IGSCC

Extrabudgetary Programme on Mitigation of Intergranular Stress Corrosion Cracking in RBMK Reactors

Welcome to the IAEA's Extrabudgetary Programme on Mitigation of Intergranular Stress Corrosion Cracking (IGSCC) in RBMK Reactor web pages. IGSCC of chromium nickel stainless steel piping in BWRs has had a major impact on plant availability since the early seventies. Cracks in BWR piping have occurred mainly in the sensitised heat affected zones of welds subject to relatively high residual tensile stress due to welding processes and water chemistry. In 1997, a similar cracking phenomenon has been revealed on a number of RMBK reactor pipings in Lithuania, Russia and Ukraine. Early in 1998, the Agency initiated activities to assist the countries operating RBMK reactors to address the issue.

For further information please contact Antonio Godoy.

Programme history

The Agency initiated this Extrabudgetary Programme in May 2000 to assist countries operating RBMK reactors in effectively mitigating IGSCC in austenitic stainless steel 300 mm diameter piping. The Programme is implemented in line with recommendations of a workshop and follow-up expert group meetings, which were convened in 1998 - 1999 within the framework of the Agency's Technical Co-operation Department regional projects in Europe.

The Programme relies on extrabudgetary funding from Japan, Spain, UK and the USA, as well as in-kind contributions from Finland, Germany, Lithuania, Russia, Sweden and the Ukraine. Major input is provided through related national or bi-lateral activities, such as the Swedish International Project Nuclear Safety (SIP) and the US Department of Energy International Nuclear Safety Program (INSP).

The Programme objectives are achieved through technology and information transfer, training, and guidance formulated on managing IGSCC in RBMK reactors.

A Handbook containing final reports of the Steering Committee, and Working Groups, Minutes of the Programme meetings and other technical information will be prepared upon completion of this Programme.

Back to top

Programme implementation

The activities of the Programme are conducted in four Working Groups, which focus on:

The Working Groups meet regularly to co-ordinate work in their respective areas. The efforts of the Working Groups are guided, monitored and co-ordinated by the Programme Steering Committee, which is scheduled to meet four times throughout the Programme. The results of the work are summarized in the Minutes of the Steering Committee and Working Group Meetings.

Programme implementation relies on the work of experts from organizations involved, which includes all RBMK power plants, regulatory authorities and technical support organizations of RBMK operating countries as well as various organizations from countries supporting the Programme.

Training

An important element of the Programme is training. Seven training courses/workshops have taken place to date:

One more training course on weld overlay ultrasonic testing techniques, and one seminar on risk based inspection pilot study for Ignalina NPP, are planned to be held in March/April 2002. Training course participants are provided with comprehensive training materials; results achieved are summarized in course reports.

Back to top

Information transfer

In addition to the information and technology transferred in the course of Working Group activities and training, a comprehensive information package on repair and mitigation techniques developed in the USA was made available by EPRI to each of the RBMK facilities.

The results of the International Piping Integrity Research Programme, "The Pipe Fracture Encyclopaedia", have been provided by the US NRC to the RBMK operating countries.


Back to top