ML19220B512
| ML19220B512 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/07/1979 |
| From: | Satterfield R Office of Nuclear Reactor Regulation |
| To: | Grimes B Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7904260475 | |
| Download: ML19220B512 (13) | |
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' E'-f Pf *TUf' FrP : "rian c ires, assistart T irector for "rd naering "ro?. cts, Pr" r
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E. M. l'anauer, /ssistant "irectar 'cr Plant Systors, "cc F"D":
R. ". Satterfield, Chief, Instrtmentation and Centrcl Systers Cranch, CSS SUPJECT:
SU??'f RY CF PECE"T STf FF EFFCPTS TO ASSESS EiNIPr*?'E"Tf L OCALIFICATInt OF SAFETY PELFED ELECTDIC/L En!!r"E':T INSTALLEC AT "'I-2 In response to the recent cveat at T"I-2, an effort was initiated Su CSS and Mr ;ersonnel to establish t'e radiation vif thstand carability cf speci#ic pieces of safety related electrical equipment installed at TI-?.
Th i s i n #c r. a-tion, tecether with calculated radiatien levels inside of contaiarent, was to he used to assess the possibility of failure cf this equincent due to radiation exresure as a function of time. This creran<*cr stnarizes t'e stctus of this effort.
- lork thus far indicates that tire c# #ailure is difficult to establish 'ecause o# uncertaintics in *"e calcula*ed dose rates at varicus locations inside contain cr*.
r tter predictions ' culd 'e ossibln e
only vten better data beccre available on @ich to base ecse calct.lations.
1.
ualification Cata 'cr Selected Sa'etv n
."UP I -2 elated Electrical n irren+ Installed e
1.
Instrurentation Pelated tn e 71 ant Tc cerature, ')rersure and Fim.'
c "easurererts Ta'le I lists those prassura and dif#orential cross':re tra-rit+ers ar '
- e terature senscrs located insido cmtaiment
'4ch arn considered i nor+. art
+c the currer.t " ode o' creration ('eactor cco!3r+ mra enrratim' ard rovivim-OFFICE >
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._ flow tFrcu;h one stean generator.) This table also Fresents the elevation of the transmitters above the containeert floor (2P2' E" level). All instre-rents are located in the annular region between the shielding wall and the containment t:all. The table also shows the radiation dose for which the transmitter was designed and/or tested.
In an attenpt to gather more information on those transnitters suspected to be particularly susceptable to radiation damage (i.e. both the Bailey and Foxhoro transmitters), COE t'aval Reactors and Sandia Laboratories were asked to search their files for radiation test data on trese instrurents.
While neither organization had made use of the specific model instru-rents of concern, Sandia Laboratories discovered thrcugh discussicrs with the equip ent nanufacturer that certain Foxboro pressure transritters installed at TMI-2 are equipped with radiation hardened arplifiers and r
that these transritters have survived doses as hipb as 2 x 10' rads. These instruments are used to reasure reactor coolant purp seal cavity Pressure at R:I-2.
(The identification nw-bers for these instrurents are RC22-PTa through -PTO).
Should existino reactor coolant pressure transmitters fail, these hardened transritters ray continue to be available to measure reactor coolant pressure.
1.2 'llis Chairers Peacter Ceclant Puro "otors C?,4 has established that the surge capacitors are radiation sensive.
They estirate that capacitor failure is expected to cccur betveen dose levels
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3 will Icad to short-circuitry of the capacitor wFich uill trip the supply circuit breal.er.
If the capacitor rcrains short-circuited.
the rcotor cannot be rester +ed or ocerate<!.
If the capacitor sFould cren-circuit, the rotor can be started and operated witFcut it.
Therefore, it appears worthwhile to attecpt a restart in the hope that either tFe capacitor has opened up or that the starting purp will cpen it up.
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!.3 Pressuri2er Vent, 31cch and Relief Valves With regard to tFe block and relief valves, C?.9 estimates that the design radiation level is 2 x 10" rads. This value was based on tests rerforred 4
on sinilar valves.
The pressurizer vent valves were supplied by Rurns and Doe and tSat organization has been contacted to establish the appreoriate design radi-ation level for those valves.
1.4 26" Reca-biner Isolation Valves These valves were supposedly cualified to 2 x 10 Pads. Uct;ever, on "pril 6,1970, Pegion III actified NPR that the valve ranufacturer Fad filed a Part 21 nctification indicating that at least one corrennot of 5
the valve had heen tested only to 4 x 10 P ds.
- in rated Folcu, +Fe effect of this reduced desien radiation level F3s yet to he assessed.
This issue is beinq pursued uith tie manu'acturcr.
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4 1.5 Fan Cooler "otors It was established that tFe fan cceler "otors survived expnsure to 10 rads.
1.6 Pecay Feat Removal Systen Ccrponents Cceronents of the decay heat reroval systen which c:ay be affected by radiation have been identified. However, design radiation leve!s have yet to be established.
In view of current plans not to use the D!y systea, there are ro efforts underway to develop this information.
2.
