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Design and construction of BNCT irradiation

facility at Tehran research reactor

1Nuclear Science and Technology Research Institute (NSTRI), Iran2Department of Physics, K.N.T University, Iran

Yaser Kasesaz

Isfahan

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Contents

BNCT project at Iran

Introduction to TRR

Structure of thermal column

Epithermal neutron beam design

Main challenges in construction process

Thermal neutron beam design

New challenges

Measurements of the neutron beam parameters

Conclusions

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BNCT project at Iran

Yazd

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~ 1990: The first attempt was conducted by Dr. Marashi & Dr. Pazirandeh

2009- Continue: A new Project has been defined at NSTRI:

in 5 International Symposium on Neutron Capture Therapy (1992)

The results showed that the neutron flux at none of the beam exits is not sufficient

Construction of BNCT facility at TRR

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Boron Drug

Phantom

TPS

ShieldingBoron Measur.

Dosimetrysystem

Simulatorroom

Medical room

Neutron Beam

The project has different sub-projects

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Introduction to TRR

Kashan

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Seven Beam Tubes

TRR is a 5 MW MTR, pool type research reactor

fuel assemblies : LEU, plates ,U3O8 Al alloy

Reactor pool has two major parts, stall-end and open pool

Irradiation facilities:

In-core irradiation boxes

Two rabbit systems

Medical room

Gamma room

Main application: radioisotopes production

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it has been shown that the thermal column is the best facility which can be adapted for BNCT

Appl. Radiat. Isot, 90, 132-137 (2014).

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Structure of Thermal column

Shiraz

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Is it possible to remove all graphite blocks?

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All parts placed in their position for routine TRR activity

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Epithermal Neutron Beam Design

Shiraz

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Core

Lead Graphite

Reactor pool

Concrete

Concrete

Reflector

Reflector

Moderator

Collimator

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Moderator: Al (30 cm)

Reflector : Pb (35 cm)

Gamma filte: Two Bi Layers (5 cm)

Thermal neutron filter: Cd (2 mm)

Ann. Nucl. Energy (2014) 234–238

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Main Challenges in construction process

Shiraz

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high gamma dose caused by activated materials in the reactor structure

Access to 3th and 4th graphite layers

a new project is defined to design the thermal beam instead of epithermal beam

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Thermal Neutron Beam Design

Ramsar

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the 3Th and 4Th graphite layers are fixed

From the first layer only 9 special blocks are removed

For the 2Th layer three different configurations have been studied

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three different configurations

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Thermal neutron Flux: 2.6E7 (n/cm2.s)

Cadmium Ratio: 112

Measurement of neutron beam parameters: at 90 kW

Gamma Dose Rate: failed

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New Challenges

Isfahan

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The new challenge : Gas and particle contamination at the reactor hall

Air

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Solution 1: using wood blocks

Not effective

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Solution 2: re- arranging the blocks in the second layer

It is effective

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Designed Neutron Beam Parameters

Isfahan

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Gamma Dose Rate: 0.19 mSv/Min (at 100 kW)

Neutron beam parameters:

Thermal neutron Flux: 1.7E8 (n/cm2.s) at 1.5 MW

Cadmium Ratio: 186

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Conclusions

Shiraz

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Conclusions

The designed beam has two major advantages:

We impose minimal changes in the thermal column structure

A sample or phantom can be irradiated outside of the thermal column

thermal neutron beam has been constructed based on the use of thermal column.

The arrangement of graphite blocks has been modified to provide a thermal neutron beam.

The final results have been shown that the thermal neutron flux at the beam port is 1.7E8 (n/cm2.s) at 1.5 MW which is appropriate for BNCT.

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Thank you ….

Isfahan