that the SER finds the criteria for inclusion of standard component = stiffness as.specified in Section 3.8,of the. Design Specification',

to be acceptable. No further action 11s required with>res'pectEtolthis item.

NRC SER ITEM 5 GGNS has performed stud'iosJindicating.that a chdek for-support flexibility based on-simultaneous applicationtof all loads tends to underestimate theLactual support-flexibliity,:and that the proper: approach is to bare the flexibility check on the application of unit l loads'in the direction ~of the required.' stiffness.- The Design Specification has. been ievised'(Section 3.8 of Reference.

1) to include this requirement, which we find' acceptable, SERI RESPONSE:

ri It is noted that;the SER finds the critoria provided'in the Design.

j Specification to'bc acceptable. 'No further action is required with respect l

to this item.

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A9004161/SNLICFLR - 7 j

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ATTACHMENT,1 TO AECM-90/0072-MC_RER_.!TER,6 The= response to AQF 89/006 included a comparison of n simplified procedure for. determining wold sizea ~ in acute angle welds with a'more accurate procedure which, includes certain loss factors. Our calculations show that if the accurate procedure is based on the loss' factors shown in ANSI /AWS D1.1-88 it is unconservative for.certain angles less than 60*.

We therefore recommend that the calculation of acute angle weld sizes be based on a more accurate procedure and the loss factors as specified in ANSI /AWS D1.1-88 or a later edition of this code.

SERI_ RESPONSE:

Pipe Supports including structural steci members at GGNS utilize ASME Section IX welding procedure; however, the criteria provided in AWS D1.1-1988 will be used to establish loss factors as recommended by the SER.

The Design Specification has been revised to require the consideration of:

loss factors stipulated in ANSI /AWS D1.1-88.

RC SER Dased on a review of a sample of GGNS pipe support CJiCLjlSBN:

calculation, packages, the licensee design practices and the responses provided by the licensee to our concerns,;

we conclude that there is no significant safety concern for existing piping and supports. The licensee has revised his piping support. Design Specification to:

address most of our concerns to be applicable to new supports.

Ilowever, the licensee has also provided information on an ongoing snubber' reduction' program.. We recommend that the Design' Specification be revised to-address all remaining concerns, and that it.be applicable to all supports which are reevaluated under this program.

l; SER_I RESPONSE:

1 Except for SER Item #1 portaining to warping normal stress loads on welds, SERI agrees in general with the NRC recommendations and has revised the current GGNS Pipe Support Design Specification to address those recommendations.

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The revised Design Specification will be applied to future design activities involving piping system additions or modifications.

In addition, the i

revised Design Specification will 1e applied to the snubbor reduction program design packages.

SERI wishes to clarify that the GGNS design spec.ification limits the application of standard component stiffness to new l

supports as found acceptable in the SER Item 4.

Therefore, standard component stiffnesses will only be~ applied to new supports resulting from the snubber reduction program and those resulting from future piping changes,

and modifications and not to existing installed or modified supports that are reevaluated.

A9004161/SNLICFLR - 8

ATTACHMENT 2 TO AECM-90/0072 MRC Request for_ Additional _ Information_ Cover _ Letter:

Describe design criteria for cabic tray supports in the Turbine Building.

RESPONSE

Cable tray supports inside the Turbine Building are classified non-safety.

i reinted.

They are' designed ~to criteria provided in the enclosed document NSR91-0-00000Y01.

Standard designs were developed and utilized,for the installation of the cabic tray supports.

These are shown on the following drawings:

FSK-E-278A-0725-G Rev.

8 FSK-E-278B-0725-G Rev.-

9 FSK-E-2780-0725-G

-Rev. 11 FSK-E-278D-0725-0 Rev.

6 FSK-E-278E-0725-0 Rev.

4 FSK-E-278F-0725-G Rev.

6 FSK-E-2780-0725-G Rev.

6 FSK-E-27811-0725-G Rev.

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FSK-E-278J-0725-0 Rev.

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A9004161/SNLICFLR - 9

WP&lR NO. NSR91-U-00000Y01 REVISION 1-PAGE'1 0F 6 l

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i GRAND GULF NUCLEAR POWER STATIDN Design Guide for Structural Design of Non-Seismic Supports for Electrical Raceways 1.0 Introduction This document is a guide to the design of non-seismic electrical raceway support systems.

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2.0 References 2.1 Specification 9645-E-034.0 2.2 Speci*'ica tion' 9645-E-036.0 2.3 Specification 9645 E-037.0 2.4 Specification 9645-C-131.1 3

2.5 Spe:ification 9645-C-13.1 2.6 Rat eway Notes & Details - E0725 1

2.7 Manus) of Steel Construction by American institute-o* Steel Construction (AISC) 2.9 f oecification for the Des 19n'of Cold-Forned Steel

' tructural Nembers by American Iron and Steel Institute-L (AISI) 3.0 Dese iption The system consists of two basic elements:

5.1 Raceway i

Electrical raceway, supports electrical ' cables and may run horizontal, vertical or skewed in respect to the building t

ames. Electrical raceway consists of cable tray, conduit, wireway, june. tion boxes, and associated fittings.

j 3.2 Raceway Supports Raceway hanger systems support eloctrical raceway loads.

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WP&lR NO. NSR91-t1-00000YO1 REVISION 1 PAGE 2 OF 6 j

j 3.3 Materials 3.3.1 Cable tray shall be as specified by Specification No. 9645-E-034.0 with tray widths of 6", ~ 2",18",

24", 30" and 36", as required by the electrical layout drawings.

