The misuse of spreadsheets in the nuclear fuel industry: The falsification of safety critical nuclear fuel data using spreadsheets at British Nuclear Fuels Limited (BNFL)

This paper considers the management, technological and human factor issues that led to the BNFL fuel rod spreadsheet data falsification incident in 1999. BNFL discovered in 1999 that some data supporting quality assurance and safety processes had been falsified by BNFL workers using spreadsheets. The implication of this finding was that some of the Mixed Oxide Fuel Pellets shipped to customers in Japan for use in nuclear reactors were of an unknown mass and quality. This meant that the use of the MOX pellets fuel produced by BNFL would introduce uncontrolled factors into the safe operation of nuclear reactors. This could result in uncontrolled nuclear reactions and may have serious implications. The BNFL workers had cloned spreadsheets containing micrometer measurements and adjusted lot and batch numbers so that each spreadsheet appeared to be a genuine reflection of the quality and safety procedures put in place to ensure that the pellet dimensions, density and surface features are known and within acceptable tolerances. This paper will examine the production of MOX pellets at the Sellafield site, the falsification of data and the report commissioned by HM Nuclear Inspectorate. The paper will then identify a number of managerial and technological failings that led BNFL to use spreadsheets for recording such data.