Ringhals (Sweden)

Map of Ringhals

Map Loading...

unit-1: 800 MW BWR constructed by Asea-Atom grid connection in 1974
3 *900 MW PWR units; constructed by Westinghouse; grid connection in 1974 and 1981/82.

Facilities in Ringhals

plantreactor typconstruction startoperation startshut down

Threat levels raised after power plant 'bomb' find

"After the discovery of explosives on the premises of Swedish nuclear power plant Ringhals south of Gothenburg on Wednesday afternoon, authorities quickly raised the threat level at all Swedish nuclear facilities.

“They have all raised the threat level as a precaution,” said Maria Stråhle at the Swedish Radiation Safety Authority (Strålsäkerhetsmyndigheten) to news agency TT.

The explosive device was found on a large truck that had been on the industrial estate belonging to the plant and was returning into the reactor area, which is more heavily guarded.

“Under the first step onto the truck there is a fire extinguisher and that is where the explosive had been placed,” said Gösta Larsen of the Ringhals plant to TT.

He said that police suspect that a civilian has prepared the explosive and that it was the size of a “small fist”.

The device was not primed and was not large enough to do damage to a reactor, according to Larsen. However, he confirmed that the threat levels had been raised as a result of the find and said that any discovery of explosives on the plant’s premises was “worrying”.

According to the county police, the device was in the shape of “plastic explosive” and the truck where it was discovered never leaves the plant’s immediate environs.

“The truck was entering the guarded area when the device was found by the plant’s own sniffer dogs,” said police spokesman Tommy Nyman.

The entire premises were searched with sniffer dogs over night but no other discoveries have been found and police so far have no suspects.

However, a preliminary investigation is under way and the incident has been classified as a suspected sabotage attempt.

Police will question truck drivers and officers are currently trying to find out where and when the suspected explosive could have been placed on the vehicle.

“We will speak to everyone we think could have information about the incident,” Nyman said to TT.

The device was sent off to the National Laboratory of Forensic Science (Statens kriminaltekniska laboratorium – SKL) in Linköping for testing soon after the discovery and scientists have since confirmed that it was an explosive found on the plant premises."

(source: http://climatesceptics.org/europe/sweden/ringhals/threat-levels-raised-after-power-plant-bomb-find)


Approval of power uprate in Ringhals unit 3
The Swedish Radiation Safety Authority (SSM) announced that it has given Ringhals AB approval to raise the thermal output of unit 3 of the Ringhals nuclear power plant by some 5%, from 3000 MW to 3144 MW. As a first step, the pressurized water reactor (PWR) will be allowed to operate at the higher level on a trial basis until the refuelling outage planned in 2010. At the end of the trial operation, Ringhals AB will need a separete approval from the SSM for the unit to be operated at the higher level as routine. Ringhals applied to SSM's predecessor the Nuclear Power Inspectorate (SKI) for a major uprate on the 915 MWe unit, on the basis of steam generator and low-pressure turbine replacement. Early in 2008 it was operating at 985 MWe net. In August 2008, work was completed to allow it to operate at 1050 MWe pending approval by SSM. A further uprate to 1105 MWe is envisaged.
(source: http://www.world-nuclear-news.org)


On Friday, a fire broke out on the roof of a turbine facility at Ringhals-2. It has already been brought under control.
A spokesman for the plant said there was no risk to the reactor.
Ringhals spokesman Gosta Larsen however said that roof workers had accidentally set construction material on fire but that any blaze had already been extinguished."
source: RSS wordpress


A generator fire broke out at Sweden’s Ringhals 3 - the fire is thought to be caused by a mislaid tool.
The unit is expected to be back up to full power in mid October when the broken generator has been replaced.


A fire in a transformer in the onsite electrical distribution system occured at Ringhals-3. The trip of the two turbines was followed by a reactor trip. SKI will initiate an investigation of the event.


Ringhals unit 3 tripped after a fire in a transformer in the onsite electrical distribution system.


In 2005 three events occured at Ringhals-1 below INES labelling: because of salt deposits caused by the storm "Gudrun" the generators were disconnected from the grid due to flashovers of the switchyard, a leak in the reactor coolant cleaning system, and leakage inside the reactor containment.


In 2005 two events occured at Ringhals-2 below INES labelling: because of salt deposits caused by the storm "Gudrun" the generators were disconnected from the grid due to flashovers of the switchyard, and leakage from the bottom of the reactor containment because of extensive corrosion damage on the toroid plates.


In 2005 four events occured at Ringhals-3 below INES labelling: because of salt deposits caused by the storm "Gudrun" the generators were disconnected from the grid due to flashovers of the switchyard, failure of seals in two condensate system pumps of one of the turbines, the spurious closure of a valve in the feedwater system, an internal leak in one of the reheaters at a turbine.


In 2005 five events occured at Ringhals-4 below INES labelling: because of salt deposits caused by the storm "Gudrun" the generators were disconnected from the grid due to flashovers of the switchyard, a low-pressure preheater drainage pump in the condensate system in a turbine leaked, problems with the turbine occured at restart, three times power had to be reduced because of a shutdown of a main coolant pump caused to vibrations.


