Current status of NPP I&C in the United Kingdom

T P Smyth

AMEC, Knutsford, Cheshire, UK

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

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

TWG-NPPIC, May 2009, Vienna: UK status 3

Nuclear Power Plants in the UK (1)

201619762 x 610 MWeAGRHinkley Point B

201619762 x 605 MWeAGRHunterston B

Expected shutdown

Start operation

Unit capacityTypeReactors

11 035 MWeTotal (19)

203519951 x 1196 MWePWRSizewell B

202319882 x 625 MWeAGRTorness

202319882 x 615 MWeAGRHeysham 2

201419852 x 615 MWeAGRHeysham 1

201419842 x 595 MWeAGRHartlepool

201819832 x 545 MWeAGRDungeness B

201019712 x 490 MWeMagnoxWylfa

201019682 x 217 MWeMagnoxOldbury

TWG-NPPIC, May 2009, Vienna: UK status 4

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/

TWG-NPPIC, May 2009, Vienna: UK status 5

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

TWG-NPPIC, May 2009, Vienna: UK status 6

AGR : Reactor Protection Systems (2)

Neoprene insulation degradation

TWG-NPPIC, May 2009, Vienna: UK status 7

AGR : Reactor Protection Systems (3)

Neoprene insulation degradation

TWG-NPPIC, May 2009, Vienna: UK status 8

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

TWG-NPPIC, May 2009, Vienna: UK status 9

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

TWG-NPPIC, May 2009, Vienna: UK status 10

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

TWG-NPPIC, May 2009, Vienna: UK status 11

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

TWG-NPPIC, May 2009, Vienna: UK status 12

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

TWG-NPPIC, May 2009, Vienna: UK status 13

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

TWG-NPPIC, May 2009, Vienna: UK status 14

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

TWG-NPPIC, May 2009, Vienna: UK status 15

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