Criticality investigations for the fixed bed nuclear reactor using thorium fuel mixed with plutonium or minor actinides

Şahi̇n, Sümer; Şahi̇n, Hacı Mehmet; Acır, Adem; Al-Kusayer, Tawfik A.

doi:10.1016/j.anucene.2009.06.003

Cited by 33 publications

(11 citation statements)

References 15 publications

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“…[7][8][9] Other workers have assessed the performance of HG-Pu in fixed bed nuclear reactor with prospective outcome. 10,11 High neutron economy of heavy-water-moderated Canada Deuterium Uranium (CANDU) reactors promises to be an attractive option for the exploitation of rich world thorium reserves, which was subject of different work. [12][13][14][15][16][17][18][19][20][21] In a series of systematic studies conducted with the SCALE5 code package, 22 the utilization potential of HG-Pu, reactor-grade plutonium (RG-Pu), and minor actinides (MA) as mixed with thorium in CANDU reactors has been investigated.…”

Section: Discussionmentioning

confidence: 99%

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Large-scale energy production with thorium in a typical heavy-water reactor using high-grade plutonium as driver fuel

Şahi̇n

Şarer²

2018

Int J Energy Res

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Summary Thorium can be introduced into the energy vector in combination with high‐grade plutonium (HG‐Pu). Excellent neutron economy of heavy‐water moderator allows use of mixed ThO2/HG‐PuO2 fuel in heavy‐water reactors with high efficiency, leading to the exploitation of large world thorium reserves and extending the availability of the nuclear energy by two orders of magnitude. In the present work, the criticality calculations have been performed with the code MCNPX 3‐D geometrical modeling of a typical heavy‐water reactor, where the structure of all fuel rods and bundles is represented individually. In the course of time calculations, nuclear transformation and radioactive decay of all actinide elements as well as fission products are considered. Five different fuel compositions have been selected for investigations: (1) 97% thoria (ThO2) + 3% PuO2; (2) 96% ThO2 + 4% PuO2; (3) 95% ThO2 + 5% PuO2; (4) 94% ThO2 + 6% PuO2; and (5) 92% ThO2 + 8% PuO2. The behavior of the criticality k∞ and the burn‐up values of the reactor have been pursued by full power operation at 640 MWel (2180 MWth) for approximately 7 years. Time calculations have been conducted with MCNPX and CINDER codes under consideration of all nuclear transformation and radioactive decay processes on the actinide isotopes and fission fragments. As the reactor allows fuel recharging at on‐power operation mode, the reactor criticality has been followed down to keff,end = ~1.05. The corresponding burn‐up values and operation periods for the investigated modes are (1) 18 GWd/MT and 780 days; (2) 27 GWd/MT and 1200 days; (3) 35 GWd/MT and 1560 days; (4) 44 GWd/MT and 1940 days; and (5) 60 GWd/MT and 2640 days. Among the investigated four modes, 94% ThO2 + 6% PuO2 seems a reasonable choice under consideration of the high price of the HG‐Pu as driver fuel. The mixed fuel has the potential of an extensive exploitation of thorium resources. Reactor will run with the same fuel charge for approximately 5 years and allow a fuel burn‐up approximately 44 GWd/MT, comparable with conventional light‐water reactors (LWRs). Plutonium component of the mixed fuel will become nonprolific after few months of plant operation through the accumulation of even isotopes. Addition of few percent natural uranium to the initial mixed fuel charge will keep the 233U component below 22% and hence at nonprolific level over the entire plant operation period. Replacement of 4% ThO2 with 4% nat‐UO2 will practically not change main technical parameters of the reactor.

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Section: Discussionmentioning

confidence: 99%

“…The utilization of HG‐Pu in GT‐MHR and of pebble bed modular reactor (PBMR) has been pursued by literature . Other workers have assessed the performance of HG‐Pu in fixed bed nuclear reactor with prospective outcome …”

Section: Introductionmentioning

confidence: 99%

Large-scale energy production with thorium in a typical heavy-water reactor using high-grade plutonium as driver fuel

Şahi̇n

Şarer²

2018

Int J Energy Res

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“…A series of analyses have been performed dealing with different aspects of FBNR, such as the variation of reactor criticality by change of core height and boron concentration in the moderator, 3 utilization of 233 U, 4 thorium mixed with nuclear waste minor actinides or reactor grade plutonium 5 and other with alternative fuels 6 . All this work had been conducted using 1‐D codes and for an ad hoc assumed moderator volume.…”

