2. Plant Layout

   1. Plot Plan

A plot plan of a typical PWR NPP is shown in Figure 3.2.1. The plant is composed of a reactor coolant system, consisting of a nuclear reactor and its related systems, and other attached facilities. The reactor building and the reactor auxiliary building accommodating the reactor coolant system and other attached facilities are based on a hard bed rock and constructed with thick concrete floors and walls to meet the strict earthquake design, and safety and shielding requirements. These buildings are partitioned by concrete walls into smaller compartments in which components, piping and valves, cable trays and ducts of heating, ventilating and air conditioning systems are installed. In the PWR plant design, the reactor coolant system and its related systems are designated as primary systems, while secondary systems mean the turbine-generator systems.

The turbine-generator of the PWR plant is larger than that of a fossil-fueled plant of the same capacity, since the former uses relatively low pressure saturated steam which is generated in steam generators. Therefore, the turbine building of a PWR plant is large. However, since all areas of

the turbine building are not radiation controlled, the building structure is steel-framed without any shielding concrete, like the turbine building of a fossil-fueled plant

Besides these main buildings in the plant, there are intake and discharge structures, a switchyard, a service building, a radioactive waste storage building, a make-up water system, plant internal roads and many other facilities which are necessary to manage the power plant. Additionally, as all PWR NPPs in Japan are sited on the sea, there are harbor facilities including quays and lifting cranes. In accordance with the plant site conditions, these facilities are laid out in an optimum arrangement in relation with the main buildings.

The arrangement design requirements for the major facilities are shown below.

1. Intake and discharge structures

All PWR plants in Japan use sea water to cool turbine-generator units.

After cooling the turbine-generator and reactor components, large amounts of warm discharged water should be effectively diffused into the sea. Care should be taken of the arrangement and the selection of the type of intake structures, so that the once discharged sea water will not be taken in again.

(3) Reactor Building © Auxi L iary Butiding

©Radwaste Storage Building (B Switchyard

Controlled Area

txxwi Access-controlled Area

© Turbine Bui Iding

Figure 3.2.1 Plot plan of nuclear power plant

3~5

NSRA, Japan