venus-1# 装置脉冲源实验分析
DESCRIPTION
VENUS-1# 装置脉冲源实验分析. 谢金森 ( [email protected] ) 南华大学. Contents. Background and Purpose Core Composition & PNS Experiment of VENUS-1# Preliminary Results from PNS Experiment Simulation of PNS Experiment on Certain Condition Comparison of Simulated and Experimental Results - PowerPoint PPT PresentationTRANSCRIPT
NEAL-Nuclear Energy & Application Lab, University of South China
第一届新型反应堆安全及发展研讨会,中国 兰州, 2013.10.10 ~ 12
VENUS-1# 装置脉冲源实验分析谢金森( [email protected])
南华大学
第一届新型反应堆安全及发展研讨会
CONTENTS
Background and Purpose Core Composition & PNS Experiment of VENUS-
1# Preliminary Results from PNS Experiment Simulation of PNS Experiment on Certain
Condition Comparison of Simulated and Experimental
Results Summary & Future Suggestions
第一届新型反应堆安全及发展研讨会BACKGROUND AND
PURPOSEBackground
R&D on Accelerator Driven System for MA and LLFP Transmutation
Supported by two “973” Projects The World-first Fast-Thermal Coupled ADS core- VENUS-1# has
been built in 2005; Abundant research works on Sub-critical neutronics have been
carried out on VENUS-1#.
Supported by Chinese Academy of Science 5MWt~10MWt Pb-Bi cooled ADS core will be built (First-step,
Critically Operation; Second-step, Accelerator coupling with sub-critical core );
Although massive meaningful results has been obtained, some issues on Sub-criticality measuring still exist.
第一届新型反应堆安全及发展研讨会BACKGROUND AND
PURPOSEBackground
To support the development of sub-criticality measuring technique, Pulsed Neutron Source experiments on VENUS-1# has been performed
2005, VENUS-1# was coupled with CPNG (CIAE Pulsed Neutron Generator), five different Sub-critical levels;
2007, the first PNS experiment analysis work was published (Thesis of Shanghai Jiaotong Univ.) ;
2011, PNS experiment simulation work was performed, three different Sub-critical levels, D-T, 252Cf, Am-Be neutron sources(Thesis of CIAE).
All the above works indicate: Prompt neutron attenuation constants depend on detectors’ locations & driven source energy.
第一届新型反应堆安全及发展研讨会
Fuel pins of Thermal
blanket
Prompt neutron attenuation constants
Detector_6th Detector_10th Detector_R Detector_S
2046 1627.6±22.4 (1)
795.33 (2)1705.0±25.0
763.762495.4±67.8
709.701350.4±36.4
--2022 1716.2±26.4
840.021702.0±14.4
832.112426.2±23.4
758.171576.4±17.9
--1998 1771.8±41.4
960.641888.0±48.0
985.873056.6±83.2
879.901671.2±62.0
--1962 1823.6±14.4
967.851922.4±16.4
985.873868.8±32.2
921.401646.6±17.5
--1926 1928.8±14.4
1119.501946.4±11.9
1076.404311.4±18.2
1076.401662.4±33.6
--(1) Experimental results of CIAE;(2) MC simulation results of SJTU.
BACKGROUND AND PURPOSE
第一届新型反应堆安全及发展研讨会BACKGROUND AND
PURPOSE
Purpose
Confirm the results from former researches;
Feasibility study of PNS method on Fast-thermal coupled core;
Investigate the potentially special phenomenon of Fast-thermal coupled core under pulsed neutron condition.
