ML062340605

GS-Final Response to Task Interface Agreement - TIA 2005-05, Evaluation of Main Steam Isolation Valve (MSIV) Local Leakage Rate Testing (LLRT)

ML062340605
Person / Time
Site:	Columbia
Issue date:	09/12/2006
From:	Holden C Plant Licensing Branch III-2
To:	Howell A NRC/RGN-IV/DRP
Benney B, NRR/DORL, 415-3764
References
TAC MC7040
Download: ML062340605 (8)

Text

Se ptembe r 12 , 20 06 M EM ORAN DU M TO:

Arthu r T. Ho w el l, III, Di recto r D i v i si o n o f R e a ct o r P ro je ct s R e gi o n I VF R OM:

C o rn e l i u s F. H o l d e n , D e p u ty D i re ct o r /R A/

Di v is io n o f Ope rati ng Re acto r Li cen si ng Of f ic e o f N ucl ear Re acto r R egul ati onS U B JE CT:

F IN A L R E S P ON S E TO TA S K I N TE R F A C E A GR E E M E N T -

T IA 2005-05, EVALUAT IO N OF M AIN ST EAM ISO LAT IO N VALVE (M S IV) L OC A L L E A K A GE R A TE TE S TIN G (L L R T) A T C OL U M B IA GENE RA TING STATION (TAC N O. M C7 040)Du rin g an in spe cti on at C ol umbi a Ge nera tin g Stati on, the resi den t i nsp ecto rs o bse rv ed that En ergy N orthw est use d th e n on-s afety-rel ated i nstru ment ai r sy stem d uri ng M SIV LL RT an d that Energ y Nort hw est's use of instru me nt air pro vi ded mo re valv e seating press ure t han w ould be av ai la bl e d uri ng a des ign-b asi s a cci den t. The i nstru ment ai r sy stem p rov id es abo ut 108 po und s p er s quare in ch gauge (ps ig) to he lp se at th e M SIV s, w here as the safety-rel ated acc umul ators w oul d p rov id e o nl y ab out 65 psi g of se ati ng pre ssu re. En ergy N orthw est sub sequen tly pe rf ormed sen si tiv ity tes tin g and co ncl ude d th at th e d iff eren ce in ai r pre ssu re c an hav e a no n-co nse rv ati v e i mpact on the LLR T resul ts. The re gion al i nsp ecto rs found tha t performin g Techni cal S pec ifica tio ns Su rv ei ll anc e R equi rement (TSSR) 3.6.1.3.1 1 w ith the us e of the in strumen t ai r sy stem to cl ose an d s eat the v al v es doe s n ot e nsu re th at l eakage p ast the M SIV s i s l ess tha n o r equa l to th e l imi t i den tifie d i n E nergy N orthw est's d esi gn-basi s a cci den t ana ly si s (1 1.5 stan dard cu bi c feet p er h our (scfh) pe r v al v e). By l etter date d M ay 3, 200 5, Re gion IV su bmi tted TIA 20 05-0 5 re questi ng ass is tanc e from the Of f ic e o f N ucl ear Re acto r Re gula tio n (N RR) to dete rmin e: 1.

Is E nergy N orthw est in co mpl ia nce w ith TSS R 3.6.1.3.11 , the ir pri mary co ntai nmen t le akage rate tes tin g program, an d P art 5 0 o f Titl e 1 0 o f the Co de of F ede ral R egu la tio ns (1 0 C F R), A p p e n d i x J , w i t h t h e u s e o f t h e i n s t r u me n t a i r (c o n t a i n me n t a i r) M S I V L L R T?2.

Do es TSSR 3.6.1.3.1 1 v eri f y the l ow est f unc tio nal ca pab il ity for the M SIV requi rement of 10 CF R 50.3 6(c)(2) w hen the i nstru ment ai r sy stem i s u til iz ed to c lo se and se at th e v a l v e s fo r L L R T?3.

Is E n e rgy N o rt h w e st's te st i n g me th o d a d e qua te t o e n su re t h a t 1 0 C F R P a rt 1 0 0 l i mi ts w i l l n o t b e e x ce e d e d d u ri n g a d e si gn-b a si s a cc i d e n t?4.

