V. A. SILIN, A. M. ANTONOV.

I. V. Kurchatov Institute,

Moscow

A. M. AFROV, M. P. NIKITENKO, A. V. BUHTOYAROV Experimental Design Organization Hydropress,

Podlosk

Russian Federation Abstract

Pressure increase in the primary circuit to above the critical value gives the possibility of constucting the V-500 SKDI (500 MWe) lightwater integral reactor with natural circulation of the coolant in a vessel with a diameter less then 5 m. The proposed reactor has a high safety level, simple operability, its specific capital cost and fuel expenditure being lower than a conventional PWR. The development of the V-500 SKDI reactor is carried out taking into consideration verified technical decisions of current NPPs on the basis of Russian LWR technology.

1. Introduction

Nowadays together with improvement in the conventional NPP designs some organizations are developing reactors characterized by fewer potential accidents initiators and higher level of inherent safety. Integral PWRs may be considered as an example of such new generation reactors. These reactors can satisfy the safety principles formulated in [1], especially in the case of coolant natural circulation.

However their high specific capital cost may be the reason for their noncompetitiveness with other power plants. It is connected, first of all, with low specific power in such reactors, because of the difficulty of placing the steam generator (SG) large heat transfer surfaces within a steel pressure vessel and providing necessary coolant flow.

Under the constant heat transfer surface of SG and the secondary circuit parameters the amount of heat power of the reactor transferred from the primary circuit to the secondary one can be increased due to the temperature increase of the coolant in the primary circuit. However at subcritical water pressure the possibility of the departure from nuclear boiling hampers the increase of the reactor heat power.

The problems connected with the departure from nuclear boiling are eliminated at supercritical pressure as at supercritical pressure (SCP) the liquid is of one phase through all the range of temperatures. This property also simplifies the provision of the stable coolant circulation.

Increasing the temperature of the coolant at supercritical pressure and corresponding increasing of the temperature difference between the primary and secondary sides gives the possibility of increasing by several times the reactor power.