ML20086B256

AO 50-267/74-19:per Dro Bulletin 74-3 Instruction,Class I Support Structures Inspected.Potential Problem May Exist Re Natural Vibrational Frequency.Structures Being Examined & Deficient Structures Will Be Reanalyzed

ML20086B256
Person / Time
Site:	Fort Saint Vrain
Issue date:	09/23/1974
From:	Reader J, Swart F PUBLIC SERVICE CO. OF COLORADO
To:
Shared Package
ML20086B259	List: ML20086B256
References
AO-50-267-74-19, NUDOCS 8311170121
Download: ML20086B256 (5)

Text

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Director "..[rpl> *'*

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Dear Sir:

Enclosed please find a copy of Abnormal Occurrence Report No. 50-267/74/19, submitted to the Directorate of Licensing, for your information. Additional distribution of this report is being nade as indicated on the attached.- l Very truly yours, ALE!

Frederic E. Svart Superintendent Fort St. Vrain Nuclear.

Generating Station FES:11 9

8311170121 741105 S o -29 , .

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PDR ADOCK 05000267 *

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l. O O Date: Sept. 23, 197h ABN010!AL OCCURRENCE 1

I FORT ST. VRA'IN NUCLEAR GENERATIUG SYSTD PUBLIC SEltVICE CO: IPA::Y OF COLORADO t P.O. BOX 361 PLATTEVILLE, COLORADO 80651

) REPORT HO. 50-267/7h/19 PRELIMIHARY IMDEITI'IFICATION OF i

OCCURHMMCE: .

As requested in AEC DRO Bulletin No. 74-3, Public Service company * '

i of Colorado and General Atomic Company have conducted an inspection of some of the Class I support structures at Fort St. Vrnin.

f Preliminary indications are that a potentini problem uny exist, and is considered reportable under paraCraph B-3 o-f AEC DRO

! Bulletin Ho. 7h-3.

CONDITIO::S i'RIOR TO OCCURill:NCU* Steady State Power Routine Stitdown ll. Rot Shutdown Routine Load Chnnge -

X Cold Shutdown Other (Specify)

Refueling Shutdown - - - - - - - - - - - - - - - - - - - -

Routine Startup - - - - - - - - - - - - - - - - - - - - - -

The major plant parameters at the time of the event were as follows:

l

! Nth Power RTR, 0 ELECT, o MUc Secondary Coolant Pressure N/A psig

- Tenperature n/A *F Flow 0 f/hi.

Primary Coolant Pressure O psig Temperature 100 *F Core Inlet' i 100 *F Core Outlet

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i Flov 0 f /hr. . =

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O O l DEGCllIFfIOt OF O

_ CCURHi::!CE' The prelinin try recultn of a nanple innpection of varioun C] ann I l heat exchancer :,upport structures indicaten that a potential '

prob 1cm ex.ints with regardn to the seinnic design of these nupport structuren. The review of the support etructuren exanined indicates that a design problen nay exist relating to the support structure natural vibrational frequency and the design carthquake vibrational frequency on eight (8) heat exchanger cupport structuren examined

• to date.

APPAllEi;T CAUSE 0F OCC11BRP::CI : X Denign Unucual Service Cond.

Including Environ -

Manufacture Component Failure ,

Installation /Const. Other (Specify)

Operator

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AI!ALYSIS OF

,0CCURRE :CE:

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The analysis of this potential prob 1cn is proceeding in conjunction vith the Clacs I support structure inspection. If the results of the inspection program indicate that a problen actually exists, the support structure rigidity vill have to be re-analyzed and appropriate action taken.

• CORRECTIVE ACTIOi:

An examination of all Class I support structures is presently in progrecs to determine the extent of the potentitl problem. Upon completion of this examination a re-analysis of the design of the deficient structures vill be made. The specific corrective measures to be undertaken vill depend upon the renults of the design analysis.

FAIL 11RE DATA /SIIIILAR REPORTED OCCURRE: CES:

l To date, no_ne o of the Claus I support structurec have evidenced any nign of actual failure.

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Superintendent I!uelear Production Fort St. Vrain !!uclear Generating Gtation ,

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1333 Broo<!way

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Calif. Patent Croup *

.1 Division of Reactor Research .

