The claims come two weeks after The Independent revealed that checks at the company's Sellafield plant in Cumbria had been falsified. At the time, BNFL insisted that the falsification involved only fuel under production in the UK - not the consignment due to dock in Japan today.
However, an investigation into that fuel, earmarked for the Takahama 4 reactor, in Fukui prefecture, has shown that one rogue set of tests might have allowed imperfect mixed plutonium and uranium oxide (MOX) pellets through the safety net. Information supplied by BNFL to Kansai Electric Power Company, which runs Takahama 4, also shows that the British company knew data had been falsified as early as 20 August, but did not tell Mitsubishi, Kansai's contractor, until 9 September.
The Independent had been making inquiries around this date and challenged BNFL on 10 September. Kansai was not told until the 13 September, the day before the news broke.
Suggestions that a batch of pellets on board the Pacific Pintail, which is carrying the BNFL MOX, might be suspect follow an examination of data by Professor Hidiyuki Koyama, of Osaka Prefectural University, on behalf of anti-nuclear campaigners.
It relates to tests on a batch of 200 pellets, numbered P824, in which 68 bore exactly the same microscopic measurements as their corresponding numbers in the previous batch. The suspicion now is that the results were simply copied to save time.
Politicians were left even more unsure of the fuel heading towards them when a legislator asked: "Do you consider this problem to be at the BNFL corporate level?", to which a Kansai representative replied: "There is no ethics education [at BNFL]."
The company is expected to come under more pressure tomorrow, when the US Senate will be asked by a number of politicians to launch an investigation into the shipments of MOX.
Under a US-Japan agreement, MOX vessels were to be escorted at all times by armed vessels in government service. BNFL's ships, the Pacific Pintail and Pacific Teal, have been fitted with 30mm cannon and have effectively been escorting each other.
Aileen Mioko Smith, director of the Japanese environmental group Green Action, said: "Doubts over BNFL's quality control ... have seriously damaged its reputation here. People are asking what sort of operation it is and whether Japan should be dealing with it." BNFL said Kansai and the Agency of National Resources and Energy in Japan accepted its figures and were happy the fuel on Pintail had not been subjected to falsified tests.Reuse content