ML20215G181
| ML20215G181 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 06/17/1987 |
| From: | Domer J TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| NUDOCS 8706230149 | |
| Download: ML20215G181 (10) | |
Text
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f l-x TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNESSEE 374o1
'l SN 157B Lookout Place TVA-SQN-TS-80 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter of-
)
Docket Nos. 50-327 i
Tennessee Valley Authority
)
50-328 f
I SEQUOYAH NUCLEAR PLANT - TECHNICAL SPECIFICATION CHANGE 80 - REQUEST FOR I
l ADDITIONAL INFORMATION The subject technical specification change concerning the proposed revision to the Auxiliary Building Cas Treatment System (ABGTS) and the Emergency Gas Treatment System (EGTS) duct heater requirements was transmitted to NRC on
. April 16, 1987.
During a May 14, 1987 telephone call with Sang Kim, TVA was requested to provide a copy of Nonconformance Report (NCR) SQN NEB 8408. This NCR was referenced in the justification of the proposed technical specification change.
Copies of the NCR and the engineering evaluation for it are provided as an enclosure to.this letter.
Very truly yours.
TENNESSEE VALLEY AUTHORITY
. h-itWWL J. A. Domer, Assistant Director Nuclear Safety and Licensing Swornto3pdsubscQedbeforeme th
/7#May of 7rh1987 AdlEd Y b l Notary Public, My Commission Expires r
i Enclosure ec:
see page 2 8706230149 870617 PDR ADOCK 05000327 P
pon
,8 An Equal Opportunity Employer
l j
-e-
. 4 U.S.-Nuclear. Regulatory-Commission JUN 171987 cc (Enclosure):
Mr.' Michael H. Mobley, Director (w/o Enclosure)
Division of Radiological Health T.E.R.R.A.. Building' 150 9th. Avenue, N Nashville.-Tennessee 37203-1 Mr. G. G. Zech Assistant Director for. Inspection Programs office of. Special Projects U.S. Nuclear Regulatory Commission 101 Marietta Street,'NW, Suite 2900 Atlanta, Georgia. 30323.
i Mr. J. A. Zwolinski, Assistant Director for Projects Division 'of TVA Projects ~
- Office of Special Projects
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U.S. Nuclear Regulatory Commission i
4350 East West Highway j
1 EWW 322 Bethesda, Maryland 20814 Sequoyah Resident. Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road' Soddy Daisy, Tennessee 37379 l
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ENCLOSURE SEQUOYAH NUCLEAR PLANT TVA-SQN-TS-80 j
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REQUEST FOR ADDITIONAL INFORMATION i
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Failure Evaluation / Engineering Report form TVA 10826 (EN DES 3 84)
R$v. No. - i
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l To/H. L. Abercrocible, Site Director, NUC PR MEDS Acceneon Numraer
/ hequownh h.1 m 51 m t 9
. Chief Nuclea, kI"31850215 2 9 ~
_ M A J ;
,_s Engineer W10C126 C-K i
Dase Plant and Unit g 96CauoVAN I82 NCR and Revision Deveation Report and Revision Af f ected S tructures/ Systems / Components EOmES6408 Ro EGTS h M~ sunsect Mowr i-EwemWL D N
- A.e 6. CATA Fett. EGT S C osMrgoL,5 AW hou CQ,,npug("'
> Attached is a copy of NCR SGtNEMOS This nonconformance should be reviewed by you for potential reportability under 10CFR50.36, Regulatory Guide 1.16, and 10CFR21. This NCR is also being transmitted for your determination of the corrective actions required, in order that we may close this item in our files, please confirm receipt of this NCR in your monthly update. 4 1 k ,. J W5lllh Prepared bv/date f { Nuclear Discipline Proiect Ecgineer Concurrence /datel 84*/' N 8# l \\ l .ZEnV 2lS D l h[ fflQ jfg )QUk'L/l/p J Reviewed by/cate , Design Proiect Manager Concuf[ enc //date / [h j h kI $1).u s Y40 /. U5 Approved by/date
- U U ** I' W3 W: l/db5^
wv.o [\\ / f' s do @/pr FEB 20 '85 hs A bes kWL% / SEQuDYet i ~ A TA i > The deficient condition ioentified by the abg gwn.yg pg-ctuh,M .): the a moonent(s) hLM ! l .I l /j
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~,/w I , g. 1, Acceptable for all modes of eposatiori and cesigr) confitions. E h =f -no .h N . E [L.i II. Not acceptable for some depgn we og w'..dd or design condition. However.
