Two presentations on understanding and addressing the ageing and obsolescence of research reactors were given by Panel 2.2 speakers: H.-J. Roegler (an independent consultant from Germany, formerly with Sie­mens[40]) described an International Atomic Energy Agency (IAEA) initiative on research reactor ageing and ageing management (Roegler, 2011). E. P. Ryazantsev (Kurchatov Institute) provided a historical description of the research and test reactors at the Kurchatov Institute (Ryazantsev, 2011).

IAEA Initiative on Research Reactor Ageing and Ageing Management

H. — J. Roegler

The IAEA’s activities in ageing and ageing management for research re­actors began in the mid 1990s. In March 1995, the IAEA issued a TECDOC report (IAEA, 1995) on how to manage ageing in research reactors. Two months following the release of this report, the IAEA sponsored a confer­ence on research reactor ageing; the conference was held in Germany and involved more than 100 participants. In December 2008—more than a decade after publication of the TECDOC and sponsorship of the follow-up conference—the IAEA hosted an expert meeting at its Vienna headquarters to review the history of the agency’s efforts on ageing, including the ade­quacy of existing documentation, and to consider whether an initiative to collect additional information was warranted.

As the result of this expert meeting, the IAEA initiated the development of a database on research reactor ageing. This database is intended to ad­dress ageing as a technical and safety issue and explicitly excludes reactor conversion to LEU fuel. Information for the database was collected from research reactor operators using a standard template that was developed by the IAEA. The template permitted the reporting of a maximum of 3 ageing problems, classified by 13 possible ageing mechanisms in 76 reactor systems arranged in 9 groups. The template provided space for descriptions of ageing problems and actions taken to mitigate or cure them. A contact address for the reporting reactor was also required.

The templates were distributed in February 2009 to 133 research re­actor operators plus 28 other manufacturers and authorities. Responses from these organizations were incorporated into the database in October that same year. A total of 188 templates were initially submitted from 77 reactor facilities plus 6 other institutions (contributors were permitted to submit more than one template per facility). After review and revisions of the initial submissions, a total of 155 templates reporting on 367 ageing problems were included in the database.

There was a rather high-level of non-participation (43 percent) in this survey, which could have been caused by several factors, including language barriers, inexperience with completing these types of templates, or concern that the ageing problems might be publicly disclosed. One non-respondent justified the lack of participation as follows:

We do not have an ageing management program, because we do not have the funding for such a thing. We fix things when they break. That is un­fortunately the nature of our business here due to monetary constraints.

For me to fill out your template with something that is irrelevant is not worth your time, or ours. …We also do not necessarily wish to have this information be publicly available.

However, a convincing number of useful observations emerged from the template data that were submitted to the IAEA: [41]

Other frequently reported ageing problems included mechanical fatigue and wear and radiation-induced ageing (Figure 2-8).

• There were more ageing problems reported for younger reactors than for older reactors. This suggests that ageing problems begin with the initiation of operation of a research reactor.

Taken together, these data demonstrate the need for the future management of ageing in research reactors.

Although the database intentionally excluded information related to conversion, as noted previously, the information in the database is still potentially useful for conversion planning, because conversion needs to consider past as well as future ageing. The information in the database could be used, for example, to identify:

• Ageing systems and mechanisms to investigate

• Issues to discuss with the authorities

• Contacts for advice on addressing every type of ageing problems

The IAEA is planning to undertake a first update of this ageing da­tabase in August 2011. This will involve the reconfirmation of research reactor operator contacts, updates to the content of templates, and fresh approaches to the research reactor operators who did not provide informa­tion in 2009.