ML20126F925

Forwards NRC Comments on Proposed IE Bulletin, Flow Blockage of Cooling Water to Safety Sys Components by Corbicula Sp (Asiatic Clam) & Mytilus Sp (Mussel). Draft IE Bulletin More Appropriate as IE Info Notice

ML20126F925
Person / Time
Site:	Arkansas Nuclear
Issue date:	03/10/1981
From:	Novak T Office of Nuclear Reactor Regulation
To:	Jordan E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
References
NUDOCS 8103230191
Download: ML20126F925 (7)

Text

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Y 16 6.. .  :: a \ # .g MEMORANDUM FOR: E. L. Jordan Deputy Director Division of Resident and Regional

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- "'8N/lEl 3 7pgA (~2, Reactor Inspection, IE  %%c ,,df^roo '

b d FR0:1: T. M. Novak, Assistant Director / \

for Operating Reactors, DL

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SUBJECT:

IE DRAFT BULLENTIN ON FLOW BLOCKAGE OF COOLING WATER SYSTEMS BY CLAMS AND SILT In response to your memorandum dated February 23, 1981 we have invited the principal NRR staff members involved with this matter as it arose on ANO-2 to coment on the proposed bulletin. Their comments are attached.

In summary, while we believe that collection of the large quantities of information required by the currently proposed ACTION STATEMENT would provide more comprehensive knowledge of where the clans and mussels reside we feel that a balancing of the valve of this information against the licensee resource requirements to provide it does not justify issuance of the raft document as a Bulletin. This conclusion takes into account that the most significant safety related aspects of cooling water system performance degradation are addressed by Technical Specification Surveillance Requirements on safety related cooling water systems, We suggest that the draft docunent is more appropriate for issuance as an IE Infonnation Notice.

Original cisned byr Thomas M. Novak T. M. Novak, Assistant Director for Operating Reactors, DL Attacnment: As stated DISTRIB M (fontral Fii2 )

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E NUCLEAR PEGULATORY COMMISSION Wiq3HINGTON, D. C. 20555

• a March 10, 1981

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MEMORANDUM FOR: E. L. Jordan, Deputy Director Division of Resident and Regional =

Reactcr Inspection, IE [

FROM: T. M. Novak, Assistant Director for Operating Reactors, DL .

SUBJECT:

IE DRAFT BULLENTIN ON FLOW BLOCKAGE OF COOLING WATER SYSTEMS BY CLAMS AND SILT In response to your memorandum dated February 23, 1981 we have invited the  !

principal NRR staff members involved with this matter as it arose on ANO-2 to comment en the proposed bulletin. Their comments are attached.  ;

In summary, while we believe that collection of the large quantities of 1

information required by the currently proposed ACTION STATEMENT would provide more comprehensive knowledge of where the clams and mussels reside we feel that a balancing of the vclue of this infctmation against the licensee resource rec;uirements to provice it does not justify iss6ance of the draf t document as a Bulletin. This conclusion takes into account that the most ,

significant safety related aspects of cooling water system performance  !

degradation are addressed by Technical Specification Surveillance Requirements  !

cn safety related cooling water systems. We suggest that the draft document is more appropriate for issuance as an IE Information Notice. ,

t T 'W T. M. Novak, Assistant Director for Operating Reactors, DL i

Attachment:

As stated f-k I

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t COMMENTS OF: R. Martin, PM for ANO-21  !

Operating Reactors Branch r3 l

It is recommended that this information be issued to licensees as an Information '

Notice since the chief safety concern 1s already believed to be addressed .

by-the Technical Specification Surveillance Requirements. If, on the other  !

hand, the existing TS's are considered-inadequate.to address this problem,  !

then it would appear that if 1ssued as a Bulletin, it snould concentrate '

on remedying the TS inadequacies.- 3

'I I am concerned about the incremental effect that issuance'of this draft as a Bulletin, with its presently stated ACTION requirements, will have on the licensees' capability to devote attention to safety issues that may be more significant. When such requirements are imposed by decree on the licensees .;

it reduces both the resources and the flexibility tney nave available'to i respond to other issues-that, from a technical viewpoint, may be more .!

significant to the safe operation of the plant. A consideration of the costs ,

versus the benefits of sending the draft out as a Bulletin versus sending 3 it as an Information Notice needs to be made. .;

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Tne sixty day licensee' response period is arbitrary. Considering the relative  ;

severity of this matter as a safety issue and the TS Surveillance Requirements 3 in effect, 120 days is a more appropriate response time if it is to be sent 3 as a bulletin.