W hat is the mea ni ng of the term "no rmal op erati on" as use d i n A ppe ndi x J and rel ated Nu cl ear En ergy Ins titu te d ocu mentati on?

A. Ho w el l NR R's D iv is io n o f S afety S y stems, Co ntai nmen t an d V enti la tio n B ranc h, a nd Di v is io n o f Com ponent Inte g rity, Com ponent Perf orm ance and T est ing Branch have complet ed their a ss e ss me n t o f th e a b o v e t e ch n i ca l i ss u e s. The s ta ff's a ss e ss me n t i s a tt a ch e d. Do cket No. 50-397 Attac hmen t: A s s tated A. Ho w el l NR R's D iv is io n o f S afety S y stems, Co ntai nmen t an d V enti la tio n B ranc h, a nd Di v is io n o f Com ponent Inte g rity, Com ponent Perf orm ance and T est ing Branch have complet ed their a ss e ss me n t o f th e a b o v e t e ch n i ca l i ss u e s. The s ta ff's a ss e ss me n t i s a tt a ch e d. Do cket No. 50-397 Attac hmen t: A s s tated DIST RIBUT IO N: Public BDennig , NRR/ADRA

SUnik ew icz, NRR/ADES L P L IV R e a d i n g TLi u , N R R/A D E S V B u cc i , OIG Ri dsN rrDo rl Ri dsN rrDe Ei cbRidsNrr DorlLpl4 SRichards , NRR/ADRO Ri dsN rrPM BB enn ey Ri dsN rrDra Aa db R i d sN rr L A L F e i z o l l a h i JJ a co b so n , IP JPulsipher , NRR/ADRA

CAnders on, RIAC CE SS ION N o.: M L06 234 060 5 NR R-0 95OFFICE LPL4/PM LPL4/LA SPSB/BC CPT B/BC LPL4/BC DORL/DD NA M E BB enney LFei z ollah i BD ennig T Liu DT era o CH olden DA T E 8/30/06 8/30/06 9/5/06 9/1/06 9/5/06 9/12/06 OF FICI A L RECORD COPY S TA F F A S S E S S M E N T B Y TH E OF F IC E OF N U C L E A R R E A C TOR R E GU L A TION FOR TASK IN TERF AC E AGRE EM EN T (TI A) 200 5-05 EVALUAT IO N OF M AIN ST EAM ISO LAT IO N VALVE LO CAL LEAKAGE RAT E TEST ING A T C OL U M B IA GE N E R A TIN G S TA TION DOCK ET N O. 50-3 97 1.0 IN TR OD U C TION By l etter date d M ay 3, 200 5, R egio n IV su bmi tted TIA 20 05-0 5 re questi ng ass is tanc e from the Offi c e o f N u c l e a r R e a c t o r R e gu l a t i o n (N R R) i n e v a l u a t i n g t h e l o c a l l e a ka ge r a t e t e s t i n g (L L R T)o f th e ma i n s te a m i so l a ti o n v a l v e s (M S IV s) a t C o l u mb i a Ge n e ra ti n g S ta ti o n (C o l u mb i a). In parti cul ar, R egio n IV reque sted res pon ses to f our questi ons: 1.

Is E nergy N orthw est in co mpl ia nce w ith Tech ni cal S pec ifica tio ns Su rv ei ll anc e Re quire ment (TSSR) 3.6.1.3.1 1, th ei r pri mary co ntai nmen t l eakage ra te te sti ng program, a nd Pa rt 50 of Titl e 1 0 o f the Co de of F ede ral R egu la tio ns (1 0 C F R), A p p e n d i x J , w i t h t h e u s e o f t h e i n s t r u me n t a i r (c o n t a i n me n t a i r) fo r M S I V L L R T?2.

Do es TSSR 3.6.1.3.1 1 v eri f y the l ow est f unc tio nal ca pab il ity for the M SIV requi rement of 10 CF R 50.3 6(c)(2) w hen the i nstru ment ai r sy stem i s u til iz ed to c lo se and se at th e v a l v e s fo r L L R T?3.

Is E n e rgy N o rt h w e st's te st i n g me th o d a d e qua te t o e n su re t h a t 1 0 C F R P a rt 1 0 0 l i mi ts w i l l n o t b e e x ce e d e d d u ri n g a d e si gn-b a si s a cc i d e n t (D B A)?4.