Estirates of Tice of Failure cf Safety ' elated Ecuirrent nue to 9adiatier Excosure In an attempt to predict when critical electrical equip ent installed at Ti'I-2 might fail due to radiation exposure, dose rates calculated for varicus points inside containrent were used in conjunction with tFe design radiation levels described in the Trevious section to establish equirr$at lifetire.
The e rate calculations vere based on analyses of containment air and coclant samples taken on " arch 31, 1979.
(See Enclosure 2)
It was assured that the air sarrie was representative of the average containrent atresphere ard that the ccolant samcle represented the liquid on the contaircant floor. It was further assumed that the centributions to the calculated dese due tc radiation frn-the reacter vessel, stear, generaters and pressurizer were negligible, because of the shielding between these crrronents and t':e equirecnt of concern.
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This latter assurotion was surrorted by calculations teich sFored that little of the radiation prcduced by coolant witrin these vessels renetrated the vessel walls.
2.1 ORNL Estirate of Padiation Dose at location of Foxboro and Railey l
Transnitters.
4 CENL, using a two dimensional carputer calculation, estirated the dose rate delivered to those Foxboro and 7ailey transnitters that are a part of the reactor cool' ant pressure and flow neasure syster.
(See Table 1) These trarsmitters are located in the annular region between the conteirrent vall and the shieldinq wall. They are installed on an instrument rack and are positioned several feet (See Table 1) above the containment floor. The dose to these instrurents is due to radiation from both the containrent atmosphere and the contaminated liquid covering the containment flocr.
Cne cause for inaccuracy of the dcse rate estinates is the assumptien that the coolant sample taken on arch 31 is resfresentative of the water en the containrent floor. This sarple was taken several days after the event whereas a significant portion cf the water on the containment ~ floor ras deposited during the early stages of the event and should, therefore, be much less contaminated than the " arch 31 sample.
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-n-Fror tFese calculations it Uas esticated that the transnitters are exrosed to a dose rate of 1 x 10 Pads /hr. The Failey odel RY pressure transritter
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vtas tested to withstand E x 10 Pads with no effect or cutput and 4 x 10 Pad with slight shift in calibration of 4"' (F A" ~10002 ). Several of these trans-r.itters apparently continue to function nemally.
It is therefore assured 4
that their capability above 5 x 10 Pad is being used.
2.2 Calculated Doses to Other Cerronents Inside Containment Other calculations t+cre perfomed by the ITC staff to estirate the dose received by certain other 1"rortant corpenents inside containment. In these calculations it was assumed that tFe only isotope of importance in the containment atnoschere is Xe The l33 analysis of the containment air sample shored ye to be present in the concentration of 675 microcuries/cm3 (Table II). To be conservative and to account for additional Xe " beir.g vented into the centainren+
1" fron the pressurizer as a part of the degassinc of the prirary coolant, in the calculations tcre perforred assuring a Xe concentration of Irro cicrecuries/cc.
l The irrersion dose due to Xe was estirated as a function of rom size.
The roor enclosure was assured to be spFerical and to be Econded by a significant crount of shieldinc for tFe soft garra (r..n3,"ev) associated l
9.'it' Xe decay. Pose rates at various locations in t! e containrent
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In addition to this air dcse #r?, Yel ' '", t he doep (r e.
{ l 1 f4 33c}ypd in the water on tre containrent flocr was also calculsted o':ere arplica'la.
This calculation Fa perferred using tFe concentratien reasure' in t' e prirary coolant sar.ple (Table II). Tbcse calculations are entire!v dependent on the radioactivity concentrations assumed in +bc air and water. Uncertainties in these values would intrcduce corresfordinc uncertainties into the calculational results.
These calculations produce radiation dcsc rates as follo1s:
Various valves located on top of the pressurizer "Cr 9ad/Sr Reactor Coolant purp surge capa.citors llrn "ad/hr*
Electrical penetrations IMO Pad /hr Pased en current knculedce of the design radiation level for rrcssurizar r.
Slock and relief valves, the lifetire is estir.ated to Se 2.5 x 1* 'ours.
The surge cacacitors are calculated to last 2T Srs. The desien radiaticn level for tre renetrations has not yet teen estelisFrd.
In estinate.,'as also -ade c' the dose delivered to the 'F" ?ccrr51rer Isolation Valves. In this calculaion it was assu ed tFat the a'or Har2 e
.'echanis~.+'as exrosure of t'e valve coat due to *Fc fic 4 of cert 3 f rrort estimatec trat tFe intocrated dose to the surre caracitcrs M r#
S nri l '*, 1 n7 ua s 1.:' x 10 " a h.. ncv es*irata tPat '"er al rurmt cculd benin 1" days a' tor tc event. The "" inse cal cul atiM e ' am"'
on consi,Ieration of cartribution: 'r ri 'cth ccatair~ent atrcr~"c"e '"'
linui<! at te botto c' the con' air-cct.
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It is believed tat the retal exterier o' the valve till serve to shield valve cmrenents fre" t'e radiatien #ror tbc enn-tainrent atrosphere surrcunding the valve.
