Collaboration between IGCAR and FNAL B K Panigrahi

Collaboration between IGCAR and FNAL B. K. Panigrahi and P. Mohanakrishnan Materials Science. Group, Indira Gandhi Centre for Atomic Research, Kalpakkam -603102, India. bkp@igcar. gov. in

Back ground • IGCAR – late starter in collaboration proposals • Compilation of Proposals based on TIFR meeting and subsequent internal discussions • Visit of Prof. Shekhar Mishra • Presentation at TIFR B. K. Panigrahi C. David S. Amirthapandian S. Murugan S. Balaji V. Kartihik V. Gopalkrishnan P. Mohankrishnan Prof. Y Gohar ANL

IGCAR Proposals Areas of Collaboration (a) Material Science (b) Nuclear Data

0. 75 MW proton beam Spallation reactions produce ~1017 neutrons per second Neutrons generated through spallation reactions in tungsten

Radiation damage process Defect generation at high temperature V Atomic displacements I Point Defects (Voids) A highly non equillibrium envirnoment which can give rise to new materials physics phenomenon including formation of bubble and void lattices 400 -700 15 -30 appm

Vacancy and Point Defects interstitial Point defect evolution Secondary defects Temperature and irradiation Recombine Migrate to Sinks Changes in Clustering Voids Dislocation loops Segregation Effects local composition Phase Stability Planar vacancy clusters (dislocation loops) stable; 3 D vacancy cluster Voids (stable if gas (He atoms))

Hardening Instability embrittlement Void swelling Creep GB Embrittlement

Materials Science with high intensity beam

High temperature irradiations carried out under such conditions would result in swelling, irradiation induced hardening and embrittlement of target materials. Thus such an irradiation facility would help design materials (suitable for high performance neutron sources) with tailored microstructures and composition, in order to obtain optimal values of swelling and irradiation induced mechanical properties. ØVoid swelling, - Strong function of He/DPA Ø irradiation induced hardening ØShift in DBTT ØHelium embrittlement RAFM and other advanced ferritic steels

Radiation damage effects in reactor structural materials Enhanced hardening from He bubbles high density of uniformly distributed nanoscale particles can reduce can have new mechanism of fracture swelling and high temperature embrittlement swelling is a function of He/dpa ratio Helium embrittlement of grain boundaries Temperature range (normalized to the melting point Tm) where radiation-damage effects on changes of macroscopic properties occur. (Y-axis in the figure has no significance). Irradiation growth is restricted ot non-cubic materials. Hydrogen embrittlement is expected only for cases with high production rates for hydrogen isotopes such as in spallation target materials and structural materials in PHWR.

ØRastered beam : Dimension to be decided by target design 15 mm nominal spot width 21 mm wide target face The rastered beam provides nearly uniform current density over a 60 mm x 15 mm beam spot Vertical slew covers 60 mm nominal spot height in 750 sec macropulse Fast raster is 20 k. Hz sinusoid plus 8. 8% 60 k. Hz to make it more sawtooth shaped. Subsequent macropulses arrive at a different temporal phase, smearing the average spot vertically. Eric Pitcher, Los Alamos National Laboratory, AHIPA Workshop, Fermilab

Target design 1. reflector materials samples proton beam Beam stop reflector 2. reflector materials samples spallation target proton beam Beam stop materials samples reflector Spatial distribution of the fast neutron flux depends on target design

Neutron flux spectrum To be calculated as per MCNP(X) model H and He production rate (appm/dpa) And displacement rate in Fe to be calculated (dpa/year) Eric Pitcher, Los Alamos National Laboratory, AHIPA Workshop, Fermilab

• Beam raster system for uniform beam spot on target, instrumentation for beam diagnostics and beam dump • Target design for required neutron spectrum • Controlled temperature irradiation- sample cooling • Remote handling : Irradiated samples are transferred to shipping casks in service cell-hot storage and hot cells for measurements target chamber service cell shield wall beamline shield Eric Pitcher, Los Alamos National Laboratory, AHIPA Workshop, Fermilab raster magnets

Design of facilities for Post Irradiation Characterization • The post irradiation characterization of samples for void swelling, mechanical properties studies - setting up of remote handling facilities, hot cells A typical design concept is comprised of : • a suite of six steel-, or steel and concrete-walled hot cells • Adjacent enclosed space for characterization • Ancillary spaces and equipment for sample handling • Waste management, equipment maintenance and transfers, and heating, ventilation, and air conditioning (HVAC) equipment

• Studies on defect interactions at microscopic levels are important in order to understand the evolution of irradiation induced micro-structure FIB method of sample preparation: • Reduces residual activity • enhances the detection sensitivity of characteristic X-rays which often are obscured by background radiation emitted from the radio-active sample Apply state-of-the-art material science tools to irradiated materials and fuels Integrate state-of the art post-irradiation analytical and testing capabilities in hot cells The Advanced Test Reactor National Scientific User Facility Mitch Meyer, Todd Allen, Frances Marshall, Jeff Benson, Mary Catherine Thelen

Nuclear Data Most of the neutron sources, including the reactor neutron sources that have been used in the crosssection measurements, cover the energy range of 0 -15 Me. V, and the data at still higher energies are found to come from predictions. Apart from improving the accuracy of the data in this range, the objective of the proposed measurements under the project-X is to extend the energy range of measurements beyond 15 Me. V, using the advanced technology spallation neutron sources. Results of the measurements for actinides are important in selecting advanced technology options for safe disposal of long lived actinide waste.

The nuclides proposed (with their half-lives given in brackets) are 91 -Pa 231(3. 3 x 104 y), 93 -Np-237 (2. 14 x 106 y), 95 -Am-241 (433 y), 95 -Am-242 m (141 y), 95 -Am-243 (7. 4 x 103 y), 96 -Cm-243 (29 y) and 96 -Cm-245 (8. 4 x 103 y). Of these nuclides, initial experiments are planned for Np-237, Am-241 and possibly Pa-231. Neutron energy dependence of reaction rates The incident neutron spectrum is estimated by (a) standard multi-foil activation measurements and subsequent theoretical interpolation and (b) possibly by a time of flight (TOF) measurement setup. The TOF setup will provide accurate data, but the energy range of measurement will determine the design of TOF facilities.

Actinide samples for irradiation. These valuable and rare isotopes are purchased and stored safely. The weight of the samples will vary from a few mg to a few gm levels. Higher actinides will be available only in very small quantities. Reusable sample cans with variable moderator and shielding. Sample cans are designed for easy handling for introduction and retrieval of irradiated samples. They are designed where necessary for remote handling and quick transfer to the activity measurement setups. Activity measurement setups Individual energy dependent gamma measuring equipments. Total beta-gamma measuring equipments. As some rare activities will be measured, the sensitivity requirements are high. Development of New Time of Flight(TOF) Equipment for Spectrum Measurement Special TOF equipments need to be developed and deployed for measuring the energy spectrum of spallation neutrons. This is planned in collaboration with other experimental groups which plan to use these beam facilities

75 crores from 12 th plan (2012 -2016), 75 crores from 13 th plan (2017 -2021) Salary for students, technicians, faculties and administration, consultancy – 10 crores

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