COMMENTS OF: D. Pickett-Operating Reactors Assessment Branch Doug provided the verbal comment that he had no comments on the detailed  ;

format and content of the proposed Bulletin. Doug also commented that he felt that this matter would more appropriately be addressed by issuance

• of an Information Notice. l COMMENTS OF: M. Masnik ,

Environmental Engineering Branch ,

i Mikes comments are penciled onto the attacheo copy of the proposed bulletin. l l

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UfJITED STATE 5 tiUCLEAR REGUU.iCRf C?"'.1551:!!

OFFICE OF ItiSPECTI0ti R.3 E!. C . EMEth ~

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WASHI!!GT0ti, D.C. 2C555 February 23, 1951 Draft IE Bulletin El- : FLOW ELOCKAGE OF CCT.ItG WATER TO SAFETY SYSTEM COMPCi?Et?TS EY COPEICULA SP. (ASIATIC CLAM) A!O MYTILUS SP. (fUSSEL) F l t'l Cesc-iction of Circumstances: i Cn September 3,1950, Arkansas !!uclear One (A!O), Unit 2, was shut cc.cn af ter the fiRC Resident Inspector discovered that Unit 2 had f ailed to ces tne technical specification recuirements for cirima: service water flew rate '

thrcugh the containment cooling units (CCUs). . Arkansas Pcwer and Lignt Ccepany, v fice was due to extensive piu::in: ~~ ~

ne

f theLicensee, CCUs by Asiatic determined that the inaceqhua-clams (Corbicula :ies, a non-native ~ fresh water tivalve ecllusk). ef ter pian;Cians snc.n v.ere

.a [.nefet licensie

.d in the digasst.

NE4;ihster b}ed the senice suppi) i

.a Er piping at the cciers.

Si .; at the inlet to the CCUs and in the c:cler inist water bcxes. Sc:e of

e cians frend were alive, but mest cf tre - The si

e cf

. ,e :iars was apprcximately L'S '..:?.'"'i',@i@scris rvice water,5.s which e shells, is taken frc /

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e Earcanelle Reservcir, is filtered before it is p: ped thrcugn the syster.

- ,e 5.rainers an the service water pump disenarces were examined and found te .

ti irta::. Since these strainers have a I'- '.".MllfMM.'s c.::n ses11e- / '

1 an stre cf tne shells found, it appears tna . clats had bean grcwing in tre

! system.

F:11:<ing the discovery of Asiatic clacs in tre con ainment :cclers cf Unit 2, ,

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er.see examine.: cther equipment cec 1ed ::y service water in bcth Units I ar: 2. Ins;tcticn of other heat excr. angers in tne Unit 2 service wa.e- l systs: revealed some fouling or plegging of adcitional coolers (seal water '

cclers for both redundant contain:ent spray pu:;s and one icw pressure saf e y injection purp) due to a buildup of silt, ccrresica products, and debris ,

(ros:1y clam shell pietes). The high pressure safety injecticn (HPSI) pump t and seal cociers were found to have substantial pluoging in the 3,1c,.3gihsarin:J.: pipe service water supply lines. Tne ple;;ing res51ted frc:4 silt and / 1 c rr:sien products. e m ...,W ,d .q i Clar shells were found in some auxiliary building r:cm coolers and in the ,

auxiliary cooling water system which serves aca-safe .y related equipment. t i

Fic.e rates measured during surveillance testing thrcugh the CCUs at A!O-2 tac

sterierated frc a cc binedover a nu1ber flow rate throughofthe conths "C" and with "D"theCCOs ecstofsicnificant W4-fis'iEJh6di re. duction c .in -

@ ,' M P ,1' 't c on August 20, 1950. Flushing af ter plant shutdewn esulted in a fur:nse i redu: tion in ficw. Proper ficw rates Nere restored only a$er f the cla . detris had :een re..cved canually from the CCUs.

