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NOTICE PORTIONS fl~ T!+:3 l?EPi)RT .RI!E !!.LEG18LE. TITLE COMPACT FUS ION REACTORS ———_ . _ It has kk’i: r:~roduccd ?rom the best availoblc copy to permit !he hroadeti P0SSihJ8 avallabJJJtg

AuTPIoa[s) R. A. tiraho~skl Los Alamos National Laboratory, Los Alamos, !1!1S7545

R, L. liil~(211SOll ‘1’cchnologv International Inc. , Ames, Iowa 500i9 MASTER

SUB~IfTED TO 5th ANS Tupical Mcctini! on the Technnlokv of I%sif}n Hncrjv Knoxville, T:/ (April ‘26-2N, 1983)

“l-hisrcporlwasprcpmcdusm ucimuntdwork spuniurcdhyxnMKcncyur[hc[JnimdSIaIa (iuvcrmncn{.Neithcrihc(JnilcdSlohx+(iuvcrnmcntII,)rtinyngcncylhcrw(,nurnnyorlhcir cmplnyw.nmkcsunywnrran[y,caprcmurim])licd,m nmumcsunyIcguliinhllilyurrccpunai. hilityIurtheuccurncy,cumplclcncm.nrusrfulnckso(tinyinkwmuliun,qqwrnius,prducl,nr prucxMdiccluscd,orrcp-nlsthutilsutcwIIuldnulinfrin~cprivatelyuwncdrights.Ncfcr. CIILZhereinlounyqwci[iccommcrciulprmluct,prwxc,urservicehytraocname,Irudcmurk, mrinuructurcr,orotherwiseIJ(RMnwincucxmrilyamti[i[utcorimplyihcndurwmenl,rccwm. mcrrdnllun,or(nvuringhy the[Jni~cdStuIcK(invcrnmcnlw UIIVngcrwyIhqrcur.llc vlcwa nmlnpiniomd uuilw+cqwcmcdhcrclntlunotncwcurilyMIMIC.w rcllcwIhucaofIho UniuxlSlwcb(iuvcrnmcnlurunyugcrwy[hcrcul.

LosAlamos NationalLaborator LOWbWililOSbsAiamos,NewMexico87541 ,M, COMPACT FUSION REACTORS*

R. A. KRAKOWSKI, Los Alamoa National Laboratory R. L. HAGENSON, Technology International, Inc. ?. O. BoX 1663 2515 Elwood Prive LOS Alamos, New Mexico 87545 Ames, Iowa 50010 (505) 667-5863 (515) 296-2233

ABs’ImcT

Compact, high-power-density approaches to ● Implication: these KFE ayatema will be are proposed to improve ecunomic appreciably more expensive than alternative, viaoility though the use of less-ad~anced tech- long-term energy aourcea in spite of a nology ir systems of considerably reduced negligible fuel charge. scale. The ratiGnale for and the means by which these systems can be achieved are dla- ● Solution: FPCa of considerably higher power cus.aed, as are ualque technological problems. denuity that simultaneously operate with acceptably low recirculating power fractions 1. INTRODUCTION (~ 0.1-0.2) and reasonable extrapolation of present technology will be required. The engineering development needs for the mainline tokmak have been quantified by Concern over this dominance in FPClmags detailed conceptual deeign 8tudiea of both and coet for many MI% approached - , first-generation engineering experiments:” and therefore, has led to consideration of more commercial power reactors,3 while eimilar compact options.lo-13 Thie generic category Otudiea of the Tandem Mirror Reactor (TKR)4-6 includes the as well as nearer-term engineering devicea7‘8 Reactor (CRFPR),12c~m!iact1 the ‘everaed-Fieldreuctor embodiment‘inchof are being conducted. The statue of reactor the Ohmically-Heated Toroidal Experiment deeignN for tokamaku, tandem mirrors, and tokamaka (l.O., alternative fusion conce ts (APCa) has been :%%)l~~f~:fi::; certain aubeletuentaof aummarizzd quantitatively,!,lOand a qualita- the Compact Toroida (CT, 1.s., a heromka and t~i,l~aaaeeement of the engineering nnd tech- field-reversed configurationa).28-27 Tl)cword nology tl~eds of toe major AFCN hau been “compact” deecribea approached chat would presented recently.11 The aaueatimunt of operate with high engineering or uyatem power econ.~micviqbil ty for magnetic fuaion energy density (i,e,, total thermal power per unit of (MFE) provided by these atudieu can become FPC volume) and does not necea8arily imply somewhut conv,,lutedand obHcurod by tho lnter- small plant capacity, Also, “compact” doc~ not depent.lenccot’complex phy.stica,engineering, and neceftoarily rcfsr to or limit a #pccific coMtlng/econor~lc~. In order to circumvent in confinement achemn; juef.aa the Rever~ed-FieltJ part the am’aiguity thlit ueually actompanien Pinch (RFP) has a viable “conventional” reactcr attamptH to combine and interpret reault# from embodiment2e, compact raact.oroption~ for the 11 lnrgc numhcr of relatively independent tokamakis-l~, the stellar/ltor/toruatron/ atudi(!n,this paper proceedu 011 the baai~ of heli>tron (S/T/H)29, and certain CT config- Onc wimple obeervutlon and one atralghtforwurd uratlonu c14n be enviu~god, Gen~ral remedy propouod to reduce tile itnplication of cheracteriutlc~ being aou~ht by the comptict that ob~orvation, Specificuily: reuctor option~ art?:power denaitieH within thQ F1’Capproaching those of ligl~t-water L’i.sMion retictoru (i.e., 10-15 MWt/m3 or 10-30 time* grautur than fttrother WE ayutemg); projoctod tot4tl coetu thu~ are rttlativalyinuonuitiva to l~trgt?chattgeH in uuit coots ($/kg) uaud to e8timuCe tl’(:and itaguciatad reactor plunt equlpmr?nt(WI;) c.08t#,theruby reducing tho im- pact of unccrtaintie~ in the aattociittatjphyuic.~ ttll(ft.uchIIuIcRyOn total CO#t; conuidcrably re- ducvtl FI)C alzc and matim with pctentiul for “block” (lie., Mingle or fcw-piec~!) intittill- ation and maintenance; and the potenti~l for reactor, while considerably reducing develop- rapid, minimum-coat development and deployment. ment requirements and coata.

