Current status of NPP I&C in the United Kingdom

1. T P Smyth AMEC, Knutsford, Cheshire, UK Current status of NPP I&C in the United Kingdom 22nd Meeting of the Technical Working Group on Nuclear Power Plant Instrumentation and Control, 20-22 May 2009, Vienna TWG-NPPIC, May 2009, Vienna: UK status

2. TWG-NPPIC, May 2009, Vienna: UK status Current status of NPP I&C in the United Kingdom • Nuclear Power Plants in the UK • Status of I&C at nuclear plants • Reactor Protection Systems • Data Processing Systems • Refuelling machines • Status of regulatory environment affecting I&C • Recommendations

3. TWG-NPPIC, May 2009, Vienna: UK status Nuclear Power Plants in the UK (1) Reactors Type Unit capacity Start operation Expected shutdown Oldbury Magnox 2 x 217 MWe 1968 2010 Wylfa Magnox 2 x 490 MWe 1971 2010 Hinkley Point B AGR 2 x 610 MWe 1976 2016 Hunterston B AGR 2 x 605 MWe 1976 2016 Dungeness B AGR 2 x 545 MWe 1983 2018 Hartlepool AGR 2 x 595 MWe 1984 2014 Heysham 1 AGR 2 x 615 MWe 1985 2014 Heysham 2 AGR 2 x 615 MWe 1988 2023 Torness AGR 2 x 625 MWe 1988 2023 Sizewell B PWR 1 x 1196 MWe 1995 2035 Total (19)‏ 11 035 MWe

4. TWG-NPPIC, May 2009, Vienna: UK status Nuclear Power Plants in the UK (2)‏ Electricity sources 19% nuclear 36% gas 38% coal Need to plan for energy replacement 7 plants will close in next 9 years 14 reactors 7359 MWe 13% of electricity sources North Sea oil and gas will be limited in future New build Generic Design Assessment (AP1000, EPR) Target completion of GDAs June 2011 Sites identified http://www.hse.gov.uk/newreactors/

5. TWG-NPPIC, May 2009, Vienna: UK status AGR : Reactor Protection Systems (1)‏ Neoprene insulation degradation Magnox Oldbury power station Degradation with age Perishing Sweating Hygroscopic Becomes conductive - resistance < 1 MΏ Stray currents in sensitive circuits Thermocouple amplifiers

6. TWG-NPPIC, May 2009, Vienna: UK status AGR : Reactor Protection Systems (2)‏ Neoprene insulation degradation‏

7. TWG-NPPIC, May 2009, Vienna: UK status AGR : Reactor Protection Systems (3)‏ Neoprene insulation degradation

8. TWG-NPPIC, May 2009, Vienna: UK status AGR : Reactor Protection Systems (4)‏ Neoprene insulation degradation Survey of all safety equipment Presence of neoprene State of neoprene Circuit function Replacement equipment at older stations Obsolescent anyway Repairs at newer stations Heysham 2 / Torness 6 years work, 1 more year to finalise all equipment Prioritised by susceptibility

9. TWG-NPPIC, May 2009, Vienna: UK status AGR : Reactor Protection Systems (5)‏ • Neutron Flux measurement systems • AGR detectors located in core at 8 locations • High temperatures • Detector spares • Wide range detector – integral cable • Manufacturing spares – re-establishing production processes • Currently a batch of 10 in progress • Electronic units • Neoprene • Repairs at Heysham 2 / Torness • Replacement at other stations

10. TWG-NPPIC, May 2009, Vienna: UK status AGR : Data Processing Systems Safety claims on equipment Some reactor control functions Some alarms Hinkley Point B New DPS installed (1999)‏ Dungeness B New DPS being installed Control / equipment protection functions segregated Ready for works testing Other AGR's Stabilization of equipment Adequate spares provision / hardware support. Improved air conditioning Heysham 2: specification phase

11. TWG-NPPIC, May 2009, Vienna: UK status AGR : Refuelling Machines Online refuelling Stringent safety requirements Equipment obsolescence Key focus at present Heysham 2 / Torness Replacement of Reypac controllers with Siemens S7 I/O replaced, emulates original equipment Reypac controller replacement Software reverse engineered and ported Safety functions partitioned Successful implementation, scope of replacement expanded. Safety standards Modern standards considered when replacing equipment

12. TWG-NPPIC, May 2009, Vienna: UK status Regulatory Environment (1)‏ Standards hierarchy NII SAPs and TAGs (http://www.hse.gov.uk/nuclear) IAEA standards IEC standards IEC 61226 Modern standards reviews Design, Operation and Maintenance Part of Periodic Safety Reviews PSA based assessment Target 10-7 / year Limit of reliability claims for software based systems Assume 1 demand / year 10-4/demand Require diverse protection to make up 10-3/demand

13. TWG-NPPIC, May 2009, Vienna: UK status Regulatory Environment (2)‏ Application to Sizewell B Primary Protection System Four channels, 2 out of 4 tripping Software based Production excellence IEC 60880 Independent confidence building Extensive testing Independent code safety assessment Secondary Protection System Four channels, 2 out of 4 tripping Protection for frequent faults Laddic – magnetic amplifiers Diverse technology

14. TWG-NPPIC, May 2009, Vienna: UK status Regulatory Environment (3)‏ New build In general, same regulatory requirements as Sizewell B Diversity requirements in reactor protection systems Possibly less onerous protection system targets Passively safe systems will make fewer demands Smart Instruments Regulator considering application to nuclear facilities Assessment of evidence Plant owner collaboration Shared qualification and licensing assessments SIL1 No fieldbus

15. TWG-NPPIC, May 2009, Vienna: UK status Recommendations • IAEA topics • Estimating and extending life of I&C equipment to address ageing and obsolescence • Supporting the evaluation, acceptance and licensing of digital I&C system • Lessons learned from I&C project implementation and guidance for modernisation and new plant project