Progress in Nuclear Energy

M. M. R. Williams, R. Sher

• Publisher: Pergamon
• Year: 2013
• Print ISBN: 9780080271156
• eBook ISBN: 9781483103365
• Topic: Technology & Engineering
• Subtopic: Physics
• Index: Physics

Progress in Nuclear Energy, Volume 5 covers the significant advances in several aspects of nuclear energy field. This book is composed six chapters that describe the progress in nuclear and gas-cooled reactors. The introductory chapter deals with the development and evolution of decay heat estimates and decay heat Standards, and illustrates the use of these estimates through comparison of both the actinide and fission product decay heat levels from typical fuel samples in a variety of reactor systems. The succeeding chapters present different practical methods for handling resonance absorption problem in the case of thermal reactor lattices and review the physics of the different noise phenomena. These topics are followed by discussions of the developed methodology for the description of breeding, conversion, long-term fuel logistics, and related subjects derived from the detailed mathematical description of the fuel cycle. The concluding chapters consider the historical development of heat transfer surfaces for gas-cooled reactors. These chapters also provide a complete set of differential nuclear data on the three technologically important americium isotopes, 241Am, 242Am, and 243Am, suitable for incorporation into the computer-based U.K. Nuclear Data Library. This book will prove useful to nuclear physicists and nuclear energy scientists and researchers.

DECAY HEAT

A. TOBIAS, Central Electricity Generating Board, Berkeley Nuclear Laboratories, Berkeley, Gloucestershire GL13 9PB, England (Received 1 August 1979)

Summary

Many aspects of the nuclear fuel cycle require accurate and detailed knowledge of the energy release rate from the decay of radioactive nuclides produced in an operating reactor. In addition to the safety assessment of nuclear power plant, decay heat estimates are needed for the evaluation of shielding requirements on fuel discharge and transport routes and for the safe management of radioactive waste products extracted from spent fuel during reprocessing. The decay heat estimates may be derived by either summation calculations or Standard equations.This paper reviews the development of these evaluation methods and traces their evolution since the first studies of the 1940s. In contrast to many of the previous reviews of this subject, both actinide and fission product evaluation methods are reviewed in parallel. Data requirements for summation calculations are examined and a summary given of available codes and their data libraries. The capabilities of present-day summation methods are illustrated through comparisons with available experimental results. Uncertainties in summation results are examined in terms of those in the basic nuclear data, irradiation details and method of calculation. The evolution of decay heat Standards is described and a brief examination made of their reliability and ability to provide suitably conservative decay heat estimates. Finally, to illustrate the use of present summation methods, comparisons are given of both the actinide and fission product decay heat levels from typical fuel samples in a variety of reactor systems.