The compact option will require the III. RATIONALE extension of exlating technologies to accommo- date’ higher heat and particle fluxes, higher Although the compact approached reduce the power densities, and, In some instancea, higher stored plaama energy requirea for commercial magnetic fielda required to operate FPCS with fuaioc by an order of magnit~de, while higher ayetem power densities. Both the almultaneoualy giving enhanced uyatcm power advantages and limitations of the compact density and FPC maaa utilization, ulti~tely, option, aa well as related technological needs, the decision on an optimal ayatem powex density have recently been sur~rized.30 must be made on the baa;a of economics. The direct coata of a fiaaton ur fusion reactor ia After suaznarizingin Sec. II. th~ status divided into the Reactor-Plant-Equipment (RYE) of fusion reactor designs in relationship to and the Balance-of-plant (BOP) coata. The SOP present and projected near-term experiments, conaiata of all aubayatema o,~~aidethe ~econd- Sec. 111. gives a rationale for investigating ary containment. The RPE coat for fiaaion higher power density options. The pathway to reactora la approximately 25% of the plant the high-power-density approach ia described in total direct coat (TDC). Moat of the studies Skc. Iv. After summarizing a zzvher of recent autmaarizecion Table I, however, project RPE compact reactor design poinca in Sec. V., key coata that range from 50 to 75 parcent of the technology needa are summarized in Sec. VI. TDc. The BOP coata for a fiaaion and fusion Summary concluaiona are given in Sec. VII. plant of the same electrical power output are expected to be approximately the same, although 11. STATUS the reactor-building coata for the latter can be greater. Hence, TDC ear.imatea for fusion Although the achievement of phyafca energy reactora predict higher valuea th&n for fiaaion breakeven and eventual deuterlum-tritlum pcwcr planta becauae of high RPE coata related ignition repreaenta major near-term and primarily uo expensive (i.e., ~aaive, high- practically achievable goala, these conditions technology) FPCa. This simplified view must be will be demonstrated in devices containing tempered with certain caveata. Fus~ou reactora total plaama kinetic energies that differ capable of a18nificant direct conversion attain significantly from the requiramenta projected higher overall energy conversion afficienciea for commercial power reactora. This difference and, therafore> Project smaller BOP coata; the is beat illustrated on Fig. 1 by plotting the TDC , however, will be smaller only if the coat confinement paratnete~againat the total kinetic of the direct e~~ergycor.vertorala sufficiently energy stored in the plaama, Given steady low, Aleo, ayatemo with high recirculating progreaa towarda achieving tmproved confinement power fractidntivill require larger BOPa and at reactor-like plaanm denuitiea and temper- aaaociated coats, even thouch the F?C maaa ature, the gap exl~ting batwaen cxperimenta utilization may be low. and FED-like devices, @a well a~ between FED- like devlceu and commercial reactoru, trana- A correlation of the ratio RIE/TDC with latea into a need for uignificcnt technology the Unit Direct Coete (UDC) for a range cf development. conceptual fuuion power plants (Table 1) ia givan in Fi8. 2; the dominance of the RPE cocta Key plaama, FPC, and power-plant for both mainline and major alternative iua”lon parameters emerging from recent raactor design concepte la indicated. The UDC and the ratio studieu arc aunnarized on Table I. Given RPE/TDC uee nominal values of - 900 $/kUe and continued atoadj progre~~, improved plauma 0.25, rebpet!tively,in Fig. 2 to normalize the confin~taent leuding to plaema if ltion app~ara fuaiol~pro,jection8to LWRE, The TDC for fv,aion m u re~{sonahlyattainable goml, ExtenHion to reletive tu fiat4ion can then be determined tt]t!~ddltlonal 10(]-1000fold lncreuue in stored under the aoeumption that ttte BOP coste for plabtna energy require:! for the commercial likp fuoion and f’irnsjonpower planttl are raactoru aummarizod in Tablu I and listed on nominally equivalent; thio curve of itDC = Fig, 1, however, will requiro mbjor technological devclopmef~tand attandant coaitu, ;~)!Y3*li;~;Z~F;{Z;0?lte ‘;ua;;’”a~;;y ~; Significant reduction in FPC matin Utilization, axpend more on capitnl invaatment hacauue of a storud and magnatlc-field energie#, anJ nagliglble fuel co~tl thirncradaoff of fuel for Proj@ctud IInit coetN utw pon~ible for tl,e capital coat becomeo marginal for R c valuea in compuct llyut~m~, Thenu ~maller, more compact mxceus of -- t.3 if the fuel coo,t For fi.aion appruwhfa~ may lead co u leae-costly commercial nominully compriten 1/4-1/3 of tha energy coIit, Gtnorally, oparation in the low-economlc- 102’ STARFIRE b) CTOR 4 ,Cl ‘- ~RFPR ‘“+-” dw E8TR C66102+ RIQQATRON’FED bC~FPR I O TFTR

