PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY
Series: Nuclear and Reactor Constants

since 1971

Русский (РФ)

ISSN 2414-1038 (online)

BROND-3.1

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2024 Issue 3

SIMULATION OF THE LB LOCA ACCIDENT PROCESS IN CASE OF VVER-SKD COLD SECTION MAIN CIRCULATION PIPELINE GUILLOTINE BREAK WITH RELAP5 CODE

SIMULATION OF THE LB LOCA ACCIDENT PROCESS IN CASE OF VVER-SKD COLD SECTION MAIN CIRCULATION PIPELINE GUILLOTINE BREAK WITH RELAP5 CODE

EDN: RJALSG

Authors & Affiliations

Sujyan A.M., Sedov A.A.
National Research Center “Kurchatov Institute”, Moscow, Russia

Sujyan A.M. – Researcher. Contacts: 1, pl. Academica Kurchatova, Moscow, Russia, 123182. Tel.: +7 (919) 723-03-87; e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it., This email address is being protected from spambots. You need JavaScript enabled to view it..
Sedov A.A. – Deputy Head of the Department.

Abstract

This paper presents results of the LB LOCA accident process in case of VVER-SKD cold section main circulation pipeline guillotine break. RELAP5/MOD3.3 system code was used as a calculation tool, which is widely used for the analysis of transient and accident processes in light-water-cooled reactors. To solve this problem, using the capabilities of RELAP5/MOD3.3, a calculation model of the VVER-SKD was developed. The reactor emergency cooling system is included in this model, and the scenario according to which they were triggered is determined. The calculation was performed without taking into account neutron-physical feedbacks, however, taking into account the residual energy release in the reactor. As a result of modeling the accident process, it was noted that the mass flow rate of the coolant through the sections of the main circulation pipeline reached maximum values about 4,5 t/s, and after 10 seconds from the moment of rupture, its oscillations were observed around the value of 200 kg/s. The maximum temperature of the fuel in the time interval between the moment of rupture and the activation of the first emergency core cooling system tank was 1572 °C, and the maximum temperature of the fuel element shell was 1096 °C. The proposed version of the emergency cooling system and the corresponding scenario according to which it was triggered made it possible to quickly reduce the temperatures of fuel and fuel element shells, as well as transfer the system to the asymptotic phase of reliable core cooling, at which temperatures in it were maintained at 100–150 °C, and pressures at 0.25–0.58 MPa.

Keywords
computational analysis, accident process, coolant loss, reactor, VVER-SKD, LB LOCA, guillotine break, RELAP5, emergency cooling system, scenario, pressure, mass flow, temperature

Article Text (PDF, in Russian)

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UDC 536.24.083

Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants, 2024, no. 3, 3:18