study of a con cep tual ac cel erator driven sys …2 departm ent of energy, sys t ems en gi neer...

STUDY OF A CON CEP TUAL AC CEL ER A TOR DRIVENSYS TEM LOADED WITH THO RIUM DI OX IDE MIXED WITH

TRANS URANIC DI OX IDES IN TRISO PAR TI CLES

by

Gizem BAKIR 1, Gamze GENC 2, and Huseyin YAPICI 2*

1 De part ment of Man u fac tur ing En gi neer ing, Tech nol ogy Fac ulty, Cumhuriyet University, Sivas, Tur key2 Department of Energy, Sys tems En gi neer ing, En gi neer ing Faculty, Erciyes Uni ver sity, Kayseri, Tur key

Sci en tific pa perDOI: 10.2298/NTRP1603197B

Nu clear spent fuel man age ment is one of the top ma jor sub jects in the uti li za tion of nu clearen ergy. Hence, so lu tions to this prob lem have been in creas ingly re searched in re cent years.The ba sic aim of this work is to ex am ine the fis sile breed ing and trans uranic fuel trans mu ta -tion po ten tials of a gas cooled ac cel er a tor-driven sys tem. In line with this pur pose, firstly, thecon cep tu ally de signed sys tem is op ti mized by us ing sev eral tar get ma te ri als and fuel mix tures, from the point of neutronic. Sec ondly, three dif fer ent ma te rial com po si tions, namely, purelead bis muth eutectic (LBE), LBE+nat u ral UO2, and LBE+15 % en rich ment UO2, are con -sid ered as tar get ma te rial. The tar get zone is sep a rated to two sub-zones but as one within theother. The outer sub-zone is pure LBE tar get, and the in ner sub-zone is ei ther UO2 or pureLBE tar get.The UO2 tar get sub-zone is cooled with he lium gas. Fi nally, the tho rium di ox idemixed with trans uranic di ox ides, dis charged from PWR-MOX spent fuel, in peb bles com -posed of graph ite and TRISO-coated spher i cal fuel par ti cles, is used for breed ing fis sile fueland trans mut ing trans uranic fu els. Three dif fer ent tho rium-trans uranic mix tures, (Th,Pu)O2, (Th, Cm)O2, (Th, Pu, MA)O2, are ex am ined with var i ous mix ture frac tions. Thepack ing frac tions of the fuel peb bles in the trans mu ta tion core and the tristructural-iso tro piccoated fuel par ti cles in a peb ble are as sumed as 60 % and 29 %, re spec tively. The trans mu ta -tion core is also cooled with a high-tem per a ture he lium cool ant. In or der to pro ducehigh-flux neu trons that pen e trate through the trans mu ta tion core, the tar get is ex posed to the con tin u ous beams of 1 GeV pro tons. The com pu ta tions have been car ried out with thehigh-en ergy Monte Carlo code MCNPX us ing the LA150 li brary. The nu mer i cal out comesshow that the ex am ined ac cel er a tor-driven sys tem has rather high neutronic data in terms ofthe en ergy pro duc tion and fis sile fuel breed ing.

Key words: ac cel er a tor-driven sys tem, spent fuel trans mu ta tion, spallation neu tron tar get,tho rium breeder, TRISO fuel

INTRODUCTION

In com mer cial nu clear re ac tors, highly ra dio ac -tive ma te ri als oc cur as high-level wastes. They mainlyin clude trans uranic iso topes (Np, Pu, Am, and Cm)and long lived fis sion prod ucts. In most coun tries, it ispre ferred that they are bur ied un der ground in con cretecon tain ers in the sea bed. In ad di tion to this, an im -proved ap proach is to trans mute these wastes in fu -sion-fis sion hy brid re ac tors or ac cel er a tor driven sys -tems (ADS) by driv ing high-en er getic neu tron and/orpro ton source. Law rence [1] first as serted to trans mute tho rium to 233U with fast neu trons re leased from aspallation tar get bom barded with high-en er getic pro -tons. In our pre vi ous stud ies (Yapici [2-4], Yapici et al. [5-7]), the po ten tials of nu clear fuel trans mu ta tion and

fis sile fuel breed ing have been in ves ti gated in var i ousfu sion-fis sion hy brid re ac tors fu eled with var i ousspent fu els dis charged from con ven tional nu clear re -ac tors.

The sim plest pro ce dure in an ADS is the trans -mu ta tion of nu clear fu els us ing high en er getic pro tonsource. An ADS in cludes el e men ta rily three parts: (1)high en er getic pro ton ac cel er a tor, (2) spallation neu -tron tar get (SNT), and (3) sub-crit i cal core con tain ingnu clear fuel or wastes. The tar get is bom barded withhigh en er getic pro ton par ti cles to pro duce sev eral tensof high en er getic neu trons, im me di ately af ter, theseneu trons pen e trate to the sub-crit i cal core. In the nu -clear waste trans mu ta tions, two re ac tions in the coreare mainly con sid ered: (1) neu tron cap ture and (2) fis -sion. In both re ac tions, the nu clear waste or fuel istrans muted or burned.

