ML20206G519

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SER Supporting Employee Concern Element Rept OP 30105, Questionable Design & Const Practices
ML20206G519
Person / Time
Site: Sequoyah  Tennessee Valley Authority icon.png
Issue date: 11/04/1988
From:
NRC OFFICE OF SPECIAL PROJECTS
To:
Shared Package
ML20206G037 List: ... further results
References
NUDOCS 8811220303
Download: ML20206G519 (3)
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Text

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SAFETY EVALVATION REPORT BY THE OFFICE OF SPE', At PROJECTS EMPLUYEE CONCERN ELEMENT REPORT OP 30105, "OUESTIONABLE DESIGN AND CONSTRUCT!ON PRACTICES" TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR POWER PLANT UNITS 1 & 2 DOCKET NOS. 50-327 AND 50-328 l I. Sub!e:t I Cate;:ry: Cperations (30000) I l

t Sub:stegory: Mechanical Ecut; ment Reitability/ Design (30100) l Eleme-t- Quest.':nable Design and ccnstruction Practices (30105)

E p<oyee Cencerns: ine folle>:ing tnroe specific and unrelated concerns were eveluated in revisien 3 of this element report, dated Feervary 7, 4957: ,

"Impreper ounting of limit 5,< itches on 2 FCV-30-15."

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1. u.AS-56-007. :
2. RCM-85-001:

Faited check valve on B-CST allowed water on top of bladcer. Bladder could get into ERCW suction."

3. 1-56-233-SCN: " An anonymous individual mailed in a potential safety nazard , associated with the condensate demineralizer waste evaporator (CDVE) on elevation 706 of the Auxiliary Building at Sequoyah Nuclear  :

Plant (SCN). The original stainless steel piping for pumping "Bottoms" from the CCWE was removed and replaced b.v a temporary rubber hose. Extensive modifications are being performed over the hose.

  • Welding hot chips have been cbserved falling on the ruocer hose. Damage to or rupture of the hose wovid result in possible personnel exposure of a Sign a-ount." ,

These three concerns ae specific to SCN. Concerns PAS-86-002 i a c R:v-55-::: -e e deter-ice :) T '.' A te be c:te9tially nuclear t j 5 & f e *. ., r e l &

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0911220303 G811Q4 PUR ADOCN 0500u327 PDC p

. i II. Sue arv of Issues  !

1. MAS-86-002: The issue defined by TVA is that a mounting problem with 20hE limit switches (ZS) on t'utterfly valves with circular  ;

novecent of the actuator was identified for six Systerr 30 (contain- '

, ment ourc0 valves. This condition had been identified by the SON '

electrical maintenance sect. ion as a result of a one-time fielt' '

inspection under SMI-0-0-1 to verify the installation of qualified j switches in accordance with 10 CFR 50.49 requirements, i i

2. RCM-85-001: The issue defined by TVA is that five styrofoam float  !

(che:k.) valves at the top of the B-CST failed to properly seal due '

to shrinkage of the styrofoar discs. Additionally, TVA evaluated >

the possibility of the CST bla._er being drawn into the AFV suction j line, potentially clogging the line downstream of the ERCW suction .

! and ci.using loss of auxiliary feedwater.

l l

3. I-$6-253-50N: The concern is whether personnel could be exposed to j

a raciological ha:ard due t'o rupture or damage to the rubber hese ,

used to transfer bottoms, offgrade distillate, and distillate from i j

the CDWE to tre Floor Drain Collector Tank (FDCT). TVA focused their i

evaluation on the transfer of highly radioactive bottoms rather than f the slightly radioactive offgrade distillate. Due to the impossibil-

) ity of cerrari g the tire when work that could potentially damage the l hose was occurring and COWE bottoms were being transferred tnrough i the hcse, T"A took the approach of showing that administrative

centeel of the cottoms trant,fer operation would prevent personnel

l' frc accessing aress through which the hose runs during transfer l Operations, there0y rreventing excessive personnel exposure. i J

