IAEA Prelim Exam Mod4

Question 1

What is the first step in the nuclear fuel cycle?

Answer 1

Mining natural uranium

This involves extracting uranium from the earth.

Question 2

What is the product of mining natural uranium?

Answer 2

Uranium ore, which is left in powdered form called uranium oxide

Uranium oxide is often referred to as yellowcake.

Question 3

What happens to uranium after it is mined?

Answer 3

It is converted to enriched uranium

Enriched uranium has a higher concentration of the fissile isotope U-235.

Question 4

What is the chemical form of enriched uranium before it is processed further?

Answer 4

Uranium hexafluoride

Uranium hexafluoride is used in the enrichment process.

Question 5

What process is used to create uranium pellets?

Answer 5

Centrifugation of uranium hexafluoride

This process separates isotopes to increase U-235 concentration.

Question 6

What is the purpose of the uranium pellets?

Answer 6

They are fissioned in the reactor

Fission releases energy used for power generation.

Question 7

What happens to spent fuel after it has been used in the reactor?

Answer 7

It is temporarily stored

This storage is typically on-site before further processing or disposal.

Question 8

Where is spent fuel ultimately disposed of?

Answer 8

Underground

This is part of long-term waste management strategies.

Question 9

What are the mining methods used in the extraction of uranium?

Answer 9

mined in open pit, underground, or in-situ leaching mining methods

In-situ leaching involves passing chemical solutions through ore beds to dissolve uranium.

Question 10

What is extracted from crushed ore in the milling process?

Answer 10

Uranium

This process is crucial for obtaining uranium from mined materials.

Question 11

What is the predominant product at the conversion stage of uranium processing?

Answer 11

UF6

UF6 is a key compound used in the enrichment process.

Question 12

What does the enrichment process aim to increase in uranium?

Answer 12

The proportion of 235U

Natural uranium consists of about 0.7% of 235U, necessitating enrichment.

Question 13

What methods are used for uranium enrichment?

Answer 13

Gaseous diffusion or centrifuge

These methods help to separate isotopes of uranium.

Question 14

What form is enriched uranium converted to in fuel fabrication?

Answer 14

UO2 powder

UO2 powder is used to create fuel pellets.

Question 15

What material are the fuel pellets loaded into?

Answer 15

Zircaloy tubes

Zircaloy is a corrosion-resistant alloy used in nuclear reactors.

Question 16

What type of assemblies do the rods form in a nuclear reactor?

Answer 16

Core fuel assemblies

These assemblies are crucial for the operation of the reactor.

Question 17

How many types of reactors are operating in the world?

Answer 17

6 types

The types include PUR, BWR, LWR, and FBR.

Question 18

What does fission in a nuclear reactor generate?

Answer 18

Steam, turning turbines

This process is essential for electricity generation.

Question 19

What is the initial storage method for nuclear fuel?

Answer 19

Stored in ponds or at the reactor site until moved to a central national storage facility for conditioning and ultimately placed in a geological disposal facility.

Question 20

How long is the initial storage period for nuclear fuel?

Answer 20

9 months to allow both decay and radiation levels to decrease.

Question 21

What must be monitored in storage ponds?

Answer 21

Chemistry of water.

Question 22

What is one alternative storage method for nuclear fuel?

Answer 22

Dry storage in vaults or containers.

Question 23

How much spent fuel does a 1000 MW reactor produce per year?

Answer 23

25 tonnes.

Question 24

What isotopes are still available for use after nuclear fuel processing?

Answer 24

• 235U
• 239Pu

Question 25

What type of fuel can be made from plutonium?

Answer 25

MOX (Mixed Oxide) fuel.

Question 26

How is plutonium prepared for MOX fuel fabrication?

Answer 26

Separated plutonium is converted into oxide powder.

Question 27

What must a-plutonium be accessed with in MOX fuel fabrication?

Answer 27

Carrier material - uranium.

Question 28

Is the design of the reactor and assembly for MOX fuel different from traditional designs?

Answer 28

No, it is pretty much the same.

Question 29

What is the typical operating lifetime of a nuclear power plant?

Answer 29

60 years

Question 30

What is decommissioning in the context of a nuclear power plant?

Answer 30

The administrative and technical actions taken to allow the removal of regulatory controls from a facility

Question 31

What are the two current strategies for decommissioning a nuclear power plant?

Answer 31

* Immediate dismantling * Deferred dismantling

Question 32

What does immediate dismantling involve?

Answer 32

Starting permanent shutdown and utilizing renovation of equipment and structures, systems, and components from a facility

Question 33

What is deferred dismantling?

Answer 33

All or part of a facility is maintained in such a condition that it can go into safe storage until it is subsequently decontaminated and dismantled

Question 34

How long can dismantling of a nuclear power plant take?

Answer 34

Up to 20 years

Question 35

Fill in the blank: Decommissioning involves the removal of _______ from a nuclear power plant.

Answer 35

[regulatory controls]

Question 36

True or False: The immediate dismantling strategy can be started immediately after shutdown.

Answer 36

True

Question 37

What does deferred dismantling allow for in terms of facility maintenance?

Answer 37

The facility is maintained until subsequent decontamination and dismantling

Question 38

What is enrichment?

Answer 38

Refers to the process of increasing the proportion of a particular isotope in a material, typically uranium for nuclear fuel. Primarily done now by centrifuges

Question 39

What is mox fuel?

Answer 39

Mix of uranium and plutonium ## Footnote MOX (Mixed Oxide) fuel is a type of nuclear fuel made from a mixture of plutonium and natural or depleted uranium.

Question 40

What is the minimum time that spent fuel rods would be stored in a cooling pond?

Answer 40

9 months ## Footnote Spent fuel rods require cooling to allow radioactive decay and heat dissipation before further processing or storage.