This report is a continuation of that submitted last year (PAR2010) regarding the collaboration between ENEA and IRSN (Institut de Radioprotection et de Sureté Nucléaire) dealing with safety issues related to the thick steel reflector of a typical large size GEN III+ reactor designo Concerning the impact of the steel reflector on the signal in the ex-core detectors, issues left open from the previous report (moving the 252Cf primary source assemblies frorn their outer core positions one assembly position inwards towards the core centre; generation of results for the Sb-Be secondary source assemblies) are addressed. All the results for the ex-core detectors were summarized in a paper at the TopSafe-2012 meeting in April, 2012, which is appended to this report. In current operating plants with large cores, flux tilt can be a problem. Although it may be due to a variety of factors and also involve positive feedback effects, one possible contributory cause that may be simply modelled is a variation in the coolant density. It is known that relatively small azimuthal variations in the coolant density in the external assemblies can induce a praportionately high power asymmetry throughout the core (especially at low power) with a conventional baffle-water configuration as reflector. To understand what impact the thick steel reflector has on this effect, results have been generated with a 2-dimensional model of the reactor core at HZP and at 30% NP.

Continuing Analysis with Monte Carlo Techniques of the Impact of the Heavy Reflector of a Typical Large Size GEN III+ Reactor Design on Some Safety Features: Completion of the Ex-Core Detector Calculations from PAR2010 and Examination ofthe Impact on the Phenomenon of Flux Tilt

Burn, Kenneth William
2012

Abstract

This report is a continuation of that submitted last year (PAR2010) regarding the collaboration between ENEA and IRSN (Institut de Radioprotection et de Sureté Nucléaire) dealing with safety issues related to the thick steel reflector of a typical large size GEN III+ reactor designo Concerning the impact of the steel reflector on the signal in the ex-core detectors, issues left open from the previous report (moving the 252Cf primary source assemblies frorn their outer core positions one assembly position inwards towards the core centre; generation of results for the Sb-Be secondary source assemblies) are addressed. All the results for the ex-core detectors were summarized in a paper at the TopSafe-2012 meeting in April, 2012, which is appended to this report. In current operating plants with large cores, flux tilt can be a problem. Although it may be due to a variety of factors and also involve positive feedback effects, one possible contributory cause that may be simply modelled is a variation in the coolant density. It is known that relatively small azimuthal variations in the coolant density in the external assemblies can induce a praportionately high power asymmetry throughout the core (especially at low power) with a conventional baffle-water configuration as reflector. To understand what impact the thick steel reflector has on this effect, results have been generated with a 2-dimensional model of the reactor core at HZP and at 30% NP.
Rapporto tecnico;Reattori nucleari ad acqua leggera;Gen III+;Ex-Core Detectors;Heavy Reflector;Flux Tilt
File in questo prodotto:
File Dimensione Formato  
RdS-2012-003 Frontespizio.pdf

accesso aperto

Licenza: Creative commons
Dimensione 115.83 kB
Formato Adobe PDF
115.83 kB Adobe PDF Visualizza/Apri
NNFISS-LP2-084.pdf

accesso aperto

Licenza: Creative commons
Dimensione 2.91 MB
Formato Adobe PDF
2.91 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.12079/7408
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
social impact