ML19318B676

Final Deficiency Rept Re Use of Improper Seismic Design Criteria for Design of QA Level I 3/8-inch & 5/8-inch Instrumentation & Control Tubing.Improperly Designed Tubing Sys Already Installed Will Receive Appropriate Mods

ML19318B676
Person / Time
Site:	Fermi
Issue date:	06/10/1980
From:	Casiglia J DETROIT EDISON CO.
To:
Shared Package
ML19318B670	List: ML19318B669 ML19318B676
References
NUDOCS 8006270286
Download: ML19318B676 (3)

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USE OF D'PFCPER SEISMIC DESIO: CRITERIA FOR SI CESIC: CF OA trVFL I 3/8-r:Ci I? D 5/8-r:QI DT7-:-TFER D:SULE.TATICt!

AND CTmtCL TUrDY; D7".%CCCTICt:

, Secticn 3.9.2.7 of tPc Enrico Pami Pcwer Plant-LP.it 2 Final Safety Analysis Pepcrt (FSAR) descriLcs tPc acthods, technigacs, and principal criteria which are applicd = :Pc Code Cualificaticn Design, including Sels-ic Das T. of Safety Fclated held Run Small Piping Systems. hnile not explicitly stated m tPc F'IAR, it was intended that tre 3/8-inch and 5/8-inch dia eter Safety Fclated Instnrentaticn and ccr. trol Tubing Systems,

'ce designed to the same criterta as the Safety related Field F= S all Pip =q Systcrs.

CESC:lWIC:: Cr 92 CFTICIE' Of i~

We acthcds, tec'T.iT22s, and criteria which are applicd to tPc Ccd2 Qualificatica Cesign, =cluding seismic design, of tPc neld Run S all Piping and Tubing Syste s, were develcped for Femi 2 by Edisco's Principal piping Analysis Ccnsultant. 2.4.s work is docrented in tPc fo= cf a technical re-port, 'inich is entitled "We S all Pininc D3sim Standard". (1) Ccrrect appli-caticn of tic procedures and techniques developed in that rcport results in the cctplete specificaticn of tPc pipmg systc= gecretry, suppcrt lccatice.

orientation and type, and support system leading. Se repcrt dcos nct provid2 criteria for tha detailed design of tre suppcrt Pard.eare.

In order to supplcrent Tre S all Picirc Cesian Sta: drd, a series of generic tubing suppcrt designs, for both safetf related and non-safety related tubing syste s, were develcred. Tnis work was prepared for Ediscn by a lccal Architect /E .gineering fi= and doctrented in the form of a Project Specification. (2)

In addition to providing detailed support hard.eare design infc=ation, this speci-ficaticn also provid:s support locatica criteria for ncn-safety related tuttnc systers. W.is criteria censiders tPc effects of dead suight an ope =al expa.n-sica enly: it dccs not censider the effect of seismically induced inertia cr anc?cr acve:ncnt lecd.i .gs en tPe tubing syste s.

i During a site. engineering m2eting, it was determined that tha tubing support locaticn criteria for non-safety related tubing, which was doct=nnted in tre specification, was applied, in part', to tPc design of the safety related 3/8-inch and 5/8-inch tubing syste s, rather than tPc criteria specified in ?e S all Pic-inc D2sicn g_ andard.

(1) Edisen Eccirent !!c. A30-01-G-900-FA-037 (2) Specificatica 3071-185 0h g eoomo a '  % 4.gn2h7

NUCLEAR REGULATORY COMMISSION NOTIFICATION In accordance with the' rules of the Commission, verbal notifica-tion of the previously described design deficiency was provided to the NRC Region III Staff, by the Director-Project Ouality Assurance, on April 14, 1980.

CORRECTIVE ACTION When it was initially determined that a non-conservative criteria might have been applied to the design of the safety 'ralated instrumen-tation and control tubing systems, a stop work order was immediately .

instituted on the construction of all safety related instrumentation and control tubing. It is intended that this stop work order will be lifted gradually as designs, revised in accordance with project licensed criteria are produced, reviewed, approved and released for construction.

Reconciliation of that work which is already installed, or finally designed but not installed, will be handled in several different ways as appropriate to the specific situation, and outlined below:

1. For the Control Center EVAC Pneumatic Control Tubing which is installed over the Control Center ceiling, detailed "as-built" drawings of the tubing installed configuration will be pre-pared. The installed configurations will then be subjected to rigorous computerized piping stress analysis to ascertain whether their design meets the relevant ASME Code criteria.

If the analysis dictates the need for modification of the tub-ing or tube supports, those modifications will be instituted.

This approach is being taken in order to limit changes to the installed tubing and tube supports, thus minimizing construc-tion activities in the Control Center, which is at a high degree of construction completion. Approximately 60% of the total required tubing for the Control Center HVAC system is installed and falls in this category.

2. Safety related Instrumentation and Control Tubing Systems in the balance of the Reactor Building which were designed to improper criteria and have been installed, will be reviewed for conformity to correct design criteria, and appropriate modifications to the existing installations will be made.

Approximately 7% of the tubing in this category is installed.

3. Safety related Instrumentation and Control Tubing Systems which were designed to improper criteria, and released for construc-tion but which have not been installed, will be redesigned to the proper criteria prior to installation.

White much of the design work to be accomplished in Items 2 and 3 above will be done by application of The _Srall Piping Design Standard,

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. . . s it is anticipated that some detailed computerized piping analysis will be taquired to supplement that activity and to provide solutions to special design problems, particularly problems associated with thermal expansion.

I All revised designs, and those new designs not previously issued, which are done in accordance with The Small Piping Design Standard will be reviewed and approved by cognizant engineers from Edison's Mechanical and Instrumentation and Control Design Grvops (Troy), prior to their release for construction. Revised or new designs which are qualified by detailed computer analysis, will be reviewed and approved by cognizant engineers representing the organization who performed the analysis, prior to their release for construction.

SAFETY IMPLICATION OF THE DEFICIENCY Comparison of the non-safety related criteria used for the initial design of the safety related 3/8-inch and 5/8-inch Instrumentation and j Control Tubing with that provided in The Small Piping Design Standard indicates two areas where significant differences exist. They are:

1. The support spacings provided in the non-safety related cri-teria are based upon dead weight design, and are longer than

. the seismic span spacings provided in The small Piping Design

' Standard. The longer spans provided by the non-safety related criteria increase the probability that resonant vibra-tion may occur during a postulated site seismic event. Such resonant vibration, if severe enough, could result in tubing and support system overstress or structural failure.

2. The non-safety related design criteria does net specifically provide for the axial support of long straight tubing runs.

l During a postulated site seismic event, the inertial accelera-

, tion of these long runs could result in bending or buckling failures in the tubing, thus compromising its intended safety

} ' function.

It is concluded that by reviewing and/or revising the existing 4

designs, 'using the methods previously described, it can be demonstrated that the originally intended margins against safety related Instrumen-tation and Control tubing structural failure, during a postulated site seismic event, will be preserved and that the tubing systems will be capable of performing their intended safety function.

j: Prepared by: J.H.- Casiglia, P.E.

Principal Engineer f

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