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{{#Wiki_filter:Se ptembe r 12 , 20 06 M EM ORAN DU M TO:
{{#Wiki_filter:September 12, 2006 MEMORANDUM TO:           Arthur T. Howell, III, Director Division of Reactor Projects Region IV FROM:                   Cornelius F. Holden, Deputy Director /RA/
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:
Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
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 -
==SUBJECT:==
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.
FINAL RESPONSE TO TASK INTERFACE AGREEMENT -
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.
TIA 2005-05, EVALUATION OF MAIN STEAM ISOLATION VALVE (MSIV) LOCAL LEAKAGE RATE TESTING (LLRT) AT COLUMBIA GENERATING STATION (TAC NO. MC7040)
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.
During an inspection at Columbia Generating Station, the resident inspectors observed that Energy Northwest used the non-safety-related instrument air system during MSIV LLRT and that Energy Northwests use of instrument air provided more valve seating pressure than would be available during a design-basis accident. The instrument air system provides about 108 pounds per square inch gauge (psig) to help seat the MSIVs, whereas the safety-related accumulators would provide only about 65 psig of seating pressure. Energy Northwest subsequently performed sensitivity testing and concluded that the difference in air pressure can have a non-conservative impact on the LLRT results. The regional inspectors found that performing Technical Specifications Surveillance Requirement (TSSR) 3.6.1.3.11 with the use of the instrument air system to close and seat the valves does not ensure that leakage past the MSIVs is less than or equal to the limit identified in Energy Northwests design-basis accident analysis (11.5 standard cubic feet per hour (scfh) per valve). By letter dated May 3, 2005, Region IV submitted TIA 2005-05 requesting assistance from the Office of Nuclear Reactor Regulation (NRR) to determine:
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.
: 1.     Is Energy Northwest in compliance with TSSR 3.6.1.3.11, their primary containment leakage rate testing program, and Part 50 of Title 10 of the Code of Federal Regulations (10 CFR), Appendix J, with the use of the instrument air (containment air) MSIV LLRT?
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?
: 2.     Does TSSR 3.6.1.3.11 verify the lowest functional capability for the MSIV requirement of 10 CFR 50.36(c)(2) when the instrument air system is utilized to close and seat the valves for LLRT?
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
: 3.     Is Energy Northwests testing method adequate to ensure that 10 CFR Part 100 limits will not be exceeded during a design-basis accident?
: 4.     What is the meaning of the term normal operation as used in Appendix J and related Nuclear Energy Institute documentation?


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
A. Howell                                  NRRs Division of Safety Systems, Containment and Ventilation Branch, and Division of Component Integrity, Component Performance and Testing Branch have completed their assessment of the above technical issues. The staffs assessment is attached.
Docket No. 50-397


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.
==Attachment:==
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.
As stated
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.
A. Howell                                    NRRs Division of Safety Systems, Containment and Ventilation Branch, and Division of Component Integrity, Component Performance and Testing Branch have completed their assessment of the above technical issues. The staffs assessment is attached.
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.
Docket No. 50-397
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.
==Attachment:==
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.
As stated DISTRIBUTION:
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.
Public                      BDennig, NRR/ADRA            SUnikewicz, NRR/ADES LPLIV Reading                TLiu, NRR/ADES              VBucci, OIG RidsNrrDorl                  RidsNrrDeEicb RidsNrrDorlLpl4              SRichards, NRR/ADRO RidsNrrPMBBenney            RidsNrrDraAadb RidsNrrLALFeizollahi        JJacobson, IP JPulsipher, NRR/ADRA        CAnderson, RI ACCESSION No.: ML062340605                NRR-095 OFFICE        LPL4/PM       LPL4/LA     SPSB/BC     CPTB/BC     LPL4/BC     DORL/DD NAME          BBenney      LFeizollahi  BDennig      TLiu        DTerao      CHolden DATE          8/30/06       8/30/06     9/5/06       9/1/06       9/5/06     9/12/06 OFFICIAL RECORD COPY
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}}
 