- E'S j of the comoonent!s) is not ihm.
p tune::ormi immanpint X f. 8d* i o D;3" I n f 6 4>A r.,t~ li t. Unable to perform its reovired cesign function (s) unless corrective mocificationt_ ere mace. # I , 6 --- ,w y ~ S00 850220 0'0r % *s NOTE XC - WU ge-n1 M L Various items of tnis form may be compieted as recuireo to make the category U, ll, or ill) cetermination above. Items 1,2, and B (en pages 2 and 3) must be compieted in every case. For category ill evaluations all apoticacie items must be comple in as much detail as possible whnin tne time allowed. and data as necessary. Every item on tne form is not applicable to every oeficiency. Ace snects Category I incluees (but is not limited to) ceficiencies whicn are prograrnmatic in nature, ceficiencies wnich are wrt ten for tracking Durposes only, and oeficiencies whien are resolved Inrough otner enanneis (suen as those on environmental cualificati of class 1E electrical ecusoment). Any programmatic ceficiency should be evaluated for the hardware effec
- of the deficiency.
since all involved harcware can De considered suspect as a result of the programmatic ceficiency. '2'*U Attachments cc ( Attachments): E. 3. Rankin, Sequoyah NUC PR J. W. Euf ha::, 1630 CST 2-C J. W. Anderson, 255 SP3-K L. W. Lau, 'i10D220 C-K D. B. Sowen, W11A8 C-K J. 9 Vineyard, A8 Secuoych ESG F. W. Chandler, WSC126 C-K R. C. Weir, W103121 C-K C. A. Chandley, W7C126 C-K K. W. Whitt, 249A E3B-K C. F. Dilworth, W11A12 C-K MEDS, SL26 C-K u
r s Page 2 cf 3 1, Summary of Nonconformance: include Cate discovered; method of discovIry;the specific compornnt, mechanism, or system which f ailed;and its failure mode. (The NCR form may not give a complete description.) Enwcon mu.,a.,\\ denwin 415 2.W-81 does no+ ape.d c n i% cad. md% Les:. b +W.E.G.T5 fehs. The, dost % tom pon g 3 ba nuc..}.heg Lwus k ner Ixici mas. h n,s. was.c,-ores ccetc % + gJ g gf6cA 6 in &4. o% 4 % Che- ( e.g. %Q he,,e, e o%gs3 was pi.f r*C.MScd Cgvahke d, M 1 k I I"'c d S. .ud h Nce. us, disc.wed reo n d islis /84 dweing c, w o n U R. m der pay b e., - c, en..c. m. g[ 2. Causeif Nonconformance and/or Justification for its Classification: For instance, discuss program breakdown, new regulations, erroneous analyses, design errors, test results showing deficiency, and/or failure to meet design l criteria and/or purchase specifications. Inclutie calculation % analysis results, test results, and/or purchase l I l q requirements not met, or other bases which justify the category designation. k Thc CyAC.4 CAV E L. d 4hL NM, ts nok known Cnod LS me J-prMl} tMEMC d ec,w.*n g (T :.ccs - s'5 ) i +o k yn.,c n.u cee, Whe ^ pecparin$ +bc. dag fe r ' h e. Nr.e e4oAto 7.W) + b u c. W5 Seed ct k\\vec, 4-o re g n c.c Ahc,5lcf,0&c, ~ c O L. khtx' %A SourCL. O PAMcM'Q% 40 C\\etMesc.cA f.Cl[gmed 4 4.h g SPC c8. 3 Cr' 4-weg n adycAM( o.[NCd. Svbice ved Lbechn'eg, indepg 4 y g ceview, cmd Sque.d C.heckin of thL druings in acc ce 6nce w% eM&d el tcc.+ 4 e. ca,hden. i proccc ore s dld no4 e 3. Tabulate Specific Failed and/or Affecteri Comoonent(s). Structure (s). or System (s): State whether or not the problem is generic, identity alternate uses of the component (s), structure (s), of system (s) in the plant. ~ EG~I~5 P4 hNL hVwdd s% moisWy d % @S,o.ungg(togg3* 7-7 , m. a M r a. h -C %~p. F-b,J % A %T S ^ % 0. - ^' W-W b.M"~ rma:w3 p.3