3.3.2 Conduit and conduit fittings shall be'as specified i

by Specification No. 9645-t-036.0..

3.3.3 Support systems may be composed of cold-fomed meri6ers as e

specified by Specification No. 9645-E-037.0.: and/cr miscellanonus structural steel moabers to ASTM-A-36

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and steel tubing to ASTM-A-501'.

3.3.4 Wireway, trough and junction boxes shall be as

, specified in Drawing 9645 E-0725.

3.3.5 Miscellaneous' steel members, embedded plates,'

l and clips shall be ASTM-A 36 and h19h strength-bolts shall be A325 all confoming to the applicable provisions of. Specification 9645-C-131.1.

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3.3.6 doncrete expansion anchors shall be in accordance with the applicable paragraphs of Specification 964 0-C-103.1.

t 4.0 Support Spacing Tray supports shall not' exceed 12 feet maximum spacing (elbow 4.1 for vertical and horizontal straight runs. Tray fittings reducers, etc.) will be supported within 2 feet of each fitting, before and after the fitting connection, unless otherwise noted on the layout drawings. A support shall also be placed within 2 feet of. tray ending.-

i 4.2 Conduit supports shall be.in accordance with the following criteria:

a)

Within 3'0" of the end of non-flexible conduit, b)

Within a 10 feet maximum spacing' for all non-flexible conduit.

t 4.3 Wireway and trough box support spacing shall not exceed 4 feet maximum or 6s reconenended by the manufacturer (indicated by mounting holes or tabs).

J 4.4 All junction boxes and pull' boxes shall be supported inde--

pendently, as required..

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WP&IR NO. NSR91-U-00000Y01 i

REVISION 1 PAGE 3 OF 6 d

J 5,0 Support Locations and Structural Considerations 5.1 Vertical supports shall be supported as indicated below:

5.1.1 Where main structural steel framing members are perpendicular to the raceway, vertical supports at the centerline of the transverse. framing moder -

will be provided.

5.1.2 Where main structural steel framing moders are riot perpendicular to the raceway,' additional structure steel shapes will be placed between main framing meters to provide support at specified support spacing.

i 5.1.3 Where raceway is parallel to the building walls, embedded plates, unistrut or equal inserts may

• be used to prSvide support at the well side. If no ededded plate or insert exists, plates or strut meters will be mounted by use of concrete expansion anchors.

5.1.4 All connections.to the structural framing meders shall have minimum eccentricity to avoid torsional-i

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stresses in the main members. ~

1 5.1.5 Where raceways am close to the top of concrete floor i

or close to the bottom of concrete floor, supports may be connected to plates mounted on the concrete

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floors by expansion bolts.

5.2 Vertical raceway run supports may be' brackets attached to the walls, floors, and steel columins. Cold-fomed or hot-fomed' members me.y be installed as^ columns between floor. levels.

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5.3 The design of bolted connections between all cold-formed shapes shall be in accordance with the manufacturers

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instructions.

6.0 Structural Design

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6.1 Design Specification '

t 6.1.1 Raceway design loads shall be the vertical

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deadweight as calculated in Appendix A, except using 1.5 times the total tray load, n.l.2 The design of cold-fomed meders and connections

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shall be in accordance with AISI specification for

.the design of cold-formed steel structural members.

t,1.3 The design of hot rolled me d ers and connections-shall be in accordance with AISC Manual,of steel' c on', t Y ut ' i on.

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WP&IR NO. NSR91-U-00000Y01 REVISION 1

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6.1.4 Cold-formed member properties.used shall be based

'on Unistrut material properties. -See unistrut,

" General Engineering Catalog". Powerstrut, Globe, Whiz, 8-line and S @erstrut may be used, providing

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material and ph,sical properties are checked and are in compliance.with Specification 9645-E-037.0.

6.2 Analysis and Design Checks

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6.2.1 The raceway support system shall be considered as' a pinned system.

t 6.2.2 Horizontal members of supports will be: checked for compItance with the AISC and A!$! code design

.allowables for bending stress,. shear stress and deflection.

6.2.3 Vertical members of supports will be' checked for,

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compliance with the AISC and AISI code design allowables for alenderness ratio and tension or compression-stress.

6.2.4 Welded connections will be checked for allowable

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stresses in accordance with AISC specification.

6.2.5 Allowable forces for cold-formed fittings shall be in accordance with the manufacturer's catalog (Unistrut). ' Special test reports on fittings. shall also be utilized..Where welded connections are-utilized, fitting capacities.eay be higher, because-smaller eccentricities can be achieved inherent to detailing of welded connections.

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CP&IR NO. NSR91-U-00000Y01 i

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REVISION 1 PAGE 5 OF 6

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i APPENDIX A.

Vertical Deadweight Load Calculations Load Considerations 1

Tray load to be considered 10 lbs/ linear ft.

2 Cable load to be considered is.;

.12.5 lbs/ linear. ft. for 6 inch tray.

25.0 lbs/ linear ft. for 12 inch tray 37.5 lbs/ linear ft. for 18 inch tray.

50.0 lbs/ linear ft. for 24 inch tray 62.5 lbs/ linear ft. for 30 inch tray 75.0 lbs/ linear ft. for 36' inch tray-3 A load factor of 200 lbs. shall be added for the weight of hanger material.

4 Supplemental steel weight shall be added in for each hanger as required.

Design example:

W = P x (L) + L2) x N + 200 2

P - Total load (tray & cable)-

L = Span length to one side 1

of support '

i L = Span length to other side 2

side of support N = Nutter of trays.

(of same side)

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.UP&IR NO. NSR91-U-00000YO3

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