In late 2014, AREVA notified Autorité de Sûreté Nucléaire (ASN) of the results of material tests carried out on a component manufactured at the Creusot Forge.  These tests were undertaken by AREVA as part of the much-delayed Qualification Technique of components for the European Pressurised Reactor (EPR) presently under construction at the Flamanville 3 nuclear power plant.  The part tested was a supernumerary equivalent of each of the two components, the upper and lower head shells, that had already been incorporated into the FA3 reactor pressure vessel now installed within the nuclear island at the NPP site.

To much consternation the test results revealed that the material characteristics, particularly the impact or fracture toughness, did not conform to the design-basis specification and, moreover, it arose from a small but nevertheless significant increase in the carbon content across a large zone of macrosegregation present throughout most of the thickness of the equivalent head shell – this is the so-called ‘carbon anomaly’.

This Review traces the origins of the carbon anamaly and identifies fundamental flaws in the quality controls applied across the AREVA manufacturing route of the Creusot Forge. Similar problems are identified in the steam generators manufactured by Creusot Firge and the Japanese Casting and Forging Company (JCFC}.

R3229 Tephra Fall-Out and Operational Safety of Sendai Nuclear Power Plants

The Review comprises three aspects of the present nuclear safety measures relating to the functioning of the Sendai nuclear power plant (NPP) when subject to high levels of tephra ash fallout from an erupting volcanic event.

First, the LargeAssociates Review seeks to describe the present regulatory constraints and requirements placed upon the Sendai NPP operator to adequately forecast the nature and risk of occurrence of the general volcanic hazard; second, the effectiveness of the screening process adopted to determine which volcanoes and to what extent these represent a hazard to the Sendai NPP; and, third, if the severity of the projected volcanic event complies with the 2013 revised design-basis requirements of the Nuclear Regulation Authority (NRA) and, in this regard, if the preparation and countermeasures at the Sendai NPP site are sufficient to protect the region from a significant radiological outcome in the event that nuclear plants are subject to a prolonged period of tephra fallout.

R3218 San Onofre Nuclear Generating Station - Replacement Steam Generator

After 25 years of operation, the San Onofre operator, Southern California Edison (SCE), replaced the original steam generators of Units 2 and 3 reactor power plants. Units 2 and 3 are virtually identical pressurized water reactors (PWR) built by Combustion Engineering (CE) and commissioned in 1983 and 1984; each original plant included two steam generators (SGs), both containing about 9,400 thin-walled tubes.

The four Mitibushi replacement steam generators (RSGs) were installed and commissioned into service in April 2010 and February 2011 in the Unit 2 and 3 plants respectively. However, on January 31 2012, while the Unit 2 fuelling outage was in progress, the virtually identical Unit 3 was forcibly shut down when an alarm alerted SCE operators that a breach had occurred with reactor primary circuit water leaking across the RSG tube interface to the secondary steam circuit.

Large & Associates provided technical evidence to the Atomic Energy Licensing Board in the Friends of Earth successful challenge to shut down the two San Onofre nuclear power plants. This Review includes this evidence, analysis and other technical representations compiled by Large & Associates.