第一届新型反应堆安全及发展研讨会CORE COMPOSITION & PNS EXPERIMENT OF VENUS-1#
Core Composition Main parameters of VENUS-1#
External source region: coupled with accelerator, neutron tube, or isotopic neutron source;
Fast spectrum blanket: natural uranium pins + aluminum block, 10 layers;
Thermal spectrum blanket : 3wt% uranium pins+ CH2 block, 15 layers maximum;
Reflector: CH2 block, 200mm thick;
Shield: CH2+B, 200mm thick;
第一届新型反应堆安全及发展研讨会CORE COMPOSITION & PNS EXPERIMENT OF VENUS-1#
CPNG neutron generator(CIAE Pulse Neutron Generator )
Main parameters of CPNG
Type: Cockcroft-Walton
High voltage: 200~600kV
Pulse beam frequency: 50~200Hz
Pulse width:1~5us
第一届新型反应堆安全及发展研讨会
Experimental conditions & instrument system
Detectors
Sub-criticalities: adjusted by thermal fuel pin loading; 1926, 1962, 1998, 2022, 2046;
Detectors: 3 3He tubes (6th, 10th layer of fast blanket & reflector); 1 BF3 tubes (Shield)
Electronic system: 60 multi-channels; 50us/channel;
Data collection: 3 groups data; 105 pulses; statistical errors for first several channels < 1%;
CORE COMPOSITION & PNS EXPERIMENT OF VENUS-1#
第一届新型反应堆安全及发展研讨会PRELIMINARY RESULTS FROM PNS EXPERIMENT
0 10 20 30 40 50 60
-0.010.000.010.020.030.040.050.060.070.080.090.100.110.120.130.140.150.160.170.18
6th 10th R S
Nor
mar
ized
Neu
tron
Cou
nt R
ate
Channel Number
Thermal blanket with 1926 fuel pins
0 10 20 30 40 50 60
-0.010.000.010.020.030.040.050.060.070.080.090.100.110.120.130.140.150.160.17
6th 10th R S
Nor
mar
ized
Neu
tron
Cou
nt R
ate
Channel Number
Thermal blanket with 1962 fuel pins
0 10 20 30 40 50 60
0.00
0.02
0.04
0.06
0.08
0.10
0.12
6th 10th R S
Nor
mar
ized
Neu
tron
Cou
nt R
ate
Channel Number
Thermal blanket with 1998 fuel pins
0 10 20 30 40 50 60
0.0000.0050.0100.0150.0200.0250.0300.0350.0400.0450.0500.0550.0600.0650.0700.0750.0800.085
6th 10th R S
Nor
mar
ized
Neu
tron
Cou
nt R
ate
Channel Number
Thermal blanket with 2022 fuel pins
0 10 20 30 40 50 60
0.00
0.02
0.04
0.06
0.08
0.10
0.12
6th 10th R S
Nor
mar
ized
Neu
tron
Cou
nt R
ate
Chanel Number
Thermal blanket with 2046 fuel pins
Fuel pins of
Thermal blanket
Prompt neutron attenuation constants
6th 10th R S
2046 1627.6±22.4 1705.0±25.0 2495.4±67.8 1350.4±36.4
2022 1716.2±26.4 1702.0±14.4 2426.2±23.4 1576.4±17.9
1998 1771.8±41.4 1888.0±48.0 3056.6±83.2 1671.2±62.0
1962 1823.6±14.4 1922.4±16.4 3868.8±32.2 1646.6±17.5
1926 1928.8±14.4 1946.4±11.9 4311.4±18.2 1662.4±33.6
第一届新型反应堆安全及发展研讨会PRELIMINARY RESULTS FROM PNS EXPERIMENT
Discussion on the experimental results
Prompt neutron attenuation constants show strong spatial dependence;
The attenuation constants obtained by detectors show large discrepancies;
The experimental results conflict with theory of experimental reactor physics (lumped parameter Point Reactor Dynamics) ;
Which attenuation constant should be used as a sub-critical indicator, or how to make spatial corrections.
第一届新型反应堆安全及发展研讨会SIMULATION OF PNS EXPERIMENT ON CERTAIN CONDITIONTheoretical considerations
Harmonics neutron flux seriously affects detector responses in deep sub-critical condition (both static & transient ) ;
For Fast-thermal coupled system, typical prompt neutron life time is 10-5 second, width of multi-channel should be correspond to the condition for better inferring of harmonics (can be easily realized in simulation);
To obtain the prompt neutron attenuation constants (fundamental mode), harmonics should be filtered.
第一届新型反应堆安全及发展研讨会SIMULATION OF PNS EXPERIMENT ON CERTAIN CONDITIONTheoretical considerations
( , ) ( ) ( )r t r T t
In transient conditions, neutron flux can be expressed as:
Consider Alpha Eigen-value problem, neutron density in PNS:
1
00 )()()()()(),(i
tii
tt ierrAerrAerStrN
Contribution of external source
Contribution of fundamental Alpha mode
Contributions of the ith harmonic Alpha modes
terS )(terrA )()( 00
tii
ierrA )()(
第一届新型反应堆安全及发展研讨会SIMULATION OF PNS EXPERIMENT ON CERTAIN CONDITIONTheoretical considerations
Relationship of each attenuation constant:
When harmonics and source contribution disappeared:
i21
constrrArrA
trNtrN
tt
)()()()(
),(),(
2020
1010
2
1
0
第一届新型反应堆安全及发展研讨会SIMULATION OF PNS EXPERIMENT ON CERTAIN CONDITIONMethodology of simulation Simulation conditions:
MCNP4CTM selected as PNS simulation code;
2046 thermal fuel pins loading for comparison with experiment;
Multi-channel width set as 5us for better inferring harmonics effect, totally 600 channels (0~3000us, the same as experiment);
Data processing technique:
Detector response of R selected as benchmark;
Relative responses to R used for fundamental attenuation time region search;
第一届新型反应堆安全及发展研讨会
Simulation results
SIMULATION OF PNS EXPERIMENT ON CERTAIN CONDITION
0 100 200 300 400 500 60010-4
10-3
10-2
10-1
100
101
102
6th
R10th
6th 10th R S
Rel
ativ
e N
eutro
n C
ount
(s-1)
Time(5s)
S
0 50000 100000 150000 200000 250000 3000000.01
0.1
1
10
100
1000 6th/R 10th/R S/R
Rel
ativ
ed N
eutro
n C
ount
rate
Time(10-8s)
Fundamental decay mode
Simulated detector responses Simulated relative detector responses
第一届新型反应堆安全及发展研讨会
Simulation results
Detector responses in time interval 500~3000us selected as fundamental attenuation constant fitting
SIMULATION OF PNS EXPERIMENT ON CERTAIN CONDITION
Detectors 6th 10th R SAlpha values 1430.30±8.7
11436.76±3.9
91436.60±3.4
91417.35±1.1
2Correlationcoefficients 0.99087 0.99809 0.99853 0.99984
第一届新型反应堆安全及发展研讨会COMPARISON OF SIMULATED AND EXPERIMENTAL RESULTS
Comparison of detector responses The simulated data use the same channel width of experiment; Quite different attenuation trends observed.
