Research & Development Activities – Research Projects:Critical Facility , BARC
Source: http://www.barc.gov.in/randd/cf.html
Archived: 2026-04-23 17:09
Research & Development Activities – Research Projects:Critical Facility , BARC
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हिन्दी
Advanced Heavy Water Reactor – Critical Facility (AHWR-CF)
The long-term energy needs of India require utilisation of its large Thorium reserves. Advanced Heavy Water Reactor (AHWR) being developed at BARC envisages large scale utilization of Thorium. A Critical Facility is operational at BARC for validating the reactor physics design and nuclear data for AHWR.
AHWR-CF is a low power research reactor with a nominal power of 100 W. The aluminium reactor tank houses fuel assemblies and moderator. A square box above the reactor tank houses the lattice girders from which the fuel assemblies are suspended. The lattice girders can be moved to vary the pitch. These lattice girders also support the reactor shutdown devices. The top of the square box is closed by a revolving floor, which also permits access to any of the lattice location for handling operations.
Salient features of AHWR-Critical Facility
Parameter
Description
Nominal reactor power
100 watts
Average Neutron flux
108 n/cm2/sec
Moderator
Heavy Water
Reflector
Heavy Water
Lattice pitch
Adjustable (215 mm~300mm)
Shut down
Six fast acting Cd shut off rod
Moderator dump
Neutron monitoring
Independent safety and regulating channels to monitor the neutronic power.
Reactor trip
Partial moderator dump along with shut off rod drop
Power control
By manual control of moderator level.
By Inventory control of Moderator
Uses
Validation of reactor physics design codes, nuclear data, activation analysis, detector testing
The major core configurations of AHWR-CF are:
Reference Core
The reference core was initially configured with 55 lattice locations in a lattice pitch of 245 mm, where 49 were occupied by 19 pin natural uranium metal fuel clusters and 6 locations with shut-off rods. Later in 2014, the core was extended to 61 locations with 55 locations for fuel cluster for gaining reactivity in order to perform experiments with thoria based fuel.
AHWR Representative Core
The core for performing detailed experiment with AHWRF will be constituted by replacing the central natural uranium metal fuel clusters with AHWR type of fuel, i.e.54 pin AHWR (Th-Pu Oxide, Th-U233 Oxide) Clusters. Experiments will be performed with AHWR fuel in a typical AHWR neutron spectrum.
AHWR-CF attained its first criticality on 7th April, 2008. The observed critical height for the Reference core configuration was 226.7 cm which agreed well with the estimated value of 226.5 cm.
A large number of reactor physics experiment has been performed in the Reference core of the facility. These experiments ranged from the initial commissioning experiments to various integral and differential measurements. Some of the important experiment carried out at AHWR-CF are as follows:
First approach to criticality of AHWR-CF
Reactor power calibration by absolute flux measurement by activation method
Reactivity worth measurement of six Shut-off Rods and Absorber rod
Differential flux measurement experiments
Axial flux distribution measurements on the central fuel cluster
Flux measurement at detector location
Neutron spectrum measurement on the central cluster by Foil-Activation Technique
Measurement of level coefficient of reactivity of Reference Core
Fine structure neutron flux measurement in Nat. U Experimental Cluster and Mixed Pin Thoria Cluster placed in central location
Gamma scanning of Nat. Uranium and Thorium pin irradiated at central location
Integral measurements
Critical height measurement with various types of experimental clusters
(NU – ThO
2
) Mixed 19-Pin
(Th-Pu (1%)) Six Pin Special Cluster
(Th-LEU) Six Pin MOX Cluster
(NU-ThO
2
-NU) 19-pin Sandwich Cluster
((Th-1%Pu) MOX, NU-ThO
2
-NU) Mixed 19-pin cluster
Measurement of the Moderator Temperature Coefficient of Reactivity
Measurement of Westcott neutron spectrum parameters
Photoneutron decay studies
Subcriticality measurement using neutron noise method
Radial and axial flux profile in experimental mixed 19-pin cluster AHWR type fuel with {(Th-1%Pu) MOX, NU-ThO
2
-NU}
Coolant void worth measurement in experimental Mixed 19-pin cluster AHWR type fuel with {(Th-1%Pu) MOX, NU-ThO
2
-NU}
Spotlight for AHWR Critical Facility
Layout of the AHWR Core with lattice girders
Natural uranium fuel cluster
Some experimental results from AHWR-CF"
Skip to main content
A+
A
A-
A
हिन्दी
Advanced Heavy Water Reactor – Critical Facility (AHWR-CF)
The long-term energy needs of India require utilisation of its large Thorium reserves. Advanced Heavy Water Reactor (AHWR) being developed at BARC envisages large scale utilization of Thorium. A Critical Facility is operational at BARC for validating the reactor physics design and nuclear data for AHWR.
