Nuclear installations must meet stringent safety requirements, and so require design strategies accordingly, but which are not covered by conventional plant and construction rules. In 1972, therefore, the Federal German Ministry of Education and Research (BMBW, now the BMU or Federal Ministry for the Environment, Nature Conservation and Nuclear Safety) set up the Nuclear Safety Standards Commission (KTA), on the model of the German steam boiler committee. The Nuclear Safety Standards Commis­sion has assumed responsibility for drawing up safety rules in nuclear systems and promoting their use, through bringing about consistent opinions amongst specialists from those who build, install and operate nuclear power plants, inspectors and the authorities.

Safety Standards of the Nuclear Safety Commission (KTA safety standard) [14] lay down safety requirements, compliance with which provides the precautions required when building and operating plants in accordance with the state of the art of science and technology. These precautions required under the Atomic Energy Act are necessary to achieve the safety targets as laid down in the Atomic Energy Act and radiological protection ordinance and in more detail in the safety criteria for nuclear power plants and design basis accidents guidelines.

The KTA safety standards cover more than 100 fields which include all the issues relevant to nuclear technology and relevant disciplines. They are reviewed regularly (every five years) to see if they need revising: that means more than 50 proposed rules are currently being considered.

KTA safety standards must be regarded as mandatory overall standards in Germany which must always be complied with. They can be varied, in theory, but that means those involved (nuclear regulators and inspectors) would have to reach a consensus viable in law. KTA safety standards are publicly available, and are not used in Germany alone: there are many countries, especially in Europe, that accept these codes or would even like them to be used for their nuclear installations, so that KTA safety standards are largely available in English also.

3.1.2 DIN Codes

The codes of DIN, the German standards institute, are generally accepted as codes of the art which are reflected in the KTA safety standards. These standards do not normally apply to nuclear facilities, or are even expressly excluded from applying to them; so the DIN has set up a nuclear technology standards committee, now standards committee materials testing (NMP) specialist area 7 — nuclear technology, which is responsible for producing and updating specifically nuclear standards.

As far as construction technology is concerned, there are two of these codes whose status means that they are also applied internationally: DIN 25449 [15] and DIN 25459 [16]. DIN 25449 covers designing reinforced concrete and pre-stressed concrete components to allow for the rare effects from inside (EVI) and outside (EVA) as safety levels 3 and 4 (see Section 2.5). DIN 25459 also lays down rules for designing safety containments using reinforced and pre-stressed concrete. Due to the integrity requirements involved, such containments also require additional claddings such as steel or plastic liners; this standard also deals with their design, including laminate effects with the reinforced or stressed concrete design. DIN 25459 only exists to date as a pre-standard, which is currently being revised and should be published as a fully fledged standard in the near future.