W hat is the mea ni ng of the term "no rmal op erati on" as use d i n A ppe ndi x J and rel ated Nu cl ear En ergy Ins titu te (N EI) doc umen tati on?2.0 BACKGRO UND Du rin g an in spe cti on at C ol umbi a, th e re si den t i nsp ecto rs o bse rv ed that En ergy N orthw est use d th e n o n-s a fety-r e l a te d i n st ru me n t a i r sy st e m d u ri n g M S IV L L R T a n d t h a t E n e rgy N o rt h w e st's u s e o f i n s t r u me n t a i r p r o v i d e d m o r e v a l v e s e a t i n g p r e s s u r e t h a n w o u l d b e a v a i l a b l e d u r i n g a D B A. Th e i n st ru me n t a i r sy st e m p ro v i d e s a b o u t 1 0 8 p o u n d s p e r squ a re i n ch ga u ge (p si g) t o help seat th e M SIVs, w here as the saf ety-r elated acc um ulator s w ould provide only about 65 psig of seati ng pre ssu re. En ergy N orthw est sub sequen tly pe rf ormed sen si tiv ity tes tin g and con cl ude d th at th e d iff eren ce in ai r pre ssu re c an hav e a si gnifica nt, n on-c ons erv ati v e i mpact on the LLR T resul ts. The re gion al i nsp ecto rs found tha t pe rf ormi ng TSSR 3.6.1.3.1 1 w ith the us e of the in strumen t ai r sy stem to cl ose an d s eat the v al v es doe s n ot e nsu re th at l eakage p ast the M S IV s i s l e ss t h a n o r e qua l t o t h e l i mi t i d e n ti fie d i n E n e rgy N o rt h w e st's D B A a n a l y si s (1 1.5 st a n d a rd c u b i c fee t p e r h o u r (s cfh) p e r v a l v e). 3.0 D IS C U S S ION Va lv e Op erati on B o i l i n g-w a te r re a ct o r M S IV s a re c o n ta i n me n t i so l a ti o n v a l v e s a n d mu st me e t th e r e qui re me n ts o f A p p e n d i x J t o 1 0 C F R P a rt 5 0 , "P ri ma ry R e a ct o r C o n ta i n me n t L e a kage Te st i n g for W a te r-C o o l e d P o w e r R e a ct o rs." A t C o l u mb i a , th e M S IV s a re t y p i ca l a i r-a n d-s p ri n g-o p e ra te d v a l v e s. The v al v es use a non-safety-rel ated co mpress ed ai r su ppl y (e.g., i nstru ment ai r) to ope n (ope ni ng i s a no n-sa f ety functi on) and ai r an d s pri ngs to cl ose (the sa f ety functi on). In the ev ent of an acc id ent, a v al v e o n th e a ctua tor o pen s to v ent the in strumen t ai r mai ntai ni ng the M SIV op en, and a sec ond v al v e o n th e a ctua tor o pen s to ad mit ai r to cl ose the M SIV. The sou rce of ai r for cl osi ng the M SIV s (to gether w ith the sp rin gs) i n th e e v ent of an acc id ent w il l be the non-saf ety air supply , if it i s avai lable. If the non-saf ety air i s not avail able (e.g., as a result of a se is mic ev ent), the M SIV ac tuato rs a re s upp li ed w ith sa f ety-rel ated ai r ac cumul ators for acc id ent miti gatio n. The a ccu mul ators i ni tia ll y sta rt at the non-safety-rel ated ai r sy stem pres sure (i.e., 1 08 psi g at C ol umbi a) a nd dep ress uri z e to a lo w er p ress ure (i.e., be tw een 55 and 65 ps ig a t C ol umbi a) d uri ng the cl osi ng stroke.