1 D#

● DATF-: 1 PLT W -3ZUA

FR)(.c ‘m -H-E 1

~(OJ3 MA) /’ 1 EB;-S ●@ n ,“ CTXm rPf= ./’ TMXn ‘“M- dZT-40M(0.2 MA) NBT 1016L 1 1 I 1 1 1 1 1 10° 10’ 102 ,03 ,04 105 toe 107 ,~e ,09 ,010

PLASMA ENERGY (J]

FIG. 1. Achieved, projected, and reactor valuee of the confinement parameter, nln, plotted versus total kinetic energy stored in ~he plasma, ED. Soiid points correspond to experimental achievements, and open points are projections. Sources of Information: Alcator-C (Ref. 31); Doublet-III (Ref. 32); PLT tRef~ 33); Heli~tron-E (Ref. 34); Wendlstein-ViIA (Ref. 35); ZT-40H (Ref. 36); ET.’.-BETAII (Ref. 3’); TPE-IFu4(Ref. 38); ELT-5 (Ref. 39); NBT (Ref. 40); FM-C (Ref. 41); CTX (Ref. 42); T?lX (Ref. 43).

leverage regjrne, where RPE/TDC : 0.3, will compcnaated (e.g., mesa of drained bla!,ket). require the FPC to be R leaa dominant component The maaa ot an entire fieeion power plant, of the TDC, For reasonable unit costs (S/kR)-- exclusive of concrete but includinx all of fabricated, high-technology component~$ this reinforcing bar, ia 10-15 tonne/MWt, whic~ for criterion can be met unly by decreaaed FPC maab some fuai.on reactors is approached by the FPC utilization (tonne/!lWt) or increased [,yatem maaff utilization alone. The FPC ma~s power density; more compact syareme wL1l be utilizatlona predicted fur a r~nge of required. commercial fusion reactor deaigna la shown Lr Fig. 3; an average FPC unit cent of - 30 $/kg The FPC mae~ utilization for moat fu~ion la indicated. Importantly, the total cost of plunts iu projcctad to lie in the range 5-10 aystema with RPE/TDC ~ 1/3 (Fig. 2) will be tonne/MWt, compared to 0.3 tonneNWt for LWRS. less .senaitivc to physics and technology The mn@u utilization for the LWR la computed ks uncertalntiee aqaociated With the aenumed the maea of the primary containment vessel plasma performalico and FPC operatior; both (lo.ti~the fuel) divided by the tc~al thermal significantly affect plant pe:fomnance and power, The mauu utilization mutat be used cost, which in turn can lead to appreciable car[lfully au a comparative m~nsure of fiyatem costing uncertainty and eignificr.nt under- pertorrnance;cleurly, such compariuomu imply u eetimuteaoQg monoLunic relationship bet.wccnm~f.sNnd cu~t, Syotera~with a HG comprised of iarl~ ma~~cu of The ’dlructcapital cost repreeentu only illeXpalNliV~!cool[lnt (i.e., PbLi) should Ullfl Ollc component used in eetimatillRthe cost of muu Utiii:utioliu that aru appropriately electricity (ucE), Figurt! 4 gruphictilly TAMS I SUU2AlY Of UY P6AAJSITS2S YW A ~ 09 0“ 7VS1OM sL6170R COUCS7TS