CONTENTS

1 INTRODUCTION

1.1 Discovery of nuclear fission

1.2 Sources of decay heat

1.2.1 Heavy elements—actinides

1.2.2 Fission products

1.2.3 Structural and cladding materials

1.2.4 Delayed neutron-induced fission

1.2.5 Reactions induced by spontaneous fission neutrons

1.3 Basic concepts in decay heat evaluation

1.3.1 Instantaneous burst of fissions

1.3.2 Infinite irradiation

2 EVALUATION OF DECAY HEAT

2.1 History of decay heat measurements

2.2 History of summation studies and decay heat reviews

2.2.1 Actinides

2.2.2 Fission products

2.3 Present summation methods

2.3.1 The build-up of actinides and heavy elements

2.3.2 The generation of fission products

2.3.3 Inventories following shutdown

2.3.4 The summation step

2.3.5 Data and codes

2.3.5.1 Actinides

2.3.5.2 Fission products

3 CONFIRMATION OF SUMMATION CALCULATIONS

3.1 Comparisons of nuclide inventories

3.2 Comparisons of decay heat results

3.2.1 Decay heat burst functions

3.2.1.1 ²³⁵U thermal fission

3.2.1.2 ²³⁹Pu thermal fission

3.2.1.3 ²⁴¹Pu thermal fission

3.2.1.4 ²³³U thermal fission

3.2.2 Integral decay heat

3.2.2.1 ²³⁵U thermal fission

3.2.2.2 ²³⁹Pu thermal fission

3.2.2.3 ²³³U thermal fission

3.2.2.4 Other fission processes

3.2.3 Beta and gamma spectra

3.2.4 Decay heat following infinite irradiation

4 THE EFFECT OF NEUTRON ABSORPTION IN FISSION PRODUCTS

5 UNCERTAINTIES IN DECAY HEAT SUMMATION CALCULATIONS

5.1 Uncertainties due to actinide nuclear data

5.2 Uncertainties due to fission product nuclear data

5.2.1 Uncertainties in yield data

5.2.2 Uncertainties in half-lives

5.2.3 Uncertainties in decay energies

5.2.4 Uncertainties in cross-sections

5.2.5 Uncertainties in other parameters

5.2.6 Total uncertainties due to input data

5.3 Uncertainties due to irradiation parameters

5.3.1 Uncertainties in neutron flux level and fuel rating

5.3.2 Uncertainties in neutron spectrum temperature

5.3.3 Uncertainties in irradiation time

5.3.4 Uncertainties in fuel burn-up

5.4 Uncertainties due to the method of calculation

5.4.1 The assumption of constant fuel rating

5.4.2 The length of the irradiation steps

5.4.3 The use of channel-average parameters

5.4.4 The use of load factor

6 THE DEVELOPMENT AND USE OF DECAY HEAT STANDARDS

6.1 Fission product standards

6.2 Actinide standards

6.3 The influence of energy release in fission

6.4 The adequacy of decay heat standards

6.4.1 Actinides

6.4.2 Fission products

7 COMPARISONS OF DECAY HEAT PROPERTIES

7.1 Decay heat from different fissile nuclides

7.2 Decay heat from different reactor systems

8 CONCLUSIONS

9 REFERENCES

1 INTRODUCTION

Since the first self-sustaining chain reaction was achieved, by the group under Enrico Fermi, on 2 December 1942 on the squash courts of Chicago University, man has learned to harness successfully the energy from nuclear fission for peaceful purposes. From the variety of experimental reactor piles which rapidly followed world-wide a number of quite different commercial reactor systems have evolved.

In the U.K. efforts have been directed primarily to the development of the graphite-moderated, gas-cooled reactor system. This began with the magnox system, named after the magnesium alloy fuel cladding, and has been followed by the Advanced-Gas-Cooled (AGR) Reactor. Elsewhere in the world, e.g. France, Germany, Japan and the U.S.A., the Boiling Water and Pressurized Water Reactor (BWR and PWR) systems have been developed while Canada has produced the unique Pressurized-Heavy-Water-Moderated and -Cooled CANDU system.

Despite the widely varying designs of reactor systems in operation in the world today, many of the countries involved are now taking an interest in the controversial Liquid-Metal-Cooled Fast Breeder Reactor (LMFBR), which is theoretically capable of producing more fuel than is consumed.

Irrespective of which reactor system one may consider, there are a number of important design and operating criteria which require a knowledge of the radioactivity levels, or heat generation, from the entire reactor, or an individual fuel element, at times ranging from a few seconds to hundreds of days, and possibly years, following shutdown of the reactor. For example, in order to cater...

Table of contents

• Cover image
• Title page
• Table of Contents
• Inside Front Cover
• Copyright
• Chapter 1: DECAY HEAT
• Chapter 2: RESONANCE ABSORPTION CALCULATIONS IN THERMAL REACTORS
• Chapter 3: NOISE INVESTIGATIONS IN BOILING-WATER AND PRESSURIZED-WATER REACTORS
• Chapter 4: FAST REACTOR BURNUP AND BREEDING CALCULATION METHODOLOGY
• Chapter 5: THE HISTORICAL DEVELOPMENT OF HEAT TRANSFER SURFACES FOR GAS-COOLED REACTORS ANALYSED WITH A SIMPLE CRITERION
• Chapter 6: EVALUATION OF DIFFERENTIAL NUCLEAR DATA FOR AMERICIUM ISOTOPES PART I: 241Am
• Chapter 7: ERRATA TO: DECAY HEAT
• SUBJECT INDEX
• CONTENTS OF PREVIOUS VOLUMES