ML20052A771
| ML20052A771 | |
| Person / Time | |
|---|---|
| Site: | Vallecitos File:GEH Hitachi icon.png |
| Issue date: | 12/02/1957 |
| From: | Price H US ATOMIC ENERGY COMMISSION (AEC) |
| To: | |
| Shared Package | |
| ML20052A734 | List:
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| References | |
| FOIA-81-483 NUDOCS 8204290151 | |
| Download: ML20052A771 (6) | |
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.I. N. THE.Mr.I.T.I.R.O.F GE::F3*l phCTRI,C CCTANY TFST_ r.3., CT3:, D?O2r NO. J0-70 PART-I: DZSchT.?IIO:7 0F '!EE FACILITY The General T' ntric Conrany proposes to build a 30 nt gavstt test rsactor at its Vallecit.s Atonic Itboratory in California. This reactor is designed to provide i.xperimental facilities capable of irradiating fuel elennts and cc=-
pensnts of nuclear power plants at high neutron fluxes.
The reactor core in c pr:ssure vessel is subnerged in a pool of water.
The experir. ental facilitics, located both inside the pressure vessel and outside the vessel in the WEter pool, consist of loops through the core, hairpin loops las external to the core, beam and rabbit tubes, and 3S positions in which capsu,0 the maximxn thernal flux will be 2 x 10 can be irradiated. At 30. megawatts,15 and the zu.imum fast flux vill be 10 Fuel for the reactor consists of 28 flat-plate assemblics containing a total of 7.8 kg fully enriched uranium. The fuel assemblics contain 19 plates each and are sinilar in design to those in the ETR reactor. The fuel assembly is about 17 inches x 17 inches in cross-section.
For control and regulation of the reactor, there are 6 bottom-entry control rods which penetrate vertically into the core region with their drive nechanisns being located outside and underneath the pressure vessel. Each rod consists of a poison section above a fuel-bearing section.
h* hen the rods are inserted (upward), the fuel section is in the core region with the poison :ection project-ing above the core.
In a ser,am, the rods fall, thus removing the fuel from the core and inserting the poison sections of the rods.
The delta k value of each rod from its fully inserted to its fully withdrcvn position is between 3 and b per cent. One of the rods is selected as a regulating rod and is so arranged that its length of travel from any given position is only b inches. This li.it-ation is achieved by a positive mechanical stop in the drive mechanism which must be manually moved in order for the rod to move further than the permissibic h inches. In any position, the b-inch motion pernitted for the regulating rod could only change the equivalent reactivity by less than one dollar.
The pressure vessel containing the core for this reactor is an aluminu;n pipe 2h inches in irside dia.eter, 23 feet long and having a wall thickness of cne
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is r.ounted in a vertical position with the reactor ccre approlinst'ely 5 feet ab';ve the botton.
The vestol has flances on either end to thich are bolted flat, stainless steel closure platcs. The control rod drive ncchsnisms pene-trate the vcscel through the flat bottom plcte of stainless steel.
Cooling vater enters the cooling vessel through two 12-inch diameter inlets located aro2nd the periphery 180 apart, about 3 feet below the top of this 0
vessel. Two sinilar outlet nozzles are located one foot above the Icwer end of the vesrel.
Cooling water circulates downward through the core at a rite of eleven t!.ousand call.pns per minute with an entrrnce temperature of 1200F3 r.n exit tonperi.ture of IL0oF, and at a pressure of ILO psi.
In two septrate cxte;nal circulating utter lines, heat is transferred to a secondary systen through two pr;=.ry heat exh4.n;ers and is disciptted to cooling towers outside of the building.
The pressure vecrel stands in the center of a pool of water 9 feet in dia.eter and 3!J fect deep.
Eleven feet of water extends above the top of the presrure vessel.
In case the forced circulation cooling ystem should fril durinC reactor cpera-tion, exercency cooling vill be provided by convection circulation er wcter from the pool into the bott:m of the pressure vessel uprard through the ccre, and out at the top into the pool again. Pressure-cer.sitive valves vill auto-natically provide openi~ngs at the top and the bottom to pernit this circulation.
The details of this nechanism have not been described by the applicant.
Refueling of the reactor will be acco plished by nanual operation through the top. A canal, projecting laterally outward from the reactor pool, will be pro-vided for storage of spent fuel and servicing of reactor experinents.
Cooling water which nay beccme radior.ctive will be stored in three 25,000.gr.11on retention tarAs.
Two such tanks (50,000 gallons) are sufficient to contain three conplete flushes of the prin.ary cooling system plus one volu te of unter in the pool. Water in these retentioninnks will be relecsed when the activity has decayed to a suitabic level. If decay does not inter the level sufficiently, the water will be treated in the aste disposal treatnent facilities to be con-structed on the site. Tetails of these facilitics and how they will operate to remove radioactivity from liquid wastes have not been described.