mnvmrxONM wcmss COWAC7 B.UCYOSS—— ~“...... g~+> -.1 a hvice ST6MUZ3 SYP1’t ~t. CEYPR. ) oli7E1’ RICCATSW i$

7m*1g. data: :91J2(lYw_0) 1960 1980 1979 19.92 1960 1981 1981 I982

?ku rsdl.s (=) 0.81(2.1s) 2.18 1.0 1.2 0.42 0.71 C.66 0.12 Major radius (m) 23.0(27.9)7.0 35.U 12.7 150.(~) — 1.8 6.32 0.s0 ?1- *OIU9(m]) 298(27Sa) 781 691 361 .s1. 38. 54. 1. ,,4(. ) AV.r.~*d8Mic Y (1020/93) 1.64(1.38)0.8! 0.95 2.m 1.0 ,.O(f) 2-30 Taw. rat. ra (kaV) 8.0(8.0) 22 29 15 15 .. 20(. ) ,S-z](t) 12-20 Plaw ●mrsy (U) 0.4(1.5) 0.67 0.9i 0.81 >.64 — 0.12 O.lb 0.01 ?I.ld ●.nr$y (CJ) 109(230) 61. 111. l&.7 — ,.$(t) ~(g) 0.6 km.a primt.r (1020+3) 1.43(3.74)3.0 1.7 2.0 6.6 1.6 1.$ 2.0 A?*rasa 69c* 0.08(0.04)0.067 0.17 0.10 0.40 — 0.20 o.&l e.20 PIUM P-or dcuity (@;/m]) 12.4(1.7) 4.$ 6.1 7.0 42. > 90 72.4 51.0 X30 . Pmk MSMCIC fl*ld (T) 11.6(11.2)Il. 10. 3.0 2>.o(b) — ~+o(h) 13.7(~) 16.0(1) Nmcrc.n currant (W/92) 2.0(.,C) 1.6 1.4 2,7 >.0 i9.5 14,0 68.4 Th@rml ?wcr (NW) aao(>loo) 4013 4028 2ooa 4536 24042. 32m. 1)2$. )(6Lpear (w) 1102(1660)120Q 1214 7$0 I>!abl(c) IOoo 1000. b75 155 Srscm p.mer dtrnity(K. tlm3) 0.60(0.10)0.10 0.24 0.50 19.8(7.$,(~) 12.0 2.7 5.2 16uc utlllastlm (Colzwmvt) 6.3(8.6) 5.? ;0.85 1.1 $.7(a) 0.13 0.36 -1.0 0.28 fhtruleOnv*r#iO~●fflcl*cIcY0.1$(0.15)o.l\ 0.3> 0.10 0.40 0.11 0.1> 0.3> 0.61

l.circuhtlos pw. r fracclc.o 0.07(0.07)0.167 0.1s 0.i7 0.26 0.17 0.40 0.33 Met plane dficl*Ocy 0.11(0.31)0.10 0.10 O.i> 0.43 — 0.10 0.21 0.2) lznlcdiractCOB1(Slklh) 12b\(:4d2) 1438 1737 1104 -160> 900 815 -. C4natructloa C* (yaara) 10(10) 6 > 10 8-1o 5 — “Thm-cur.’9mt” data 1990(199C) 1966 198) 196s 1981 1981 COt (ml I;c/kU.h) 10(78) 67 72 66 40 42. > —

‘C)laamd on 28CQ W a’ Mucroa power, wblch 19 mltlpllad in th. bla?acc bl 1.)7 and 10 aloha-vart[cla DW*K of 700 MU4 (1>00 W fusion Dwar), nhlch 19 dir-cc ..nwart*d wllh ●n *111.1. KY at 0.s. (4) :ncludlq *t. rd ~crurac.ar volum. (*l,~at Cw., pCur. profile, JO1(az) d@M:t Y Profll*.