STAFF ASSESSMENT BY THE OFFICE OF NUCLEAR REACTOR REGULATION FOR TASK INTERFACE AGREEMENT (TIA) 2005-05 EVALUATION OF MAIN STEAM ISOLATION VALVE LOCAL LEAKAGE RATE TESTING AT COLUMBIA GENERATING STATION DOCKET NO. 50-397
 
==1.0     INTRODUCTION==
 
By letter dated May 3, 2005, Region IV submitted TIA 2005-05 requesting assistance from the Office of Nuclear Reactor Regulation (NRR) in evaluating the local leakage rate testing (LLRT) of the main steam isolation valves (MSIVs) at Columbia Generating Station (Columbia). In particular, Region IV requested responses to four questions:
: 1.     Is Energy Northwest in compliance with Technical Specifications Surveillance Requirement (TSSR) 3.6.1.3.11, their primary containment leakage rate testing program, and Part 50 of Title 10 of the Code of Federal Regulations (10 CFR),
Appendix J, with the use of the instrument air (containment air) for MSIV LLRT?
: 2.     Does TSSR 3.6.1.3.11 verify the lowest functional capability for the MSIV requirement of 10 CFR 50.36(c)(2) when the instrument air system is utilized to close and seat the valves for LLRT?
: 3.     Is Energy Northwests testing method adequate to ensure that 10 CFR Part 100 limits will not be exceeded during a design-basis accident (DBA)?
: 4.     What is the meaning of the term "normal operation" as used in Appendix J and related Nuclear Energy Institute (NEI) documentation?
 
==2.0     BACKGROUND==
 
During an inspection at Columbia, the resident inspectors observed that Energy Northwest used the non-safety-related instrument air system during MSIV LLRT and that Energy Northwest's use of instrument air provided more valve seating pressure than would be available during a DBA. The instrument air system provides about 108 pounds per square inch gauge (psig) to help seat the MSIVs, whereas the safety-related accumulators would provide only about 65 psig of seating pressure. Energy Northwest subsequently performed sensitivity testing and concluded that the difference in air pressure can have a significant, non-conservative impact on the LLRT results. The regional inspectors found that performing TSSR 3.6.1.3.11 with the use of the instrument air system to close and seat the valves does not ensure that leakage past the MSIVs is less than or equal to the limit identified in Energy Northwest's DBA analysis (11.5 standard cubic feet per hour (scfh) per valve).
 
3.0    DISCUSSION Valve Operation Boiling-water reactor MSIVs are containment isolation valves and must meet the requirements of Appendix J to 10 CFR Part 50, "Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors." At Columbia, the MSIVs are typical air-and-spring-operated valves.
The valves use a non-safety-related compressed air supply (e.g., instrument air) to open (opening is a non-safety function) and air and springs to close (the safety function). In the event of an accident, a valve on the actuator opens to vent the instrument air maintaining the MSIV open, and a second valve on the actuator opens to admit air to close the MSIV. The source of air for closing the MSIVs (together with the springs) in the event of an accident will be the non-safety air supply, if it is available. If the non-safety air is not available (e.g., as a result of a seismic event), the MSIV actuators are supplied with safety-related air accumulators for accident mitigation. The accumulators initially start at the non-safety-related air system pressure (i.e., 108 psig at Columbia) and depressurize to a lower pressure (i.e., between 55 and 65 psig at Columbia) during the closing stroke. The accumulators air helps to seat the valves during the initial part of the accident, but the accumulators will eventually depressurize to ambient conditions.
Non-safety-related air system compressors are non-seismic and powered from a non-safety-related source and are not credited (are assumed lost) for all DBAs.
Requirements Appendix J, Option A states, in part:
Each valve to be tested shall be closed by normal operation and without any preliminary exercising or adjustments (e.g., no tightening of the valve after closure by valve motor). [emphasis added]
For an Appendix J, Option B plant, the following equivalent passage from American National Standards Institute (ANSI)/American Nuclear Society (ANS)-56.8-1994 applies:
Closure of primary containment isolation valves for Type C testing shall be accomplished by normal or equivalent means and without adjustment (e.g., no hand tightening of remotely operated valves after closure). Exercising valves for the purpose of improving leakage performance shall not be permitted.
[emphasis added]
As set forth in Technical Specification (TS) 5.5.12, Appendix J, Option B requirements apply to Columbia.
Most plant valves are either motor-operated or simple air-operated valves (spring to close/instrument air to open - closing being the safety direction). For these valves, the closure methods and seating forces under accident and non-accident conditions are essentially the same. While motor-operated valves may be tested with offsite power available, offsite power is not a superior power source when compared to the sites' safety-related emergency diesel
 