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and "D" containment coolers were clagged by clars. Clats were fcund in the 7e on /

l 3 n n) 3 .:. inlet hea:ers and in the inlet water b xes. However, no clams were found in the "A" and "E" cociers. This fculing was not discovered curing surveillance testing be:ause there was no flow instrumentation on these coolers. Further investigation revealed that the service water strainer serving the "A" and "'" ccolers was inta:t, whereas the ene servin; the "C" and "D" c0ciers was broken. The licensee c:n:luded that the cla s fcund in tne "C" and "D" ccelers cid not gros in the syster but were sweet in inrce:h -

the broken strainer.

Ine servi:e vater syste: in Unit I was not f:uled other than stated ateve, an:

e licensee attricuted this to the fact that tne service water pump su

:icns are iccated behind tne tzin condenser circulatin; pu ps in the intake stru:ture.

It was thought that silt and clams entering the intake ba.vs would te swe< .

taroe;h the condenser by the main circulating pumps and would not a::: ulate in t .e ta:L Of the intake tays. In contrast, Unit 2 has no main circulating ;ur;s in its it.take structure because condenser heat ise re.'e ted thr cc.h a ccolin.

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in certain areas of the intakr. bays. 1 7: Id r" T e rsiatic clam was first found in the United States in 1935 in the Cele:bia -

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:.ntry and is rea reecrted in at leas- 33 s a.es. The Te..essee Valle.v A.:n:rity (TVA) power plants also have experienced fculing caused by these c l a r.s . Tney were first found in the conder.sers and service water systers at ~

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t.e fact that. curi r.: the final stac.es cf c nstructi:n. the coolin: water systers were alicwed to remain filled with water for long perieds of tiie while '

tre systems were not in use. This conditicn was conducive to the growth an:

a::umulation of cla s. Since that time, the Asiatic clam has spread a:r:ss

ne Ten .es see Valley region and is found at virtually all the T'/A stear-ele: ric a d ryd cele:tric cer. crating stations, r

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Fr:se..t ::ntrci precedures f r Asiatic clams vary from station to station an:

in their cecree of ef f ectiver.ess. Tne use of shock chlorination during 5.rveillan:e testing as the on'ly ag4f:d of centrolling bicf0uling by inis

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; anis appears to be i.. effective. The level of fculing has bean redu:ed to a: e:te-le levels at TVA sta-icns by using continuous chlorination during peak 5:3.nin; tericds, cla- traps, and.cechanical cisaning c'uring station cutaces.

Tre res its of a series :( tests en mollusks perferned at the Savannah Fiver Fs:ilitv sh:.ed that cature Corbicula sp. had ase eu:h as a 10 percent survivai c..

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f.0 :: 4 0 ;;-) f r up 10 5 .0urs, nen . e: 27 s v t r e al l e e d *."0r e. a i n b u r *.~ e d i a ::.;ie inches Of tw:, their survival rates eere as high as 65 per int.

'. Tr: 21- (c aft)

February 23, 1951'

. Page 3 of. 4 In studies en shellec larvas, approxirately -2:: ti:rons in si e, TM reported creliminary results incica .ing that a total chicrir.e residual of 0.30 to 0.40 pp: '

fer 95 to 103 hours0.00119 days <br />0.0286 hours <br />1.703042e-4 weeks <br />3.91915e-5 months <br /> would be required to achieve 100 percent control ;of the Asiatic clam larvae.

Corbicula sp. has also shown an amazing ability to survive even when re::ved f rom tne water. Average times to death when le.ft in the air have been reported i for icw relative humidity as 6.7 days at 30*C (55'F) ar.;; 13.9 days at 20*C (65 F) and for high relative humidity as 8.3 cays at 30*C and 25.6 cays at '

20*C.

Cc-bicula.sp. on the cther hand, has sn:wn a sc:h greater sensitivity to heat.

iests perforced by young clams, and c1Iswhenthey 2r=QA resul .ed in 100 percent c:rtality of clax. larvae, 7 ve 2 r.inutes. Mature ciams, up to 14m:[(were ex;csed e'ri aise tested and allto died 47atC47 (117*F) 0 y wate fo11cwing a 2-minute exposure. A statistical analysis of the minute '

ex;.:!ure tast data revealed int.t a tenperatt.re cf 49:C (120 F) was necessary '

c reach the 99 percent confidence level of sortality for clams of the si:e ested.