, and1]cvelopment. ,

USAEC * .

Washington, D. C. 20545 . , ,

Attn Director 1

. Asst. Dir. for L'!TER Programs . -

, Asst. Dir. for Cas Cooled Reacter Project -

2 Asst. Dir. for Engrg. and Technology . 1

,. Acst. Dir. for Reactor Safety -

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USAEC-SCRPO-SD ,

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(Chairman.hTSC) ' Oscar Lee . 11 (copy of Ilovard 1 letter & xeNocras) ma F. Svart ..

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September 30, 1974 amm gy'W9 ' e Mr. E. Morris llovard, Director Directorate of Regulatory Operations Region IV, USAEC 10395 West Colfax, Room 200 Denver, Colorado 80215 REF: Facility Operating License No. DPR-34 Docket No. 50-267

Dear Mr. Iloward:

Enclosed please find a copy of Abnormal Occurrence Report No.

50-267/74/19, submitted per the requirements of the Technical Specifications.

Very truly yours,

,LCa s .Y& l Frederic E.. Swart Superintendent Nuclear Production Fort St. Vrain Nuclear Generating' Station FES:ll cc: Mr. Angelo Giambusso

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, o Date: Sept. 23, 197h AB:! Orc:AL OCCURRE::CE 9

FORT ST. VRAI:I!!UCLFlin GE:ERATI!iG SYSTE'!

PUBLIC SERVICE CO:!PA::Y OF COLORADO P.O. BOX 361 PLATTEVILLE, COLORADO 80651 REPORT I!O. SC-f:67/7h/19 PRELII!II!ARY II!DE!!TIFICATIC:1 0F OCCURHl::!CI:-

As requested in AEC DRO Bulletin No. Th-3, Public Service Company of Colorado and General Atomic Company have conducted an increction of some of the Class I support structures at Fort St. Vrain.

Preliminary indications are that a potentini problen may exist, and is considered reportable under paraCraph B-3 of AEC DRO Eulletin !!o. Th-3.

COIIDITIO::C PRIOR TO OCCURRl"'C"- Steady State Power Routinc~Sutdown Hot, Shutdown Houtine Lond Change X Cold Shutdovn Other (Specify)

Refueling Shutdown - - - - - - - - - - - - - - - - - - - - -

Routine Startup - - - - - - - - - - - - - - - - - - - -

The najor plant parameters at the time of the event were as follows:

Power RTR, 0 !Wth ELECI', 0 !We ~

Secondary Coolant Pressure II/A psig l

Temperature n/A *F l

Flov 0 f/hr.

1 ~

Primary Coolant Pressure o psig Tenperature 300 *F Coi e Inlet s

. 100 *F Core Outlet Flov 0 #/hr.

- y) f' Fnge 2 DESCRIP2IO,:1 OF -

OCCURRI::!CI:-

The prolininary results of a cumple inspection of varioun Class I heat exchancer support structures indicaten that a potential

! problem exintn with regards to the seicnic design of these nupport structuren. The review of the support structures exnnined indicaten that a design problem nay exint relating to the support ctructure natural vibrational frequency and the design carthquake vibrational frequency on eicht (8) heat exchanger support structures examined to date.

APPAR12.'? CAUSE OF OCCt!Ri'E:,0:': X Design Ununual Service Cond.

Including Environ Enufacture Component Failure Installation /Const. Other (Specify)

Operator

-Procedure M;ALYSIS OF OCCURRE! CI': .

The analysia of this potential prob 1'em is proceeding in conjunction with the Clacc I support ntructure inspection. If the results of the inspection prcgran indicate that a problen actually exists, the support structure rigidity vill have to be re-analyzed and appropriate action

~

taken.

CORRECTIVE ACTIO!I:

An examination of all Class I' support structures is presently in progresc to deternine the extent of the potential probler Upon completion of thic examination a re-analysis of the design of the deficient structuren vill be made. Tne specific corrective neasures to be undertaken vill depend upon the results of the design analysis.

FAILURM DATA / sit!!UJR REPORTED OCCURRF::CFS:

To date, none of the Class I support structuren have evidenced any nicn of actual failure. .

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