A Lack of Knowledge Acquisition Can Impair Nuclear Power Plant Safety

Abstract

A lack of knowledge acquisition (LOKA), among engineering staff members in supply firms (e.g., vendors), owner/operator utilities (e.g., licensees), and in regulatory agencies (e.g., the NRC), can impair nuclear power plant (NPP) safety in ways that can persist throughout the operating lifetime of an NPP. A LOKA occurs when experienced technical reviewers fail to pass enough information, or technology, to less-experienced technical reviewers. The existence of a LOKA, among technical reviewers, can lead to errors and omissions that can result in misleading or incomplete licensing bases. Eight examples of errors and omissions are presented, each of which is evaluated in the context of physical phenomena, logic, licensing strategy, and effects upon regulation. These errors and omissions could be attributed to several causes, one of which could be a LOKA. Reliable attribution to a LOKA or its causes is not directly addressed, since attention is focused principally upon the safety implications of errors and omissions that may possibly, but not exclusively, be due to a LOKA. The epistemology of a LOKA, which may consider training or human relations, is generally addressed in other studies, which apply to issues that affect more than the nuclear power industry. If those who design, analyze, license, operate, and regulate NPPs do not adequately understand and apply proven engineering principles, standards, and established regulations, critical thinking, and sound logical reasoning, then it could be said that a LOKA exists. A LOKA could hamper the development of defensible conclusions in safety analyses, viable licensing strategies, and fair regulatory judgments. Eight examples of errors and omissions are presented, each of which leads to a conclusion that seems to conflict with an industry standard, a federal regulation, an engineering principle or physical phenomenon, or just plain logic. The examples are generally evaluated in accordance with the requirements of a well-known, oft-cited nuclear industry standard, which is now almost half a century old. This standard was published in 1973 by the American Nuclear Society (ANS) (1973, Nuclear Safety Criteria for the Design of Stationary Pressurized Water Reactor Plants, La Grange Park, IL, ANS-N18.2-1973). It expresses the fundamental principle of nuclear safety and licensing, which is applied by vendors, licensees, and regulators alike. This Standard defines nuclear safety criteria and plant design requirements for plant operating situations or events according to their expected frequencies of occurrence. Those events that have high frequencies of occurrence must not pose a danger to the public. Events that could pose the greatest danger to the public must be limited, by design, to extremely low expected frequencies of occurrence. This concept is implemented by grouping postulated plant situations (or events) into categories that are defined according to their expected frequencies of occurrence. Licensees are required to present analyses and evaluations of the events, in each category, to demonstrate that the events’ consequences do not exceed the category’s specified acceptance limits. Furthermore, licensees are required to demonstrate that certain events would not develop into more serious events (e.g., events that would be grouped into more serious, higher-consequence categories), without the concurrent occurrence of independent faults. That is, the Standard (American Nuclear Society, 1973, Nuclear Safety Criteria for the Design of Stationary Pressurized Water Reactor Plants, La Grange Park, IL, ANS-N18.2-1973) requires that NPPs must be designed in a way that does not allow high-frequency, low-consequence events to degrade into high-frequency, high-consequence events. The errors and omissions that are considered in the example evaluations could be due to a LOKA, among other possible causes. In each example, a LOKA is sufficient

but not necessary, to produce the noted errors and omissions. Attention is focused upon the safety implications of a LOKA, not its epistemology. The LOKA in the nuclear power industry, including its regulators, is ongoing, since it is not recognized and remedied.