In designing the core of this reactor the applicant is follouing closely the design of the core in the Engineering Test Reactor and hence expects that si.~.ila-nuclear and physical characteristics vill be obtained.
For example, it is stated that the temperature coefficient and the overall void coefficient will be nega-tive. In any event, both the ETR reactor and ETR Mock-up Critical Facility will have been operated for extended periods before the final design of the reactor is firmly fixed.
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...- hy :.t 5 : ri.- It t, c: c.ci t;. to..ith.t nd 6.?i pt.i (121% of cbsign) prest.rc ar.d it Ic M: rate will L: teettd t*: ore the ru.ctor is ;.lsced in cperation.
The proposed test reactor uill be the fifth nucle:r facility at the applicant's Vallecitos Vallry site in California. The Des clop".cntal Et ildin;; h*ater Reactor, the 30 ku Resesrch R: actor, the Dresd:t. noch-up critical facility and the Spanith reactor critical ScilityuD1 be in operation ct the site 1.rior to cor.pletion of the test rer.ctor.
The In tter will be loccted in a septr te building at a distance of 1200 feet fron its nearest neighbor, the Boiling *.?ater Reector.
_P/J_tT., I.I.: HAT.I_:.U.F. A_'.:ALYSIS
'(1) The s mall c:!carance between the ed;;es of the core and the walls of the pressure vescr". reises the porribility of cooltnt flew problens.
The dire.eter of the core is nly a little less then the tuo-foct r!ianeter of the prrsarc vessel. Exanin:. tion of this design indicates that no serious problems should occur through its use.
Hevever, this _4cture is rat'.:er unusual F.nd further study will be need d cs the design progresses, to detcrninethether ther..o-r.nd hydro-dynr. &. ;.roblens will arice andthather nuch.r.- interaction betueen the core and c).periments plcced outside the pressurc vessel can b:. contrciled.
If such problems are shown to exist, it is reascnsble to believe. that they can be resolved satisfactorily by r.odifications of the design.
(2) Tha use of cluminun for the pressure vessel is unique.
Ecucver, the appli_
cant believes that, even taking into account the effect of gr;:::a heating, the vessel vill be able to neet ASE r> oiler snd Tressure Vessel Code specifications.
Our independent analysis indicates that the' vescel will neet the code specifi-cations.
(3) The core itself is quite similar to the ETR core. The ETR will have been in operation for a considerable period of time by the time the GETR is cenpleted.
Information obtained from the o;.eration of the ETR should point up any difficult-les which might arise in the operation of GETR and will give r. better idea of the magnitude of the temperature and void coefficients to :ce expceted in the GEIR. Prelinincry data from the operation of the ETR indicate that the ter.per-ature and void coefficients of the GETR will be satirfactory.
(b) A conplete description of the experinental facilities and plcns which will be followed in the experimental program has not been given.
The fact that all the experinental loops are located in water, either in the pool rurrounding the core' or in the water filled pressure vessel, will require that e ach experinent will have its own separate container. This will orovide another barrier against the release of radioactivity from experiments.
No discussion is given in the report of the expected effect experiments will have on reactivity and on local and overall temperature and void coefficients.
A complete discussion of this subject will have to be submitted in the final hacards report. A normal experi-nental progran of the general type described can be conducted at the proposed f: et ' ! * - v' "
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(S) The mxinur credible accident is considrered ley the applicant to Le the
.=i.ultaneous rupture of the pri :.ry inlet cooltnt liccs und failure of the control rods to enter the core. The only mechanism other than acts of sabotate cr uar, uhich the applicant considers es ccpable of initiatin such an accident is a ce tore cLrthquake..
a T: calculate the cnergy release frcw. such an accident, the applicant assuned that 50% of the fuel elementr. and thcir citeding r.elted and that half of the r.elted :r.aterial was involved in a cht icci reaction with water.
Since experi-ments r.sy contribute to the severity of the accidr.nt, the energy relesse thus calculutsd was increased by 255. Such an enercy release could result in a r.ufficiently crest pressure rise to rcpturc the reactor pressure vasrcl.ad to raise the pressure within the conteir. :nt building to 3 psi.
Sin:n this is well Leicw the 5 psi design pressure tnd the 6.25 psi test prescura, ti.e ' u21d-r ing should not te ruptured.
In evaluating the conceouences of such an accident, it was assumed that 2~.~s of the fission products.cresent at the end of an cperating cycle (appre:.frately 25 dcy;) at 30 IN, would be released to *.he facility containcr.
At,the. nearest site boandary (2800 feet) the radiaticn shine is ecleulated to be 12 r for an integrated dose over a hcif-hour period beginning 5 ninu.es after the accident.