generators. For simple air-operated valves, the springs alone work to close the valves under accident and non-accident conditions. Therefore, for motor-operated and simple air-operated valves, closure under non-accident conditions reasonably duplicates valve closure under accident conditions.
Unique MSIV Design MSIV design is unique, compared to that of other containment isolation valves. The MSIVs have the unique design feature of safety-related air accumulators to assist in closing the valves under accident conditions. Of the valves subject to LLRT at Columbia, the MSIVs are the only valves with safety-related air accumulators.
Interpretation of "Normal Operation" There have been varied opinions as to the correct interpretation of "normal operation" or "normal means." The licensee states that the non-safety-related air system is the normal means of closing the MSIVs. The licensee stated that non-safety-related air would normally be available when the licensee closes the valves during normal plant operations. While non-safety-related air would normally be available, the normal method for closing the MSIVs during normal operations is with springs only (slow closure, no instrument air or accumulator air). The licensee normally slow closes the valves to prevent damaging the valves. Testing the MSIVs by closing them with the springs could result in the MSIV's failure to satisfy the LLRT in most, if not all cases.
The Final Safety Analysis Report (FSAR) states in Section 5.4.5.4, "Inspection and Testing" that "all MSIVs are closed utilizing both spring force and air pressure on the operating cylinder."
This section, however, does not indicate the source of the air pressure. If the non-safety air supply is available in the event of a DBA, it will provide air to close the MSIVs. While there is no assurance that the non-safety air supply will be available during a DBA, its availability likewise cannot be ruled out, even during or after a seismic event. Under such circumstances, the term normal or equivalent means could reasonably be understood to include the non-safety air supply. To require otherwise would be to rewrite ANSI/ANS-56.8-1994 (and 10 CFR Part 50, Appendix J) to require safety-related or design basis means for closing MSIVs for LLRT purposes.
Guidance on Similar Matters The generic instructions were intended to dissuade licensees from taking advantage of inappropriate non-credited valve closure/seating techniques to artificially enhance valve test results. The licensee's use of the non-safety-related air system during these tests could have a similar effect on the results as the tightening of a valve after closure with a valve motor, which is specifically cited as a prohibited practice.
Moreover, the U.S. Nuclear Regulatory Commission (NRC) has previously addressed a similar issue in NRC Information Notice 85-84, "Inadequate Inservice Testing of Main Steam Isolation Valves," dated October 30, 1985. The information notice states, in part:
 
The practice of performing inservice testing of components, which are relied on to mitigate the consequences of accidents, with sources of power not considered in the safety analyses is not in keeping with the objective of periodic testing.
This objective is to test equipment to verify operational readiness under conditions that reasonably duplicate the design basis.
While the staff believes that the above should apply generically to all inservice testing, and LLRT is a type of inservice test, the specific issue addressed by the information notice involved ASME Code-required testing (versus LLRT).
While the licensee's MSIV LLRT methods meet the requirements in 10 CFR Part 50, Appendix J, they are inconsistent with the general guidance provided in NRC Information Notice 85-84, in that the licensee performs the testing with a source of power (instrument air) that was not considered in the safety analyses. The licensees test conditions do not conservatively represent design-basis conditions.
Compliance with 10 CFR 50.36 The Commissions regulation in 10 CFR § 50.36(c)(3) requires that TSs include surveillance requirements (SR), which are requirements relating to test, calibration, or inspection to assure, among other things, that the limiting conditions of operation (LCOs) will be met. A question has been raised regarding whether there is any violation of 10 CFR § 50.36(c)(2) with respect to the lowest functional capability or performance level of the MSIVs. However, there does not appear to be any defect in the MSIV LCO itself. Rather, the SR associated with the LCO does not appear to be sufficient to assure that the LCO will be met.
Effect on Leakage Rate Lower air pressure means less force to push the valve closed and hold it closed. The current testing could underestimate the accident leakage rate and could falsely indicate an operable containment, when in fact, the containment leakage rate during an accident might be greater than considered in the accident analysis.
Answers to Specific Region IV Questions
: 1.     Is Energy Northwest in compliance with TSSR 3.6.1.3.11, their primary containment leakage rate testing program, and 10 CFR Part 50, Appendix J, with the use of the instrument air (containment air) system for MSIV LLRT?
Answer: Yes. The FSAR states in Section 5.4.5.4, "Inspection and Testing," that "all MSIVs are closed utilizing both spring force and air pressure on the operating cylinder."
The term normal or equivalent means can reasonably be interpreted to include the non-safety air supply.
: 2.      Does TSSR 3.6.1.3.11 verify the lowest functional capability for the MSIV requirement of 10 CFR 50.36(c)(2) when the instrument air system is utilized to close and seat the valves for LLRT?
 