Section: Introductionmentioning

confidence: 99%

3D Analysis of a multipurpose modular reactor for small energy production

Şahi̇n¹,

Şarer

2020

Int J Energy Res

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Summary The Fixed Bed Nuclear Reactor (FBNR) is a modular reactor for small energy needs (70‐120 MWel). FBNR is pressurized water reactor, but uses GEN‐IV reactors fuel. UO2 kernels of 500 μm diameter with 25 μm thick SiC cladding are embedded in graphite matrix form the spherical fuel elements with a diameter of 15 mm and covered by 300 μm thick Zircaloy‐4 cladding. FBNR has high level safety features and operates without On‐site Refueling. Approximately 1.62 million spherical fuel elements are suspended in a core height of 200 cm and inner and outer diameters of 32 cm and 224 cm by upwards flowing light water coolant with 280°C entry and 340°C exit temperatures. The unit lattice geometry is dodecahedron with fuel element in center and surrounded with light water coolant‐moderator.In the present work, 9% enriched UO2 fuel is used. Neutronic analysis has been performed with the MCNPX‐2.7.0 code. As, it is not practical to tackle millions of fuel elements separately, at first run unit fuel cell calculations are performed in spherical geometry for one single lattice consisting of separate fuel, cladding and volume‐equivalent moderator regions. In the second run, the fuel cell is homogenized. Infinite cell calculations have been executed for variable moderator/fuel (H/235U) ratios in order to determine under‐ and over‐moderated criticality values. The criticality values for the homogenized cell geometry are slightly lower and remains <5% range, that is, on the conservative side, which is acceptable for the purpose of this study. This allows us to homogenize the entire core for the full 3‐D reactor with core and reflector regions. Reactor criticality increases with increasing H/235U ratios in the, under moderated region, where H/235U = 18 is selected for further investigations. Temporal variation of the reactor criticality is pursued for full reactor power of 210 MWth (~70 MWel net) with keff = 1.36 at the beginning of life down to keff = 1.02 over 1260 days with a plant factor of 1.0. The final fuel burn up was found as 57.3 GWd/ton.

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“…Recently, a number of studies have been conducted to search the possibility of further exploitation of these precious RG-Pu and MA in heavy water or graphite moderated nuclear reactors, having a better neutron economy than LWRs. Previous work has investigated intensively the utilization potential of RG-Pu and MA in the form of a mixed ThO 2 /PuO 2 fuel in CANDU reactors and fixed bed nuclear reactors [10][11][12][13][14][15][16][17][18]. These studies have been conducted under consideration of the transmutation and radioactive decay of all heavy metal isotopes with high precision in S 8 -P 3 energy groups using 238 neutron groups.…”

Section: Introductionmentioning

confidence: 99%

Utilization of nuclear waste plutonium and thorium mixed fuel in candu reactors

Şahi̇n

Şarer

Çelik

2016

Int. J. Energy Res.

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SUMMARYSpent nuclear fuel out of conventional light water reactors contains significant amount of even plutonium isotopes, so called reactor grade plutonium. Excellent neutron economy of Canada deuterium uranium (CANDU) reactors can further burn reactor grade plutonium, which has been used as a booster fissile fuel material in form of mixed ThO 2 /PuO 2 fuel in a CANDU fuel bundle in order to assure reactor criticality. The paper investigates incineration of nuclear waste and the prospects of exploitation of rich world thorium reserves in CANDU reactors.In the present work, the criticality calculations have been performed with 3-D geometrical modeling of a CANDU reactor, where the structure of all fuel rods and bundles is represented individually. In the course of time calculations, nuclear transformation and radioactive decay of all actinide elements as well as fission products are considered.Four different fuel compositions have been selected for investigations: ① 95% thoria (ThO 2 ) + 5% PuO 2 , ② 90% ThO 2 + 10% PuO 2 , ③ 85% ThO 2 + 15% PuO 2 and ④ 80% ThO 2 + 20% PuO 2 . The latter is used for the purpose of denaturing the new 233 U fuel with 238 U. The behavior of the criticality k ∞ and the burnup values of the reactor have been pursued by full power operation for~10 years.Among the investigated four modes, 90% ThO 2 + 10% PuO 2 seems a reasonable choice. This mixed fuel would continue make possible extensive exploitation of thorium resources with respect to reactor criticality. Reactor will run with the same fuel charge for~7 years and allow a fuel burnup~55 GWd/t.

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Criticality investigations for the fixed bed nuclear reactor using thorium fuel mixed with plutonium or minor actinides

Cited by 33 publications

References 15 publications

Large-scale energy production with thorium in a typical heavy-water reactor using high-grade plutonium as driver fuel

Large-scale energy production with thorium in a typical heavy-water reactor using high-grade plutonium as driver fuel

3D Analysis of a multipurpose modular reactor for small energy production

Utilization of nuclear waste plutonium and thorium mixed fuel in candu reactors

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