Human error classification and data collection - Survey in an Indian nuclear power plant

Any amount of automation and computerised control systems cannot tackle all the postulated and unpostulated abnormal events and hence there is a need to have the human interaction in the operation of a nuclear power plant. With such human interactions, it is likely that certain errors might be committed even though it may be infrequent. These errors may be due to spontaneous actions by the operating staff or due to lack of understanding, coordination or communication. A detailed review of all the abnormal events in Madras Atomic Power Plant in India indicates that about 6 to 8% of the unusual/abnormal incidents and reactor scrams are due to human error. Most of the human errors occur while carrying out certain non-routine operations, while carrying out certain surveillance tests, or while putting back the systems/equipment in service after maintenance. This paper reviews the incidents in Madras Atomic Power Station Units 1 and 2 for the last 6 years and quantifies the causes attributable to various categories cited above. Even though the incidents due to human-error remained high during the first year of the operation of the plant, it has come down gradually in subsequent years due to better on the job training of the operating staff, better understanding of the equipment and system behaviour during normal operation as well as abnormal operations. 1 diagram, 3 tabs