G. Bakir, et al.: Study of a Con cep tual Ac cel er a tor Driven Sys tem Loaded with ...Nu clear Tech nol ogy & Ra di a tion Pro tec tion: Year 2016, Vol. 31, No. 3, pp. 197-206 197

* Cor re spond ing au thor; e-mail: [email protected]

Dur ing the re cent years, a lot of re search workson trans mu ta tion of nu clear waste in the ADS havebeen car ried out. Some of them are pre sented in here.Abanades and Perez-Navarro [8] have pre sented thetrans mu ta tion of nu clear waste in an ADS cooled withgas and mod er ated with graph ite. Nu clear wastes areused in the case of TRISO peb ble bed. This workshows that plu to nium ex cept for 242Pu can be trans -muted in ra tio of 95 %. Takizuka et al. [9] andTsujimoto et al. [10] have an a lyzed the trans mu ta tionof mi nor actinides (MA) in a lead-bis muth cooledADS. Study of Takizuka et al. de notes that the wastetrans mu ta tion of 250 kg per year is achieved by 80 %plant fac tor, and a study of Tsujimoto et al. shows thatthe MA are ef fec tively trans muted and burned in theirADS de sign in the case of the ef fec tive neu tron mul ti -pli ca tion co ef fi cient, keff = 0.97. Fur ther more, the real num ber of peb bles fit ting in a cy lin dri cal ADS corehas been an a lyzed in de tail by Gar cia et al. [11].Malyshkin et al. [12] have stud ied only spallation tar -gets con tain ing ura nium and am er i cium by mod el lingde signs of spallation tar gets with Monte Carlo. Sev -eral ge om e tries and ma te rial com po si tions have beenex am ined for the spallation tar gets. All ex am ined de -signs op er ate in the case of keff = 0.5. Nu mer i cal re -sults of this pa per show that over 4 kg of Am can beburned dur ing the first year of op er a tion. Yapici et al.[13] have in ves ti gated the neutronic data of var i ous in -fi nite tar get me dium (Lead-bis muth eutectic, mer cury, tung sten, ura nium, tho rium, chro mium, cop per andbe ryl lium) bom barded with a pro ton source of 1000MeV. It is ex hib ited that the in fi nite me dium ap proachwould lead for real ADS de signs.The po ten tials of nu -clear waste trans mu ta tion of an ADS cooled withlead-bis muth eutectic (LBE) have been in ves ti gated in other stud ies of Yapici et al. [14, 15] for the dif fer entcon fig u ra tions and fuel com po si tions. The re sults ofthese stud ies bring out that the con sid ered ADS has high neutronic data for both nu clear waste trans mu ta -tion and fis sile breed ing, be sides en ergy pro duc ing. Mar ti nez et al. [16] have stud ied on neutronic char ac -ter is tics of nu clear waste trans mu ta tion of ac cel er a -tor-driven sys tems. They as sert in this study that highen er getic neu trons are re quired for trans mu ta tion oftransuraniums (TRU) and long-lived fis sion prod ucts.Ismailov et al. [17] have ex am ined a ura niumspallation tar get in ac cel er a tor-driven sys tem loadedwith MA. They have com pared lead-bis muth (PbBi)tar get with ura nium tar get. They have found that theura nium tar get lim ited geo met ri cal size has a betterneu tron mul ti pli ca tion. Fur ther more, var i ous types ofADS have been worked for en ergy pro duc tion andtrans mu ta tion of ra dio ac tive wastes [18-28].

COMPUTATIONAL MODEL OFACCELERATOR DRIVEN SYSTEM

In this work, a con cep tual semi-spher i cal ac cel -er a tor-driven sub-crit i cal sys tem is con sid ered for

trans mu ta tion of tho rium-di ox ide (ThO2) along withtrans uranic di ox ides (TRUO2) ex tracted from spentfu els. PWR-MOX fuel (Man son, et al. [29], fuel withplu to nium re cy cle, 1000 MWe re ac tor, 80 % ca pac ityfac tor, 33 MWd/kg, 32.5 % ther mal ef fi ciency, 150days af ter dis charge) is con sid ered as the spent fuel.The den si ties and frac tions of the con sid ered fu els areex hib ited in tab. 1.

The mixed nu clear fu els, (mix tures of ThO2 andTRUO2s) are con fig ured as tristructural-iso tro pic(TRISO)-coated mi cro spher i cal fuel par ti cles em bed -ded in car bon ma trix peb bles. The MCNP model of the con sid ered ADS is il lus trated in fig. 1. As seen in thisfig ure, there are four dif fer ent zones in the con sid eredADS:– spallation neu tron tar get, (SNT),– trans mu ta tion zone, (TZ), – re flec tor zone, (RZ), and – shield zone, (SZ).

