ML19309E614

LER 80-020/01T-0:on 800404,investigation Revealed That Several vendor-designed Pipe Supports Were Designed Utilizing Manufacturer Std 0.25-inch U-bolt Which Overstressed During Seismic Event.Caused by Design Error

ML19309E614
Person / Time
Site:	Sequoyah
Issue date:	04/17/1980
From:	Lagergren B TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19309E606	List: ML19309E604 ML19309E614
References
LER-80-020-01T, LER-80-20-1T, NUDOCS 8004220707
Download: ML19309E614 (2)

Text

.

n v

) s..

nnCroRusse u.s. NUCLEAR RtGUL AToRY COYMIS$10N (7 77) 1.lCENSEE EVENT REPORT EXHIBli A CoNTaot cLocit I ! I l l I e@ >

l (PLEASE PRINT oR TYPE ALL MEQUIRio INpoRMATICN) foTileei TINvus...

> I S I uas NIP l 1l@:l 0 l O!- uca

i. . l 0al,.Ol0101v.. Ol- l 0l0

• l@lu411

2. l lli ul 11@!

u .. ,,,a . .;.. l l@

Co*fi . .

lo.MJ I

,"E!U Lt_-)@l 015 ' 0 ! O f 0131 217 l@L2_L4 I 014 I 81 Ol@l0'I' 41'1 l' 71 siO I@ ~~

8 GJ 66 0,*,;t E r r.yug g g f4 GJ Ev4#TQATE 34 JS 44 Rif09T3 Aft avesv orsca PTroN ANo raesasLs C NsscurNC s @

roTT11 d Several vendor (EDS) d,esigned pipe supports that support 3/4-inch class t

~

o 1 ' A' pipe -from- d'15rge 'proce$is" pipe' were designed utilizing a manufacturers t f TTI I standard 1/4-inch U-bolt. Investigation has shown that this 1/4-inch  !

io,3i f U-bolt'is overstressed during a seismic event based on the loadings l I m ,shown on the individual drawings.  ;

o 7 l l

1014 I l I 7 8 9 'O

$Y S TI *.' CAU' E Cau:E CO"P. vA(vg COG 4 CD:t SUSCOCE CC .*FO*. INT CODE $UgCOE $wscCO3 rr m ix i xl@

, m W@ tsJ@ IS i u'i riO a ir i@ gl@ g @

i

,, ,, J

,. Stoua NTI AL OCCU*

• t ".Ct .et* ear afvissoN

<., n'y'. ,

I8l n ,,

l 2 10 l M,

, l,. 11.,I Id,,

.. J. ,,

b Nt$ 'AYTEo"- o [e's T $YTN m'ovat h #Sa IT s Fo "t a s *t AE a.* s'f$Y.U =

W. LF_j@[lj@ LZil@

3J 34 36 Lz_j@

4 10 1 010 i Of LY_J 46

@ LY_l@ L3J@ l x i 919 I 9 'f 3' 4J 42 44 44 47 CAUSE of 50RIPTICN ANo COARECrlVE ACTICNS 27 tiloll Design error - Designer used incorrect seismic loadines in the desicn of g Ithe supports. EDS designed the U-bolt in the lower (3/4-inch) pipe as i g ian anchor but it was intended to be used as a 2-way lateral restraint. r mI I -

E! a ,

l n

' STA '3 *b 7CV:{ n $TM(R$7ATV C3. V OfSCOvCnv oE30'*i87tCN A LHJO IO I O! 0'S! N/A i Laj@! Resnalv=dec suonorts I

- ,' ' A!nv., Y Cc'ht T natu,u o enifLiteif A'.'Q J';T QF ACitviry LCCAfiON Ca ngtg.ist

' a N/A I- N/A 7 is, L,2] @ NLI.j@l se 44 I

43 I

6J Pf oto .*.f t ( s PQw.et:

NF'.88 Tvil CC t,8 tPrio% -

li ii; I 010 l O!$!121 N/A I

' ,,. ,w.sc.

. t .,

. a'. .u'.t.a

( Ld_.J l 0! O ! 0lS!uc,cmen:.@ N/A _ I o c > ,, .

.a

. '$i *' 9 fC.',';'/,? "4" "' @

fit 1 L, ;iSI N/A I

...w.t.r....,,,c.@

lr . i ...>! W3 !~ N/A I  !fI !'I se so -

Ne...T e,. m ti.. m . 3111 Iafercron p..c2N e 615-%2-0095 t90423g ,,y 7 d 7

o .- o Tennessee Valley Authority Sequoyah Nuclear Plant LER SUPPLEMENTAL INFORMATION SQRO-50-327/ 8020 Technical Specification Involved SR 6.9.1.12.1 Reported Under Technical Specification 6.9.1.12.1 Date of Occurrence: 4/4/80 Tine of Occurrence: 1215' hrs. CST Unit 1 Identification and Description of Occur'rence:

Several vendor (EDS) designed pipe supports that support 3/4-inch class 'A' pipe from a larger process pipe were designed utili=ing a manufacturers standard 1/4-inch U-bolt. Investigation has shown that this 1/4-inch U-bolt is overstressed during a seismic event based on the loadings shown on the '

individual drawings.

Conditiens Prior to Occurrence:

I Unit 1 in Pode 6 with all fuel loaded.

Action specified in the Technical Specification Surveillance Requirements met due to inocerable ecuineent. Describe.

N/A Apparent Cause of Occurrence:

Design error - Designer used incorrect seismic loadings in the design of the supports. EDS designed the U-bolt in the lower (3/4-inch) pipe as an anchor -

but it was intended to be used as a 2-way lateral restraint.

Analysis of Occurrence There was no hazard to public health and safety.

Corrective Action:

• 6+-

The affected supports are being reviewed by SU? and EDS engineccs and will be redesigned. The U-bolts on the 3/4-inch pipes will be reanaly ad and redesigned to act as a 2-way lateral support. Modificatien vill bc =ade to the supports in the field by icosening the branch line U-bolts so they provide only lateral restraint. The modification will be ccepleted prior to initial criticality.

Failure Data:

N/A

.