Change Register

New changes
0
This month
Awaiting approval
1
Under review by the change board
Ready for implementation
1
Approved by all disciplines
Rework required
1
Rejected with comments

Project Change History

5Chronological register of engineering, technical and design decisions
Period:—
CHG-2024-156Under reviewTechnical

Upgrade of the VVER-1200 reactor control and protection system

Originator: Matthew Gardner2024-12-1414:30

Implement a redundant microprocessor-based control system for reactor protection actuators with enhanced reliability classification.

Affected SSCs
4 engineering database objects
PBS
10JNA10CR001• 10JNA · Reactor control and protection
Reactor protection system
PBS
10JNA10EM001• 10JNA · Reactor control and protection
SHEM-3 control rod drives (set of 121)
PBS
10JAA10• 10KBA · Reactor coolant circuit
VVER-1200 reactor assembly
GBS
10UKA-C301• 10UKA · Reactor Building
Reactor protection equipment room (+26.000 m)
CHG-2024-155ApprovedDesign

Update of primary circuit piping drawings

Originator: Laura Henderson2024-12-1311:15

Revise instrumentation impulse line routing and reactor coolant piping supports.

Affected SSCs
4 engineering database objects
PBS
10JAA10• 10KBA · Reactor coolant circuit
VVER-1200 reactor assembly (DN 850 nozzles)
PBS
10JEA10• 10KBA · Reactor coolant circuit
PGV-1000MKP steam generator No. 1
PBS
10JEB10• 10KBA · Reactor coolant circuit
GCNA-1391 reactor coolant pump No. 1
PBS
10JEF10• 10KBA · Reactor coolant circuit
KD-79 pressurizer
CHG-2024-154ImplementedOrganizationalProgress: 100%

Revision of preventive maintenance procedures

Originator: Aaron Blake2024-12-1216:45

Optimize turbine oil system and pump maintenance procedures.

Affected SSCs
4 engineering database objects
PBS
10KTA• 10KTA · Turbine Hall
K-1200-6.8/50 turbine generator unit
PBS
10KTB• 10KTB · Mechanical plant
Regenerative feedwater heating system
PBS
10PE• 10PE · Electrical systems
6 kV station auxiliary power supply
GBS
10UMA-00• 10UMA · Turbine Hall
Unit turbine hall (+0.000 m)
CHG-2024-153RejectedTechnical

Revision of reactor trip logic

Originator: Dylan Nash2024-12-1109:20

Proposal to revise the reactor trip setpoint for reduced feedwater flow through the steam generators.

Affected SSCs
4 engineering database objects
PBS
10JDH10AP001• 10JDH · ECCS
High-pressure ECCS pump No. 1
PBS
10JET10AP001• 10JET · Emergency boron injection
Emergency boron injection pump No. 1
PBS
10JNA10CR001• 10JNA · Reactor control and protection
Reactor protection system
FBS
E1• FBS · Safety
Nuclear reactor control (FBS function)
Reason for rejection: Insufficient safety justification for the proposed changes. Additional transient analysis is required.
CHG-2024-152In progressDetailed designProgress: 45%

Improved steam generator supports

Originator: Maria Hernandez2024-12-0810:00

Strengthen steam generator snubbers to withstand seismic intensity up to 8 on the project’s specified intensity scale.

Affected SSCs
3 engineering database objects
PBS
10JEA10• 10KBA · Reactor coolant circuit
PGV-1000MKP steam generator No. 1 (supports)
PBS
10JDH10BB001• 10JDH · ECCS
First-stage ECCS accumulator No. 1
GBS
10UJA-12• 10UJA · Containment
Reactor Building — steam generator compartment (+12.600 m)