The a ccu mul ators' ai r he lp s to se at th e v a l v e s d u ri n g th e i n i ti a l p a rt o f th e a cc i d e n t, b u t th e a cc u mu l a to rs w i l l e v e n tu a l l y d e p re ss u ri z e t o ambi ent con di tio ns.No n-sa f ety-rel ated ai r sy stem c ompres sors are no n-se is mic and po w ered from a non-safety-rel ated so urce an d a re n ot c redi ted (are ass umed l ost) f or a ll D BA s.R e qui re me n ts A p p e n d i x J , Op ti o n A s ta te s, i n p a rt:Ea ch v al v e to be tes ted sha ll be cl ose d b y n ormal ope ration and w ith out any prel imi nary ex erci si ng or adju stments (e.g., no ti ghteni ng of the v al v e a f ter cl osu re b y v al v e mo tor). [empha si s a dde d]For an Ap pen di x J, Optio n B pl ant, the f ol lo w in g equiv al ent pas sage from Ame ric an Na tio nal Sta nda rds Insti tute (AN SI)/A meri can N ucl ear So ci ety (A NS)-56.8-199 4 a ppl ie s:Cl osu re o f pri mary co ntai nmen t i sol ati on v al v es f or Ty pe C testi ng sha ll be ac co m pli sh ed by nor mal o r e quiv alen t mea ns an d w ith out adju stment (e.g., no han d ti ghteni ng of remotel y op erate d v al v es after cl osu re). Ex erci si ng v al v es f or th e p u rp o se o f i mp ro v i n g l e a kage p e rfor ma n ce s h a l l n o t b e p e rmi tt e d. [empha si s a dde d]A s se t fort h i n Te ch n i ca l S p e ci fic a ti o n (TS) 5.5.1 2 , A p p e n d i x J , Op ti o n B r e qui re me n ts a p p l y t o Co lu mbi a.M o st p l a n t v a l v e s a re e i th e r mo to r-o p e ra te d o r si mp l e a i r-o p e ra te d v a l v e s (s p ri n g to cl o se/i n st ru me n t a i r to o p e n - c l o si n g b e i n g th e s a fety d i re ct i o n). F o r th e se v a l v e s, t h e c l o su re method s a nd sea tin g f orce s u nde r ac ci den t an d n on-a cci den t co ndi tio ns are ess enti al ly the sam e. W hile motor-ope rat ed v alv es ma y be test ed w ith of f site power av ailable, of f site power is not a s upe rio r po w er s ourc e w hen co mpared to the si tes' safety-rel ated eme rgency di ese l genera tors. F or s imp le ai r-ope rated v al v es, the spri ngs al one w ork to c lo se the v al v es und er acc id ent and no n-ac ci den t co ndi tio ns. There f ore, f or mo tor-op erate d a nd si mpl e a ir-o pera ted v al v es, cl osu re u nde r no n-ac ci den t co ndi tio ns reas ona bl y du pl ic ates v al v e c lo sure un der acc id ent con di tio ns.U n i qu e M S I V D e s i gn M SIV desig n is uni q ue, com pare d to that of other containm ent isolation valv es. T he M SIVs hav e th e u ni que d esi gn f eatu re o f sa f ety-rel ated ai r ac cumul ators to ass is t i n c lo si ng the v al v es under accident con ditions. Of the val ves subject to LLRT at Columbia, the M SIVs ar e the only v al v es w ith sa f ety-rel ated ai r ac cumul ators.Interp retati on of "Normal Ope rati on" There hav e b een v ari ed opi ni ons as to the corre ct i nterp retati on of "normal op erati on" or"normal mea ns." The li cen see sta tes that the non-safety-rel ated ai r sy stem i s th e n ormal mean s o f cl osi ng the M SIV s. The l ic ens ee state d th at n on-s afety-rel ated ai r w oul d n ormal ly be avail able w hen the licensee closes the val ves during norm al plant operat ions. W hile non-saf ety-r elated air w ould norm ally be av ailable, the nor ma l meth od f or closing the M SIVs duri ng no rmal op erati ons i s w ith sp rin gs onl y (sl ow cl osu re, n o i nstru ment ai r or acc umul ator ai r). The l ic ens ee normal ly sl ow cl ose s th e v al v es to p rev ent dama ging the v al v es. Testi ng the M SIVs by closing the m wi th th e spring s could result in the M SIV's f ailure to sat isf y the LLRT in mo st , i f no t a l l c a se s. Th e F i n a l S a fe t y A n a l y s i s R e p o r t (F S A R) s t a t e s i n S e c t i o n 5.4.5.4 , " I n s p e c t i o n a n d T e s t i n g" th a t "a l l M S IV s a re c l o se d u ti l i z i n g b o th s p ri n g for ce a n d a i r p re ss u re o n t h e o p e ra ti n g c y l i n d e r." T his section, how ever, does not indicate the sour ce of the air pres sur e. If the