Nuclear reactors

摘要

In a nuclear reactor installation comprising a fluid-cooled nuclear heat source within a primary pressure vessel, the latter is enclosed within a secondary containment means which comprises a lower wall portion surrounding the primary pressure vessel, an annular portion extending out from the lower wall portion, and an upper portion integral with the annular portion and extending over it and over the primary pressure vessel and housing handling means for lifting fuel and other reactor components through normally sealed vertical penetrations in the roof of the primary pressure vessel (giving access to the reactor core) and in the said annular portion (giving access to new and spent fuel stores and other auxiliary facilities disposed outside the secondary containment and wholly or partly below the said annular portion).