Two auxiliary feedwater pumps were not ready for operation at Ringhals-2. This event was preliminarily classified INES 1.


In 2003 a water leakage from the containment was reported. Ringhals has not yet been able to verify the exact location of the leakage, the leakage is continously monitored.


In 2002 and 2003 cracks have been identified in some nickel base alloy safe end welds of the reactor pressure vessel nozzles at Ringhals 3 and 4. Repairs were made.


Extensive stress corrosion cracking was observed years ago in consoles and supports of the emergency core spray systems. Most of the damaged supports were replaced. Follow-ups in 2002 showed that some of the remaining cracks had propagated, but no new cracks were identified. The core spray has been completely replaced to less sensitive material.


Ringhals-3 experienced for the second time a locking of a gate valve in the RHRS with the unit in hot shutdown. This valve had earlier not been identified as susceptible of locking phenomena. The blocked valve did not fulfil the requirements for accidental conditions.


Two incidents followed the annual maintenance at Ringhals-2 and -4 in summer 1997.

The operators at Ringhals-2 discovered that they had failed to notice that automatic safety systems had not been turned on after the unit was reconnected to the grid. It took two days before the incident was reported to SKI.

The incident was followed by a similar one at Ringhals-4 involving the containment spray.

The incidents were subject of a legal review.
Swedish regulators decided that they will not file charges against the employees for violating the country's nuclear law, saying they do not believe there was criminal intent.
.Regulators said further that SKI´s oversight principles are designed to encourage openness among plant management and employees in reporting events and incidents.


The Swedish government has granted a new, short-term operating license to Ringhals-2. The new permit expires June 30, 1997.
Phase-out advocates had lobbied for decommissioning to begin with Ringhals-2, since its license was expiring. Normally, Swedish reactor licenses have no expiration dates. However, when the steam generators at Ringhals-2 were re-placed in 1989, owner Vattenfall was granted a power uprate, conditioned on a five-year license limitation. The license expires at the end of 1995.


Second incident involving control rod malfunction in the two 900 PWRs since August 1994: problem occured during a test of the CR: 3 of the 48 CR stopped a few cm short of their normal position. As in unit-4 function of CR was restored by changing the fuel elements in the positions were the CR assemblies did not work.
CR problems are connected to the Fragema fuel. Fuel has been shifted. After restart another problem occured: uneven power distribution, therefore the unit is operating at only 50% power.
End of April the unit is again at 100 % power with no further core tilt problems that exceed the safety specifications.


Unit was taken down on 11. unit 3 & 4 followed an 13 because an analysis of computer printouts showed setpoints of SG safety valves were too high. Cause is unclear: some 20 years has elapsed since setpoints were calulated and documentation is lacking. On 17.12. all units were back on line.


Westinghouse finished installing new rotor blades on the turbine: cost US$26- 40 million


SCRAM 2 days before the planned refuelling outage: it was found that the 48 control rods could not be completely inserted into the core - a few more rods had varying degrees of friction resistance.
More rigid fuel element and a lighter overhead spring load are two likely solutions to the problem of bowed Fragema fuel.


For the first time a circumferential crack has been found in a weld on a vessel head penetration. 4 axial cracks were found on vessel head penetrations in May 1992 and a fifth later. all cracks found in EdF's vessel head penetrations were axial. too. Circumferential cracking is considered more serious because of the increased risk that a penetration might snap during operation and be ejected.That would create a difficult to isolate leak in RCS. The circumferential crack is 18 mm long and in a circumferential weld that attaches the penetration to the vessel head. The weld is of nickel-steel alloy (alloy 182, not alloy 600 of which the penetrations are made) - Crack is probably a manufacturing defect. Further investigations revealed more circumferential crack indications (10).
Exchange of vessel head is planned for 1996 by MHI (for unit 4) costs for the total job US$ 6,5-8 million).


Further problem with control rod drive mechanism, a small leak was also found in the control rods hydraulic system.


During restart after a long outage one control rod didn't move at all and between 4 and 7 rods moved too slowly. The rods had worked correctly during testing.


Extended refueling aoutage due to cracks in FW nozzles and modifications to the ECCS: Each of the 4 FW tubes leading to the core has several cracks in the inner stainless steel lining. the cracks are caused by thermal stress and are between 6 and 8 mm deep, most are axial, but some are circumferential.


Extended outage due to cracks in the reactor vessel head. first inspection outside France after detection of cracks in EdF reactors, first time such craks were found on a Westinghouse plant. as in France the penetrations at Ringhals-2 are made of Inconel 600. of 65 penetrations 12 have been examined and 5 have been found to have indications of cracks ( one : 16 mm length and 4 mm deep, one: 2 mm deep - all are axial not circumferential). penetrations were repaired by electronic erosion. At Ringhals-3 no cracking was found.


During refueling outage damage on the control rod guide tubes in 3 fuel assemblies was discovered.