Evaluation of CANDU NPP containment structure subjected to aging and internal pressure increase

Abstract The objective of this study is to investigate the long-term performance of a typical CANDU® 1 containment structure. A three-dimensional nonlinear finite element model was built to realistically evaluate the performance of the structure under service load as well as a hypothetical beyond-design level internal pressure. Consideration is given to the time-dependent effects, such as shrinkage, creep, and relaxation of prestressing tendons, over a 60-year timeframe. In addition, the sensitivity of the response of the containment structure against support condition, internal temperature profile and temporary construction openings was also investigated. The accuracy of the numerical model was validated against structural measurements made during a routine leak rate test. The analysis results show that the containment structure would develop a ductile mechanism if the internal pressure significantly exceeded the design pressure. The pressure-deformation relationship of the structure is sensitive to the considered time-dependent parameters.

[1]  D. K. Paul,et al.  Non-linear response of reinforced concrete containment structure under blast loading , 2006 .

[2]  Farid Benboudjema,et al.  Early-age behaviour of concrete nuclear containments , 2008 .

[3]  Keun-Joo Byun,et al.  Creep prediction of concrete for reactor containment structures , 2002 .

[4]  E. Bentz.  Sectional analysis of reinforced concrete members , 2000 .

[5]  Michael F. Hessheimer,et al.  Results of Overpressurization Test of a 1:4-Scale Prestressed Concrete Containment Vessel Model , 2002 .

[6]  Z. Hora,et al.  Analysis of long-term behaviour of nuclear reactor containment , 2007 .

[7]  B. Shenton,et al.  Aging management program of the reactor building concrete at Point Lepreau Generating Station , 2011 .

[8]  D. J. Naus,et al.  Inspection of Nuclear Power Plant Containment Structures , 1998 .

[9]  F. Vecchio,et al.  THE MODIFIED COMPRESSION FIELD THEORY FOR REINFORCED CONCRETE ELEMENTS SUBJECTED TO SHEAR , 1986 .

[10]  Lars-Olof Nilsson,et al.  Evaluation of prestress losses in nuclear reactor containments , 2011 .

[11]  In-Kil Choi,et al.  Probabilistic seismic risk analysis of CANDU containment structure for near-fault earthquakes , 2008 .

[12]  Sun,et al.  Nuclear power plant life extension： How aging affects performance of containments ＆ other structures , 2013 .

[13]  V. D. Loktionov,et al.  Numerical investigation of the reactor pressure vessel behaviour under severe accident conditions taking into account the combined processes of the vessel creep and the molten pool natural convection , 1999 .

[14]  Comite Euro-International du Beton,et al.  CEB-FIP Model Code 1990 , 1993 .

[15]  Y. R. Rashid,et al.  Recent results on the evaluation of the overpressure response of concrete and steel containments , 1985 .

[16]  C. F. Zhao,et al.  Damage mechanism and response of reinforced concrete containment structure under internal blast loading , 2012 .

[17]  Tomio Nakano,et al.  Study of ultimate seismic response and fragility evaluation of nuclear power building using nonlinear three-dimensional finite element model , 2010 .