Checks on Finnish reactor parts continue

No inadequate or counterfeited documentation related to the manufacture of forged steel parts used in Finnish nuclear power plants has so far been identified by the plant operators. However, the country's regulator has requested detailed investigations be completed by the end of April.

In May 2016, the French nuclear safety regulator said an ongoing quality audit at Areva's Le Creusot forge - which Areva bought in 2006 - had identified "irregularities" in paperwork on some 400 plant components produced there since 1965. The issues "comprise inconsistencies, modifications or omissions in the production files, concerning manufacturing parameters and test results", it said.

The following month, the Finnish Radiation and Nuclear Safety Authority (Stuk) requested utilities Fortum and Teollisuuden Voima Oyj (TVO) investigate whether equipment whose material quality cannot be fully guaranteed had been supplied by the forge to their nuclear power units.

TVO submitted its findings for units 1 and 2 of its Olkiluoto plant to Stuk at the end of October. According to TVO's report, Stuk said: "No counterfeits were detected in the parts delivered to the operating units and all inspected devices were compliant."

Fortum submitted its report on the Loviisa plant at the end of December, which also concluded no parts had been supplied with deficient or counterfeited documentation. However, the company told Stuk its investigations "partly need to be continued because they are difficult and time-consuming". Fortum is expected to submit further information by the end of March.

TVO said it is also continuing investigations concerning parts supplied by the Creusot Forge for use in the EPR under construction as unit 3 of the Olkiluoto plant. TVO supervised the manufacture of these parts at the forge, as did Stuk. In addition, the regulator supervised testing of the parts and also inspected them prior to their installation.

Stuk said these are part of the reactor's primary circuit, "so they are very important in view of safety". It noted, "Acceptable specifications are the precondition for obtaining an operating licence."

Stuk section head Martti Vilpas said, "We must not leave room for even the slightest doubt, so TVO and the plant provider must investigate the matter thoroughly."

Stuk has called for more detailed investigations to be completed by 30 April.

The upper and bottom heads of the reactor pressure vessel for the EPR under construction as Flamanville 3 were manufactured at the the Creusot facility in September 2006 and January 2007, respectively. A high carbon content in those parts prompted Areva to review the company's quality process in 2015.

The French nuclear safety authority has identified 18 French nuclear power reactors whose steam generators could contain high carbon concentrations. Checks of manufacturing documentation are also being carried out at other reactors around the world incorporating parts supplied by the Creusot facility or by Japan Casting and Forging Corporation.

Researched and written
by World Nuclear News