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b [ pi,v.L 1.4. g-C i = 'f1b EGTS CT Q ok a 5 u 12 p -d a.7m va a r i 4 Data on Specific Component (s). Structure (s). or Svrtem(s): Give description, model and manufacturers' numbers, and original anc revisec cesign criteria and/or specifications. l Hy r_a 1 inh.\\ e. H 55.5 52-B 120 H 5 c._\\ & 'ns,J,6, mo ish-c-x.<co r, R1 k no, cle s.La 1,q y to' M s, 5. Failure Meenanism (cescription and extent of the effects of the failure mechanism on the component or electrical system identified or involved in the deficient condition) C. d CUkA g d e; m M 4"LCC. dC#\\h DO 'O^ CLC E-- P rcS u & n a i h c., e W 5 'c d Icceon M. 2.* u'farir. J{ % uGM: (f -d 4 ck< w W L uh fu) muu m Q,
x i Pege 3 ef 3 ' - 6. ; Failure,Model(open or, closed, inoperative, shortened life, shorted, reduced accuracy, increased drift, reduced - capacity, etc.). Indthrkin SnF,. Eleme,M. M .noi vatf.( qv q((- p r. -.rn .h b +. bnc.Moh[ peopvI l + ,l . ) jg ua 7 f Consecuences of Failure (identify the device (s) and their failure modes) i lh hh(.,' mo sbro e,lbd doer, no4 uccN Ck g hv4 b g be54cr dM nok N bened on w%j humid JJ)?'lO 7e 6 _ pw. : The. et w e d mq ben o~ wi., hen h-pro get3 ; y +. m LE.not caoew o n $_l4 r 15 '/. TL. cle.--.d % his _ - Yec 5A A "A Y h16 ) $ e.g.,, I$ A h. A 8. Conclusions (definitive statement on the component's/ structure's/ system's ability to perform its intended des function) t s ~ ^/ 1 ,y 'l f.. ,/ ,f' / /
- 9. ' Discuss Succested Mocifications and/or Solutions:
A({cw - Ce\\e, vt hum t d i hrA h St@ E WbM C N-N cad re_*s 4 3 p s, w o c. +wc. m e e. w %._, # Ac-whem pur pose.: on k 4 Ei rd. c.J 7 ' " 75 "'+ " " I' wbb ek ~ A' *W M."^ h c,.tce.phrh k. n )tLnQH A S Y W$ > YH = \\ &eAs wo h 6, sme s ceg LL <J = JJ k 6 h ne. EEeQ9, j I m
8. Conclusion (definitive statement on the component's/ structure's/ system's ability to perform its intended design function A functional impairment of the emergency gas treatment system (EGTS) relative humidity (RH) moisture element is likely if the radiation dose exceeds the qualified value. Therefore, the condition is evaluated as category III. However, additional information is provided below which concludes that from a safety standpoint the system is acceptable for all modes of operation. 1. Activating the heater when the RH is less than 70 percent is not a safety concern. 2. Alarming the main control room (MCR) when RH is less than 75 percent could result in operator action to shutdown that EGT9 unit and activate the redundant unit. The redundant unit could also fail in a similar manner, causing operator anxiety and possible shutdown of the EGTS systems when they are in reality functional for their intended safe ty function. However, if both EGTS units indicate high RH, the logical operator action is to continue operati'on, since units are relatively efficient even at high RH. 3. Failure of the element to function would make the RH heater inoperative and also not alarm that the heater is nonfunctional. Such a condition could result in potentially greater than 70-percent RH air passing through the EGTS units. This is not considered to be a significant safety concern for the following reasons: Carbon filter beds at Sequoyah Nuclear Plant (SQN) in the EGTS a. have two 2-inch-deep beds in series for a total depth of 4 inches (approximately 10 cm). Test pgja shows that the efficiency of removal of methyl iodide (CH 3 I in 10,c-deep beds of potassium iodide (KI) impregnated activated carbon at 0.4 seconds residence time reduces from 99.9999 peycent at 70 percent RH to 99.92 percent at 98-100 percent RH; All other conditions being equal, it appears that the degradation of filter efficiency at the higher RH levels will be less than 0.1 percent. I b. Regulatory