(f)prO( ii.. ,LVan ~ ;l.(rtrp)2)a, mar. m - 2 for i(.) on 0.2$for n(r).

‘#)+..k ,IMrsy la OH CO1l kfOU PIUU mt~rcup. reducad 10 - I G2 ;CRFPR) and - 5 U (OUTR) Lh. r.. tl. r, (h),t~ (’old On oU CO, I br, q ,cartup, ,educed by a f*c COr 0( 2-1tharmftar. II)r,ti ~i,:d ,C tr CO II, fi.lda .C OH coil WI1l approach Jo t. summarizes all major cost components and to fusion, primr.ly because of the lower RPE indicates the combination of these components cost. The annual euer~y ouLput (kWeh/yr) for to determine the C~E. Issues that impact on compact and other fusior. reactors of equal the COE are alao 61110wn. The annual fixed capacity mey not be equal because the charges for conventional and compact fusion recirculatin~ power fractions and the capacity reactors will be approximately proportional to factora mMy be different. the TDC because the indirect capital Coet is nominally the same pert.antageof the TDC for Compact fusion reactors clearly must be both compact and conventional fueion reactora. higher performance devices relative to other Furthermore, tltefixed charge rate will be the fuuion approached becauae of higher power sane ~lnless,for example, the cotnptsctresctors den~itiee, thermal lcade, fl~xes, and require leaa time to construct and are mofe in some case, higher magnetic fields at the amenable to maas production methods. Fuel coil. These more “atreeaed” opzrating expeneea will be equal for the same fusion conditions, however, are eimilar to operating power, and ope”:at.ionand maintenance (O&M) condir.ionti encountered in fissitm systems, coat8 are expected to be approximately equal albeit in a more favorable coolant geometry, for the same plant electrical capacity. The Furthermore, operating in the compact-reactor 06M coata will vary if the coats of replacing regime should not necessarily reduce the plunt the FPC differ, Both conventlGnal and compact capacity factor if equal engineering design re~ctors, however, require replacement of crit~rla are used; a higher unit coat for thQ approximately equal maaees of materia?.per unit compact uppruachee, however, may reeult. time (-200-400 tonne/yr) for the aamc FW/B lifetime (MWyr/m2). The annuni generating coet for u compact ftlfsionreactor, therefore, is expatted to be lower than for ~ther appronchc~ I 8000 1000❑ wo i 3000[ (1-am/ TocILw-Q-- t ‘lie? z I , In De= (,-=,*)

u I w c c& 800*IOO(U IO,J 7‘ (-s0.0S/*cl I 4 I I I

Rl!ACTOnFLANT I!OUIPUCMT(RPE~ TOTALOlnCCTCOSr (TDC) FIG. 3. Correlation of the UDC projected for a number of fusion reactor dea.gns on the FPC maaa utilization. The small variation FIG. 2. Plot of UDC versus RPE/TDC for a range resulting from differences in total power out- of fusion reactor deaigne. N@noalizing theee ?Ut have been reduced by normalizing all costs to the LWR (UDC = 900 .$/kWe, FPE/TDC Y designs to 1000-HWe(net) plant capacit:?. 0.25), the curve of RDC - ‘uDc)FUSI014[ (UDC)FISSION ia also shown as a function RPE/TDC under the assumption of nearly equal can be estimated. The system power density, BOP cost for comparable fusion and fission expreaaed in terms of the neutron first-wall powet plants. loading, ~(MW/m2), blanket energy multipli- cacion, ?%:, first-wall radiua, rw, blanketfshield thickneea, Ab, and nominal coil tnickneaa, 6, is given by Because of the significantly ruduced t?ae8 utilization, the compact eystems can allow Pm 21%(MN + l/4)rw “block” maintenance of the FPC, with the (i) ~ - ‘-—— “ attendaat potential for relatively rapid FPC (rw+ Ab + 6)2 change out, replacement, and restart. Nevertheless, a potential exists for a lover Baaed 9vlely on Euclidian argumenta for a plant factor, perhapa dLmininhing the promise toroid that- can be cpprox~mated by a of reduced COE related to reduced TDC and cylindrical geometry, the maximum system power con.9truction tlme (Fig. 4), Finally, the density occurs for rw ~ Ab + 6 and equals compact fu8ion opt?.one may offer cost and for the overall deve!.opment schedule advantage~ ,pm Iw(Mh,+ 1/4) of u usable product for fusion, these ad- * (2) (~) 2(Ab Y 6) “ vantages Q1OO being related to the les~cr role c MAX,Iw,ttN pl~yed by the FPC and associated Bupport eyateme in devLce8 leoding to the reactor; a In arriving at this expression, IQ, Ab, and 6 bolder reuoarch and development progra”~ may are held conotant, ignoring the rclati~ely week ensue. interdependence between Ab, Iw, rw, MN, and the desire to achieve a given radiation/henting xv, PATHWAY level at the coil pouitlon. Within these limit&tion8, Bq. (2) indicates three approached By focueinu on the eytitempower density, to inct’uused8yste,cpower density and decreased P~{/Vc, Vhule PT,l is ‘.hctotal UBef’Ui ther.uul FPC matlljUtllizutton. power and Vc is tl)cFPC volume, the generui characturiutica for a compsct fuajou :cuctor —- “~: %R=RLwY--- -—-—- —-- 11 ● BLOCK WPATCHMAINTENANCEO —- —-—--—. — ● AVAILA84LITVAND FIELIABILllYO— - —- — - _ - — - —O RECIRCULATINGFOWER ● — - -—- . uA (b -—. *AJ3mwALIf140 ● —-—- —- ● C41WTRUCTIW TIME● — - — - I ● FPC~LfJUTV/~ 11