Spallation neu tron tar get: mainly, 44.5 % lead(Pb)-55.5 % bis muth (Bi) eutectic (LBE) is used as atar get ma te rial, which has good neutronic, chem i caland ther mal prop er ties. There fore, it is the most cho -sen tar get ma te rial for ADS im ple men ta tions. Asshown in fig. 1, the tar get zone is sep a rated to twosub-zone space done within the other: (1) the outersub-zone is pure LBE tar get part, and (2) the in nersub-zone is ei ther UO2 cooled with the he lium gas or

G. Bakir, et al.: Study of a Con cep tual Ac cel er a tor Driven Sys tem Loaded with ...198 Nu clear Tech nol ogy & Ra di a tion Pro tec tion: Year 2016, Vol. 31, No. 3, pp. 197-206

Table 1. Isotopic fractions and densities of the materialsused in the investigated ADS

Material Density [gcm–3] Nuclide Fraction [%]

LBE11.344 Pb 44.5

9.8 Bi 55.5

He 0.1786 He 100

ThO2 9.88 232Th 100

UO2 10.54235U 0.7-15238U 99.3-85

*NpO2 11.10 237Np 100

*PuO2 11.50

238Pu 3.53535239Pu 45.0154240Pu 26.3505241Pu 15.9640242Pu 9.13483

*AmO2 11.88241Am 21.5213243Am 78.1942

*CmO2 10.55

242Cm 3.91520243Cm 0.04721244Cm 85.5422245Cm 9.54125246Cm 0.95413

Graphite 2.10 12C 100

B4C 2.5210B 18.43111B 81.569

*Dis charged PWR-MOX fuel with plu to nium re cy cle, 1000 MWe

.re ac tor, 80 % ca pac ity fac tor, 33 MWd/kg, 2.5 % ther mal

.ef fi ciency, 150 days af ter dis charge (ref. Man son et al., [29],

.p. 370, Ta ble 8.5)

pure LBE tar get part. Ac cord ingly, three dif fer ent in -ner spallation tar get cases are con sid ered as fol lows:

Case 1: The in ner spallation tar get part con sists ofTRISO-coated nat u ral UO2 par ti cles and is cooled withthe he lium gas, (cool ant vol ume frac tion, VFc = 40 %).

Case 2: The in ner spallation tar get part con sistsof TRISO-coated 15% en rich ment UO2 par ti cles andis cooled with the he lium gas, (VFc = 40%).

Case 3: The in ner spallation tar get part also con -sists of the pure LBE.

The neu tron re ac tions oc cur in the spallation tar -get bom barded with high en er getic pro tons, and sev -eral tens of neu trons per pro ton are re leased in these re -ac tions, de pend ing on in ci dent pro ton en ergy. Thesepro duced neu trons dif fuse through the sub-crit i cal fuel zone to make more re ac tions.

Trans mu ta tion zone: This zone, also named asub-crit i cal core, con tains the mix ture of ThO2 and thetrans uranic di ox ides (TRUO2) to trans mute the nu -clear wastes and to breed fis sile fuel. TheTRISO-coated fuel mix ture par ti cles, hav ing a highburn-up abil ity and quite high neutronic per for manceat high tem per a tures, are used as nu clear fuel. Thesepar ti cles con sist of a fuel ker nel in the cen ter, coatedwith four lay ers made of three iso tro pic ma te ri als, (1)po rous car bon buffer, (2) in ner pyrolytic car bon(IPyC), (3) sil i con car bide (SiC), and (4) outerpyrolytic (OPyC) [30]. The TRISO fuel par ti cles areem bed ded in a car bon ma trix peb ble with a cer tainpack ing frac tion, and then the peb bles are placed in the TZ with a cer tain pack ing frac tion. The TRISO pack -ing frac tion (PFt) and the peb ble pack ing frac tion(PFp) are as sumed as 29 % and 60 %, which can go upto 32 % and 74 % [31] ac cord ing to pack ing ar range -ment, re spec tively. The spher i cal ge om e tries of aTRISO fuel par ti cle and car bon ma trix peb ble are il -lus trated in fig. 2. This zone is cooled with high-tem -per a ture cool ant he lium, (VFc = 40 %). And also, geo -met ric char ac ter is tics of the TRISO par ti cle [31] aregiven in tab. 2.

Re flec tor zone: The role of this zone re flects andre turns back the en er getic neu trons es cap ing from theTZ, in or der to en hance trans mu ta tion re ac tions. Forthis rea son, graph ite (car bon) is se lected as a re flec tive ma te rial. Scat ter cross-sec tion of graph ite is com par a -tively much greater than its ab sorp tion cross-sec tion.At the same time, the graph ite is a good neu tron mod -er a tor. There fore, graph ite, also hav ing a high-tem per -a ture-re sis tant prop erty, is largely used in nu clear re -ac tors as an ef fec tive mod er a tor and re flec tor.

Shield zone: This zone is made of bo ron car bide(B4C) to ab sorb the neu trons ul ti mately es cap ing fromthe RZ. B4C is most com monly pre ferred and used as anab sor bent for neu tron ra di a tion in nu clear power plantsdue to the fact that it has a very high ab sorp tion cross-sec -tion and ex cel lent thermo-me chan i cal prop er ties.

It is de ter mined by com par ing this semi-spher i -cal con fig u ra tion with our pre vi ous cy lin dri cal con fig -u ra tion in ref. Yapici et al. [14] that in the semi-spher i -cal con fig u ra tion, the value of keff can reach up 0.98with lower en rich met of ura nium (15 %).