Answer: Use of the non-safety air supply system to close the MSIVs, during the performance of SR 3.6.1.3.11, may not alone directly assure that the associated LCO will be met during accident conditions. However, such testing is not a violation of 10 CFR § 50.36(c)(2), wherein surveillance tests attempt to approximate accident conditions, and many tests are modified to take this into account.
: 3. Is Energy Northwests testing method adequate to ensure that 10 CFR Part 100 limits will not be exceeded during a DBA?
Answer: The purpose of the test is not to specifically confirm that Part 100 limits are met. There are significant conservatisms in the dose calculations associated with Part 100, including the 11.5 scfh per MSIV. The method of testing does not and cannot exactly mimic DBA conditions (e.g., pressurizing between the valves at a pressure less than Pa , absence of steam assistance to close valves, cold piping, likelihood that instrument air is available), but it provides useful information about the functionality of the valves, and the testing meets regulations.
: 4. What is the meaning of the term "normal operation" as used in Appendix J and related NEI documentation?
Answer: This is answered in detail above.
Principal Contributors: J. Pulsipher S. Unikewicz}}

Latest revision as of 15:50, 23 November 2019

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 Energy Northwest icon.png
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)
v • d • e


Text

September 12, 2006 MEMORANDUM TO: Arthur T. Howell, III, Director Division of Reactor Projects Region IV FROM: Cornelius F. Holden, Deputy Director /RA/

Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

SUBJECT:

FINAL RESPONSE TO TASK INTERFACE AGREEMENT -

TIA 2005-05, EVALUATION OF MAIN STEAM ISOLATION VALVE (MSIV) LOCAL LEAKAGE RATE TESTING (LLRT) AT COLUMBIA GENERATING STATION (TAC NO. MC7040)

During an inspection at Columbia Generating Station, the resident inspectors observed that Energy Northwest used the non-safety-related instrument air system during MSIV LLRT and that Energy Northwests use of instrument air provided more valve seating pressure than would be available during a design-basis accident. The instrument air system provides about 108 pounds per square inch gauge (psig) to help seat the MSIVs, whereas the safety-related accumulators would provide only about 65 psig of seating pressure. Energy Northwest subsequently performed sensitivity testing and concluded that the difference in air pressure can have a non-conservative impact on the LLRT results. The regional inspectors found that performing Technical Specifications Surveillance Requirement (TSSR) 3.6.1.3.11 with the use of the instrument air system to close and seat the valves does not ensure that leakage past the MSIVs is less than or equal to the limit identified in Energy Northwests design-basis accident analysis (11.5 standard cubic feet per hour (scfh) per valve). By letter dated May 3, 2005, Region IV submitted TIA 2005-05 requesting assistance from the Office of Nuclear Reactor Regulation (NRR) to determine:

1. Is Energy Northwest in compliance with TSSR 3.6.1.3.11, their primary containment leakage rate testing program, and Part 50 of Title 10 of the Code of Federal Regulations (10 CFR), Appendix J, with the use of the instrument air (containment air) MSIV LLRT?
2. Does TSSR 3.6.1.3.11 verify the lowest functional capability for the MSIV requirement of 10 CFR 50.36(c)(2) when the instrument air system is utilized to close and seat the valves for LLRT?
3. Is Energy Northwests testing method adequate to ensure that 10 CFR Part 100 limits will not be exceeded during a design-basis accident?
4. What is the meaning of the term normal operation as used in Appendix J and related Nuclear Energy Institute documentation?

