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

since 1971

Русский (РФ)

ISSN 2414-1038 (online)

BROND-3.1

ISSUES

2023, Issue 4

EFFECT OF CORE BURNUP OF VVER-1000 TYPE REACTOR ON READINGS OF IONIZATION CHAMBERS

EFFECT OF CORE BURNUP OF VVER-1000 TYPE REACTOR ON READINGS OF IONIZATION CHAMBERS

EDN: GIBAOK

Authors & Affiliations

Starova N.A.
Scientific and Engineering Centre for Nuclear and Radiation Safety, Moscow, Russia

Starova N.A. – Junior Researcher. Contact: 2/8, bld. 5, Malaya Krasnoselskaya st., Moscow, Russia, 107140. Tel.: +7 (499) 753-05-24; e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it..

Abstract

The method of numerical modeling of reactivity measurement developed at SEC NRS is based on numerical modeling of measurement of the current of the ionization chamber (IC) and its further processing by the formula for the inverse solution of the kinetic equation. Using the methodology, computational modeling of reactivity measurements was successfully carried out for the stage of physical start-up of NPP power units with VVER. The numerical modeling of the IC current measurements is based on the calculation of the coefficients of the influence of fuel assemblies on the IC readings, and, thus, includes the calculation of the thermal neutron flux density at the location of the IC. It is known that more than 80 % of the contribution to the value of the neutron flux density at the location of the IC is made by the fuel assemblies of the last row. The paper presents the results of calculations of the coefficients of influence of fuel assemblies of the last row for fresh and burnt cores of the V-392M reactor plant. The analysis of the results obtained is a numerical confirmation of the independence of the influence coefficients from fuel burnup. The article presents the results of numerical modeling of measurements of the IC current during the reset of the reactor emergency protection at the beginning of the 2nd and 8th fuel campaigns of the 12-month fuel cycle of the VVER-1200 reactor using sets of influence coefficients calculated for both fresh and burned-out active zones. The result obtained is obvious and demonstrates the coincidence of the IC currents calculated using the mentioned sets of influence coefficients.

Keywords
VVER, ionization chamber’s current, influence coefficients, numerical simulation of reactivity measurements, fuel assembly, ionization chamber

Article Text (PDF, in Russian)

References

UDC 621.039.51

Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants, 2023, no. 4, 1:6