300+ [REAL TIME] Nuclear Waste Interview Questions

1. Is There A Difference Between Spent Nuclear Fuel And Used Nuclear Fuel?

There is no substantive difference; the difference is in name only. Some people do not like to use the term “spent nuclear fuel” (SNF) because it implies that the fuel is “spent” when it has energy remaining in it that could be recovered and reused in another reactor; thus, the preference of some is to use the term “used nuclear fuel” (UFS). By highlighting that the fuel is not “spent” but “used,” it raises awareness that there is energy remaining in the fuel.

2. Are There Any Long-term Storage Or Disposal Solutions Already In Place In The United States?

There is one long-term disposal site for nuclear waste in the United States. The Waste Isolation Pilot Plant (WIPP) located in Carlsbad, New Mexico, is approved to accept and dispose of defense related transuranic waste. Defense-related transuranic waste is waste that resulted from the development and production of nuclear weapons in the United States. WIPP has suspended operations until it can recover from a release of radioactive material in February 2014.

3. How Long Is The Nuclear Waste Radioactive?

The length of time that nuclear waste is radioactive depends on the radionuclide’s (or radioisotope) in the waste. Different radionuclide’s have different half-lives (the time it takes for half of the radionuclide to decay). For spent nuclear fuel, the waste will remain radioactive for hundreds of thousands of years.

4. Is Dry Cask Storage Safer Than Pool Storage?

Spent nuclear fuel (SNF) is stored either in pools of water designed to hold the SNF or in large, concrete enclosures called dry casks. The NRC provides requirements for the safe and secure storage of the SNF and based on satisfying those requirements, issues a license for SNF storage. Either method of storage is safe. However, SNF fuel requires a degree of cooling which is dependent on the time passed since it was removed from the reactor: the longer the time out of the reactor, the less cooling required.

SNF pools cool the fuel by circulating cool water throughout the pool, which requires a system of pipes, valves, and pumps. Dry cask storage also provides cooling but in a passive way by using natural convection which requires no pipes, valves, or pumps. All things being equal, passive systems (natural convection in this case) have advantages over active systems (mechanical pumps) that accomplish the same function of cooling.

5. Would Waste Be Transported By Rail Or Truck If It Needed To Be Moved To A Regional Or National Storage Facility?

Waste is likely to be transported by both rail and over the road by truck. Also, where it makes sense, waterways could be used. The spent fuel transportation packages are certified by the NRC to meet very stringent requirements for shipment by rail, truck, or ship.

6. I Heard The Federal Government Is No Longer Collecting A Disposal Fee From Nuclear Energy Generators. Why Did That Stop?

That is true. The federal government is no longer collecting the waste fee from nuclear energy generators. The waste fee of 1 mill/kWh was set to zero by DOE in May 2014. This action was the result of a U.S. Court of Appeals decision in a lawsuit brought by the National Association of Regulatory Utility Commissioners and the Nuclear Energy Institute. The court found that because the Obama administration’s termination of the Yucca Mountain program, for which the fee was intended, DOE could not continue collecting the waste fee. Setting the waste fee to zero complied with the Court’s intention.

7. What Does The Top Of The Pressurizer In Pressurized Water Reactor Consists Of At Primary System Pressure?

The pressurizer is a pressure vessel with a heater at the bottom and water spray at the top. The top of the pressurizer is filled with steam at primary system pressure. If the primary loop pressure drops, the heater is energized to increase the steam content in the pressurizer and thus increases the pressure of primary cooling system.

8. What Does Lwr Stands For ?

The light water reactor is a type of thermal-neutron reactor that uses normal water, as opposed to heavy water, as both its coolant and neutron moderator – furthermore a solid fissile element is used as fuel. These are most common type of Thermal-neutron reactors.

9. In Which Reactor Is The Coolant In Direct Contact With The Heat Producing Nuclear Fuel?

In boiling water reactor, the coolant is in direct contact with the heat producing nuclear fuel and boils in the same compartment in which the fuel is located. The reactor pressure is maintained at 70bar. The coolant thus serves the triple function of coolant, moderato and working fluid.

10. How Many Types Of Boiling Water Reactor Cycles Are There?

There are three different types of BWR cycles commonly used:

Single cycle internal circulation:
This system uses internal recirculation system to generate power ranging from 50- 100 MW.

Single cycle forced circulation:
This type uses a forced circulation system using a circulation system using a circulating pump. The heat in the reactor is used to generate steam.

Dual cycle forced circulation:
this arrangement has two cycles, steam cycle and gas cycle.

11. Which Country Invented Candu Heavy Water Reactor?

The CANDU is a Canadian pressurized heavy water reactor design used to generate electric power. Heavy water nuclear reactors and light water nuclear reactors differ in how they create and manage the complex physics of nuclear fission or atom-splitting which produces the energy and heat to create steam to drive generators.

12. In Which Of The Following Reactor Is Heavy Hydrogen Isotope H-2 Is Used As Moderator?

Heavy water composed of heavy hydrogen isotope H-2 is used as a moderator and coolant in some power and research reactors. These reactors use heavy water as a moderator and primary coolant and light water as secondary coolant.

13. What Does Candu Stand For?

The CANDU, for Canada Deuterium Uranium, is a Canadian pressurized heavy water reactor design used to generate electricity. The acronym refers to its deuterium oxide (heavy water) moderator and its use of (originally natural) Uranium fuel.

14. Which Reactor Consists Of Both Fertile And Fissile Material?

If the reactor produces more fissionable material than it consumes, it is fast breeder reactor. The breeder fuel consists of both fertile and fissile material. The number of neutrons released is sufficient to propagate the fission reaction and to produce more fissionable material by conversion of fertile isotopes to fissile isotopes.

15. What Is Acronym Of Lmfbr?

LMFBR stands for Liquid metal fast breeder reactor. The fuel consists of 80% by weight of UO2 by weight of PuO2 in small diameter stainless steel clad tubes operating at temperature of 670^oC – 700^oC.

16. What Does Gcfbr Mean?

The GCFBR stands for Gas cooled fast breeder reactor; it is cooled by helium gas at 85bar. Also helium doesn’t become radioactive under neutron bombardment AND hence secondary coolant is not needed.

17. Using Helium Gas In Gcfbr Has Many Advantages?

Using helium as coolant posses less severe metallurgical and safety problems. Heat transfer coefficient of helium is much superior than sodium with artificial roughening of fuel rod surfaces. Low doubling time as compared to sodium cooled reactors.

18. Which Reactor Uses Orthometaerhenyl And Paratherphenyl As Coolant And Moderator?

Organic substance cooled reactor uses enriched uranium as fuel and a mixture of orthometaterhenyl and paratherphenyl as coolant and moderator, and boron control rods, generating 11.4 MW capacities with an overall efficiency of 25%.

19. Nuclear Plant Is Located Near The Area Where Cooling Water Is Available.?

Some of the major factors to locate a nuclear station considered are, Availability of cooling water, transportation facilities, Distance from load centre, safety, radioactive waste, disposal facility and foundation requirement.