A. Howell NRRs Division of Safety Systems, Containment and Ventilation Branch, and Division of Component Integrity, Component Performance and Testing Branch have completed their assessment of the above technical issues. The staffs assessment is attached.

Docket No. 50-397

Attachment:

As stated

A. Howell NRRs Division of Safety Systems, Containment and Ventilation Branch, and Division of Component Integrity, Component Performance and Testing Branch have completed their assessment of the above technical issues. The staffs assessment is attached.

Docket No. 50-397

Attachment:

As stated DISTRIBUTION:

Public BDennig, NRR/ADRA SUnikewicz, NRR/ADES LPLIV Reading TLiu, NRR/ADES VBucci, OIG RidsNrrDorl RidsNrrDeEicb RidsNrrDorlLpl4 SRichards, NRR/ADRO RidsNrrPMBBenney RidsNrrDraAadb RidsNrrLALFeizollahi JJacobson, IP JPulsipher, NRR/ADRA CAnderson, RI ACCESSION No.: ML062340605 NRR-095 OFFICE LPL4/PM LPL4/LA SPSB/BC CPTB/BC LPL4/BC DORL/DD NAME BBenney LFeizollahi BDennig TLiu DTerao CHolden DATE 8/30/06 8/30/06 9/5/06 9/1/06 9/5/06 9/12/06 OFFICIAL RECORD COPY

STAFF ASSESSMENT BY THE OFFICE OF NUCLEAR REACTOR REGULATION FOR TASK INTERFACE AGREEMENT (TIA) 2005-05 EVALUATION OF MAIN STEAM ISOLATION VALVE LOCAL LEAKAGE RATE TESTING AT COLUMBIA GENERATING STATION DOCKET NO. 50-397

1.0 INTRODUCTION

By letter dated May 3, 2005, Region IV submitted TIA 2005-05 requesting assistance from the Office of Nuclear Reactor Regulation (NRR) in evaluating the local leakage rate testing (LLRT) of the main steam isolation valves (MSIVs) at Columbia Generating Station (Columbia). In particular, Region IV requested responses to four questions:

1. Is Energy Northwest in compliance with Technical Specifications Surveillance Requirement (TSSR) 3.6.1.3.11, their primary containment leakage rate testing program, and Part 50 of Title 10 of the Code of Federal Regulations (10 CFR),

Appendix J, with the use of the instrument air (containment air) for MSIV LLRT?

2. Does TSSR 3.6.1.3.11 verify the lowest functional capability for the MSIV requirement of 10 CFR 50.36(c)(2) when the instrument air system is utilized to close and seat the valves for LLRT?
3. Is Energy Northwests testing method adequate to ensure that 10 CFR Part 100 limits will not be exceeded during a design-basis accident (DBA)?
4. What is the meaning of the term "normal operation" as used in Appendix J and related Nuclear Energy Institute (NEI) documentation?

2.0 BACKGROUND

During an inspection at Columbia, the resident inspectors observed that Energy Northwest used the non-safety-related instrument air system during MSIV LLRT and that Energy Northwest's use of instrument air provided more valve seating pressure than would be available during a DBA. The instrument air system provides about 108 pounds per square inch gauge (psig) to help seat the MSIVs, whereas the safety-related accumulators would provide only about 65 psig of seating pressure. Energy Northwest subsequently performed sensitivity testing and concluded that the difference in air pressure can have a significant, non-conservative impact on the LLRT results. The regional inspectors found that performing TSSR 3.6.1.3.11 with the use of the instrument air system to close and seat the valves does not ensure that leakage past the MSIVs is less than or equal to the limit identified in Energy Northwest's DBA analysis (11.5 standard cubic feet per hour (scfh) per valve).