The neutronic com pu ta tions have been car riedout with a high-en ergy Monte Carlo code MCNPX 2.7[32] by us ing the LA150 li brary [33] which con sists ofre ac tion cross-sec tions for the neu trons from0.0-150.0 MeV in tab u lar range for 42 iso topes [32].Bertini INC model [34] is used for the intra nu clearcas cade of spallation re ac tions.

For each tar get case (Cases 1-3), three dif fer entmix tures of ThO2 and TRUO2, (Th, Pu)O2, (Th, Cm)O2,(Th, Pu, MA)O2, have been in ves ti gated with var i ousmix ture frac tions (vary ing in the range of 5%-55%, de -pend ing on the fuel com po si tion).In the lit er a ture and ourpre vi ous stud ies [13,14], it is found out that the gain (G) ismax i mum in the Case of pro ton en ergy Ep = 1000 MeV.Hence, pro ton en ergy as sumed in this study is 1000 MeV.Be side, it is ap proved that a con tin u ous uni form pro tonbeam, 4 cm in ra dius, bom bards on the tar get ma te rial.


Fig ure 1. Cross-sec tion of the in ves ti gated ADS (SNT:spallation neu tron tar get, TZ: trans mu ta tion zone, RZ:re flec tor zone, SZ: shield zone)

Fig ure 2. Fuel peb ble sphere and TRISO coated fuelpar ti cle, (PyC: pyrocarbon, SiC: sil i con car bide)

Table 2. Characteristics of TRISO particles [30]

Layer Size [µm] Material Density [g/cm3]

Fuel kernel 250 (radius) UO2 10.55

PyC buffer 95 (thickness) C/C 1.05

Inner PyC 40 (thickness) C/C 1.90

SiC layer 35 (thickness) SiC 3.18

Outer PyC 40 (thickness) C/C 1.90

NUMERICAL RESULTS

Neutron multiplication

Neu tron mul ti pli ca tion can mainly be pro videdwith two re ac tions; one is spallation re ac tions in thetar get, and the other is the fis sion re ac tions of fis sileiso topes. In a nu clear sys tem,the num ber of the pro -duced neu trons is the al ge braic sum of gen er ated, cap -tured and leak ing neu trons. For a good neu tron econ -omy, num bers of cap tured and leak ing neu tronsshould be op ti mized. The nu mer i cal cal cu la tion brings out that the op ti mum neu tron pro duc tion would be en -sured with the tar get ra dius of 140 cm.

Fig ure 3 shows the vari a tions of the pro ducedneu tron num ber (PN) for all tar get and fuel com po si -tion Cases with TRUO2 frac tion in the fuel mix tures.

As ap par ent from this fig ure, in all tar get cases,more tho rium is uti lized in the fuel mix ture case of(Th, Cm)O2. This means that the fis sile 233U morebreeds, (see eq. 2a). The neu tron pro duc tions in thetar get case of pure LBE (Case 3) are about two timesthose in the other tar get cases, which means up to 930neu trons per pro ton. These re sults bring out that pureLBE tar get is more ef fec tive, from the point of neu tronecon omy.

Energy gain and effective neutronmultiplication coefficient

The ef fec tive neu tron mul ti pli ca tion co ef fi cient,keff is de fined as the ra tio of neu tron quan tity pro ducedin one gen er a tion to the neu tron quan tity in the pre ced -ing one. This co ef fi cient is less than 1 in the sub-crit i -cal ADS, (0.95-0.98).In this work, the fuel com po si -tions are ad justed that keff is pro vided in the range of0.80 to 0.98.

The en ergy gain, G, is de scribed as the ra tio be -tween the to tal fis sion en ergy pro duc tion the fuel coreand the en ergy of the pro ton beam.

GR E

E= f f

p

(1)

where Rf is the num ber of fis sion re ac tion and Ef – theen ergy per fis sion (200 MeV).

The vari a tions of G and keff are plot ted in fig. 4vs. the TRUO2 frac tion in the fuel mix tures for all tar -get and fuel com po si tion cases. The value of G canreach up 96 in the Case 3. It is quite a high value interms of en ergy mul ti pli ca tion. As in the PN vari a -tions, also, the G val ues in the Case 3 are two timesthose in the other tar get cases.

Fissile fuel breeding

In the ADS, not only en ergy pro duc tion but alsofis sile fuel breed ing is one of pri or ity is sues for the op -ti mi za tion of the ADS de sign. There fore, the con sid -ered ADS is op ti mized, from the points of both en ergypro duc tion and the fis sile fuel breed ing. The fis silebreed ing re ac tions taken into ac count in this study areas fol lows

232 233 233 233Th Th Pa U( , )n g b b¾ ®¾ ¾ ®¾ (2a)

238 239 239 239U U Np Pu( , )n g b b¾ ®¾ ¾ ®¾ (2b)

238 239Pu Pu( , )n g (2c)

240 241Pu Pu( , )n g (2d)

242 243Pu Pu( , )n g (2e)


Fig ure 3. Vari a tions of the neu tron pro duc tion num berwith the TRUO2 frac tion in the fuel mix tures(Th, TRU)O2

244 245Pu Pu( , )n g (2f)

242 243Cm Cm( , )n g (2g)

244 245Cm Cm( , )n g (2h)

Fig ure 5 de picts the cap ture re ac tion den si ties of232Th, which equal to 233U fis sile breed ing den si ties(see eq. 2a), vs. the TRUO2 frac tion in the fuel mix -tures for all tar get and fuel com po si tion cases. In alltar get cases, the pro duc tion of 233U in the fuel mix turecase of (Th, Cm)O2 is much higher than that in theother fuel mix ture cases, (about 2.5 times), and tho -rium in this fuel mix ture case is much more uti lizedthan that in the other fuel mix ture cases.

