atw 2018-05v6


atw Vol. 63 (2018) | Issue 5 ı May


Gundremmingen C


Operating sequence in 2017

Electrical output in %












January February March April May June July August September October November December

In the review year 2017, unit C of the Gundremmingen nuclear power

plant was operated at full load except for two planned outages for

refuelling, one unplanned outage for preservation works and several

periods of power reduction due to malfunction of a reactor coolant

pump and preservation works on a block transformer.

On order of the grid operator grid supporting services were often

provided, especially in the months of February, April, September/

October and December.

During the special outage for refuelling in the beginning of the

year, a total of 76 fuel elements were unloaded and replaced with

72 fresh and 4 partially spent fuel elements.

From 3 April to 8 July unit C was in stretch-out operation. During

100 the shutdown a total of 82 fuel elements were unloaded and replaced

with 76 fresh and 6 (2 MOX) partially spent fuel elements.

80 During both refuelling outages all safety-related relevant

workings were monitored by the relevant nuclear controlling

authority, 60 the Bavarian State Ministry of the Environment and

Consumer Protection (StMUV), and consulted authorized experts.


The inspection of the technical systems with regard to safety and

reliability confirmed the excellent condition of the plant. A gross


total of 9,929,820 MWh of electricity was produced.


Planned shutdowns

11 December 2016 to 5 January 2017: Special outage for refuelling.

The following major activities were carried out:

• Refuelling and sipping of all fuel elements inside the core;

result: Positionierung:

One defective fuel element.

• Mechanical seal replacement on a feed water pump and a service

Bezug, links, unten

water pump.

• Works in the condensation chamber.

• Clearing VGB: of HKS6K main cooling 30 water % system.

• Repair atw: works 100 on service 60 0 water 0 and auxiliary steam system.

• Exchange of ground fault monitoring relay and works on voltage

regulators of two emergency diesel generators.

8 July to 12 August: 31 st refuelling outage and 20 th overall

maintenance inspection.

The following major activities were carried out:

• Refuelling and inspection of fuel elements.

• Inspection of main isolation valves of feedwater, main steam and

residual heat removal system.

• Emptying of redundancies 2 and 5 for preventive measures on

valves, torque motors, motors, pumps and tanks.

• Branch point clearing for inspection of block transformers and

repair of a leak on generator circuit breaker.

X = 20,475 Y = 95,25 B = 173,5 H = 38,2

• Inspection of two emergency diesel generators.

• Inner inspection and pressure test of low pressure preheater

strings and turbine condenser pre-evacuation system.

• Inspection of pumps and cooling units.

• Preservation works on pipes of auxiliary service water system.

• Extensive non-destructive testing of pipes and tanks.

• Replacement of carbon bearing on a reactor coolant pump with

extensive preservation works.

Unplanned shutdowns and reactor/turbine trip

8 January to 12 January: Unplanned shutdown for sealing

replacement on safety and relief valve and preservation works on

reactor coolant pump.

Power reductions above 10 % and longer than for 24 h

April to July: Stretch-out operation.

June: Malfunction of reactor coolant pump

September: Shutdown of block transformer due to gas warning,

subsequently preservation works.

Delivery of fuel elements

In 2017, for Gundremmingen unit C 160 fresh fuel elements were


Waste management status

Refer to unit B.

General points

Refer to unit B.

Twinning Program

Refer to unit B.


Operating results 2017 – Part I*

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