-o date, biat has been shown tc be the r:st ef's:tive way of producing 100

ercent c:.r:Elity for the Asiatic clam. At AN , the service water system was Gusr.ed witn 77 C (170 F) wa er cbtainec frc: ;re auxiliary boiler for a;;r:xicately one half heur; 100 percent mer ality was expected.

I s # .ila ;rebie: has o urred with russels O' t'!us sp.). Infestati:ns cf

.us sels ns.e caused fica clotta;e of ecoling ws:Er to safety related e:;uipment a . nu: lear pla .ts such as Pilgrim and Mills::ne. Unlike the Asiatic clam, r.'s sels cause bicfouling in sal; water coolirg systems.

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i n:icers of Operating Licenses or Ccnstructi:n s:.& Fermits:a W m aw6med 6eW '

1. Determine, based en the results of res.r'!i c.:acd;.iqical conitoring programs c:-d.::ted ' : ;;;rt of th:. c; .5. ..t-ica--pe+4t-eppikationm i

a. esc:Ae+ m ts f th: c o r.s t r . ; ; .. ,.-erci . . f: r--te ' ' r e n s 4 ; c f t he - f a:P ity ,

tur:: e r .it, ;-c :.n . . .i.. .c.. . 1 T :' kaMpecd.fi:Iti m whether or not Cerbicula sp. (Asiatic cla-) or Mytiles sp. (a ssel) is present in the -

vicinity of the station in either Ine s:.rce er receiving water body. A ,

re;crt shall be suositted indicating the presence or absence of 14sw e % u w .

N. crcanists in th.e,Avicinity of the static ,; if p>res.ert, indicate th.MA M 'S p h .a.. ic:rtif'. : + t m.

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the scur:e of this intercation, <tne.a clatest sample date of of the monitoring progran th:t was usec to take the cetermination of -

presence or absence, rnd a brief descri . tion of the monitoring program.

If no monitoring ;q-wes have been cordu:ted in the vicinity of the station that could reascnably be "expected to cetect these organists, this should be so stated.

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February 23,);51 Fage 4 cf 4 t

'. Lice . sees cf cperati ; plan 1 a .d .olders c' c:9stre :icn permits for nuclear pc.er plants at whicr. .nese cr;anisms r. ave been found in the source or receiving waterbody snali in:lude in the afore:entioned report the following information regarcin; the cocling water systems that ca"s be se::eptible to the intrusion of such crganisms:

a. A list of any fire protection system or safety-related systers that direct 1 circulate wa:er cbtained from the source waterbody tr.at are currently being kept full of water and the interf acing systems and eqdpment cooled by these same water systems;

b. A statement as to whether these crganisms have ever been foun: in

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c. A cescripti n f nv serveillance crocram in effect or planne: that

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assures th?b09 # f M h - systems 'are not being fouled by these organisms and the frEqsency of sur.eillance; and

d. A cescription cf ar.) prec:-u;i 7s i, terms of installed equip:t.; and prc:edures that have been er w'il :s taken to prevent su:h a ;rtb'ie

. ' :e ress cf f acilities with eperating lice ses shall provide the requested rep rt

. '; .', 50 ca,.s of the ca.e of this buile.in. _iceistes of facilities with

5; u:tien per.-its shall provice the repor; witnin 120 days.

: "':e wri .;er repo-ts as required at: .e , s '; ed e . der cath or af firra .icn,

. .:e- ine pr: visions :,f Se::icn IE2a ef the Attric Enercy Act of 1954. Re; rts ir. ail be subritted Ic t'e r Cirector cf the a;;rc:riate Regional Office and a

p3 fcrwarded te the Director, Of fice c' Irspec;i:n anc Enforcement, hRC, 1: ',;;cn, D.C. 20555.

's e:cest fcr infccma . ion was apprcved b3 G C u cer.a blanket clearance

.

i- E0072 <nich expires n'evember 30, 1953. C:m.ents cn burden and dupli:ation i

Inc.'id be directed te U.S. General Accounting Office, Regulatory Reports Review, F.o:: 5105, u l Eighth Street, N.W., Washington, D.C. 20548

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