Fig ure 6(a) shows 239Pu fis sile breed ing den si -ties ob tained from the cap ture of 238U (see eq. 2(b)) inthe in ner tar get zone, ver sus the TRUO2 frac tion in the

fuel mix tures for tar get Case 1, Case 2, and all fuelcom po si tion cases. The val ues of these breed ing den -si ties are close to each other. None the less, in the tar getCase 2, it is seen that these val ues are reached at lowerTRUO2 frac tion in the fuel mix tures.In ad di tion to thisfig ure, the 239Pu fis sile breed ing den si ties ob tainedfrom the cap ture of 238Pu (see eq. 2(c)) in the TZ areplot ted in fig. 6(b). As is ap par ent from this fig ure, thehigh est val ues of 239Pu fis sile breed ing are ob tained inthe tar get Case 3.

The other fis sile fuel breed ing den si ties, 241Pu,243Pu, 243Cm, and 245Cm, are dem on strated in figs.7-10, re spec tively. These breed ing re ac tions are givenwith eqs. (2d-h). As shown in fig. 7, as the val ues of241Pu breed ing den si ties in the fuel mix ture cases of(Th, Pu)O2 and (Th, MA, Pu)O2 are al most the same inthe tar gets Cases 1, 2, those val ues are about 2.5 timesin the tar gets Case 3.This sit u a tion ap plies also for val -


Fig ure 5. Vari a tions of 233U breed ing den sity with theTRUO2 frac tion in the fuel mix tures (Th, TRU)O2

Fig ure 4. Vari a tions of the en ergy gain andthe ef fec tive neu tron

ues of 243Pu breed ing den si ties (see fig. 8). The val uesof 243Cm and 245Cm breed ing den si ties in the fuel mix -ture Case of (Th, MA, Pu)O2 are quite low (near-zero)in all tar get cases. In sum, the fis sile breed ing fig uresshow that the best tar get CASE is pure LBE tar get(Case 3).

Fur ther more, the val ues of all fis sile fuelbreedings (in g/d) in the Case of keff = 0.98 for pro tonin ten sity (PI) of 1017 s–1 are given in tab. 3. The 239Pu,241Pu, and 243Pu fis sile fu els can be bred up to 776 g ina day. As for the tho rium uti li za tion mean ing fis sile233U breed ing, this value can reach up to 905 g in a day. The val ues of to tal fis sile fuel breed ing are in the range of 510-1459 g/day. In brief, the nu mer i cal re sults con -firm that the best tar get case is the pure LBE tar get andthe best fuel mix ture case is (Th, Cm)O2, in terms of to -tal fis sile fuel breed ing.

Thermal power

In this study, PI is as sumed as 1017 pro tons/s hav -ing en ergy of a 1000 MeV. Ac cord ing to these val ues,the pro ton beam power (PP in MW) and ther mal power (Pth in MW) can be cal cu lated

PP C E PF= × -f p 10 6 (3a)

P GPPth = (3b)

where Cf is con ver sion fac tor and equals to Cf ==.1.602210–13 J/MeV.

For keff = 0.98 and PI = 1017 pro tons/s, the val -ues of G and Pth are given in tab. 3. The value of G var -ies in the range of 35 to 96. Pth var ies in the range of562 to 1540 MW, de pend ing on the val ues of G. In theCase of pure LBE tar get, the val ues of Pth are above1000 MW. Con se quently, as re gards ther mal power,the pure LBE tar get and the fuel mix ture Case (Th,Pu)O2, proved as the best con fig u ra tion.

CONCLUSIONS

A con cep tual semi-spher i cal ADS has been in -ves ti gated to trans mute TRU and tho rium, and tobreed fis sile fuel as well as en ergy pro duc tion. Thesev eral de sign struc tures and fuel mix tures have


Fig ure 6(a). Vari a tions of 239Pu breed ing den sity with theTRUO2 frac tion in the fuel mix tures (Th, TRU)O2 at thein ner sub-zone of the tar get zone

Fig ure 6(b). Variations of 239Pu breed ing den sity with theTRUO2 frac tion in the fuel mix tures (Th, TRU)O2 at thetrans mu ta tion zone

been an a lyzed from the points of trans mu ta tion anden ergy pro duc tion. In brief, the main con clu sionsare: the pure LBE tar get, which is one of the ex am -ined tar gets, is the best tar get Case in terms of

neutronic per for mance. Sig nif i cant amount of tho -rium is uti lized for pro duc tion of fis sile 233U. To talfis sile fuel breed ing is in the range of 510-1459 g per day. The best (Th, TRU)O2 fuel mix ture is (Th,