Guide 1.52 allows credit for 99 percent efficiency for syste=s like the ECTS at SQN when hu=idity is centro 11ed to 70 percent; it does not specify efficiencies for systems not having controlled humidity. TVA assu=es 95 percent ef ficiency for the l ECTS in its analysis of 2hc accident dose. This censervative assu=ption provides some =argin for reduction in efficiency -of the filters if greater than 70-percent RH occurs. l i i 1. G. Wilhelm, Iodine Filters In Nuclear Power Stations. KFK 2449, 1 J pg 40 (1977). I l E75030.07 !EE-Feb. 8, 1985 9
s We have comple ted an analysis of RH in the annulus' (i.e., RH of c. air. entering the EGTS) and have determined that, based on licensing assumptions, it will not exceed 70 percent at any time in the 100-day period following a design basis accident (DBA). This is because heat transmitted from the primary containment substantially increases the annulus air capacity for water vapor while the rate of steam -leakage from the primary containment to the annulus is relatively small. The analysis conservatively assumes the annulus moisture content approaches that of the combined inleakage from outside plus the steam leakage from containment. Results show that the annulus temperature would need to cool to below 100 F before the RH would exceed 70 percent. It should be noted that the scientific community world wide recognizes that the TID 14844 source term used to calculate jhe offsite dose at SQN is high by at least an order _of magnitude. BMI-2104, which includes analysis of SQN under specific light-water reactor (LWR) accident conditions corroborates this perception. Numerous probabilistic risk assessment (PRA) studies in recent years have indicated that the secondary containment is not necessary to adtigate the consequences of an accident. It, there fore, is realistically i not likely that a design basis accident would result in failure of the RH moisture sensor due to high radiation. Further, if it should fail (for any reason), the decreased ef ficiency, of the EGTS and the consequent increase in accident offsite dose would be insignficant in relation to the real decrease in accident offsite dose that results from use of realistic source terms. This is, therefore, not an engineering problem. In view of all of the above, it is concluded that even. if the RH moisture sensor fails, offsite doses will not exceed 10CFR$d? fequirements, and the resulting condition will be acceptable for all modes of operation. Gieseke, J. A., et al., "Radionuclide Release Under Specific LWR Accident Conditions," 3MI-2104, volenes 1-7, Battelle Col== bus Labcrat: ries,
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1984. 1 i E75030.07 NES-Feb. 8, 1985 1 1
1 l s, OlVISION OF ENGINEERING DESIGN NONCONFORMANCE REPORT lin 584,:;. ! 3 pg / 1 @ AsPont no _ SQNNEE8408 - @ 'LANT Sequoyah @ PREPAnER/ ORGANIZATION /0' ATE h uNat 1 and 2 @ osscMIPT80N oP CON 0lTION ' B. K. Williams / NEB / December
- 13. 1984
'Some NUREC-058B replacement. components (ECTS He t drawing 47E235-81.the ECTS filter housing were purchased using a er Controls e.g.) located in dose for the. components.The drawing specified levels of 3 x 10 environmental data sp 7 may be on the order of I x 10Ingetuality,calculateddoseswillbegreater' rads integrated rada. and @'systru_ N/A g ygggogg,gg__ N/A @ oATE OP OCCURRENCE EST( X, ACT.( l 5/83 b CONTRACTNo._ N/A Q stoNiricANTCosoivioN Aovense to c METHOD OF DISCOVERY h UNIO CODE IEN DES.EP s.0f) ' Review of W.B. Vendor Dwj; vas @ No O 1
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