) III. Eva hat

  • ens

} 1. MAS-36-002: TVA's investigation consisted of reviewing documenta- f i tion between the Maintenance and Modifications Departments that  !

aedressed the ZS mounting problem. The six system 30 valves alleged l l to have 25 mi slignment problems severe enough to warrant correction 3

were discoversd during a one-time field inspection to verify that '

{ 25 installation conformed to 10 CFR 50.49 requirements. The modifi-  :

1 cation department's investigation of the six system 30 ZSs alleged by '

the Electrical Maintenance section to be counted incorrectly resulted +

j in a cetermination that only one of tNse 255 (2-Z5-30-15) wa s  !

i mounted incorrectly. This situation vas corrected by work request i

E-110369 on 4/11/96. Maintenance concurred with modification's l assess ent of the problem and the corrective action taken. An 7

' tervie. .a tn tne ele:trical Maintenance section supervisor deter-  !

mined that concurrence was based on the fact that the post-modifica-  !

tion testing of the otner five system valves was satisfactory in l c

spite of tre slight misalignment of the switch actuation lever arm i

! with tre circular strike plate. Additionally, the section supervisor  !

} stated t*at r syste- 30 valve cositien indication failures base j

_ ,: :a u -4 sa ng et ec w :. er 1 e :ss. at :.;-

i

  • t*P. t*e .* ting prCDle with 2-25*30-15 wa s  !
W tt . c ' t *- P c:Prectiet Of similar 25 counts required. TkA, (

I

    • eref et. c0Pel6ced t*at PO further Corrective action is recuired.

1

2. RCv-55-001: An interview with a ecdification engineer at SCN revealed that the check valve problem was fixed by replacing the styrefcar discs with nonshrinkable plastic discs under ECN L6515.

Tne work was completed on 3/27/E6 under work plan 11844 Ne further preolems with the check valves have occurred since the modification was cerclete . TVA concluded that no further corrective action is required.

Rega ding the issue of the bladder being drawn into the AFV suction line, this concern was validated. TVA modified the inlet grating to the AFW su: tion line to prevent the bladder from being drawn into the line ccanstreat. of the ERCW suction. The work was completed on 3/27/86 under w0rk plan 11844 TVA confirmed that no tanks other tnan the A anc B C5is were effected by this concern.

3. I-Sf-233-SON: TVA cerformed e ployee interviews and reviewed SQN c;e-atir; instrv:tieni. radiological instructions, and HP survey re:cres to as:ertain whether controls were sufficient to prevent personnel f ro- being in the pecximity of the hose during better.s transfer operatiens. TVA aise confirmed that the offgrade distillate was ret $1;n'y racica:tive and, therefore, controls to limit access to areas th cu;n which the hese runs are not required aad are not im;tsed curing of fgrace distillate transfer to the FDCT. TVA's revie- 24 501-77.153 and ROI-13 confireed that these procedures recuire W? notification by operators prior to the commen:ement of bott: .s trarsfer ::eratiers so that HP can icek and monitor areas th*cugh wnich the hose *uns. These procedures further require that tnc hote be flushed ard surveyed for hot spots oy 'AP prior to lif ting the a: cess restrictions urder RCI-13. TVA verified proper imple?en-tatten of these controls by citing a particular example in which they were ade:uately ef fected (11/29/86 bottems transfer). TVA, there-fere, con:1uded that these controls are sufficient to prevent person-nel a::ess (aad the resultant potential exposure) or work in areas wnere the hose runs during b0ttems transfer, and these controls have been preper y irpler.ented for past be* toms transfer o p e ra t', o n s .

Although the ele ent report states that no corrective action is re;uired, TVA has issue: an EON to replace tre rubber hose with pe manent piping.

IV. Coa: 1us4e s The N;; ,taff celieses tnat the TVA investigation of the three e picyee con: erns accresse: cy this ele ent report is aceovate, and their resolution of tne cen: erns in revision 3 of the eierent report is a; epta:le fe* resta*t.

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