BARC OCES Nuclear Science Mastery

Define and distinguish radiation quantities: exposure, absorbed dose, equivalent dose, and effective dose.

Convert between common radiation units: Roentgen, rad/Gray, and rem/Sievert.

Describe the biological effects of radiation: deterministic vs. stochastic effects.

Explain the ALARA principle and the three pillars of radiation protection: time, distance, and shielding.

Describe personnel dosimetry methods, including TLD badges and electronic dosimeters.

State the ICRP and AERB regulatory dose limits for radiation workers and the general public.

Identify common radiation detection instruments and their primary applications (e.g., GM counter, scintillation detector).

Explain contamination control principles and basic decontamination procedures.

Recall nuclear composition: nucleons, isotopes, isobars, and isotones.

Calculate nuclear binding energy and mass defect using mass-energy equivalence.

Interpret the binding energy per nucleon curve to explain energy release in fission and fusion.

Describe the liquid drop model of the nucleus and its key assumptions.

Explain the semi-empirical mass formula (Weizsäcker formula) and the physical meaning of each term.

Describe the nuclear shell model and explain the significance of magic numbers.

Read and interpret the chart of nuclides (Segré chart) to identify stable and unstable regions.

Describe alpha, beta-minus, beta-plus, and gamma decay modes and their physical mechanisms.

Write and balance nuclear decay equations, conserving charge, mass number, and lepton number.

Derive the exponential radioactive decay law from first principles.

Calculate half-life, mean life, and activity for a given radioactive sample.

Analyse decay chains and distinguish between secular and transient equilibrium.

Interpret nuclear decay schemes and energy level diagrams to determine decay properties.

Describe how heavy charged particles (e.g., alpha particles) lose energy in matter via ionization.

Describe electron and positron interactions with matter, including ionization and bremsstrahlung.

Explain the three major photon interactions: photoelectric effect, Compton scattering, and pair production.

Define linear and mass attenuation coefficients and their relation to photon energy.

Apply the exponential attenuation law to perform basic gamma-ray shielding calculations.

Explain the concept of buildup factor and its importance in practical shielding design.

Describe the primary modes of neutron interaction with matter: scattering and capture.

Classify nuclear reactions, including elastic scattering, inelastic scattering, radiative capture, and fission.

Calculate the Q-value for a nuclear reaction to determine if it is exothermic or endothermic.

Define microscopic cross-section and explain its physical meaning as a measure of reaction probability.

Relate microscopic cross-section to macroscopic cross-section using material number density.

Define neutron flux and calculate reaction rates using flux and macroscopic cross-section.

Conceptually describe resonance behavior in neutron cross-sections.

Describe the mechanism of nuclear fission using the liquid drop model.

Distinguish between fissile, fissionable, and fertile nuclides, providing key examples (U-235, U-238, Pu-239).

Calculate the approximate energy released per fission event and describe its distribution.

Explain the origin of prompt and delayed neutrons and why delayed neutrons are essential for reactor control.

Define the neutron multiplication factor (k) and distinguish between subcritical, critical, and supercritical states.

Define the four factors (η, f, p, ε) describing the neutron life cycle in an infinite thermal reactor.

Combine the factors to derive the infinite multiplication factor (k-inf) using the four-factor formula.

Extend to the six-factor formula by including non-leakage probabilities to obtain the effective multiplication factor (k-eff).

Classify neutrons by energy: thermal, epithermal, and fast.

Explain neutron moderation (slowing down) and the desirable properties of a moderator.

Use the average logarithmic energy decrement and moderating ratio to compare moderator effectiveness (e.g., H₂O, D₂O, C).

Explain the 1/v dependence of neutron absorption cross-sections at low energies.

State Fick's law for neutron diffusion and explain the physical meaning of the diffusion coefficient.

Set up the one-group, steady-state neutron diffusion equation for a simple homogeneous medium.

Solve the one-group diffusion equation for a bare infinite slab reactor to find the flux distribution and criticality condition.

Solve the one-group diffusion equation for a bare spherical reactor to find the flux distribution and criticality condition.

Define reactivity and express it in units of Δk/k and pcm.

Explain the quantitative role of the delayed neutron fraction (β) and express reactivity in dollars.

Conceptually explain the point kinetics equations, which relate reactivity to reactor period.

Explain the concept of prompt criticality and why it must be avoided in thermal reactors.

Describe temperature reactivity feedback mechanisms, including the fuel (Doppler) and moderator temperature coefficients.

Explain xenon-135 poisoning and its effect on reactor operation and startup.

Describe primary reactor control methods, such as control rods, chemical shims, and burnable poisons.

Identify the major components of a nuclear reactor: core, moderator, coolant, reflector, control system, and shielding.

Compare light water and heavy water as moderators and coolants in terms of neutron economy.

Describe the key design features of a Pressurized Heavy-Water Reactor (PHWR), including the calandria and pressure tubes.

Explain the process and operational advantages of on-power refueling in a PHWR.

Describe the basic design and operating principles of a Pressurized Water Reactor (PWR).

Describe the basic design and operating principles of a Boiling Water Reactor (BWR).

Describe the design principles of a Fast Breeder Reactor (FBR), including the role of liquid sodium coolant.

Explain India's three-stage nuclear power programme and the rationale for each stage.

Describe the front-end of the fuel cycle: uranium mining, milling, and conversion.

Explain why PHWRs can use natural uranium and briefly describe enrichment for LWR fuel.

Describe the fabrication of PHWR fuel bundles from natural UO₂ pellets.

Explain key in-reactor fuel performance changes, such as fission product gas release.

Define fuel burnup, conversion ratio, and breeding ratio.

Describe spent fuel reprocessing using the PUREX process for plutonium recovery.

Classify radioactive waste (LLW, ILW, HLW) and describe management strategies for each.

Explain India's closed fuel cycle policy and the strategic importance of reprocessing.

Describe radiation damage mechanisms in metals, including displacement cascades initiated by a Primary Knock-on Atom (PKA).

Explain key radiation-induced phenomena in materials: hardening, embrittlement, void swelling, and irradiation creep.

Explain the selection criteria for key structural materials (e.g., Zircaloy, stainless steels) based on neutronic properties and in-reactor performance.

Explain why zirconium alloys are the preferred fuel cladding material in most thermal reactors.

Describe unique corrosion mechanisms in reactor environments, such as Irradiation-Assisted Stress Corrosion Cracking (IASCC).

Discuss challenges and applications of NDT for in-service inspection of irradiated components in high-radiation fields.