Kinetic Analysis of Coupled Pulse Reactor for NPL Experimenttobara/research/hikarigenshiro... ·...

Kinetic Analysis of Coupled Pulse Reactor for NPL Experiment

Toru Obara Hiroki TakezawaResearch Laboratory for Nuclear ReactorsTokyo Institute of Technology

American Nuclear Society 2010 Winter MeetingNovember 7-11 2010 Las Vegas Nevada Riviera Hotel amp Casino

2

BackgroundNuclear-Pumped Laser One of Direct Nuclear Energy Conversions

Nuclear Energy Optical Energy

Laser

Direct ConversionFP kinetic energy

Nuclear Reactor for Nuclear-Pumped Laser designed by IPPE Russia

Weakly Coupled System(Decoupled Spectrum System)

Fast neutrons pulsed from pulse cores

Diffusion and thermalization of the fast neutrons in the assembly

Pulse Cores (Fast Spectrum)

Subcritical Laser-Cell Assembly (Thermal Spectrum)

tU235 fissions on the fuel-coated wall +

Nuclear-pumping of laser medium

Laser-Cell

Front view Side view

Optical ApplicationsPhotonics Society

Pulse core with high-enriched uranium

High-enriched metallic uranium coating

3

Nuclear Pumped Laser Experiment reactor in IPPE

1 Fast pulse cores2 Laser cell assembly3 Inner polyethylene

moderator4 Outer polyethylene

moderator5 Laser cells

1 Moveable core2 Core3 Core4 Reactivity control system5 U-Mo alloy core6 Core cover7 B10+moderator8 Support tube9 Transient rod10 Reactivity control rod11 Safety rod

Expeiment reactor

BARS-6 pulse reactor


① Coupled rector② Pulse

operation

4

Toru Obara ANS 2010 Winter Meeting Las Vegas Nevada (2010)

Purpose of study

bull To show the possibility of performing NPL experiments using the pulse reactor concept with low-enriched uranium by performing kinetic analysis of the prompt supercritical condition

5

Methodology

Fission Density at region i

Secondary fission density in region i provided by the first fission in region j with time deference t-trsquo

Space-Dependent Kinetic Model

Fission Probability Density Function

Integral Kinetic Model + Monte Carlo Method

αij calculation method has developed using Monte Carlo method by the modified MVP20

6

Outline of αij calculation methodIntroduction of Cij

Time from the source fission

Cumulative number of fissions in region iby the time τ provided by the source

fission in region j

7

RegionFlight TimeFission Weight

Cij calculation formula

Non-analog Neutron Transport Monte Carlo

Method

Cij Calculation Formula

Source Region

Source Weight Ws

Source Weight

Microscopic fission probability Neutron Weight

End of History

t1t2 t3

t4t5Coln

Neutron Random Walk

Collision Estimator

Cumulative number of fissions in region i by the time τ

The number of the source fissions in region j

8

Space dependent kinetic calculation

1 Based on the integral transport equation2 Forward difference3 Stepwise reactivity insertion from critical condition in low power4 No delayed neutrons5 Temperature dependent Cij(τ) for feedback effect6 Temperature rise by fission power7 Cij(τ) by modified MVP20(νp eigenvalue calculation）

Kinetic analysis code using Cij has been developed

9

Calculation geometry of high-enriched uranium reactor

Region Enrichment

Pulse cores 1000wt

U coating 1000wt

Initial power 1WTime step Δt 10 x 10-7 sKeff

p (300K) 10157Keff

p (800K) 10026

10

Calculation geometry of low-enriched uranium reactor

Region Enrichment

Pulse cores 200wt

U coating 200wt


p (300K) 1008Keff

p (800K) 09997

11

Fission power in each region

① Delay of power peak in outer region

② Delay of power peak in low enriched uranium reactor

③ Power in laser cell region

①

②

11

③

12

Peak power density in laser cell tubes

Inner region Outer region

Peak power density [Wcm3] 12x103 62x102

Full width at half maximum [s] 4x10-3 4x10-3

Delay of power peak [s] - 1x10-4

High-enriched uranium reactor

Low-enriched uranium reactorInner region Outer region




bull Threshold of laser pumping in Ar-Xe laser gasndash About 10 Wcm3 by Russian report

13

Conclusions

bull Kinetic analyses based on the method for weakly coupled systems were performed for a nuclear pumped laser experiment reactor

bull The calculation results show that it is possible to provide enough energy to the laser gas medium in the cell tubes not only in the reactor with highly enriched uranium but also in the reactor with low enriched uranium

14

Conclusions (continued)

bull It is also possible to provide enough energy to both the laser cell tubes in the inner region and the tubes in the outer region far from the pulse cores

bull It was also found that there was some delay of the peak of the power in the cell tubes in the outer region which was caused by neutron thermalization and diffusion in the thermal laser module

bull It was shown that performing NPL experiments using the pulse reactor concept with low-enriched uranium was possible



Background


Purpose of study

Methodology

Outline of αij calculation method


スライド番号 8





Conclusions


2

BackgroundNuclear-Pumped Laser One of Direct Nuclear Energy Conversions

Nuclear Energy Optical Energy

Laser

Direct ConversionFP kinetic energy

Nuclear Reactor for Nuclear-Pumped Laser designed by IPPE Russia

Weakly Coupled System(Decoupled Spectrum System)

