Abstract
Safety of nuclear reactors has been a central concern of the nuclear energy industry from the very beginning. This concern, and the resultant excellence of design, fabrication, and operation, aided by extensive engineered safety features, has given nuclear energy its superior record of protection of the environment and of the public health and safety. With respect to the fast reactor, it was recognized early in the programme that there exists a theoretical possibility of a core compaction leading to significant energy release. Early analysis of this problem employed a number of conservative assumptions in attempting to bound the energy release. As reactors have grown in size, the suitability of such bounding calculations has diminished, and research into hypothetical accident analysis has emphasized a more mechanistic approach. In the USA, much effort has been directed towards modeling and computer code development aimed at following the course of an accident from its initiation to its ultimate conclusion with a stable, permanently subcritical, coolable core geometry, along with considerations of post-accident heat removal and radiological consequence assessment. Throughout this effort, the potential role of fission products has been recognized and account taken of the effects of fission products in determining accident progression. It
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Dietrich, L W;
[1]
Jackson, J F
[2]
- Argonne National Laboratory, Division of Reactor Analysis and Safety, Argonne, IL (United States)
- Los Alamos Scientific Laboratory, Q Division - Energy, Los Alamos, NM (United States)
Citation Formats
Dietrich, L W, and Jackson, J F.
The role of fission product in whole core accidents - research in the USA.
IAEA: N. p.,
1977.
Web.
Dietrich, L W, & Jackson, J F.
The role of fission product in whole core accidents - research in the USA.
IAEA.
Dietrich, L W, and Jackson, J F.
1977.
"The role of fission product in whole core accidents - research in the USA."
IAEA.
@misc{etde_20139410,
title = {The role of fission product in whole core accidents - research in the USA}
author = {Dietrich, L W, and Jackson, J F}
abstractNote = {Safety of nuclear reactors has been a central concern of the nuclear energy industry from the very beginning. This concern, and the resultant excellence of design, fabrication, and operation, aided by extensive engineered safety features, has given nuclear energy its superior record of protection of the environment and of the public health and safety. With respect to the fast reactor, it was recognized early in the programme that there exists a theoretical possibility of a core compaction leading to significant energy release. Early analysis of this problem employed a number of conservative assumptions in attempting to bound the energy release. As reactors have grown in size, the suitability of such bounding calculations has diminished, and research into hypothetical accident analysis has emphasized a more mechanistic approach. In the USA, much effort has been directed towards modeling and computer code development aimed at following the course of an accident from its initiation to its ultimate conclusion with a stable, permanently subcritical, coolable core geometry, along with considerations of post-accident heat removal and radiological consequence assessment. Throughout this effort, the potential role of fission products has been recognized and account taken of the effects of fission products in determining accident progression. It is important to recognize that reactor safety is a very diverse topic, requiring consideration of a number of factors. While the major questions of public risk appear to be related to the hypothetical core disruptive accident (HCDA), it is necessary that the probability of having such an accident be extremely low In order that acceptable public risk be demonstrated. Such a demonstration requires sound engineering design and Implementation, with high standards of reliability, inspectability, maintainability, and operation, along with the requisite quality control and assurance. Tile current approach, typified by that taken by the Clinch River Breeder Reactor (CRBR) Project, is balanced, consisting of a reliability programme to prevent malfunctions or accidents, backup systems to accommodate malfunctions or accidents, and systems to cope with the consequences of CDAs. In connection with the CRBR, the Nuclear Regulatory Commission (NRC) has established that {sup t}he probability of core melt and disruptive accidents can and must be reduced to a sufficiently low level to justify their exclusion from the design basis accident spectrum (a goal probability of 10{sup -6} per reactor-year for dose exceeding current guidelines has been established). Thus, CDA accommodation is approached on the basis of reasonable conservatism in evaluation and mitigation. The ERDA fast reactor safety research programme is presently directed towards establishment of four 'lines of assurance' (LOA). The four lines of assurance are: prevent core disruptive accidents; limit core damage; control CDA progression; attenuate radiological consequences. The considerations of fission product effects germane to the present paper are primarily of concern in evaluation of the second and third lines. Since fission products have the potential for dispersing fuel from the core region and thereby producing reactor shutdown, knowledge of their effects can contribute to demonstrating that there is a low probability (10{sup -2} ) of a CDA initiator producing whole-core involvement. Similarly, knowledge of fission product effects can contribute to demonstrating that there Is a low probability of a whole-core disruptive accident leading to sufficient energy release to challenge the containment capability.}
place = {IAEA}
year = {1977}
month = {Jul}
}
title = {The role of fission product in whole core accidents - research in the USA}
author = {Dietrich, L W, and Jackson, J F}
abstractNote = {Safety of nuclear reactors has been a central concern of the nuclear energy industry from the very beginning. This concern, and the resultant excellence of design, fabrication, and operation, aided by extensive engineered safety features, has given nuclear energy its superior record of protection of the environment and of the public health and safety. With respect to the fast reactor, it was recognized early in the programme that there exists a theoretical possibility of a core compaction leading to significant energy release. Early analysis of this problem employed a number of conservative assumptions in attempting to bound the energy release. As reactors have grown in size, the suitability of such bounding calculations has diminished, and research into hypothetical accident analysis has emphasized a more mechanistic approach. In the USA, much effort has been directed towards modeling and computer code development aimed at following the course of an accident from its initiation to its ultimate conclusion with a stable, permanently subcritical, coolable core geometry, along with considerations of post-accident heat removal and radiological consequence assessment. Throughout this effort, the potential role of fission products has been recognized and account taken of the effects of fission products in determining accident progression. It is important to recognize that reactor safety is a very diverse topic, requiring consideration of a number of factors. While the major questions of public risk appear to be related to the hypothetical core disruptive accident (HCDA), it is necessary that the probability of having such an accident be extremely low In order that acceptable public risk be demonstrated. Such a demonstration requires sound engineering design and Implementation, with high standards of reliability, inspectability, maintainability, and operation, along with the requisite quality control and assurance. Tile current approach, typified by that taken by the Clinch River Breeder Reactor (CRBR) Project, is balanced, consisting of a reliability programme to prevent malfunctions or accidents, backup systems to accommodate malfunctions or accidents, and systems to cope with the consequences of CDAs. In connection with the CRBR, the Nuclear Regulatory Commission (NRC) has established that {sup t}he probability of core melt and disruptive accidents can and must be reduced to a sufficiently low level to justify their exclusion from the design basis accident spectrum (a goal probability of 10{sup -6} per reactor-year for dose exceeding current guidelines has been established). Thus, CDA accommodation is approached on the basis of reasonable conservatism in evaluation and mitigation. The ERDA fast reactor safety research programme is presently directed towards establishment of four 'lines of assurance' (LOA). The four lines of assurance are: prevent core disruptive accidents; limit core damage; control CDA progression; attenuate radiological consequences. The considerations of fission product effects germane to the present paper are primarily of concern in evaluation of the second and third lines. Since fission products have the potential for dispersing fuel from the core region and thereby producing reactor shutdown, knowledge of their effects can contribute to demonstrating that there is a low probability (10{sup -2} ) of a CDA initiator producing whole-core involvement. Similarly, knowledge of fission product effects can contribute to demonstrating that there Is a low probability of a whole-core disruptive accident leading to sufficient energy release to challenge the containment capability.}
place = {IAEA}
year = {1977}
month = {Jul}
}