0 10 20 30 40 50 60
1E-3
0.01
0.1
6th 10th R S
Nor
mar
ized
Neu
tron
Cou
nt R
ate
Channel Number0 10 20 30 40 50 601E-3
0.01
0.1
1
10
100
6th 10th R S
Neu
tron
coun
t rat
e
Channel number
Simulated data Experimental data
第一届新型反应堆安全及发展研讨会COMPARISON OF SIMULATED AND EXPERIMENTAL RESULTS
Comparison of Alpha constants Original experiment data; harmonics filtered simulated data; harmonics filtered experimental data.
0 10 20 30 40 50 60
1E-3
0.01
0.1
6th 10th R S
Nor
mar
ized
Neu
tron
Cou
nt R
ate
Channel Number
10 20 30 40 50 60
1E-3
0.01
0.1
B C D E
Neu
tron
Cou
nt ra
tes
Channels(50s/channel)
Original Exp. data
Harmonics filtered Exp. Data(500~3000us)
Alpha values 6th 10th R S
Original Experimenta
l data1627.6±22.4 1705.0±25.0 2495.4±67.8 1350.4±36.4
Harmonics filtered
Experimental data
1664.2±55.8 1521.0±30. 2 2902.0±78. 7 1385.6±59.0
Harmonics filtered
simulated data
1430.30±8.71 1436.76±3.99 1436.60±3.49 1417.35±1.1
2
第一届新型反应堆安全及发展研讨会COMPARISON OF SIMULATED AND EXPERIMENTAL RESULTS
Comparison of Alpha constants original experimental data; harmonics filtered simulated data; harmonics filtered experimental data.
6th 10th R S1200
1400
1600
1800
2000
2200
2400
2600
2800
3000
Original experiment Alpha Simulated Alpha with harmonics filtering Original exp. data with harmonics filtering
Alp
ha v
alue
s
Detector label
The Alpha indicated by detector 10th has been improved;
The Alpha value obtained by detector S is closest to simulated one;
The Alpha value of detector R still show big discrepancy.
第一届新型反应堆安全及发展研讨会COMPARISON OF SIMULATED AND EXPERIMENTAL RESULTS
Verification of the simulated Alpha In one neutron generation time, the prompt neutron
population:pkTlT )0()(
For sub-critical system:
( ) (0) lT l T e
Relationship between kp and Alpha:l
p ek
kp 6th 10th R SFrom α 0.92492 0.92460 0.92461 0.92558MCNP 0.94117±0.00266△kp* -1.727% 1.761% 1.760% 1.656%
第一届新型反应堆安全及发展研讨会
SUMMARY & FUTURE SUGGESTIONS
Using relative neutron count rates as an indicator, time region for fundamental Alpha mode decay can be easily obtained (a harmonics filtering technique);
The simulated data with harmonics filtering technique give a spatially independent prompt neutron attenuation constants;
Some Alpha values from experiment is improved by harmonics filtering, however some other values are worsen.
Summary
第一届新型反应堆安全及发展研讨会
SUMMARY & FUTURE SUGGESTIONSSuggestions
Since the big discrepancy between experiment and simulation, as well as the short neutron life time and harmonics influence in the Fast-thermal couple ADS core, more rapid electronics data collection system should be used in future PNS experiment;
Although the harmonics filtering technique show the capability for Alpha measuring, the accuracy of calculated prompt neutron generation time plays a key role in verification work (consider the coupling between external neutron source region, fast blanket, thermal blanket and reflector, the effective generation time should be introduced, as well as its calculation theory)
第一届新型反应堆安全及发展研讨会
Thanks for your attention!