Fuel Burnup and Fuel Management

Abstract

Nuclear fuel is removed from a reactor every few years when it can no longer economically keep a chain reaction going. This “spent” fuel remains radioactive and must be managed. At first, it goes into a pool onsite for cooling and storage. Some utilities are moving their spent fuel after several years in the pool into US Nuclear Regulatory Commission (NRC)-certified dry storage casks. These casks are specially designed to contain the radioactivity and allow hot spent fuel to cool further. In contrast to fossil fuel, the fuel in nuclear reactors cannot be converted since the fuel undergoes changes during its use in the reactor, which require the fuel elements to be exchanged.

Problems

Problem 16.1

Which weapons material is easier to handle and to create a weapon or improvised nuclear device (IND)?

Problem 16.2

List the effects from a nuclear weapon (NW) blast, and identify them in terms of energy release from the device. Which have short-term and which have long-term effects?

Problem 16.3

A 1-megaton device explodes at a height of 5000 feet. The equivalent burst height for a 1 kT (kiloton) device is 500 feet, and its equivalent time of arrival is 4 seconds. What would be the time of arrival of the blast wave from the 1 MT (megaton) devices at a distance of 10 miles from ground zero?

Problem 16.4

The Acheson-Lilienthal report and the Baruch Plan have what element in common?

Problem 16.5

Was the nuclear weapon (NW) proliferation threat around the time of Atoms for Peace based on a national or subnational effort?

Problem 16.6

Match the elements of the NPT to the keywords in the right hand column.

Article 1	(a) NW (nuclear weapon)-free zones
Article 2	(b) NWS obligations
Article 3	(c) Carrot
Article 4	(d) Stick
Article 5	(e) NNWS (non-nuclear weapon states) obligations
Article 6	(f) Nuclear disarmament

Problem 16.7

List three levels covered by nuclear safeguards, and indicate the entity responsible for their enforcement.

Problem 16.8

Which of the following countries are under International Atomic Energy Agency (IAEA) safeguards: Russia, Chile, Japan, Australia, United States, Egypt, Iran, and India?

Problem 16.9

List the two main objectives of International Atomic Energy Agency (IAEA) safeguards.

Problem 16.10

List three agreements included in the Information Circular (INCIRC/under 153).

Problem 16.11

List three measures granted to the International Atomic Energy Agency (IAEA) under the Additional Protocol (AP).

Problem 16.12

List three activities by a state under the International Atomic Energy Agency (IAEA) Additional Protocol (AP) that could put the state into noncompliance.

Problem 16.13

List the six key elements of the International Atomic Energy Agency (IAEA) safeguard approaches.

Problem 16.14

True or false. U²³³ is defined as an indirect-use material by the International Atomic Energy Agency (IAEA).

Problem 16.15

List the significant quantity (SQ) amounts for the following:

HEU. U²³³, Th, depleted U, Pu²³⁹

Problem 16.16

List the critical mass and critical mass reflected by depleted uranium for U²³³, Pu²³⁹, and HEU.

Problem 16.17

Calculate the expected neutron flux from 1 kg of discharged for light water reactor (LWR) fuel (30,000 MWd/t burnup). What is the main neutron contributor? Could Pu²³⁹ be detected by measuring neutrons alone?

Problem 16.18

Nuclear material accountancy should satisfy what requirement regarding MUF (Material Unaccounted For)?

Problem 16.19

Match IAEA assumptions of conversion time with the materials below:

• Pu²³⁹ metal weeks

• HEU in irradiated fuel days (7–10)

• U containing <20% U235 months

• Pu in MOX weeks

• U²³⁵O²

• Th containing <20%U²³³

Problem 16.20

Provide International Atomic Energy Agency (IAEA) detection timeliness goals for:

• 1. Unirradiated direct-use material

• 2. Irradiated direct-use material

Problem 16.21

Provide four scenarios for cheating International Atomic Energy Agency (IAEA) safeguards.

Problem 16.22

List the elements that go into determination of MUF.

Problem 16.23

List three general categories of nondestructive assay (NDA) measurements. NDA is a measurement of the nuclear material content.

Problem 16.24

Suppose a nuclear plant were built above ground, but at reduced cost, by using inferior materials and shoddy construction. Would that be a violation of the Non-Proliferation Treaty?

Problem 16.25

Suppose a nuclear plant were built underground, completely hidden from view. Would that be a violation of the Non-Proliferation Treaty?