GUIDELINES FOR CONTINUED OPERATION

The high capital replacement costs for reactor facilities provides strong incentive to ensure continued operation of existing research reactors. However, the first and most important operation requirement is that a research reactor shall be able to meet its safety goals at any time, independent of age or other considerations. If these goals caimot be met for any reason, the reactor must be shut down, regardless of its age. 

Experience has shown that, in most cases, it is possible to find some technically possible complementary provisions which maintain the reactor safety at an acceptable level. This is the general practice regarding research reactors. Most of the currently operating 

Very few research reactors were designed based on a specific design lifetime . Instead, very conservative design criteria were utilized. Engineering limits established for non nuclear applications were frequently set more conservatively for nuclear applications. Since a lifetime has not been established, the words lifetime extension have not been applied to research reactors. With proper operation, maintenance and replacement of components which have degraded through ageing, the lifetime of a research reactor is indefinite and usually determined by its continued usefulness and the costs of operation and maintenance. 

In order to assess continued operation of a research reactor from the reactor safety standpoint, a methodical approach should be taken. Such an approach will utilize data from the ageing management programme and should incorporate the following considerations  

A safety review of the reactor tailored to establish the actual status of the systems regarding degradation from ageing or other specific mechanisms  

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