non-saf ety air sup pl y i s a v ai la bl e i n th e e v ent of a D BA , i t w il l prov id e a ir to c lo se the M SIV s. W hi le the re i s n o ass uran ce that the non-safety ai r su ppl y w il l be av ai la bl e d uri ng a DB A, its av ai la bi li ty l ikew is e ca n n o t b e r u l e d o u t, e v e n d u ri n g o r a fter a s e i sm i c e v e n t. U n d e r su ch c i rc u ms ta n ce s, t h e t e rm"nor ma l or equ iv alent m eans" could reasona bly be underst ood to include the non-saf ety air sup pl y. To requi re o therw is e w oul d b e to rew rite A NS I/AN S-5 6.8-1 994 (an d 1 0 C FR P art 5 0, Appendix J) t o req uire "sa f ety-r elated" or "desig n basis" m eans f or closing M SIVs f or LLRT p u rp o se s. Gu i d a n ce o n S i mi l a r M a tt e rs The gene ric i nstru cti ons w ere in tend ed to d is sua de li cen see s from takin g adv anta ge of in app ropri ate non-cred ite d v al v e c lo sure/sea tin g techn ique s to arti f ic ia ll y en han ce v al v e te st resu lts. The l ic ens ee's us e o f the no n-sa f ety-rel ated ai r sy stem d uri ng the se tests cou ld ha v e a similar ef f ect on the result s as the tig hten ing of a v alv e af ter closure w ith a v alv e mot or, w hich is spe ci f ic al ly ci ted as a p rohi bi ted prac tic e.M oreo v er, th e U.S. Nu cl ear Re gula tory C ommis si on (NR C) has pre v io usl y ad dres sed a si mil ar is sue i n N RC Informati on No tic e 8 5-84 , "Ina dequa te In serv ic e Tes tin g of M ai n S team Isol ati on V a l v e s," d a te d Oc to b e r 3 0 , 1 9 8 5. Th e i n form a ti o n n o ti ce s ta te s, i n p a rt: The p racti ce of performing i nse rv ic e te sti ng of compo nen ts, w hi ch are rel ie d o n to mi tigate the con sequen ces of acc id ents , w ith so urce s o f po w er n ot c ons id ered i n t h e s a fety a n a l y se s i s n o t i n ke e p i n g w i th t h e o b je ct i v e o f pe ri o d i c te st i n g. This ob jecti v e i s to tes t equi pmen t to v eri f y op erati ona l read in ess un der con di tio ns that reas ona bl y du pl ic ate the des ign bas is.W hi le the sta f f be li ev es that the abo v e s hou ld ap pl y gene ric al ly to al l in serv ic e te sti ng, an d LLR T is a ty pe of in serv ic e te st, th e s pec ific is sue ad dres sed by the i nformatio n n oti ce in v ol v ed A S M E C o d e-r e qui re d t e st i n g (v e rs u s L L R T).W hi le the l ic ens ee's M SIV LL RT metho ds meet the requi rements i n 1 0 C FR P art 5 0, Ap pen di x J, they are i nco nsi sten t w ith the gene ral gui dan ce prov id ed in N RC Informati on N o ti ce 8 5-8 4 , i n t h a t th e l i ce n se e p e rfor ms t h e t e st i n g w i th a s o u rc e o f po w e r (i n st ru me n t a i r)that w as not con si dere d i n th e s afety an al y ses. The l ic ens ee's te st c ond iti ons do no t con serv ati v el y rep rese nt d esi gn-basi s c ond iti ons.Co mpl ia nce w ith 10 C FR 50.36 The C ommis si on's re gula tio n i n 1 0 C FR § 50.3 6(c)(3) requi res that TSs i ncl ude su rv ei ll anc e requi rements (S R), w hi ch are requi rements rel ati ng to test, cal ib rati on, or i nsp ecti on to a ssu re, amon g othe r thi ngs, tha t the l imi tin g cond iti ons of op erati on (LC Os) w il l be met. A questi on has bee n ra is ed regardi ng w heth er th ere is an y v io la tio n o f 10 C FR § 50.3 6(c)(2) w ith res pec t to the lo w est f unc tio nal ca pab il ity or performance l ev el of the M SIV s. Ho w ev er, th ere doe s n ot a ppe ar to b e a ny de f ect in the M SIV LC O i tsel f. R athe r, the S R ass oci ated w ith the LC O do es not a p p e a r to b e s u ff i ci e n t to a ss u re t h a t th e L C O w i l l b e me t.E ff e ct o n L e a kage R a te Low er a ir pres sure mea ns le ss f orce to pus h th e v al v e c lo sed an d h ol d i t cl ose d. The c urren t tes ting could underes tim ate t he accident leaka g e rat e and could f alsely indicate an operable con tai nmen t, w hen i n fact, th e c onta in ment le akage rate du rin g an acc id ent might b e grea ter than co nsi dere d i n th e a cci den t an al y si s.An sw ers to S pec ific Re gion IV Que sti ons 1.