1 1 * *AL am-ma AWUAL mm (xi I,hd . PR6EENTVALUE Lsveuao I m 1 ma AM LtVfLIZINO m FAcToa4 & ●

FIG. 4. Logic diagrzm illustrating the means b~”, which the levelized generatir,gcost of electricity (Coz) is computed. Also nhown at the top are key influences that may impact the COE when considerations of compactness are taken into account ,

Using Eq, (2) and rcqulring (P~/Vc)W ~ ● Increase blanket energy multiplication, (Pm/vc);x , the latter being a reference or

‘N’real increase: ——in situ fieeion d~eign value, - vfrt.ual increase: .—in situ fissile-fuel breeding Pm ~ (Pm/vc)& , (3) 2(2w)2(Ab + 6)2% ● Incrza*e fueion neutron fir8t-wall currant: Iw(MW/m2) = 0.57rD62BQ. where rv & Ab + 6 and a couetraint on total pow*r is implied. For inetance, if Pm < 4000 ● Decrease minor eysteinradiue, ra * rw + Ab Mwt , requiring that the major radlua ~ ~ rw + + 6, which is achieved through u reduced Ab + 6 ●U 2(3b + 6), and specifying that blankut/ut~ieldthickneafl. (PT#vc)w ~ 10 MW/m3 together lend to the fallowing constraint Pm (Ah+ 6)3 ~——— = 2.54 m3 ,(6) (Pm/vc)*~(4n)2 or that Ab + 6 ~ 1.36 m. Clearly, only thin parameters for the CRFPR, OHTE, ~.ldRiggatron -breeding blankets (Ab ~ 0.6 in)arid reactors are also given in Table I. resistive magnets (6 < 1.56 - Ab = 0.8 m) can meet these constraints. A. Compact RFP Recctor (CRFPR)13 The CRFPR ia a toroidal axisymmetric “The compact reactor option with device in which the primary confinement field P~/Vc ~ 10 MWt/mJ, therefore, Is available to is poloidal being generated by a toroidal MFE approaches that: a) can operate with long- current flowing in the plaem. Although large pulsed or steady-state resistive coils while within the plasma, the toroidal field passes consuming only a small portion ($ 5-10%) of the through zero at the plaam edge, reversin~ fu8ion power, and b) can o~erate with eteady- direction to a very low value at the magr state first-wall neutron currents given by coils. The resulting large magnetic shear allows high-B operat lon and ia maintained hy Pm intrinsic plasma proces8ea that corlvert lw(HW/m2) = (~]W ~(Ab + 6) poloidal to torofdal flux, thereby maintaining ~ + 1/4 c the reversal, All coils are positioned ext. really to the blanket, enha:,cing the 2Pm !/3 [(pm/vc)*w]2’? . 15 *O ~,m2 ability to breed tritium, providing radiation ~ , (5) protection of the exe-blanket coil, and (MN + l/4)(4rr)2/3 decreasing the recirculating power fraction. The h~gh power density is atLained with where , again, (Pm/vc!~ ‘ 10 !4Ut/m3,PWA = moderate betas (0.1-0.2) without requiring high 4000 MWt, and nN - i.1 have been used. Hence , fields at the coils, which alao substantially fusion neutron first-wall logdings that are reduces the recirculating power fraction. 5-10 greater than thase being projected for Significantly smaller plant-capacity systems other systems will be required. Furthermore, than the 1000-MWe reported in Table I are also recalling that Iw Y 0.57L32Bkrpand assuming poas:ble for the CRFPR, although at a higher ‘P a! rw~ the compact reactors must be based on unit cost. Central to the achievement of high plasmas that are capable of f3B2~ 5.1 T2, where system power density is the red,lction in B is evaluated at the plasma surface and blanket/shield thickness accompanying the use typically is less by a factor of - 2 than the of normal c~pper cofla. ~or efficient heat magnetic field at the coil. Generally, recovery and for adequate trlti,.abreeding, improvements in beta ant!