Fig ure 7. Vari a tions of 241Pu breed ing den sity with theTRUO2 frac tion in the fuel mix tures (Th, TRU)O2

Fig ure 8. Variatons of 243Pu breed ing den sity with theTRUO2 frac tion in the fuel mix tures (Th, TRU)O2

Table 3. Neutronic data in the CASE of keff = 0.98 for PI = 1017 protons/s which corresponds 16.02 MW

SNT CaseFuel mixture

(ThO2 + TRUO2)

*Fraction[%] G Pth [MW]

Fissile fuel breeding [g d–1]233U 239Pu 241Pu 243Pu 243Cm 245Cm Total

1

ThO2 + PuO2 55.0 41 648 128.4 234.4 213.0 50.3 – – 626

ThO2 + CmO2 20.0 37 583 359.6 264.5 – – 9.66 269.6 903

ThO2 + (Pu + MA)O2 74.0 38 609 71.7 217.8 161.3 39.8 0.5 18.8 510

2

ThO2 + PuO2 41.0 48 769 173.1 263.0 222.9 52.6 – – 712

ThO2 + CmO2 11.2 35 562 317.9 246.0 – – 4.5 145.2 714

ThO2 + (Pu + MA)O2 56.0 49 781 131.0 262.0 177.6 45.5 0.5 19.9 636

3

ThO2 + PuO2 46.0 96 1540 423.8 48.4 587.0 140.8 – – 1200

ThO2 + CmO2 15.2 69 1105 905.0 – – – 17.8 535.8 1459

ThO2 + (Pu + MA)O2 62.0 90 1446 279.9 46.1 430.3 110.0 1.25 49.1 917

* Frac tion of TRUO2 in the fuel mix ture

Cm)O2 in terms of to tal fis sile fuel breed ing. Thevalue of G would reach up to 96 that is quite a highvalue. The val ues of Pth are above 1000 MW in theCase of pure LBE tar get and would reach up to1540 MW. Con se quently, the ex am ined semi-spher -i cal gas-cooled ADS has rather high neutronic per -for mance for an ef fec tive en ergy pro duc tion andtrans mu ta tion of nu clear fuel wastes, and this ADScon fig u ra tion can per form more ef fec tive trans mu -ta tion of spent fuel by us ing lower en rich ment ofura nium, in com par i son with our pre vi ous cy lin dri -cal con fig u ra tion in ref. Yapici et al. [14].

ACKNOWLEDGEMENT

This study is sup ported by the Re search Fund ofthe Erciyes Uni ver sity, Pro ject no. FDK-2015-5811.

AUTHORS' CONTRIBUTIONS

The o ret i cal and nu mer i cal anal y ses were car ried out by H.Yapici and G. Bakir. G. Bakir and G. Genc an -a lyzed and dis cussed the re sults. The manu script waswrit ten and the fig ures pre pared by all au thors.

REFERENCES

[1] Law rence, E. O., AEC Re search and De vel op mentRe port, Fa cil i ties for Electro nu clear (MTA) Pro gram, Re port LWS-24736, 1953

[2] Yapici, H., Study on Trans mu ta tion of Mi norActinides Dis charged from High Burn-UpPWR-MOX Spent Fuel in the Force-Free He li cal Re -ac tor, An nals of Nu clear En ergy, 30 (2003), 4, pp.413-436

[3] Yapici, H., Burn ing and/or Trans mu ta tion ofTransuranium Dis charged from PWR-UO2 Spent


Fig ure 9. Vari a tions of 243Cm breed ing den sity with theTRUO2 frac tion in the fuel mix tures (Th, TRU)O2

Fig ure 10. Vari a tions of 245Cm breed ing den sity

Fuel and Power Flat ten ing Along the Op er a tion Pe -riod in the Force Free He li cal Re ac tor, En ergy Con -ver sion and Man age ment, 44 (2003), 18, pp.2893-2913

[4] Yapici, H., De ter mi na tion of the Op ti mal Plu to niumFrac tion in Transuranium Dis charged from Pres suredWa ter Re ac tor (PWR) Spent Fuel for a Flat Fis sionPower Gen er a tion in the Force-Free He li cal Re ac tor(FFHR) Along the Trans mu ta tion Pe riod, An nals ofNu clear En ergy, 30 (2003), 6, pp. 633-649

[5] Yapici, H., et al., Mi nor Ac ti nide Trans mu ta tion Po -ten tial of Mod i fied PRO ME THEUS Fu sion Re ac tor,Jour nal of Fu sion En ergy, 23 (2004), 2, pp. 121-135

[6] Yapici, H., et al., Neutronic Anal y sis for Trans mu ta -tion of Mi nor Actinides and Long-Lived Fis sionProd ucts in a Fu sion-Driven Transmuter (FDT), Jour -nal of Fu sion En ergy, 25 (2006), 3, pp. 225-239