The radiatien dose to the valve seat is estimated to be about Econ radfsp wiUn est of this dose due to beta rays. The staff estinated the radiation level cananility for tFe valve seat material fer this valve to be about Ir5 rads. Therefore, t'e seat sterial shculd survive at least ')1 days.
Assuming the seat is thick relative to the cenetration capability of the Seta rays, the integrity of the seat wou'd be expected to te r:aintained substantia 11v beyond that time.
As noted above, the talve ranufacturer has indicated that certain valve corpenents, particularly crganic caterial used in a solencid valve v ounted C
on the isolation valve, were tested only to a x l'" c ds.
The test a
infomaticn ncu available indicates that failure of tre solencid valve would prevent closure of the isolation valve. 'fwever, "ittout more detailed krewledce of the solenoid valve desien and tFe st 'cidira a'#crded the crganic raterial by the valve bcdy, it is inpossible to establish Retrer, and at w+ at level, radiation will cause failure of the solanoid valve.
T' e ranufacturer rill previde acpropriate drawings sFortly.
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TABLE 1 B&W Instruments Inside Containment IA - INST MOUNTED BY ITSELF IR - INST MOUNTED ON RACK Parameter Inst Ident #
- 1oun ting Type Rad Level Above 282.5' Design Test Level 7
SG "B" PRESS SPGB-PTl IM 13 Fox EllGH 10 2' 5" RC Flow LpA RCl4A-DPT-3&4 IM-14&l5 Bailey BY 10 3' 0" 7
PRZ LEVEL RC.1-LT 1, 2&3 IR-424&425 Bailey BY 10 3' 6" SG "B" PRESS SP 6B-PT2 IR-428 Fox EllGH 10 RC FLOW LpA RCl4A-DPTl&2 IR-4255426 Bailey BY 10 RC FLOW LpB RCl4B-DPT3&4 IR-429&430 Bailey BY
'0 RC FLOW LpB RC143-DPTl&2 IM-12&l3 Bailey BY 10 7
SC "A" LEVEL SPlA-LT2&3 IR-426 Bailey BY 10 SG "A" LEVEL SPlA LT4&5 IR-426 Bailey BY 10 (SU)
SG "B" LEVEL SPiB LT1, 2&3 IR-428 Bailey BY 10 7
SG "B" LEVEL SPlB LT4&5 IR-428 Bailey BY 10 y
(SU)
SGA LEVEL SPIA LT1 IR-426 Bailey BY 10 5' 2" SG "A" PRESS SP6A PTl&2 IR-426&424 Fox EllGH 10 7
RC PRESS (WR) RC3A PT3&4 IR425&427 Fox EllGH 10 7
RC PRESS (NR) RC3A PT5 IR424 Fox EllGH 10 V
RC PRESS (WR) RC3B PT3 IR429 Fox EllGH 10 8
RC TEMP (NRT ) RC5A TE2&4 Rosemount 177Y 10 c
(A LOOP) 8 RC TEMP (NRT ) RCSB TE2&4 Rosemount 177Y 10 c
(B LOOP)
RC TEMP (WRT ) RCISA TE1 g
(A LOOP)
RC TEMP (WRT ) RC15A TE2&4 H
(A LOOP)
RC TEMP (WRT ) RCISB TEl
[fC-j'143 g
(B LOOP)
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TABLE 1 (Cont'd)
Rad Level Above 282.5 Pa rati,
- r Inst Ident #
Mounting Type Design _ Test Level 8
RC TEMP (WRT ) RC15B TE2&3 Rosemount 177Y 10 (B LOOP) c PRZ TEMP RC2 TE 1&2 RCP1A SEAL MU10-FT1 BROOKS RET FLOW RCPlB SEAL Mul0-FT3 BROOKS RET FLOW RCP2A SEAL MU10-FT2 BROOKS RET FLOW RCP2B SEAL MU10-FT4 BROOKS RET FLOW F(' C Ut3
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TABLE 1 (Cont'd)
EQUIPMENT INSIDE CONTAINMENT NECESSARY FOR CONTINUED OPERATION IN PRESENT MODE Design or Elevation Component Identification No.
Type Test & Level Feet Pressurizer Vent Valve (Mov) RC-Vil7 352' 8
Block Valve (Mov) RC-V2 2.04 x 10 355' Relief Valve (SV) RC-R2 355' Spray Valve 355' Heaters 321' 9
Reactor Building Air Cooling Units 1 x 10 Containment Isolation Valves on Purge System In Core Thermocouples Reactor Coolant Pump Motor and Surge Capacitors
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Ti'PLE 2 F,csults of Analyscs of ContairrMt Sir and Conlant Sr/nles Taken :' arch 31,107' Constituents of Contarinated Coolant I]~" - 1.3 x 10" micrecuries/cc 4
1,2 I "" - 6.5 x 10" l6 Cs
- 1.G x 1r2 l
Cs
- 2.3 x 10 l^
Barium ' - 200 Constituents of Centaminated Contaivent Atmosrt'.ere 13' Xe 675 micrecuries/cc Xe" 15 13c X
8.1 I'"1 063 14 1
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