twg-nppic, may 2009, vienna: uk status1 current status of npp i&c in the united kingdom t p...
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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
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AGR : Reactor Protection Systems (2)
Neoprene insulation degradation
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AGR : Reactor Protection Systems (3)
Neoprene insulation degradation
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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
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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
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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