Belarus activity in ADS field

Transcription

1 Joint Institute for Power&Nuclear Research-Sosny National Academy of Sciences of Belarus Belarus activity in ADS field H. Kiyavitskaya, Yu. Fokov, Ch. Routkovskaya, V. Bournos, S. Sadovich, S. Mazanik, I. Edchik, A. Kulikovskaya (YALINA team) 45 th IAEA Meting TWG-FR, ANL, USA, June 2012

2 Content Introduction International cooperation YALINA facility YALINA Booster assembly Obtained experience Conclusion

3 Introduction IAEA Coordinated Research Project (CRP) on Analytical and Experimental Benchmark Analysis of Accelerator Driven Systems Contract N /R The YALINA-Thermal and YALINA-Booster benchmarks IAEA CRP Low Enriched Uranium Fuel Utilization in Accelerator Driven Sub- Critical Assembly Systems

4 Introduction (cont.) State program scientific investigations Nuclear Power, Nuclear and Radiation Technologies State program Scientific support of the development of nuclear power in the Republic of Belarus

5 International cooperation ISTC Projects B070 (EC), B1341 (USA), B1732P (USA) IP EUROTRANS EU Framework Programs The objectives of the ISTC Project #B1732P in collaboration with USA are: To use LEU fuel instead of HEU for the YALINA-Booster assembly; To evaluate the consequences of converting to LEU fuel (by enrichment <20%); To examine possible ways to maintain the original performance with HEU.

6 The YALINA facility: To develop the experimental techniques and adapt the existing ones for monitoring the sub-criticality level, neutron spectra measurements, etc; To study the spatial kinetics of sub-critical systems driven by external neutron sources; To study the maintenance and operating performance of ADS; To measure the transmutation reaction rates of minor-actinides and long-lived fission products.

7 YALINA facility

8 YALINA-Booster sub-critical assembly (to the left), neutron generator (to the right)

9 The ISTC Projects #B1341 and B1732P the experimental and theoretical studies were carried out to define the sub-critical YALINA-Booster performance in original configuration with 90% Umet+36% UO2 in fast zone and 10% UO2 in thermal zone the experimental and theoretical studies at configuration of YALINA-Booster with 36% UO2 in fast zone and 10% UO2 in thermal zone the experimental and theoretical studies at configuration of YALINA-Booster with 21% UO2 in fast zone and 10% UO2 in thermal zone (JIPNR-configuration) the experimental and theoretical studies at configuration of YALINA-Booster with 21% UO2 in fast zone and 10% UO2 in thermal zone (ANL configuration)

10 Fast zone of the YALINA-Booster assembly (rectangular and rounded geometry) D E F G H I D E F G H I EC1B 5 EC1B 6 EC2B 6 EC2B EC4B 8 EC4B EC3B EC3B 9 9 Ionguide Problem fuel channels (18) Absorber zone, 108 rods with Umet. (nat.) Absorber zone, 116 rods with B4C Fuel rods with UO 2, 21% enrichment by U-235 (601) Empty fuel channels (76) EC1B-EC3B - experimental channels in fast zone EC4B - experimental channel in fast zone Ionguide Absorber zone, 108 rods with Umet. (nat.) Absorber zone, 116 rods with B4C Fuel rods with UO 2, 21% enrichment by U-235 (595) Empty and problem fuel channels (100) sealed by hermetical SS tubes EC1B-EC3B - experimental channels in fast zone EC4B - experimental channel in fast zone

11 The obtained experience: The replacement of the 90% enriched metallic uranium fuel in the inner region of the fast zone by 36 % (first) and 21% (second) enriched uranium dioxide reduces the contribution of fast zone to the total reactivity of the assembly, softens slightly the neutron spectrum in the fast zone. The neutron spectrum in the thermal zone remains unchanged.

12 Conclusions The YALINA facility is a unique installation which was designed as a zero power model of real ADS. It is intended to study neutronics and kinetics of the sub-critical reactors driven by external neutron sources. The successful operation of this facility is a scientific contribution from the Republic of Belarus, as well as the international team from EC and USA. The experimental data are used to benchmark and validate methods and computer codes for designing and licensing ADS.

13 The facility generated valuable data in the following areas: investigation of spatial kinetics of the sub-critical systems with external neutron sources; validation of the experimental techniques for, e.g., sub-criticality monitoring, etc; estimation of probability of minor actinides and fission products transmutation; nuclear and radiation safety analyses of sub-critical systems driven by external neutron sources; neutron activation analysis; utilization of low enriched uranium fuel for studying accelerator driven sub-critical systems.

14 The YALINA-Booster experiments performed during and after the conversion of fast zone HEU fuel to use the fuel with reduced uranium enrichment reached the following conclusions: The assembly has a strong heterogeneity affecting the spatial kinetics; The interface (absorber) zone between the fast and thermal zone has clear impact on the assembly performance; the kinetic parameters (neutron generation time, effective fraction of delayed neutrons, etc.) are defined by the thermal zone; the experimental results obtained with application of PNS area method improves as the effective multiplication factor exceeds 0.8. The delayed neutron fraction value is used based on the MCNP simulation and it needs experimental verification;

15 The YALINA-Booster experiments performed during and after the conversion of fast zone HEU fuel to use the fuel with reduced uranium enrichment reached the following conclusions: The discrepancy between the experimental (PNS method) and calculated effective multiplication factor is less than 1 % without eliminating the spatial effects. After the replacement of the 90% enriched metallic uranium by 36% UO2 in the inner region of the fast zone, some additional amount of nuclear fuel was added into thermal zone to maintain keff at the proper level. The main YALINA-Booster neutronics was not affected remarkably, only the neutron spectrum softened slightly in the inner region of the fast zone.

16 The YALINA-Booster experiments performed during and after the conversion of fast zone HEU fuel to use the fuel with reduced uranium enrichment reached the following conclusions: As it was expected the second step of the conversion to LEU fuel (to 21% UO2 in fast zone) resulted in significant reduction of the effective multiplication factor. The value of keff estimated by MCNP was about 0.963, the experimental one Despite the lack of additional fuel, there was a chance to maintain the assembly s performance consisted in changing the geometry of fast and absorber zone. The ANL proposed to realize the rounded configurations of these zones in the framework of the ISTC Project B1732P. The changes were introduced, the assembly was put into operation and the planned experiments were performed. The results are being processed just now. It should be noted that new configuration of fast zone has a great potential to keep the performance of the assembly s old configuration with HEU fuel.

17 New proposal is under discussion with ANL, USA Subcritical assembly fast neutron spectrum low enriched uranium fuel (< 20% X 5 ) Neutron generator as an external neutron source In cooperation and support ANL and IAEA

18 Thank you very much