Below is a letter just sent from a supporter of Radiation Free Lakeland to EDF the operators of Hunterston B. Many thanks to David Autumns for his scrutiny on this – the nuclear industry, the most dangerous industry humans have ever engaged in, needs holding to account more than ever.
Thank you for switching off Hunterston B Reactor 4 today. Scotland (Ireland and the North of the UK) is now a safer place to be.
The Reactors at Hunterston have now been running for over 43 years. The graphite cores have multiple cracks with debris in the control rod holes and the control rods have had to be fitted with gimbals so they are able to snake down the holes in the distorted under moderated core. Hunterston, like Hinkley Point B and Dungeness, does not have the tertiary last-ditch boron ball system fitted to subsequent AGR’s. The Cooling Gas Circulators have been found to be running beyond their design life at Hunterston, like the ones at Hinkley Point B.(As noted in the Q3 site reported detailed below) The Pre-stressed Concrete Pressure Vessels in all of your AGR’s are suffering from corrosion of the tendons such that many like the one at Hartlepool leak cooling CO2 from within their nuclear cores (https://books.google.co.uk/books?id=bTaMbbZwnp0C&pg=PA33&lpg=PA33&dq=pcpv+tendon+failure&source=bl&ots=pjreQX76zx&sig=ACfU3U1HbTb6RKkgc3V2bIGUYKcam3nkXw&hl=en&sa=X&ved=2ahUKEwiG0uHUhazmAhV1Q0EAHYvWC0sQ6AEwAHoECAcQAQ#v=onepage&q=pcpv%20tendon%20failure&f=false)
Have a read from page 8 of this document form the ONR for as far as you can stomach it (http://www.onr.org.uk/operational/tech_asst_guides/ns-tast-gd-020.pdf) Especially these lines – “The Heysham 2, Torness and Hunterston B PCPVs have all been affected at various times by minor blockages of parts of the PVCS [Pressure Vessel Cooling System] with the potential for increased concrete and penetration temperatures. Blockages have been caused by small-sized debris in the system becoming trapped at the throttled back flow control valves. The potential exists for coincident blockage of both the 100% duty dual A and B circuits leading to elevated concrete temperatures and unacceptable thermal gradients. 5.34 There is the potential for loss of PCPV penetration restraint with subsequent penetration ejection or of failure due to elevated temperature of the penetrations and surrounding concrete known to be ‘non-tolerant’ to elevated temperature.”
Nuclear sites across the UK have jerry-rigged restraints built around their CO2 cooling gas circulators to prevent them from popping out, like champagne corks, of their 600PSI CO2 filled nuclear cores !!
In the Q3 Hunterston B site report, we once again have another incident reported like this
“A switching operation of power supplies to a Reserve Feedwater Tank (RFT) Transfer Pump resulted in the loss of electrical supplies to the RFT Transfer Pump. The RFT Transfer Pump was supplying feedwater to the Emergency Boiler Feed System for Reactor 3. This caused a reduction of cooling to Reactor 3 for 15 minutes. Reactor 3 has been safely shut down since March 2018 and the corresponding decay heat is very low. Furthermore, as part of the station’s defence in-depth, the Decay Heat Boiler system was at all times available to provide an alternative means of cooling to reactor 3. The nuclear safety consequences of this event were therefore minor and ONR does not consider this event posed a risk to workers or the public.
,,,because it had been shut down for so long the consequences were minor…
This echos the previous quarterly report which said
During CO2 filling operations on Reactor 3 post outage, a gas circulator low level alarm was received on the lubrication oil tank which caused the gas circulators to trip. This caused a loss of forced cooling to the reactor. The remaining available gas circulators were started up and the tripped gas circulators were returned to service following top-up of the oil tank level. Reactor 3 has been shut down for a considerable time and the brief loss of gas circulation did not challenge Reactor 3 cooling requirements. The oil leakage did not result in a spillage of lubricating oil as the oil drains to a dedicated drainage vessel. An investigation has been instigated and the site inspector will follow this up when the report becomes available.
During a routine test of a nitrogen pump, the pump failed its cool down sequence due to a valve configuration issue. The valve configuration issue led to one of the 3 pump ‘trains’ on the nitrogen system to be declared unavailable. The nitrogen system provides a common secondary shutdown capability when the reactors are operating. The reactors are shut down with all control rods inserted, thus the significance of the event was minor as the 2 other nitrogen pump ‘trains’ were available and therefore operating rule requirements continued to be met. An investigation has been instigated and the site inspector will follow this up when the report becomes available.
And in the previous quarterly report, it said
During switching of 11kV electrical supplies for Reactor 3, the electrical supply to the gas circulators was lost resulting in loss of forced circulation to the reactor for [??] short period whilst supplies were re-established. Investigations identified that a switch semaphore in the control room had indicated that an interconnector was closed when in fact the interconnector was open resulting in an interruption to electrical supplies when the supplies were switched. Reactor temperatures were monitored throughout the event and all technical specifications continued to be applied. There were no radiological consequences from this event as Reactor 3 has been shut down for a year and the cooling requirements were much reduced. The licensee has commenced an investigation and the site inspector and an electrical inspector continue to monitor the identified findings, which include a failure by the licensee to adequately risk assess the operation.
Can you see a trend developing here? There wasn’t a major Nuclear Disaster in Scotland because the Hunterston B Reactor 3 had been shut down for a long time.
Given the age of this station, the graphite damage to both cores, it’s PCPV issues with concrete ageing and tendon corrosion, the CO2 gas circulators running beyond their end of life and the inability of EDF to run this Nuclear Power Station without having to rely on it being shut down to avoid nuclear disaster…
With Reactor 4 being shut down today, without even mentioning the control panel fires, might I humbly suggest that for all our sakes, to both EDF and ONR, the 2 reactor cores of Hunterston B now remain shut down permanently.