Nuclear power plants in Vietnam regulates in details the design of items important to safety

Nuclear power plants in Vietnam regulates in details the design of items important to safety (Internet image)

Article 16 of Circular 30/2012/TT-BKHCN stipulates the design of items important to safety as follows:

First, the design of items important to safety must be consistent with national standards, technical regulations, and requirements from competent agencies. The proven design shall be used for the items important to safety. If not, the items of high quality and of a technology that has been qualified and tested shall be used. Then applying the national standards and technical regulations prescribed in Clause 1 of this Article, the applicability, conformity, and sufficiency of them must be evaluated. The application of design that ensures safety functions better than the regulations in such documents where necessary.

Second, the items important to safety must be design so that they can be manufactured, constructed, and installed in accordance with the established procedure, ensure the achievement of intended features and level of safety as prescribed. The design basis must specify the capability, reliability, and functionality of items important to safety for relevant operational states, for accident conditions, and for conditions arising from internal and external hazards; ensuring that the criteria are met over the lifetime of the nuclear power plant. The design basis for each item important to safety shall be systematically justified and documented.

Third, the items important to safety shall be designed and located to minimize the likelihood of consequences and the impacts of external hazards. Such design and location must be conformable with other safety requirements. The safety system support features (including power cabling and control cabling) must be designed to minimize the impact cause by the interactions among the buildings that contain items important to safety, and other structures of the nuclear power plant in the conditions arising from external hazards. The items important to safety must be capable of withstanding the impacts of external hazards considered in the design. If not other features, such as passive barriers, shall be provided to protect the nuclear power plant and to ensure that the safety functions of such items shall be performed.

Fourth, the potential hazards caused by the interactions among the systems important to safety when they operate simultaneously shall be evaluated and prevented. When analyzing the potential hazards cause by interactions among the systems important to safety, due account shall be taken of the physical interconnections and possible effects of a system on the working environment of another, to ensure that the changes in the working environment do not affect the reliability of the system.

Fifth, the reliability of items important to safety shall be commensurate with their safety significance, in particular:

- The quality of items important to safety are assessed and ensured in all stages of procurement, installation, qualification, operation, and maintenance to be capable of withstanding all conditions arising from design basis accidents:

- In the selection of equipment, consideration shall be given to both spurious operation and possible failures.

- The selection of equipment of which the failures are easy to repair and replace.

Finally, if two fluid systems important to safety are interconnected and are operating at different pressures, either the systems shall both be designed to withstand the higher pressure, or provision shall be made to prevent the design pressure of the system operating at the lower pressure from being exceeded.

More details can be found in Circular 30/2012/TT-BKHCN, which comes into force from February 11, 2013.   

Le Vy

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