[7] Yapici, H., et al., Trans mu ta tion-In cin er a tion Po ten -tial of Transuraniums Dis charged from PWR-UO2

Spent Fuel in Mod i fied PRO ME THEUS Fu sion Re -ac tor, Fu sion En gi neer ing and De sign, 81 (2006), 18,pp. 2093-2108

[8] Abanades, A., Perez-Navarro, A., En gi neer ing De -sign Stud ies for the Trans mu ta tion of Nu clear Wasteswith a Gas-Cooled Peb ble-Bed ADS, Nu clear En gi -neer ing and De sign, 237 (2007), 3, pp. 325-333

[9] Takizuka, T., et al., De sign Study of Lead-Bis muthCooled ADS Ded i cated to Nu clear Waste Trans mu ta -tion, Prog ress in Nu clear En ergy, 40 (2002), 3-4, pp.505-512

[10] Tsujimoto, K., et al., Neutronics De sign for Lead-Bis -muth Cooled Ac cel er a tor-Driven Sys tem for Trans -mu ta tion of Mi nor Ac ti nide, Jour nal of Nu clear Sci -ence and Tech nol ogy, 41 (2004), 1, pp. 21-36

[11] Gar cia, L., et al., Cal cu la tion of the Pack ing Frac tionin a Peb ble-Bed ADS and Re de sign ing of the Trans -mu ta tion Ad vanced De vice for Sus tain able En ergyAp pli ca tions (TADSEA), Nu clear En gi neer ing andDe sign, 253 (2012), pp. 142-152

[12] Malyshkin, Y., et al., Monte Carlo Mod el ing ofSpallation Tar gets Con tain ing Ura nium and Am er i -cium, Nu clear In stru ments and Meth ods in Phys icsRe search B., 334 (2014), Sept., pp. 8-17

[13] Yapici, H., et al., Neutronic Lim its in In fi nite Tar getMe di ums Driven by High En er getic Pro tons, An nalsof Nu clear En ergy, 34 (2007), 5, pp. 374-384

[14] Yapici, H., et al., A Com pre hen sive Study onNeutronics of a Lead-Bis muth Eutectic Cooled Ac -cel er a tor-Driven Sub-Crit i cal Sys tem for Long-Lived Fis sion Prod uct Trans mu ta tion, An nals of Nu clearEn ergy, 35 (2008), 7, pp. 1264-1273

[15] Bakir, G., et al., Neutronic Anal y sis of LBE-Ura nium Spallation Tar get Ac cel er a tor Driven Sys tem Loadedwith Ura nium Di ox ide in TRISO Par ti cles, ActaPhysica Polonica A, 130 (2016), 1, pp. 30-32

[16] Mar ti nez A. H., et al., Trans mu ta tion of Nu clearWaste in Ac cel er a tor-Driven Sys tems: Ther mal Spec -trum, An nals of Nu clear En ergy, 34 (2007), 7, pp.550-563

[17] Ismailov, K., et al., Fea si bil ity of Ura nium SpallationTar get in Ac cel er a tor-Driven Sys tem, Prog ress in Nu -clear En ergy, 53 (2011), 7, pp. 925-929

[18] Adam, J., et al., Trans mu ta tion of I-129, Np-237Pu-238, Pu-239, and Am-241 Us ing Neu trons Pro -duced in Tar get-Blan ket Sys tem 'En ergy Plus Trans -mu ta tion' by Rel a tiv is tic Pro tons, Pramana-Jour nalof Phys ics, 68 (2007), 2, pp. 201-212

[19] Artisyuk, V., et al., 244Cm Trans mu ta tion in Ac cel er a -tor Driven Sys tem, Jour nal of Nu clear Sci ence andTech nol ogy, 36 (1999), 12, pp. 1135-1140

[20] Brolly, K., Vertes, P., Con cept of a Small-Scale Elec -tron Ac cel er a tor Driven Sys tem for Nu clear WasteTrans mu ta tion, Part 2, In ves ti ga tion of Burn-Up, An -nals of Nu clear En ergy, 32 (2005), 4, pp. 417-433

[21] Haeck, W., et al., As sess ment of Am er i cium and Cu -rium Trans mu ta tion in Mag ne sia Based Tar gets inDif fer ent Spec tral Zones of an Ex per i men tal Ac cel er -a tor Driven Sys tem, Jour nal of Nu clear Ma te ri als,352 (2006), 1-3, pp. 285-290

[22] Mukaiyama, T., et al., Par ti tion ing and Trans mu ta tion Stud ies at JAERI Both un der OMEGA Pro gram andHigh-In ten sity Pro ton Ac cel er a tor Pro ject, Prog ressin Nu clear En ergy, 40 (2002), 3-4, pp. 403-413

[23] Park, W. S., et al., A Pre lim i nary De sign Study for theHY PER Sys tem, Nu clear En gi neer ing and De sign,219 (2002), 3, pp. 207-223

[24] Seltborg, P., Wallenius, J., Pro ton Source Ef fi ciencyfor Het er o ge neous Dis tri bu tion of Actinides in theCore of an Ac cel er a tor-Driven Sys tem, Nu clear Sci -ence and En gi neer ing, 154 (2006), 2, pp. 202-214