/or coil technologies minimum blanket thicknesses of - 0.6 m will be will be required for aany of ut,eapproaches required. Althwgh designed for long-pulsed listed on Table I in order to significantly operation, the potential exists ior a unique enhance the uystem yower iensity, decrease the and efficient steady-state current driveso for mass utilization, and lower the TDC and COE. the RFP. Simultaneously, these conditions must be achieved in copper-coil systec8 tltat do not. B. Ohmically Heated Toroidal Experiment require a large fraction of the fusion power to 10HTE) ReactoriW recirculated for makeup of Ohmic losses, there- ?loreconservative assumptions with respect by aesuring the cost advantages of less massive to the external control plasma energy losses FPC8 are not seriously eroded by abnormally thfit accompany the maintenance of toroidal- large BOP costs. iield reversal near the RFP plasma edge leads to the OHTE. The field reversal and associated v, OPTIONS magnetic ehear at the plasma edge is controlled by actively-driven helical coils positioned The uurvey of compact fusion concepts near the plasma edge. The high-power-density 8iVen by Cross in the Ref. 30 workshop operatton is attained at moderate to high beta, encompasses toroidal devices supporting large but with higher coil fields than for the RFP plasma current density (RFPs, OHTES, high-field without \elical windings. To ensure proper ), a variety of field-reversed config- field structure these helical coils force uration and epheromak~, and other very dense larger aspect ratio plaamas, increasing the and highly puleed :onflguratione (i.e., dense stored magnetic energy. In addition, this Z-pinch, imploding liner~, wall-confined winding produces magnetic flux in opposition to eysteme), Onl;’ the first grouping (RFPs, the ohmic heating (OH) winding requiring OHTES, high-field tokamake) is considered here, increased current swings of --25% in the OH these devices sharing common featureu of Ohmic act. Since the resistive copper coils are heating to ignition in a resist!ve copper-coil oper.nted near room temperature and are Gy#tem, while focu~ing specifically on the need positioned near the first wall, the overall for high system power densities, Typical system performance may be ruduced in terms of increased recirculating power, reduced plant (Plasma Engineering Systems, Nuclear Systems, thermal efficiency, and increased stored and Magnet Systems); some indications on Remote energy. Maintenance and Safety systems are also given.30 c. Riggatron High-Field Tokamak15 The R.iggatronis based on a high-field, compact reactora would operate at higher Ohmically-heated that uses a high plasma densities and, therefore, refueling, toroidal current density and high toroidal- impurity control, and ash removal requirements field copper coils positioned near the first differ. The higher plaama density may also wall. Set ( -rg~ production is possible in a lead LC more difficult rf current-drive relatively short burn period from a requirements for steady-state operation. The moderate-beta, Ohmically-heated plasma. The potential for low-frequency (few kHz) “F-e severe thermal-mechanical and radiatjon pumplng”s” available to the RI? and OHP., environment in which the relatively inexpemaive however, represents an attractive means to plasma chamber and coil aet must operate drive steady-state plasma currents. The first- dictates an approximately one-month life. The wal? power loads for compact reactors are overall system performance in terms of plant higher than for other fusion systems, which thermal efficiency and the ability to breed also leads to higher blanket power densities. tritium is reduced, since the coils are Although the FW/B for the compact systems wouid positioned near the first wall. Unlike the operate under nore highly stressed condition, compact RFP and OHTE reactors, the fusion these conditlxis are considered standard for ?eutron power is recovered in a fixed fiaslon energy sources. The magnetic field blanket located outside of the plasma chataber requirements for the RFPs can be lower thar.for and magnet sys..em. Recovery of Ohmic and most fusion reactor systems, but the fields are neutron heatil,gin the copper co

