Current status of NPP C&I in the United Kingdom - iaea.org · PDF fileCurrent status of NPP...

TWG-NPPIC, May 2013, Vienna: UK status 1

Current status of NPP I&C in the

United Kingdom

T P Smyth

AMEC, Knutsford, Cheshire, UK

24th Meeting of the Technical Working Group on Nuclear Power

Plant Instrumentation and Control, 22-24 May 2013, Vienna


Current status of NPP I&C in the United Kingdom

Nuclear Power Plants in the UK

I & C Modernization projects

Regulatory Environment

New build I & C status

Fukushima response

Recommendations

Hinkley Point B


Nuclear Power Plants in the UK (1)

2023 1976 2 x 610 MWe AGR

2023 1976 2 x 610 MWe AGR Hunterston B

Expected

shutdown

Start

operation Unit capacity Type Reactors

10 038 MWe Total (19)‏

2035 1995 1 x 1188 MWe PWR Sizewell B

2023 1988 2 x 625 MWe AGR Torness

2023 1988 2 x 615 MWe AGR Heysham 2

2019 1985 2 x 580 MWe AGR Heysham 1

2019 1984 2 x 595 MWe AGR Hartlepool

2018 1983 2 x 545 MWe AGR Dungeness B

Sept 2014 1971 1 x 490 MWe Magnox Wylfa 1


Nuclear Power Plants in the UK (2)‏

Electricity sources 21% nuclear (2011: 18%) 28% gas (2011: 44%) 43% coal (2011: 28%) 8% other

Need to plan for energy replacement 8 plants (15 reactors) will close in next 10 years 8850 MWe

New build Generic Design Assessment (EPR, AP1000, ABWR)

Areva/EdF EPR GDA complete Dec 2012

Westinghouse AP1000 GDA suspended

GE-Hitachi ABWR started Apr 2013

http://www.hse.gov.uk/newreactors/



New build Sites EdF Energy

2 x EPR at Sizewell

2 x EPR at Hinkley Point.

Bradwell site.

Horizon Nuclear Power (Hitachi) Oldbury and Wylfa sites.

GE-Hitachi ABWR.

NuGeneration (Iberdrola, GDF Suez) Sellafield site.

Total planned power ±19 GWe



SELLAFIELD

HINKLEY POINT

SIZEWELL

BRADWELL

OLDBURY

WYLFA


I&C Modernization projects (1)

Dungeness B

New DPS being installed

ATOS Worldgrid (ADACS)

Westinghouse (ABB AC160)

Control / equipment protection functions segregated

Lower integrity parts separated from higher integrity parts

Commissioning phase, operating in parallel with existing DPS.



Neoprene insulation degradation Magnox, Oldbury power station

Shutdown Feb 2012

44 years operation

Degradation with age

Perishing

Sweating

Hygroscopic

Becomes conductive - resistance < 1 MΏ

Stray currents in sensitive circuits

Thermocouple amplifiers



Neoprene insulation degradation‏



Neoprene insulation degradation Hunterston B

Boiler Protection Temperature Trip Units replacement

Hartlepool

Feed Flow Y trip units and pressure transducers replacement

Heysham 1

Feed Flow Y trip units and pressure transducers replacement

Duplicate Reactor Low Pressure Trip Units replacement

Obsolescence

30 years old


Regulatory Environment (1)‏

Standards hierarchy ONR Safety Assessment Principles & Technical Assessment

Guides (http://www.hse.gov.uk/nuclear)

IAEA & IEC standards IEC 61226

Modern standards reviews Design, Operation and Maintenance

Part of Periodic Safety Reviews

PSA based assessment

Limit of reliability claims for software based systems

10-4failures/demand claim limit



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



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

Common regulatory position Licensing of safety critical software for nuclear reactors:

Common position of seven European nuclear regulators and authorised technical support organisations. BEL V, Belgium ONR, United Kingdom BfS, Germany SSM, Sweden CSN, Spain STUK, Finland ISTec, Germany

1.13 Software reliability 1.13.3.1: Reliability claims for a single software based system

important to safety of lower than 10-4 probability of failure (on demand or dangerous failure per year) shall be treated with extreme caution.


GDA of UK EPRTM I&C (1)‏

GDA Regulatory Issue on UK EPRTM I&C GDA Step 3 The complexity of interconnectivity between the very

important Class 1 Safety Systems and lower Safety Class control systems. Of particular concern was that the lower Classes 2 and 3 Systems could have write access to the highest Class 1 Safety System (the main Reactor Protection System). This also challenged our important safety assessment principle that Safety Systems should be completely independent of control systems.

There was a lack of Class 1 equipment including hard-wired and simple technology as a diverse backup to the highly computerised and sophisticated screen based displays and controls in the Main Control Room and Remote Shutdown Station.

Substantiation of the reliability claims for the computer-based Systems Important to Safety.



Resolution All networked communications will be one-way, from the

Class 1 systems to lower Class 2 and 3 systems. The permissive signals that were to be implemented through the lower Class systems will now be implemented using Class 1 Safety Information and Control System (SICS) equipment including a Qualified Display System.

