Concreting work on the foundations of the Baltic nuclear power plant has been carried out, Rusatom Overseas announced.

A total of 1700 cubic meters of high-strength concrete was poured in shifts, raising the height of the reactor building foundation plate from 8.8m to 7.15 meters.

The works were carried out by the specialists of JSC United Energy-construction Corporation under the supervision of Rosenergoatom Baltic NPP construction Directorate and the general contractor JSC NIAEP.

After the poured concrete attains strength, builders will start construction of the protective lining of the reactor cavity and installation of the core catcher, Rusatom said.

UK changes for EPR. Source: UK regulator (ONR)

Changes to control and instrumentation (C&I) system architecture, including:
-Addition of a non computerised C&I safety back up system;
-Introduction of one way network communication from the protection system to lower classified systems; and
-Introduction of Class 1 displays and manual controls and indications in the main control room and remote shutdown station.

Additional reactor protection system trip signals, such as:
-A high neutron flux trip
-A high axial offset trip
-A hot leg high pressure trip
-A reactor coolant pump low speed trip.

Automation of certain actions such as:
– Activation of the emergency boration system in the event of a steam line break;
– Isolation of pipework in the event of leaks to prevent flooding; and
– Actuation of the emergency feedwater system on detection of low steam generator pressure.

Improvements to the spent fuel cooling pond, including:
– Removal of several penetrations and openings in the spent fuel pool to increase the robustness of the structure
– Installation of protection (such as penetration covers, secondary containments etc) to prevent leaks from spent fuel pond penetrations;
– Improvements to the cooling water supply systems to the spent fuel cooling pond; and Changes to SFP fuel handling procedures.

Upgrade of the safety classification of numerous structures, systems and components (SSCs) that are important to safety including:
-Parts of the C&I systems;
-The primary circuit safety injection accumulators;
-The Ultimate Diesel Generators (UDG);
-The electrical earth system;
-The actuation signals for:
– Starting the UDGs;
-Starting the Primary Depressurisation System (PDS);
-Closing the diverse full load Main Feedwater Isolation Valves;
-Actuation of the Emergency Boration System (EBS).

Other modifications that provide additional diversity, defence in depth, or other safety improvements such as
-Provision of additional diversification in the electrical power supplies to key components to reduce the probability of common cause failure;
-Modification of the primary circuit pipework to facilitate through life inspection; Strengthening part of the civil structure to improve protection against potential
dropped loads near the reactor primary circuit;
-Upgrading the heating and ventilation support systems which play an important role in cooling essential safety systems such as C&I;
-Providing a diverse heating and ventilation system;
-Upgrading the control systems for the main and diverse heating and ventilation
-Improvements to the system for detecting small steam generator tube leaks; and
-Reassessment of the irradiation embrittlement surveillance scheme to take account of the effects of the heavy reflector inside the UK EPR reactor pressure vessel.

Post-Fukushima reviews:
Directly as a result of the Fukushima lessons learnt review, EDF and AREVA identified five design change proposals, covering 16 resilience enhancements, that include the following:
-Improved flood protection for emergency electrical supplies (both AC and DC); -Extension of the capability and autonomy of emergency electrical supplies (both AC
and DC);
-Identified connection points for proposed mobile diesel generators;
-Addition of SFP instrumentation into the severe accident management C&I systems;
-Identification of a reserve ultimate water supply: and
-Delivery of water via mobile pumps for SFP make up and containment pressure control.