● The FPC IS comparable in maaa or volume co 1. C. A. FLANAGAN, D. STEINER, ;nd G. E. comparable heat sources of alcemative SMIITf, “Fusion Engineering Device Design fission energy sources. Description,” 0R14L./T?l-7948, Oak Yidge - system power density: 10-15 NUt/m3 Naticnal Laboratory (December 1981). - -ss utilization: 0.4-0.5 tenne/MWt 2. “INTOR, International Tokamak Reactor, Q UDC ($/kUe) and COE (uilla/kWeh) are less Phase I,” IAEA report sTI/PuB/619, Vienna, sensitive to large changea in FPC u.lit (1982). costs (S/kg) Jnd related physics and tech- nology. 3. c. c. BAKER (Principal Investigator), et al., “STARFIRE - A Commercial Tokati= ● Rapid development at reasonable coat may k%ion Power Plant Study,” ANL/FPP-80-1, be possible. Argonne National Laboratory (September - SM1l Bystem size, flexible ialterable) 1980). development path, possible to ex- periment with technology paths while 4. C. A. CARLSON, et ~., “Tandcm Hirror avoiding large cost and time penalties. Reactor with Then&i Barriers,” ucRL- - no need for long-lead development items 52836, Lawrence Livermore Na~ional Labora- that are sufficiently uncertain in tory (September 1979). themselves aa to impact the overall B. aDproach (i.e., large superconducting 5. BADGER, .—et al., “WITAPHR - I: A Uni- magnets, high-frequency/large-power rf, veraity of Wisconsin Tandem Mirror Reactor large-power/ steady-state neuttal-beam Design,” UWFD14-400, Untveraity of injectors, remote maintenance of Wisconsin (September 19aO). massive scructurea). 6. r.. HENNING and B. “Xirror ● “Block” installation and maintenance Adv~nced Reactor Study ?&R;~~’Lawrence becomes a possibility. Livarmore National ‘Laboratory, (1982). - off-site mass prodtiction of complete FPC. 7. B. M.DGER, ~ &., “TASKA: A Tandem - shortened construction times. MirrOi Fusion Engineering Facility,” -coaplete pre-installation thermo- UWFDM-500, University of Wisconsin (March mechnical/electromechanical/vacuum test 1982;. of FPC. - ehoriened echeduledlunecheduled down- 8. T. K. FOWLF.Rand B. G. LOGAN, “Tandem time and higher plant availability. Mirror ‘fechnoloRy Demonstration Facility,” UCID-19193, Lawrence Llvemore Naticnal Generally, the compact options require Laboratory (September 1981). extended rather than new technologies and project competitive COEa by demanding higher 9. c. C. BAKER, C. A. CARLSON, and R. A. FPC performance while attempting to ❑aintain KRAKOWSKI, “Trends and Developments in high plant factors and low recirculating power. N8gnetic Confinement Fusion Reactor Extension of existing technologies are required Concepts,” Nucl. TechnolopylFu~ionL ~, to accormnodate the higher heat fluxes and power 5-78 (January 1981). den61ties needed to operate the FPC with enhanced eystem power density and maej 1!3. Report on the Third IAEA Technical Com- utilization. The major technological chal- mittee Meeting and Workshop on Fu6ion lenge, therefore, rests with achievifig reliable Reactor Design-III, T&Yo, Japan, October rea~tor operation of a more highly “stressed” 5-16, 1981, Nicl. FUS, 22,-671:71’i(1982). FPC. [n return, a power system emerges in which baalc phy~ics and technological unknowne related t? r},e FPC exert considerably reduced 11. R. A. ~OWSKI , “Identification of Fu- 22. R. L. MILLER and R. A. KRAKOWSKI, “ ture Engineering Development Needs of Assessment of the Slowly-Imploding Liner Alternative Concepts for Magnetic Fusion (LINUS) Fusion Reactor Concept,” Proc. Energy,” National Academy of Science 4th Top. Mtg. Technol. of Controlled Workshops on the Future Engineering , CONF-8O1O11 II_,825, King Development Needs of Magnetic Fusion, of Prussia, PA (October 14-16, 1980). Washingtr,nDC (August 3-4, 1982). 23. R. E. OLSON, J. G. GILLIGAN, E. 12. R. L. EAGENSON and R. A. KRAKOWSKI, GREENSPAN, and G. H. MILEY, “The “Compact Rever&ed-Field Pinch ReactorJ Approach to High Power Density (CRFPR): Sensitivity Study and Design- Reactors,” Proc. 9th Symp. an Eng. Point Deuermlnation,” LA-9389-MS, Los Prob. Fusion Research~, 1898, Chicago, Alamos Natioaal Laboratory (July 1982). IL (October 26-29, 1981).

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-.