There will be a Class 1 SICS operational in the Main Control Room and a similar panel in the Remote Shutdown Station. The SICS will include simple hard-wired technology and will be fully operational for alarms and displays at all times.

Probabilistic claims on each of the main I&C platforms will have lower limits than in the original design for the UK. The shortfall in overall reliability of the safety systems will be made up by the introduction of a Non-Computer-Based Safety System (NCSS).



GDA Step 4 Completion of Step 3 I&C issues: categorisation of functions,

classification of systems, compliance to IEC I&C nuclear standards.

Claims-Arguments-Evidence (CAE) based review against the SAPs

Review of the principal design and implementation standards for I&C Class 1, 2 and 3 equipment. Sampling of detailed evidence predominately focused on the Class 1 systems (e.g. reactor protection) and the key Class 2 systems.

Review of safety case for the Class 1 and key Class 2 platforms and pre-developed components using appropriate guidance and standards. Development of application code, independent verification and validation, and Independent Confidence Building Measures.

Further review of the I&C architecture including provisions for defence-in-depth, independence and diversity, automatic and manual safety actuations, and appropriateness of equipment class.



GDA Step 4 Cross-cutting issues

Safety Categorisation and Classification – Alignment with IEC61226.

Smart devices.

ONR Design Acceptance Confirmation Dec 2012

5 year program

~£35 million


GDA of UK EPRTM I&C (5) ‏

In 2011



Overall I&C Architecture in 2013


Fukushima response (1)‏

Progress Interim report – May 2011

Final report – Oct 2011

European Council "Stress Tests” – Nov 2011

ONR Fukushima Implementation Report – Oct 2012

Implications for New Build Additional GDA issue



Sizewell B Emergency Response Centre 1.6km away from power station

PWR emergency actions require quicker implementation than for AGR type reactors.

Backup Emergency Control Centre

AGR reactors Three regional depots



UK EPRTM Enhancements Extension of severe accident battery storage capability from 12

to 24 hours

Establishment of a communication system suitable for operation under a total loss of electrical power situation - a network of sound-powered telephones

Qualifying the performance of instrumentation required for monitoring containment integrity and in the spent fuel cooling pool

Provision of means for re-powering the dedicated Severe Accident Instrumentation and Control equipment

Extension of SBO diesel generator autonomy by using mobile pumping of the main emergency diesel generator fuel tanks to recharge the SBO diesel generator fuel tanks

Provision of equipment and means (connection point etc.) to re-supply significant electrical power from three days post-event

Provision of a high power mobile emergency generator capacity


Recommendations (1)

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:

guidance for modernisation and new plant projects.


Recommendations (2)

IAEA topics (cont.)

Design and management of I&C systems for future

upgrading This relates to the problem of the much shorter life that can be

expected from I&C systems in comparison to that of NPPs.

It is proposed that the 'research' could address: the techniques that may be used at the design stage to promote

future upgrading,

the measures that would also be needed to ensure that the ability for future upgrading is retained,

the experience available of adopting such techniques and measures, recommendations to I&C system specifiers, I&C system suppliers

and NPP operators arising from the above.


References (1)

ONR New build website: http://www.hse.gov.uk/newreactors/

Integration testing of safety-related systems: Lessons learnt from Dungeness B DPS replacement project, System Safety 2010.

Licensing of safety critical software for nuclear reactors. Common position of seven European nuclear regulators and authorised technical support organisations. 2010. http://www.hse.gov.uk/nuclear/software.pdf

UK EPRTM Control and Instrumentation (I&C) Architecture Regulatory Issue RI-UKEPR-0002 http://www.hse.gov.uk/newreactors/ri-ukepr-0002.pdf http://www.hse.gov.uk/newreactors/closure-of-regulatory-issue.pdf

UK EPRTM I&C Architecture http://www.epr-reactor.co.uk, PCSR chapter 7, Appendix 7A.

UK EPRTM I&C Architecture. UKEPR-0002-072 Issue 04. http://www.epr-reactor.co.uk, PCSR chapter 7.2.

UK Office for Nuclear Regulation. GDA Step 4 and Close-out for Control and Instrumentation Assessment of the EDF and AREVA UK EPR™ Reactor


References (2)

UK Office for Nuclear Regulation. Japanese earthquake and tsunami: Implications for the UK nuclear industry. Interim Report. May 2011.

UK Office for Nuclear Regulation. Japanese earthquake and tsunami: Implications for the UK nuclear industry. Final Report. September 2011.

UK Office for Nuclear Regulation National Final Report on European Council “Stress Tests” for UK Nuclear Power Plants. December 2011

EDF Energy NNB GenCo response to recommendations in ONR Chief Inspector’s Report (June 2012), NNB-OSL-REP-001450.

UK Office for Nuclear Regulation “Japanese earthquake and tsunami: Implementing the lessons for the UK's nuclear industry” October 2012

UK Office for Nuclear Regulation. UK ONR ENSREG Related ‘National Action Plan’ Dec 2012.

Sizewell B ERC image: http://www.bbc.co.uk/news/uk-england-suffolk-17905186

Map: http://openstreetmap.org

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