Title: HPC for the Improvement of Tightness of Nuclear Reactor Containments in Case of Severe Accidents

Author(s): G. J. B. Ithurralde and J. L. Costaz

Publication: Symposium Paper

Volume: 140

Issue:

Appears on pages(s): 227-238

Keywords: cracking (fracturing); creep; high-performance concretes; nuclear reactor containment; nuclear reactors; prestressing; silica fume; workability; Materials Research

DOI: 10.14359/3912

Date: 9/1/1993

Abstract:
To insure the tightness function of nuclear reactor containments, a special high-performance concrete (HPC) having a high silica fume content (30 kg/m 3) and a low cement content (270 kg/m 3) has been developed. The aim of this concrete formulation, which has a 28-day compressive strength of about 75 MPa and very good workability, is both to control the risk of cracking of the concrete in the structure and to reduce creep. This paper describes the feedback from experience acquired in the construction of the first HPC containment built in Civaux, France. The advantages and the difficulties encountered and overcome in the use of this material are presented, together with the results of tightness tests of the structure. The industrial mastery now achieved of this special HPC formulation also made it possible to take the performance of this concrete into account in the engineering of the work. This led to a new containment design, presented in this paper, combining HPC and very strong prestressing using 55 T 15 cables. This new design substantially improves the safety of nuclear reactors for severe accidents (core melting and hydrogen deflagration): the structure is guaranteed gas-tight up to an internal pressure of about 1 MPa.