Is E nergy N orthw est in co mpl ia nce w ith TSS R 3.6.1.3.11 , the ir pri mary co ntai nmen t le akage rate tes tin g program, an d 1 0 C FR P art 5 0, A ppe ndi x J, w ith the us e o f the i n s t r u me n t a i r (c o n t a i n me n t a i r) s y s t e m fo r M S I V L L R T?Answer: Yes. Th e FSAR state s in S ect ion 5.4.5.4, "Ins pect ion and Tes ting ," that "all M S IV s a re c l o se d u ti l i z i n g b o th s p ri n g for ce a n d a i r p re ss u re o n t h e o p e ra ti n g c y l i n d e r." The te rm "no rmal or equi v al ent mean s" c an reas ona bl y be i nterp reted to in cl ude the n o n-s a fety a i r su p p l y. 2.

Do es TSSR 3.6.1.3.1 1 v eri f y the l ow est f unc tio nal ca pab il ity for the M SIV requi rement of 10 CF R 50.3 6(c)(2) w hen the i nstru ment ai r sy stem i s u til iz ed to c lo se and se at th e v a l v e s fo r L L R T? An sw er: Use of the no n-sa f ety ai r su ppl y sy stem to cl ose the M SIV s, d uri ng the perf orm ance of SR 3.6.1.3.11, m ay not alone direc tly assur e that the assoc iated LCO w il l be met d uri ng acc id ent con di tio ns. H ow ev er, s uch tes tin g is no t a v io la tio n o f 10 CF R § 5 0.36 (c)(2), w here in su rv ei ll anc e te sts attempt to a ppro x ima te a cci den t co n d i ti o n s, a n d ma n y t e st s a re mo d i fie d t o t a ke th i s i n to a cc o u n t.3.

Is E n e rgy N o rt h w e st's te st i n g me th o d a d e qua te t o e n su re t h a t 1 0 C F R P a rt 1 0 0 l i mi ts w il l not be ex cee ded du rin g a D BA? A n sw e r: The p u rp o se o f th e t e st i s n o t to s p e ci fic a l l y c o n fir m t h a t P a rt 1 0 0 l i mi ts a re me t. The re a re s i gni fic a n t co n se rv a ti sm s i n t h e d o se c a l cu l a ti o n s a ss o ci a te d w i th Pa rt 10 0, i ncl udi ng the 11.5 s cfh per M SIV. The meth od of testi ng do es not and ca nno t ex actl y mi mic DB A con di tio ns (e.g., pres suri z in g betw een the v al v es at a pre ssu re l ess a than P , ab sen ce of steam ass is tanc e to cl ose v al v es, col d p ip in g, li keli hoo d th at in strumen t ai r i s a v ai la bl e), b ut i t pro v id es use f ul i nformatio n a bou t the functi ona li ty of the v al v es, and the tes tin g meets regul ati ons.4.

W hat is the mea ni ng of the term "no rmal op erati on" as use d i n A ppe ndi x J and rel ated NE I do cumen tati on?An sw er: This i s a nsw ered i n d etai l abo v e.Pri nci pal C ontri buto rs: J. P ul si phe r S. U ni kew ic z