aging in nuclear power, aging nuclear reactors, concrete, containment, cooling system, HD polyethylene, high-density polyethylene, hole in nuclear containment, hole in secondary containment, Hunterston A, Hunterston B, Hunterston Nuclear Power Station, nitrogen system, nuclear energy, nuclear power, ONR, pipe layout, pipe-work layout, piping, rebar, Safety, seawater, UK, ultrasonic inspection, welds, Wylfa Nuclear Power Station
In 2012 there was a “Discovery of problems with planned pipework routes during installation of the new nitrogen system tie-ins to the Reactor 3 pressure vessel” at French State owned (EDF) Hunterston B Nuclear Power Station in Scotland. Was this problem ever rectified? All that could be found is the following statement: “the proposed pipe work layout created operational difficulties and EDF NGL decided to complete the connection to the existing system and the tie-ins were duly installed, but postpone full installation pending a new layout design following a return to service.” (UK Office for Nuclear Regulation – see more below). Also, could it be rectified without total reconstruction of this old nuclear power station?
On 3 December 1977 The Times reported that seawater had entered the reactor through a modification of the secondary cooling system. Was the bypass ever repaired? (See more below.)
These photos are believed to be from Hunterston Nuclear Power Station. They appear to match, or be similar to, some of the described problems, including in official statements, found below.
Exhibit 1 Concrete and rebar apparently bent to make way for cooling system – Structural Integrity of containment building would be compromised – Against standard safety practices
Exhibit 1B Concrete and rebar apparently bent to make way for cooling system – Structural Integrity of containment building would be compromised – Against standard safety practices
Exhibit 11 Appears to Be Cooling and Emergency Lines Crammed together – Piping codes not followed – Extreme danger to emergency piping lines
This could reflect difficulties in upgrades-repairs to old nuclear power stations, which need, rather, to be promptly shut down. Whether the photos are prior to repair, or even something else or somewhere else, we cannot say for certain. However, the “A” and “R” on another photo in the series suggests French workmanship (“Aller” “Retour“) and hence probable French ownership, meaning that they would be after 2009. Apparent lack of colour change of photos in a humid UK environment also suggests a comparatively recent date.
The seawater damage is said to have been cleaned up, but was the bypass? “On 3 December 1977 The Times reported that seawater had entered the reactor through a modification of the secondary cooling system. The secondary cooling system uses fresh water to cool various items including the bearings of the gas circulators, which circulate the carbon dioxide (CO2) coolant through the reactor to the boilers. A small leak of CO2 through a seal had developed, and a bypass pipe was installed to remove the water contaminated with CO2 to the seawater cooling ponds. When maintenance work was carried out on the reactor and the pressure in the gas cooling system was reduced, sea water was able to flow back up this bypass pipe and into the reactor. The residual heat of the reactor was such that the seawater evaporated rapidly, leaving deposits of salt in the reactor around the gas circuit. It was estimated at the time that the reactor could be out of operation for a year, that the repairs could cost £14 million, and that electricity tariffs would have to rise by between 1 and 2 per cent. Extensive modelling work was performed in the Nuclear Power Company’s (NPC) Whetstone, Leicestershire, fluid flow laboratories to determine where the salt would have been deposited, and the salt was successfully removed by technicians using vacuum cleaners and the plant returned to operation.”
Exhibit 3 Appears to be Hole in Concrete Secondary Containment Wall – Piping encased in concrete, not connected – Venting by pass line (section 31.41.1) – Who ordered this dangerous alteration?. Is this the by-pass which caused the problem in 1977? The photo appears much later or it would be faded-yellowed.
Exhibit 10 Apparent Cooling Lines with Burned Fiberglass Insolation – What happened? – What caused the fiberglass to burn? – Who authorized this repair work? (“A” and “B” may be “Aller” “Retour” suggesting French ownership, management, and/or workers). Hunterston B belongs to French State owned EDF since 2009. Hunterston A belongs to the British Government.
“Discovery of problems with planned pipework routes during installation of the new nitrogen system tie-ins to the Reactor 3 pressure vessel. EDF Energy Nuclear Generation Ltd (EDF NGL) Hunterston B Nuclear Power Station, Licence Instrument (LI) 532 Office for Nuclear Regulation (ONR) consent (under Licence Condition – LC 30(3)) to start-up Reactor 3 following its 2012 periodic shut-down.
The project to install the third nitrogen line, supplementing the existing nitrogen injection system, was started but the proposed pipe work layout created operational difficulties and EDF NGL decided to complete the connection to the existing system and the tie-ins were duly installed, but postpone full installation pending a new layout design following a return to service. The inspectors recorded that ONR is satisfied with the arguments made for postponing the full flow testing, bursting disc replacement and the installation of the pipe work for the third nitrogen injection line and will monitor progress via additional (post outage) interventions.“. OGL: http://www.onr.org.uk/pars/2012/hunterston-b-3.htm
From: “Steels and Boilers Structural Integrity Inspection for 2012 Statutory Outage of Reactor 3
Purpose of intervention
The purpose of this intervention was to inspect the arrangements and implementation of those arrangements relating to steels structural integrity, including boiler integrity, during the statutory outage of Reactor 3 at Hunterston B power station.
