Nuclear safety

Nuclear safety

[...]... accumulated experience in the fields of nuclear safety and of radiation protection This is particularly important for countries where nuclear energy exploitation has been stopped, but where it might have to be resumed in future The main accent of this book is on Nuclear Safety From another point of view, many areas developed in nuclear safety studies are of interest in the safety of process plants too and,... this book, except the few of them not concerned with the safety of nuclear installations, deal with the ways for practically achieving these objectives 1 2 Nuclear Safety 1-2 A short history of nuclear safety technology  1-2-1 The early years The first reactor, the ‘Fermi pile’ CP1 (or Chicago Pile 1, built in 1942) was provided with rudimentary safety systems in line with the sense of confidence inspired... published in 1975, was sponsored by the Nuclear Regulatory Commission (NRC – the successor to the Atomic Energy Commission in control of peaceful applications of nuclear energy and the regulatory body on nuclear safety matters) with the aim of outlining an overall picture of all the conceivable accidents and of their probabilities, in order to identify the risk connected to a nuclear plant It was the first time... strengthening of Defence in Depth and of Safety Culture 8 The forgotten safety criterion: Many safety criteria have been discussed and written about, but one which requires that a nuclear plant should never be constructed and operated in haste has not been proposed yet Perhaps, more than one criterion is involved here For example, one of the specific requirements might be that ‘no nuclear plant can operate if its... waste References USNRC (1996) ‘Standard review plan for the review of safety analysis reports for nuclear power plants’, NUREG-0800 USNRC (1992) ‘Accident source terms for light-water nuclear power plants’, NUREG-1465 This page intentionally left blank Chapter 3 Safety systems and their functions 3-1 Plant systems By necessity, a nuclear power plant is composed of the parts required to generate electric... malfunctions in safety systems, such as a ‘single failure’ consisting in the failure, simultaneous with the initiating event (pipe failure and so on), of one active component of one of the safety systems devoted to emergency safety functions during the accident (water injection system, reactor shutdown system and so on).3 On one side, the more cautious experts, generally members of public safety control... optimistic people (members of manufacturing industries and of electric utilities) maintained that the above mentioned accident 4 Nuclear Safety assumptions entailed a true waste of resources (those necessary to provide nuclear plants with huge containment buildings and powerful safety systems) It has to be noted that the ‘optimists’ were by no means imprudent or reckless: a sincere conviction existed in... differences in the fundamental approach to safety among various countries have always been thought by the general public to be a weakness of the nuclear industry, thereby affecting their acceptance of nuclear energy These differences have always been a source of confusion in the mind of the public and, therefore, they aggravate the public distrust in the safety of this energy source Many attempts have... arenas where nuclear safety is discussed (IAEA, OECD, EU), to adopt unified criteria (see Chapter 18) The aim of agreeing common criteria has been reached only at the expense of unification at a higher logical level, therefore leaving untouched the differences previously described, for example leaving to the freedom of each country the definition of acceptable distances or doses 6 Nuclear Safety In this... and incidents 331 2-1-2-6 Probabilistic safety targets 332 2-1-3-4 Single failure criterion 332 2-1-4-3-2 Complex sequences that may be considered in DEC 333 2-1-6-8 Classification of the safety functions and categorisation of the equipment 333 2-1-6-6-3 Requirements according to level of safety functions 334 2-1-6-8-4 Assignment of equipment and structures to a safety category 334 Contents 2-1-6-8-5 . future. The main accent of this book is on Nuclear Safety. From another point of view, many areas devel- oped in nuclear safety studies are of interest in the safety of process plants too and, therefore, it. 3 Safety systems and their functions 17 3-1 Plant systems 17 3-2 Safety systems and accidents 18 3-3 Future safety systems and plant concepts 23 3-3-1 General remarks 23 3-3-2 Some passive safety. safe? 243 Chapter 29 The limits of nuclear safety: the residual risk 245 29-1 Risk in general 245 29-2 Risk concepts and evaluations in nuclear installation safety 245 29-2-1 Tolerable risk 245 29-2-2