Fcr a b-heur exposure, the max 3num doses to be expected at the nearest site boundary and at the necrest small town (r. bout 3 niles), as a result of a con-tinuous release of ficsion products at the design leakage rate of the contain-nent vssuel (25 of the volume per 2h hourr at 5 psi pressure differentici) are as follo.:s:
Nearest Site Boandary Small Town a.
External dose 10.Br 15 r b.
60-day integrated dose to If2 rep 5.8 rep the it.yroid due to I-131 c.
60,-day integrated dose to 1.2 rep
.16 trp the bones due to SR-89 Enployees on the area would be much nearer the source of radiation in case of r.ajor accident, and rates of exposure would be correspondingly higher. On the other hand, the nobility of persons on the area is under strict controls, and it would thus be assumed their movements to avoid undue exposure would be one of the primary objectives of the emercency procedur?r, yet to be worked out.
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ps event ruch accid < tut.n.in t he first. I ace ani! "n iln n.verant of j arc <mn to l
prevent. :.arh v1.or;.arns i f an accident, r.hould occur.
In any event, the conunption used in cielculat ing the nninium c redib]c accider.t The appli-are sufficiently penrlinit, tic to ronder en accident highly unlikely.
cant has str.ted t. hat a r. cram interloctC.~..'..2/will chut down the reactor in th T;, r ninam credf-case of any ni.nific.nt cart hgat.he 'lir.turt..nce in t he arch.
t ble accident for thin renetor nay ut:11 be 1er.n thun that p.ctulated 1.y that applicia,t.nd in nny cvent, ue do not nee how s.n i.ccident warne than that pos-tulnte:d by the applicant could be credible.
.Th.:$e dans not appaar tte be a credit le nechanisn far bre.rM n:: tha c. utt. i ne r.
into Wile an eartir;nake could corweivt:tily cause relcare of finalun prs:t m breA1.ed either the cantainor,,:e du not t.elieve t:...t the runt ainer co::Id ba by the precoure ren11 ting froa. the n xir.n. credible aneident post uintad
..r by S:m:u at:c ahearing friccan likely to result from any carthq. :.ke in this area.
i could reault eitbar ' r an s. fault dircr:tly under the cont ainer t..did. r.g or :.y thr:
- r. hock waiver. from the quake. The hinter / of faults in thir..rea are : n-Fa rt '.
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no f.: ult vanid be e4; rcted to verus :.n.!cr ti.e c.n' ai.or.
is being touilt to alth!,tand the chark frsn the uarnt quahe re:Orded in tr.is area.
((3) because of the large quantity of hi.at ener.:j prodaced in t he purtuhted nuxim e:. credibic accid"nt and the ;.resence :.f.rosplale r.isr.iles ariring t:.ere-fron (core vest.el, ex;,erinantal crepr.ul. c. core copiir.g. ater, ctr.), tne 4ppli-be ; rovided to protect the ::or.tnin.cr.t cant. propo:cs that a r.insile shielti
- !:e re:. ort contains the reraits f ;relinint.ry crileuhtions to fcMr-b.2il:!J ug.
mine, first, that a nisvile.hield is feasible and second, an ar;r ;riate sitt.
t These calculatians 3:::licate that a t op shield thirkr.ess of 18 in::hes 4.nd a ;. ant.1 Further stJ: lies the applicant proposes gate nhield of 13 inches will suffice.
to :ul:e, in:1ude connideratian of niternnte scher.co to that des:.ribed above These considerati;r.r ar.d the before f:nal chield dimensians cro octablir.ued.
"rie final :ll.easiona vill have to be subnittea it. t!.e fird.1 hrozards rt.p:rt.
i.elieve that an ad. equate missile shiel:. is fer.si':le for this f a:ility.
Can:1asion:
40 the:e is ret.=3na:1e In sitre of ;*.c infornt. tion presently available, we feel 15 a reactor of the gcr.erni cor.:er *, frr 4 M i.nd its ;roposed nper-l
- nsarance that J-!ed v r y V.klie:it.os site without incntal pr:gra. can be construct:9 a : '
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undue risk to the-her.lth cn ! safety of the rum L erO.er, we celieve ths.,
f.isfactorily rssolve:i ;risr those safety questions which are aarcsolved p.
to operation of the facility. This con::1 arit.. is A d on an analysis of the general design of the rea: tor and an outline ut the frSposed experi. ental pro-Befare operati n of the facility, the a;;.11: ant nust sus..it a fir.al gran.
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6-4 1 azz.rd i.rnlysir. cf the t tet dhd.9a:icn of the re:.ctor t.r.d the details of the.
-; roposed experi.ntal progrea.
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1 FOR Tile IriVISTO:! 0F Cn'ILII.N APPLICATIoli h
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3 H. L. Prici.
Director j
Dated:
Deccaber 2, 1957 I
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