Date: 29 August 2003

Reactor Pool Liner Repair Strategy Approved

The CEO of ARPANSA, Dr John Loy, has approved the Australian Nuclear Science and Technology Organisation's (ANSTO's) repair strategy in relation to errors made during fabrication of the stainless steel pool liner, or tank, for the replacement research reactor at Lucas Heights in Sydney's south. As an outcome of his review of the errors, he also intends to apply three new licence conditions on the reactor construction licence issued to ANSTO in April 2002.

John Loy said: "The repair strategy proposed by ANSTO is consistent with the American Society for Mechanical Engineers Boiler and Pressure Vessel Code. This stringent Code formed the basis of my approval for construction of the tank given on 11 July 2002. Therefore, I accept that the repair strategy conforms to my original approval."

ANSTO may now instruct the fabricator to proceed with repairs to the misplaced penetrations provided two things occur. It must meet the repair criteria set out by reactor designer INVAP (and accepted by ANSTO). ANSTO must then apply the revised welding procedure recommended to the organisation by the Welding Technology Institute of Australia. There have also been substantial additional resources applied to the fabricator's workshop.

In addition to a review by the ARPANSA Regulatory Branch, the CEO engaged material scientists from the Commonwealth Science and Industrial Research Organisation (CSIRO) and Toshiba Corporation, Japan, to advise on the proposed repair strategy. The CSIRO also carried out physical tests using the tank materials and repair weld procedures. The Nuclear Safety Committee was briefed and discussed the repair strategy.

"I need to know that the authorised repairs are carried out successfully and that all manufacture, repair and testing work has been fully documented. Therefore, I am intending to apply two new conditions on the construction licence. Firstly, the completed reactor pool tank will be a 'hold point' requiring my approval before acceptance of the constructed item for installation. Secondly, ANSTO will obtain additional information about the welding of the tank to be assessed by me at the time of the 'hold point'."

John Loy continued: "There are lessons learned from this episode that can be applied to the quality assurance systems across the entire replacement research reactor project. I therefore intend to apply a further licence condition requiring ANSTO to report quarterly, the implementation of the quality assurance programs by manufacturers of Safety Category 1 systems."

The web page http://www.arpansa.gov.au/rrrp.htm lists four documents directly related to the CEO's announcement today:

  1. CEO of ARPANSA's Statement of Reasons that sets out his decisions and the evidence he relied upon in making them;
  2. An ARPANSA report;
  3. A report from materials science experts at the CSIRO; and
  4. A report from welding experts at Toshiba Corporation in Japan.

ARPANSA's Nuclear Safety Committee meeting on July 14 covered the tank fabrication error; including the sequence of events, the proposed repair strategy, and quality control issues arising. Summary minutes of the meeting are available via http://www.arpansa.gov.au/nsc_mt.htm.

ENDS