Fast neutrons pulsed from pulse cores

Diffusion and thermalization of the fast neutrons in the assembly

Pulse Cores (Fast Spectrum)

Subcritical Laser-Cell Assembly (Thermal Spectrum)

tU235 fissions on the fuel-coated wall +

Nuclear-pumping of laser medium

Laser-Cell


Optical ApplicationsPhotonics Society

Pulse core with high-enriched uranium

High-enriched metallic uranium coating

3






Expeiment reactor




operation

4


Purpose of study


5

Methodology







6




fission in region j

7




Method


Source Region

Source Weight Ws

Source Weight


End of History

t1t2 t3

t4t5Coln

Neutron Random Walk

Collision Estimator



8




9


Region Enrichment

Pulse cores 1000wt

U coating 1000wt


p (300K) 10157Keff

p (800K) 10026

10


Region Enrichment

Pulse cores 200wt

U coating 200wt


p (300K) 1008Keff

p (800K) 09997

11





①

②

11

③

12












13

Conclusions



14







Background


Purpose of study

Methodology








Conclusions


3






Expeiment reactor




operation

4


Purpose of study


5

Methodology







6




fission in region j

7




Method


Source Region

Source Weight Ws

Source Weight


End of History

t1t2 t3

t4t5Coln

Neutron Random Walk

Collision Estimator



8




9


Region Enrichment

Pulse cores 1000wt

U coating 1000wt


p (300K) 10157Keff

p (800K) 10026

10


Region Enrichment

Pulse cores 200wt

U coating 200wt


p (300K) 1008Keff

p (800K) 09997

11





①

②

11

③

12












13

Conclusions



14







Background


Purpose of study

Methodology








Conclusions


4


Purpose of study


5

Methodology







6




fission in region j

7




Method


Source Region

Source Weight Ws

Source Weight


End of History

t1t2 t3

t4t5Coln

Neutron Random Walk

Collision Estimator



8




9


Region Enrichment

Pulse cores 1000wt

U coating 1000wt


p (300K) 10157Keff

p (800K) 10026

10


Region Enrichment

Pulse cores 200wt

U coating 200wt


p (300K) 1008Keff

p (800K) 09997

11





①

②

11

③

12












13

Conclusions



14







Background


Purpose of study

Methodology








Conclusions


5

Methodology







6




fission in region j

7




Method


Source Region

Source Weight Ws

Source Weight


End of History

t1t2 t3

t4t5Coln

Neutron Random Walk

Collision Estimator



8




9


Region Enrichment

Pulse cores 1000wt

U coating 1000wt


p (300K) 10157Keff

p (800K) 10026

10


Region Enrichment

Pulse cores 200wt

U coating 200wt


p (300K) 1008Keff

p (800K) 09997

11





①

②

11

③

12












13

Conclusions



14







Background


Purpose of study

Methodology








Conclusions


6




fission in region j

7




Method


Source Region

Source Weight Ws

Source Weight


End of History

t1t2 t3

t4t5Coln

Neutron Random Walk

Collision Estimator



8




9


Region Enrichment

Pulse cores 1000wt

U coating 1000wt


p (300K) 10157Keff

p (800K) 10026

10


Region Enrichment

Pulse cores 200wt

U coating 200wt


p (300K) 1008Keff

p (800K) 09997

11





①

②

11

③

12












13

Conclusions



14







Background


Purpose of study

Methodology








Conclusions


7




Method


Source Region

Source Weight Ws

Source Weight


End of History

t1t2 t3

t4t5Coln

Neutron Random Walk

Collision Estimator



8




9


Region Enrichment

Pulse cores 1000wt

U coating 1000wt


p (300K) 10157Keff

p (800K) 10026

10


Region Enrichment

Pulse cores 200wt

U coating 200wt


p (300K) 1008Keff

p (800K) 09997

11





①

②

11

③

12












13

Conclusions



14







Background


Purpose of study

Methodology








Conclusions


8




9


Region Enrichment

Pulse cores 1000wt

U coating 1000wt


p (300K) 10157Keff

p (800K) 10026

10


Region Enrichment

Pulse cores 200wt

U coating 200wt


p (300K) 1008Keff

p (800K) 09997

11





①

②

11

③

12












13

Conclusions



14







Background


Purpose of study

Methodology








Conclusions


9


Region Enrichment

Pulse cores 1000wt

U coating 1000wt


p (300K) 10157Keff

p (800K) 10026

10


Region Enrichment

Pulse cores 200wt

U coating 200wt


p (300K) 1008Keff

p (800K) 09997

11





①

②

11

③

12












13

Conclusions



14







Background


Purpose of study

Methodology








Conclusions


10


Region Enrichment

Pulse cores 200wt

U coating 200wt


p (300K) 1008Keff

p (800K) 09997

11





①

②

11

③

12












13

Conclusions



14







Background


Purpose of study

Methodology








Conclusions


11





①

②

11

③

12












13

Conclusions



14







Background


Purpose of study

Methodology








Conclusions


12












13

Conclusions



14







Background


Purpose of study

Methodology








Conclusions


13

Conclusions



14







Background


Purpose of study

Methodology








Conclusions


14







Background


Purpose of study

Methodology








Conclusions


Kinetic Analysis of Coupled Pulse Reactor for NPL Experimenttobara/research/hikarigenshiro... ·...

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