3.0 DISCUSSION Valve Operation Boiling-water reactor MSIVs are containment isolation valves and must meet the requirements of Appendix J to 10 CFR Part 50, "Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors." At Columbia, the MSIVs are typical air-and-spring-operated valves.

The valves use a non-safety-related compressed air supply (e.g., instrument air) to open (opening is a non-safety function) and air and springs to close (the safety function). In the event of an accident, a valve on the actuator opens to vent the instrument air maintaining the MSIV open, and a second valve on the actuator opens to admit air to close the MSIV. The source of air for closing the MSIVs (together with the springs) in the event of an accident will be the non-safety air supply, if it is available. If the non-safety air is not available (e.g., as a result of a seismic event), the MSIV actuators are supplied with safety-related air accumulators for accident mitigation. The accumulators initially start at the non-safety-related air system pressure (i.e., 108 psig at Columbia) and depressurize to a lower pressure (i.e., between 55 and 65 psig at Columbia) during the closing stroke. The accumulators air helps to seat the valves during the initial part of the accident, but the accumulators will eventually depressurize to ambient conditions.

Non-safety-related air system compressors are non-seismic and powered from a non-safety-related source and are not credited (are assumed lost) for all DBAs.

Requirements Appendix J, Option A states, in part:

Each valve to be tested shall be closed by normal operation and without any preliminary exercising or adjustments (e.g., no tightening of the valve after closure by valve motor). [emphasis added]

For an Appendix J, Option B plant, the following equivalent passage from American National Standards Institute (ANSI)/American Nuclear Society (ANS)-56.8-1994 applies:

Closure of primary containment isolation valves for Type C testing shall be accomplished by normal or equivalent means and without adjustment (e.g., no hand tightening of remotely operated valves after closure). Exercising valves for the purpose of improving leakage performance shall not be permitted.

[emphasis added]

As set forth in Technical Specification (TS) 5.5.12, Appendix J, Option B requirements apply to Columbia.

Most plant valves are either motor-operated or simple air-operated valves (spring to close/instrument air to open - closing being the safety direction). For these valves, the closure methods and seating forces under accident and non-accident conditions are essentially the same. While motor-operated valves may be tested with offsite power available, offsite power is not a superior power source when compared to the sites' safety-related emergency diesel

generators. For simple air-operated valves, the springs alone work to close the valves under accident and non-accident conditions. Therefore, for motor-operated and simple air-operated valves, closure under non-accident conditions reasonably duplicates valve closure under accident conditions.

Unique MSIV Design MSIV design is unique, compared to that of other containment isolation valves. The MSIVs have the unique design feature of safety-related air accumulators to assist in closing the valves under accident conditions. Of the valves subject to LLRT at Columbia, the MSIVs are the only valves with safety-related air accumulators.

Interpretation of "Normal Operation" There have been varied opinions as to the correct interpretation of "normal operation" or "normal means." The licensee states that the non-safety-related air system is the normal means of closing the MSIVs. The licensee stated that non-safety-related air would normally be available when the licensee closes the valves during normal plant operations. While non-safety-related air would normally be available, the normal method for closing the MSIVs during normal operations is with springs only (slow closure, no instrument air or accumulator air). The licensee normally slow closes the valves to prevent damaging the valves. Testing the MSIVs by closing them with the springs could result in the MSIV's failure to satisfy the LLRT in most, if not all cases.

The Final Safety Analysis Report (FSAR) states in Section 5.4.5.4, "Inspection and Testing" that "all MSIVs are closed utilizing both spring force and air pressure on the operating cylinder."

This section, however, does not indicate the source of the air pressure. If the non-safety air supply is available in the event of a DBA, it will provide air to close the MSIVs. While there is no assurance that the non-safety air supply will be available during a DBA, its availability likewise cannot be ruled out, even during or after a seismic event. Under such circumstances, the term normal or equivalent means could reasonably be understood to include the non-safety air supply. To require otherwise would be to rewrite ANSI/ANS-56.8-1994 (and 10 CFR Part 50, Appendix J) to require safety-related or design basis means for closing MSIVs for LLRT purposes.

