R&D NEEDS AND POST- FUKUSHIMA SAFETY IMPROVEMENTS - NUCLEAR SAFETY RESEARCH · PDF...

© Teollisuuden Voima Oyj PUBLIC

Heikinheimo Liisa

R&D NEEDS AND POST-FUKUSHIMA SAFETY IMPROVEMENTS - NUCLEAR SAFETY RESEARCH IN FINLAND

Head of R&D, TVO

TECHNICAL MEETING ON POST-FUKUSHIMA RESEARCH AND DEVELOPMENT STRATEGIES AND PRIORITIES

IAEA HEADQUARTERS, VIENNA, AUSTRIA

15 - 18 DECEMBER 2015

PUBLIC© Teollisuuden Voima Oyj

1. Nuclear energy in Finland and in Olkiluoto

2. Major improvements after Fukushima

• TVO

• Fortum

3. SAFIR2018 programme

• Renewal of the national nuclear safety programme in 2014

• Post-Fukushima related topics

4. Towards comprehensive safety approaches

5. Waste management: Posiva development

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CONTENTS OF THE PRESENTATION

CONFIDENTIAL© Teollisuuden Voima Oyj

NUCLEAR POWERIN FINLAND 2015

Teollisuuden Voima Oyj, Olkiluoto:

• OL1/2: 2 x BWR 880 MW

• OL3/EPR 1600 MW towards operational license

Fortum Power and Heat Oy,Loviisa:

• Lo1/2: 2 x VVER 488 MW

Fennovoima Oy, Pyhäjoki:

• FH1 decision in principle in 2010 (max 1800 MW). AES-2006 (1200 MW VVR) ratificationin the Parliament in Dec. 2014.

• Construction license application June 2015.

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Helsinki

TVO,Olkiluoto

Fortum, Loviisa

Fennovoima,Pyhäjoki

FINLAND

CONFIDENTIAL© Teollisuuden Voima Oyj 4

• OL1 ja OL2 – continuous improvementsand modernisations, 660 MW > 885 MW.

– 2018 operational license renewal

• OL3 – construction work, automationtesting and assembly.

– Preparations for the operationallicense, submission in 2016.

• Waste management on one island, Olkliluoto

– Operational waste handling, storage and final disposal (LILW underground facility since 1992)

– Intermediate storage for the spentnuclear fuel – extension completedin 2014 (3 + 3 pools + 1).

– Spent nuclear fuel final disposal byPosiva Oy (ONKALO) in Olkiluoto received the construction license(2015).

PROJECTS IN OLKILUOTO – TOWARDS 2020

© Teollisuuden Voima Oyj

STRESS TEST ACTIONS - OLKILUOTO SITE :

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Natural hazardsR&D co-operation

Design issues Severe accidentmanagement

Updating the seismic fragility analysesof the spent fuel pools and firestrengthening systems

Conceptual design of independent way of pumping water into the RPV

Capability if dealing with multi-unitsevere accidents; updating the emergency plans and organisation

Improvements against the exceptionallyhigh seawater level on the coolingsystems of the spent fuel interimstorage

Preventing overheating of the auxiliary feed water system (independnt of sea water cooling)

Reactor building top venting for steamescape; hydrogen possibly formedcould be exhausted through this as well

Analysis of consequences of beyonddesign basis low and high temperature

Evaluation of suitability of biodieselImplementation of mobile power supply

Plans to restoring access routes to the site

Analysis of tornados and downburstson plant structures and systems

Implementation of mobile power supply(re-charge of batteries incl.)

Enhancement of the emergency planon radiation measurement patrols

Evaluation of demineralised water resevoirs

Enhancement of adequacy of the maintenance personnel in case of emergency

Evaluation of demineralised water usage in an accident concerning all units and spent fuel pools at the site

Evaluation of suitability of emergencypreparedness personnel to their duties

Ensuring the water injection into the spent fuel pools and monitoring the conditions of the pool.

