Four more Japanese utilities, Chubu Electric Power, Japan Atomic Power (JAPC), Chugoku Electric Power and Tohoku Electric Power, have been implicated alongside Tokyo Electric Power (Tepco) by Japanese authorities investigating the possible cover-up of inspection findings (see story links below).
Until recently, regulators had been investigating Tepco to determine whether the company had concealed from the Ministry of Energy, Trade and Industry (METI) information of inspection findings made by contractor GE (see story links below).
On 25 September, fresh cases came to light that suggested that the results of inspections for other BWR owners, carried out by GE, Hitachi and Toshiba, were also falsified to conceal the results. In at least some of these new cases, inspecting firms found cracks in piping and other equipment that are part of the primary coolant recirculation systems. Utility personnel concealed the crack findings from regulators. In some cases, utilities repaired primary piping and related equipment without having reported the crack findings that necessitated the repairs.
Chubu Electric confirmed that incomplete reports of inspection results had been given to regulators for Hamaoka 1 and 3. The reports failed to mention eight cracks found in core equipment inspected at Hamaoka 3. Chubu said three of the cracks had been repaired.
It was also announced that Tohoku Electric had failed to report to regulators cracks that had appeared in recirculation piping at Onagawa 1 back in 1988. On 23 September, investigators revealed that Tohoku discovered 12 cracks in the core shroud, the largest of which is 14cm long.
On 24 September, JAPC acknowledged that shroud cracks had been covered up at Tsuruga 1, following inspections done by GE in 1994, 1996 and 1998.
So far attention has focused on inspection findings at BWRs, but it is reported that METI and regulators NISA are now planning to re-examine PWR inspections. The review will focus on inspection of core internals, control rod drive mechanisms and vessel head penetrations.
METI said it wants to complete all of its investigations by mid-November.
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