BS IEC/IEEE 63332-387:2024 - Page 3

Nuclear facilities. Electrical power systems. Diesel generator units applied as standby power sources. Part 387: Diesel generator units applied as standby power sources | Status: Current

1 Scope

1.1 General

This document defines the criteria for the application and testing of diesel generator (DG) units used as safety classstandby power supplies in nuclear facilities. In general, the standard applies to new nuclear facilities as well as for upgrading or back-fitting of existing facilities. Existing facilities can voluntarily adopt the requirements to enhance the performance capabilities and reliability of the installed DG units. The standard can be used in applications where highly reliable onsite alternating current (AC) power source is required to maintain plant safety following an event with potential loss of offsite power for an extended duration. This document provides the principal design criteria, the design features, testing, and qualification requirements for the individual DG units that enable them to meet their functional requirements as a part of the standby power supply under the conditions produced by the design basis events cataloged in the plant safety analysis. Figure 1 shows the boundaries of systems and equipment included in the scope of this document. The following items are within the scope of this document:

1. a) The diesel engine, which includes the following:
   1. 1) the flywheel and coupling (if applicable),
   2. 2) the combustion air system and supply,
   3. 3) the starting system including storage of energy,
   4. 4) the starting energy system,
   5. 5) the fuel oil supply system (e.g., including the day tank, filters, piping, pumps, valves and strainers between the day tank and the engine injection pumps),
   6. 6) the lubricating oil system including keep-warm system,
   7. 7) the cooling system (jacket water), starting at the point where the cooling medium is introduced to the DG unit. (For a closed loop water-cooling system (radiator) supplied as part of the DG unit, the starting point is water/air interface),
   8. 8) the exhaust system,
   9. 9) the governor system;
2. b) The generator, which includes the following:
   1. 1) the excitation and voltage regulation system,
   2. 2) the diesel generator output breaker at the switchgear,
   3. 3) the diesel generator grounding (earthing) system;
3. c) The local control, protection, and surveillance systems associated with the diesel engine, the generator, and their auxiliary equipment and systems cited above. The design of control systems is not in the scope of this document. However, the functional criterion is provided;
4. d) The AC and direct current (DC) distribution systems associated with the diesel engine including the battery (if supplied with the generator) for starting, field flashing, the generator, and their auxiliary equipment and systems cited above, exclusive of the auxiliary power system beyond the generator output breaker;
5. e) Fuel oil storage system (e.g., storage tank, transfer pumps, filters, piping, valves, and strainers between the storage tank and the day tank);
6. f) Cooling air and ventilation system;
7. g) Those elements that are essential to the safety function of DG units within the scope of this document (see Figure 1);
8. h) Evaluation of the characteristics of the service environment relative to performance and qualification.

Figure 1 — Scope diagram