Description of BS 4975:1990 1990

1.1.1 This British Standard specifies the design, construction, inspection and testing of prestressed concrete pressure vessels (PCPV) for nuclear reactors, including components that are necessary to maintain the structural integrity and leaktightness of the vessels. However, such concrete pressure vessels are often closely integrated with the operation of the nuclear reactor and its auxiliary plant, and the various parts of the vessel may need to perform functions additional to the structural requirements of this standard.

1.1.2 The safety of concrete pressure vessels depends, firstly, on a correct assessment of the loadings likely to be applied to the vessel and, secondly, on the proper design of the vessel to accept these loadings. This standard covers only the second aspect, the first being the responsibility of the purchaser who has to meet any statutory or other regulations¹⁾.

1.1.3 The safety of concrete pressure vessels throughout their service lives also depends on proper operational procedures being adopted and adequate monitoring and inspection of the vessels during service life being carried out. As operational procedures are the responsibility of the operator they are not included in this standard. Monitoring and inspection are dealt with in 9.4.

1.1.4 Other components of the reactor pressure circuits, including those parts of the ancillary circuits that, for inspection, can be isolated from the primary circuit at any time without having to shut down the reactor, shall comply with the relevant British Standards and any additional requirements specified by the purchaser (see 1.5).

1.1.5 In addition to the definitive requirements, this standard also requires the items detailed in 1.5 to be documented. For compliance with this standard both the definitive requirements and the documented items need to be satisfied.

NOTE 1 Where the words “purchaser” and “manufacturer” occur in the text they should be taken to include representatives of the purchaser and manufacturer or inspectors mutually agreed upon.

NOTE 2 While this standard is based on current British practice which uses PCPVs in association with gas-cooled reactors, it is not intended to limit its use solely to reactors of this type. It is proposed to keep the standard under review, but it is realized that some of the requirements might be inapplicable to new developments and in such cases revised requirements should be specified by the purchaser.

NOTE 3 The titles of the publications referred to in this standard are listed on the inside back cover.

NOTE 4 Bibliographic references are identified by a letter and number in square brackets, e.g. [K4], and will be found either at the end of the relevant appendix or in Appendix N.

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