Interventions carried out by ONR
The ONR inspectors carried out interviews withvarious people on site and inspected documentation presented. Documentation was inspected using a sampling methodology. Photographic and video evidence was viewed on site, as appropriate. I performed a walk-down of both the Radiation Controlled Area (RCA) and Turbine Hall and inspected a sample of components and welds, and reviewed how these are prepared and inspected.
Key findings, Inspectors opinions and reasons for judgements made
During the walk down of the RCA and turbine halls, I observed the components and welds prepared for inspection, both for Flow Assisted Corrosion (FAC) and more general Ultrasonic Inspection of welded areas…
Remote visual inspection records and images indicated that there was no significant increase in degradation since the previous inspections.. I was satisfied with the quality of recording, reporting and analysis being performed.
EdF Energy Nuclear Generation Limited (NGL) had proposed to undertake installation of a nitrogen injection and blow-down line. Whilst the project was started the proposed pipe-work layout created operational difficulties and NGL decided to complete connection to the existing system but postpone full installation pending a new layout design. I am satisfied with the arguments made for postponing this project and progress will be monitored through ongoing interventions. The revised plan required installation of the tie-ins and a single spool of pipe terminating with a cap. The justification of this new system will be the subject of an engineering change (document EC 344544) separate to the main bucket engineering change for the steel systems. Work was being progressed in this area in accordance with two parallel quality plans. I discussed this with ONR’s specialist quality inspector for the outage, whilst this may not represent good practice, I judge it is not a matter of evident concern.
I judge that the treatment of piping hangers during this outage, including surveys and repairs and replacements, was good.
The reactor cooling water systems were upgraded from a buried cast-iron system to a modern above-ground High-Density Polyethylene and super-duplex stainless steel system. There were no issues of concern during installation of this system. When the system is brought into service it will not meet full design intent, due to the absence of crash barriers at road crossings. Site noted that they had a plant modification in place for this position and planned to complete the work approximately four weeks after the Reactor 3 restart. Traffic calming measures will be implemented in the interim to protect the duty main from impact.
The evidence from manned internal inspections indicated that the inspections of the steel components in the reactor internal structures were being completed as per the intent, and no significant issues had been found to date.
Discussions with the Pressure Systems Safety Regulations (PSSR) competent person, from Royal Sun Alliance group, did not highlight any matters of evident concern.
Discussions overflow assisted corrosion (FAC) were conducted as part of the inspection. I observedsignificant progress in replacing components susceptible to FAC, notably the Main Boiler Feed Pump Turbine Exhaust on Turbo Generator 7. This was achieved, in line with the intents documentation. Evidence was presented that this matter is being addressed suitably and action taken as appropriate. This was reinforced by observations made in the turbine hall.” OGL: http://www.onr.org.uk/intervention-records/2012/hunterston-b-9.htm
Why was above ground High Density Polyethylene plastic piping installed which may not resist fire?
As already noted, all photos are believed to be from Hunterston Nuclear Power Station. They appear to correspond to, or bear similarity to, some of the described problems. Whether they are prior to any repairs or even something else or somewhere else cannot be said with certainty. We are posting them in case they are what they are believed to be.
“British Energy was the UK’s largest electricity generation company by volume, before being taken over by Électricité de France (EDF) in 2009. British Energy operated eight former UK state-owned nuclear power stations and one coal-fired power station.” https://en.wikipedia.org/wiki/British_Energy
Hunterston A: “From construction to closure in March 1990, the power station was owned and operated by South of Scotland Electricity Board. As part of the privatisation of the Scottish electricity generators, Hunterston A was transferred, with the adjacent Hunterston B, to the new state owned company Scottish Nuclear. In 1996 upon privatisation of the UK nuclear industry, the site was transferred, this time on its own to the state-owned Magnox Electric. In April 2005, the NDA took over ownership and place the site with its Site Licence company, Magnox North Ltd.“. https://en.wikipedia.org/wiki/Hunterston_A_nuclear_power_station
EMPHASIS ADDED THROUGHOUT POST.
DISCLAIMER: The above photos were submitted anonymously. The dates and location are unknown. They are believed to be of a nuclear power station. They are believed to be Hunterston Nuclear Power Station in Scotland. Although they could be Hunterston A, they appear to match some of the problems described for Hunterston B, and appear to involve French workers-management. Hunterston B belongs to French State owned EDF. Hunterston A does not. Thus, they may be of Hunterston B. They may also be from somewhere else or something else entirely different, as we could not validate them. We are posting them to both illustrate recorded facts about Hunterston B, and in case they are what they are believed to be.