The FIP document (Ref. PIP/3/3) on the design and construction of prestressed concrete reactor vessels (PCRVs) has proved to be a valuable supplement to national codes for PCRVs since it was first published in March 1978.

Most of its content remains fully relevant, but the development of PCRV technology and the experience gained from their operation have highlighted the need for certain modifications and extensions. It has therefore been decided that these changes are best presented in the form of an addendum to the existing document. In this way, the new material can be more readily identified.

The task of preparing the addendum has been undertaken by the Working Group on PCRVs of PIP Commission No. 7, which is responsible for both PCRVs and containment structures.

P. Dawson, Chairman