Steam generator dropped at French reactor

04 April 2016

A used steam generator was dropped within the reactor building of unit 2 of the Paluel nuclear power plant in France, operator EDF has informed the country's nuclear regulator. The plant is currently offline for a maintenance outage, including replacement of all four steam generators.

Paluel 2 - a 1300 MWe pressurized water reactor - was taken offline in May 2015 for its third ten-yearly in-service inspection. The fuel has since been removed from the reactor and stored in the unit's used fuel pool. During this period, work has been undertaken to enable the unit to continue operating for at least another ten years.

Paluel 2 steam generator drop - 250 (ASN)
The steam generator came to rest over the unit's reactor cavity (Image: ASN) [Click to enlarge]

Part of this work has involved the replacement of the unit's four steam generators. In order to remove the old steam generators, they are raised using the unit's polar crane, rotated from its original vertical position to a horizontal position and then placed on a trolley. The components - each measuring 22 meters in height and weighing 465 tonnes - are then extracted from the reactor building through a hatch.

EDF informed the French nuclear regulator, the Autorité de Sûreté Nucléaire (ASN), on 31 March that an incident had occurred during the operation to remove one of the steam generators. The component was in the vertical position, with its bottom resting on chocks on the removal trolley and its top supported by a system of slings attached to a handling beam, itself connected to handling machinery on the unit's polar crane. The steam generator became unattached at the top and tipped over on to the floor of the reactor building.

The steam generator came to rest partly on the reactor building's concrete floor and also on the protection plates covering the reactor cavity. Some of these plates were damaged by the fall.

One worker was said to be slightly injured in the incident.

A team of ASN inspectors has carried out an inspection of the reactor and is currently drafting a report of its findings.

Researched and written
by World Nuclear News