AHWR-CF is a low power research reactor with a nominal power of 100 W. The aluminium reactor tank houses fuel assemblies and moderator. A square box above the reactor tank houses the lattice girders from which the fuel assemblies are suspended. The lattice girders can be moved to vary the pitch. These lattice girders also support the reactor shutdown devices. The top of the square box is closed by a revolving floor, which also permits access to any of the lattice location for handling operations.
Salient features of AHWR-Critical Facility
Parameter
Description
Nominal reactor power
100 watts
Average Neutron flux
108 n/cm2/sec
Moderator
Heavy Water
Reflector
Heavy Water
Lattice pitch
Adjustable (215 mm~300mm)
Shut down
Six fast acting Cd shut off rod
Moderator dump
Neutron monitoring
Independent safety and regulating channels to monitor the neutronic power.
Reactor trip
Partial moderator dump along with shut off rod drop
Power control
By manual control of moderator level.
By Inventory control of Moderator
Uses
Validation of reactor physics design codes, nuclear data, activation analysis, detector testing
The major core configurations of AHWR-CF are:
Reference Core
The reference core was initially configured with 55 lattice locations in a lattice pitch of 245 mm, where 49 were occupied by 19 pin natural uranium metal fuel clusters and 6 locations with shut-off rods. Later in 2014, the core was extended to 61 locations with 55 locations for fuel cluster for gaining reactivity in order to perform experiments with thoria based fuel.
AHWR Representative Core
The core for performing detailed experiment with AHWRF will be constituted by replacing the central natural uranium metal fuel clusters with AHWR type of fuel, i.e.54 pin AHWR (Th-Pu Oxide, Th-U233 Oxide) Clusters. Experiments will be performed with AHWR fuel in a typical AHWR neutron spectrum.
AHWR-CF attained its first criticality on 7th April, 2008. The observed critical height for the Reference core configuration was 226.7 cm which agreed well with the estimated value of 226.5 cm.
A large number of reactor physics experiment has been performed in the Reference core of the facility. These experiments ranged from the initial commissioning experiments to various integral and differential measurements. Some of the important experiment carried out at AHWR-CF are as follows:
First approach to criticality of AHWR-CF
Reactor power calibration by absolute flux measurement by activation method
Reactivity worth measurement of six Shut-off Rods and Absorber rod
Differential flux measurement experiments
Axial flux distribution measurements on the central fuel cluster
Flux measurement at detector location
Neutron spectrum measurement on the central cluster by Foil-Activation Technique
Measurement of level coefficient of reactivity of Reference Core
Fine structure neutron flux measurement in Nat. U Experimental Cluster and Mixed Pin Thoria Cluster placed in central location
Gamma scanning of Nat. Uranium and Thorium pin irradiated at central location
Integral measurements
Critical height measurement with various types of experimental clusters
(NU – ThO
2
) Mixed 19-Pin
(Th-Pu (1%)) Six Pin Special Cluster
(Th-LEU) Six Pin MOX Cluster
(NU-ThO
2
-NU) 19-pin Sandwich Cluster
((Th-1%Pu) MOX, NU-ThO
2
-NU) Mixed 19-pin cluster
Measurement of the Moderator Temperature Coefficient of Reactivity
Measurement of Westcott neutron spectrum parameters
Photoneutron decay studies
Subcriticality measurement using neutron noise method
Radial and axial flux profile in experimental mixed 19-pin cluster AHWR type fuel with {(Th-1%Pu) MOX, NU-ThO
2
-NU}
Coolant void worth measurement in experimental Mixed 19-pin cluster AHWR type fuel with {(Th-1%Pu) MOX, NU-ThO
2
-NU}
Spotlight for AHWR Critical Facility
Layout of the AHWR Core with lattice girders
Natural uranium fuel cluster
Some experimental results from AHWR-CF"