Guidance on Similar Matters The generic instructions were intended to dissuade licensees from taking advantage of inappropriate non-credited valve closure/seating techniques to artificially enhance valve test results. The licensee's use of the non-safety-related air system during these tests could have a similar effect on the results as the tightening of a valve after closure with a valve motor, which is specifically cited as a prohibited practice.

Moreover, the U.S. Nuclear Regulatory Commission (NRC) has previously addressed a similar issue in NRC Information Notice 85-84, "Inadequate Inservice Testing of Main Steam Isolation Valves," dated October 30, 1985. The information notice states, in part:

The practice of performing inservice testing of components, which are relied on to mitigate the consequences of accidents, with sources of power not considered in the safety analyses is not in keeping with the objective of periodic testing.

This objective is to test equipment to verify operational readiness under conditions that reasonably duplicate the design basis.

While the staff believes that the above should apply generically to all inservice testing, and LLRT is a type of inservice test, the specific issue addressed by the information notice involved ASME Code-required testing (versus LLRT).

While the licensee's MSIV LLRT methods meet the requirements in 10 CFR Part 50, Appendix J, they are inconsistent with the general guidance provided in NRC Information Notice 85-84, in that the licensee performs the testing with a source of power (instrument air) that was not considered in the safety analyses. The licensees test conditions do not conservatively represent design-basis conditions.

Compliance with 10 CFR 50.36 The Commissions regulation in 10 CFR § 50.36(c)(3) requires that TSs include surveillance requirements (SR), which are requirements relating to test, calibration, or inspection to assure, among other things, that the limiting conditions of operation (LCOs) will be met. A question has been raised regarding whether there is any violation of 10 CFR § 50.36(c)(2) with respect to the lowest functional capability or performance level of the MSIVs. However, there does not appear to be any defect in the MSIV LCO itself. Rather, the SR associated with the LCO does not appear to be sufficient to assure that the LCO will be met.

Effect on Leakage Rate Lower air pressure means less force to push the valve closed and hold it closed. The current testing could underestimate the accident leakage rate and could falsely indicate an operable containment, when in fact, the containment leakage rate during an accident might be greater than considered in the accident analysis.

Answers to Specific Region IV Questions

1. Is Energy Northwest in compliance with TSSR 3.6.1.3.11, their primary containment leakage rate testing program, and 10 CFR Part 50, Appendix J, with the use of the instrument air (containment air) system for MSIV LLRT?

Answer: Yes. The FSAR states in Section 5.4.5.4, "Inspection and Testing," that "all MSIVs are closed utilizing both spring force and air pressure on the operating cylinder."

The term normal or equivalent means can reasonably be interpreted to include the non-safety air supply.

2. Does TSSR 3.6.1.3.11 verify the lowest functional capability for the MSIV requirement of 10 CFR 50.36(c)(2) when the instrument air system is utilized to close and seat the valves for LLRT?

Answer: Use of the non-safety air supply system to close the MSIVs, during the performance of SR 3.6.1.3.11, may not alone directly assure that the associated LCO will be met during accident conditions. However, such testing is not a violation of 10 CFR § 50.36(c)(2), wherein surveillance tests attempt to approximate accident conditions, and many tests are modified to take this into account.

3. Is Energy Northwests testing method adequate to ensure that 10 CFR Part 100 limits will not be exceeded during a DBA?

Answer: The purpose of the test is not to specifically confirm that Part 100 limits are met. There are significant conservatisms in the dose calculations associated with Part 100, including the 11.5 scfh per MSIV. The method of testing does not and cannot exactly mimic DBA conditions (e.g., pressurizing between the valves at a pressure less than Pa , absence of steam assistance to close valves, cold piping, likelihood that instrument air is available), but it provides useful information about the functionality of the valves, and the testing meets regulations.

4. What is the meaning of the term "normal operation" as used in Appendix J and related NEI documentation?

Answer: This is answered in detail above.

Principal Contributors: J. Pulsipher S. Unikewicz

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