The plant has a well-managed Loan Tools Facility. The traceability of equipment used for an activity is ensured by recording the ID of the equipment on the work permit. This is then logged in the database, so that it is easy to trace which work has been performed with a given tool and where. This is not limited to only measurement and test equipment. Due to the capacity of the workshop, it can support not only the maintenance department but also the contractors, even during an outage. This was recognized as a good performance by the team.
4.5. CONDUCT OF MAINTENANCE WORK
The team noted that in the maintenance department all staff members are encouraged to improve safety margins, work practices and reduce rework based on station Maintenance Fundamentals. This has led to the positive development of improvements made by employees. This was recognized as a good performance by the team.
4.6. MATERIAL CONDITION
Although the station has several improvement plans in place, such as the Corrosion Management Process and the Leak Reduction Program, the team found examples where consistent high standards were not maintained. The team also noted a lack of attention to the state of lighting and the installation of cables. The team made a suggestion to continue, and in some cases accelerate, the improvement plans for material condition and correct the faulty lighting and incorrect mounted cabling.
4.7. WORK CONTROL
One challenge for the station is to reduce the backlog on lower prioritized actions to improve the overall material state of the equipment. The number of P3 prioritized items is 903 and P4 prioritized items 1754 with a rising trend in 2017.
The team encouraged the station to achieve a sustained reduction in the overall defect backlog.
4.8. SPARE PARTS AND MATERIALS
Spare parts and material requests are identified early in the work management process to support their timely delivery. There is also a fleet database (POMS) to record and prioritize obsolete equipment. The station is also working on improvements regarding repairable safety related stock items. However, the team found several instances in which return to service of equipment was delayed, or direct repair was not possible due the lack of spare parts, or insufficient quality of spare parts. The team made a recommendation in this area.
4.9. OUTAGE MANAGEMENT
To address an issue found in previous outages, where gaps in engagement from different departments were recognized during the outage preparation, the station has developed a Pre-Outage Milestone Plan (POMP) database for Pre-Outage accountability. The results of the last outage showed a significant improvement in POMP adherence with 65 of 69 of the milestones completed on time. At the time of the mission, POMP adherence for the 2018 outage was currently 100%. This was recognized as a good performance by the team.
DETAILED MAINTENANCE FINDINGS
4.6. MATERIAL CONDITION
4.6(1) Issue: The material condition of equipment is not always appropriately maintained to support safe and reliable operation.
Although the station has several improvement plans for material condition in place, the team noted the following:
Some cables are not well fixed to cable trays, due to missing cable ties or missing support over a greater distance than the station-specification allows:
Cooling Water pump 2A: several vertical cables not fixed with cable ties.
South East Essential Supplies building: cables to new alarm fire cabinets are not supported and fixed with cable ties (unsupported for more than 1 metre).
Junction Box 272992, cables not fixed with cable ties.
AY3 generator jacket secondary water, cable unsupported for about 3 metres.
Leaks and corrosion are evident on some components:
Common cause failures (leaks on rubber gaskets) on radiators providing cooling for all the 8 diesels have several times resulted to 1 or 2 unavailable diesel generators, when the ambient temperature is above 15º.
Secondary Liquid Nitrogen Vaporizer 2 is heavily corroded.
A Nitrogen pipe by survey point 43 is corroded.
The total number of oil leaks shows e degrading trend in the last 10 weeks, at the time of the mission there were 56 active leaks.
The overall number of leaks, including air, chemicals, gas, oil, steam and water is 221.
A significant amount of installed lighting is defective:
Room E023R01A, 5 defects
Room E02B02R01 6 defects
Turbine floor, 11 defects
RCA 1 Stair house, 5 defects
Degraded condition of equipment, which is not identified and reported in a timely manner, could lead to equipment failure adversely affecting reliable plant operation and safety.
Suggestion: The station should consider improving the material condition of equipment to support safe and reliable operation.
IAEA Bases:
SSR-2/2 (Rev.1)
Requirement 28: Material conditions and housekeeping
The operating organization shall develop and implement programmes to maintain a high standard of material conditions, housekeeping and cleanliness in all working areas.
28. The operating organization shall develop and implement programs to maintain a high standard of material condition.
7.10 Equipment that is degraded (leaks and corrosion for example) shall be identified and reported and deficiencies shall be corrected in a timely manner.
8.1 Maintenance, testing, surveillance and inspection programmes shall be established that include predictive, preventive and corrective maintenance activities. These maintenance activities shall be conducted to maintain availability during the service life of structures, systems and components by controlling degradation and preventing failures. In the event that failures do occur, maintenance activities shall be conducted to restore the capability of failed structures, systems and components to function within acceptance criteria.
NS-G-2.14
4.36. Factors that should typically be noted by shift personnel include:
Deterioration in material conditions of any kind, corrosion, leakage from components, accumulation of boric acid, excessive vibration, unfamiliar noise, inadequate labelling, foreign bodies and deficiencies necessitating maintenance or other action;
4.8. SPARE PARTS AND MATERIALS
4.8(1) Issue: Spare parts are not always available in a timely manner to support the availability of safety related equipment and systems.
During the mission, the team observed the following:
Quality of spare parts:
– There are no preventive maintenance activities on rotating equipment spare parts in the station.
– Spare parts for safety related equipment on stock, including Single Point Vulnerabilities (SPV), 80% are not checked if they are fit for purpose.
– During a planned valve overhaul the new actuator taken from stock appeared to be inoperable as it was not correctly wired. Fault finding and repairing the actuator resulted in one-day delay on the fuel route outage.
– Diesel generator BY was unavailable 2 to 3 days longer than planned, because of incorrect assembly of a spare part by the supplier.
– Locking plates were removed from stores and found completely covered with rust.
– Spare kits used for oxygen probe overhaul were found to have foreign material intrusion (a plastic like substance).
Quantity of spare parts:
– On 20-1-2018 the AX diesel was unavailable due to problems with the starting valve. The last spare part in stock was used in April 2017. No action had been taken to get this spare part for a safety related component back in stock.
– A pressure valve which is vital to refuelling activities is identified as a non-stock item.
– A new diaphragm required for the overhaul of valve and actuator R2CX-WT-0617 was registered as 1 in stock but actually there was none in stock
– A degraded vent valve on polisher cation bed 1-WC-105B could not be replaced in November 2017 due a lack of spare parts on stock. Valve replacement is planned on 10/04/2018.
– In the third quarter of 2017, twenty condition reports were related to spare parts availability. The station recognized this as an adverse trend.
Without the timely supply of spare parts, the availability of equipment and system may be adversely impacted.
Recommendation: The station should improve the availability of spare parts in a timely manner to support the availability of equipment and systems.
IAEA Bases:
SSR-2/2 (Rev.1)
8.17. The operating organization shall ensure that materials, spare parts and components are available and in proper condition for use.
NS-G-2.6
8.23. The maintenance group should be responsible for ensuring that adequate spare parts and components, tools and resources for achieving its objectives are available. It should also be responsible for establishing stock levels and authorizing the issue and use of spare items and components.
GS-G-3.5
153. Maintenance should be performed on certain items held in storage, such as large pumps and motors. Such maintenance should include periodically checking energizing heaters, periodically changing desiccants, rotating shafts on pumps and motors, and changing oil on rotating equipment and other maintenance required by the vendor.
5. TECHNICAL SUPPORT