[25] Tsujimoto, K., et al., Ac cel er a tor-Driven Sys tem forTrans mu ta tion of High-Level Waste, Prog ress in Nu -clear En ergy, 37 (2000), 1-4, pp. 339-344

[26] Wade, D. C., et al., ATW Neutronics De sign Stud ies,Prog ress in Nu clear En ergy, 40 (2002), 3-4, pp.497-504

[27] Wallenius, J., Eriksson, M., Neutronics of Mi nor-Ac -ti nide Burn ing Ac cel er a tor-Driven Sys tems with Ce -ramic Fuel, Nu clear Tech nol ogy, 152 (2005), 3, pp.367-381

[28] Westlen, D., Wallenius, J., Neutronic and Safety As -pects of a Gas-Cooled Subcritical Core for Mi nor Ac -ti nide Trans mu ta tion, Nu clear Tech nol ogy, 154(2006), 1, pp. 41-51

[29] Man son, B., et al., Nu clear Chem i cal En gi neer ing,McGraw-Hill, New York, USA, 1981

[30] Kim, H. C., et al., Monte Carlo Bench mark Cal cu la -tions for 400 MWth PBMR Core, in: 13th In ter na tionalCon fer ence on Emerg ing Nu clear En ergy Sys tems,Is tan bul, 2007

[31] Conway, J., et al., Sphere-Packings, Lat tices andGroups, third, Springer-Verlag, New York, USA,1999

[32] Pelowitz, D. B., et al., MCNPX, User's Man ual, Ver -sion 2.6.0, LA-CP-07-1473, 2008

[33] Chadwick, M. B., et al., Cross-Sec tion Eval u a tions to150 MeV for Ac cel er a tor-Driven Sys tems and Im ple -men ta tion in MCNPX, Nu clear Sci ence and En gi -neer ing, 131 (1999), 3, pp. 293-328

[34] Bertini, H. W., Low-En ergy Intranuclear Cas cadeCal cu la tion, Phys i cal Re view, 131 (1963), Aug., pp.1801-1821

Re ceived on April 1, 2016Ac cepted on July 26, 2016



Gizem BAKIR, Gamze GEN^, Husejin JAPIXI

STUDIJA IDEJNOG PROJEKTA SISTEMA UPRAVQANOGAKCELERATOROM, ISPUWENOG TORIJUMDIOKSIDOM SA

TRANSURANSKIM DIOKSIDIMA U VIDU TRISO ELEMENATA

Upravqawe utro{enim nuklearnim gorivom jedna je od glavnih tema u kori{}ewunuklearne energije, te su posledwih godina re{ewa ovog problema uporno istra`ivana. Ciq ovograda je da se ispita fisiona oplodwa i potencijali transmutacije transuranskog goriva u gasomhla|enom sistemu upravqanom akceleratorom. Sa neutronskog gledi{ta, najpre je konceptualnoprojektovani sistem upravqan akceleratorom optimizovan kori{}ewem vi{e materijala mete ime{avina goriva. Potom su kao mete razmatrane tri kompozicije materijala: ~ist olovo bizmuteutektik (LBE), LBE sa prirodnim UO2 i LBE sa 15 % oboga}enim UO2. Zona mete razdvojena je na dvepodzone, sa jednom podzonom unutar druge. Spoqa{wa pod zona je ~ista LBE meta, dok je unutra{wa‡ ili UO2 ili ~ista LBE meta. UO2 podzona hla|ena je gasom helijuma. Najzad, me{avinatorijumdioksida sa transuranskim dioksidima, izdvojena iz PWR-MOX utro{enog goriva u vidukugli sa~iwenih od grafita i tristrukturalno-izotropnih (TRISO)-obavijenih sfernih gorivnihelemenata, kori{}ena je za oplodwu fisionog goriva i transmutaciju transuranskih goriva.Ispitane su tri razli~ite torijum-transuranske smese, (Th, Pu)O2, (Th, Cm)O2 i (Th, Pu, MA)O2, sarazli~itim frakcijama komponenti. Pretpostavqeno je da frakcije pakovawa gorivnih kugli utransmutacionom jezgru i TRISO-obavijenim gorivnim elementima u kugli, iznose 60 % i 29 %,respektivno. Transmutaciono jezgro tako|e je hla|eno visokotemperaturnim helijumskimhladiocem. U ciqu stvarawa visokog neutronskog fluksa radi prodirawa kroz transmutacionojezgro, meta je izlo`ena kontinualnom snopu protona energije 1 GeV. Prora~uni su obavqeniMCNPX Monte Karlo kodom za visoke energije kori{}ewem LA150 biblioteke. Numeri~kirezultati pokazuju da razmatrani akceleratorom upravqani sistem ima visoke neutronske odlikeu smislu stvarawa energije i oplodwe fisibilnog goriva.

Kqu~ne re~i: sistem upravqan akceleratorom, transmutacija utro{enog goriva, spalacija..........................neutronske mete, oplodwa torijuma, TRISO gorivo

study of a con cep tual ac cel erator driven sys …2 departm ent of energy, sys t ems en gi neer...

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