Plans for access control and radiationmonitoring of the staff and decontamination measures in extremenatural hazards

Improvement of communicationcapabilities

SAFETY IMPROVEMENTS AT TVO OLKILUOTO SITESPENT FUEL STORAGE POOLS - EXTENSION

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SPENT NUCLEAR FUEL STORAGE – THE VOLUME HASDOUBLED IN 2014 AND THERE ARE NEW SAFETYFUNCTIONS IN THE BUILDING

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FLOODS, SEISMIC EVENTS AND WEATHERPHENOMENA

• A vertical survey of the whole plant site -> changes of level to makesure that rainwater is removed to the sea. Complete, with the exception of certain temporary OL3 site buildings.

• Interim spent fuel storage (KPA storage): penetrations betweenservice water pump house and pipe culverts have been made leak-tight to prevent water ingress into KPA basement floors

• TVO and Satakunta rescue authority have agreed upon anti-oil-spillmeasures: Rescue authority dedicates equipment and prioritizesOlkiluoto

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HYDROGEN MANAGEMENT

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Addition of ventilation hatches to the reactor hall to remove steam and hydrogen

• Work at basic design stage

• Most likely route: door on the north wall into the reactor exhaust stack

• Opening of the large cargo door on the ground level to improve natural circulation

• No investment decision yet


RESIDUAL HEAT REMOVAL DURING A LOSS OF ALLAC

Several possibilities studied

• passive isolation condenser

• active high-pressure pumping

• active low-pressure pumping

• several different starting conditions

Selected: automatic steam-driven HP pump, then manu al depressurisation and transfer to LP fire water

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Safety assessment results – Lo1/2

• Fortum’s nuclear power plants in Finland and Swedenhave high safety level and Fortum’s knowhow in nuclear safety is internationally recognized.

• Loviisa NPP has been heavily modified already in the design phase, e.g. containment and safety systems.

• Safety level has been improved throughout the plantlifetime by plant modifications. For example, new systems have been installed to mitigate the severeaccidents.

• Immediate need for additional safety upgrades was notidentified.

• During the safety assessment a few issues were raisedwhere safety level could be increased even further.

Cooling towers

• Two cooling towers for each of the plant units, one for reactor and one for fuel pools

• Designed by Fortum except the heat excangers• Heat exhanger designer and manufacturer: GEA EGI Contracting/Engineering

Co. Ltd• Initiating event: Loss of ultimate heat sink.• Safety class: Non-classified• Installations are ready, last commissioning tests early autumn 2015.

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Ultimately high sea water level

• A seismic tsunami like the one in Fukushima is not relevant for the Gulf of Finland

• Plant shutdown preparation will be started if the sea water level reaches level +1,75 m. The plant will be shut down if the sea water level reaches level +1,95 m. Power plant yard level is at +3,00 m.

• Sea water level clearly exceeding level +3,00 m long enough would result in widespread loss of safety system and safety functions.

• Fortum will install higher gates to sea water channels to prevent spreading of water inside the plant in shutdown states with open sea water system piping. Current gates reach level +2,00 m and new gates will reach level +3,00 m. Two of four gates have been renewed.

• New assessments of possible sea water level have been launched with Finnish Meteorological Institute..

– Preliminary results indicate higher levels with higher frequencies than anticipated before due to change in climatic conditions.

• Additional protections againts high sea water level in auxiliary emergency feedwater system have been implemented.

IMPACT OF FUKUSHIMA ACCIDENT ON RESEARCH PROGRAMME FOR NUCLEAR SAFETY IN FINLAND, SAFIR2014

A supplement to the SAFIR2014 Framework Plan in calls from 2012:

Fukushima induced research topics:

• Extension of existing topics and new safety issues

• Initiating events: external hazards, multiple events

• Design of NPPs: seismic events, cliff edge effects (loads, integrity of safety functions after extreme loads)

• Accident mitigation: deterministic and probabilistic assessment of long lasting accidents, heat removal, hydrogen issues, release of fission products

• Safety of the entire fuel life cycle, esp. storage of spent fuel.

Operating environment and challenges in NPP safety in Finland

Nuclear power plant decisions in Finland: licensing processes of power plants in

use, under construction, and planned to be built.

Increase in the need of expert resources

Renewal need of research infrastructure

International networking, international safety regulations and guidelines

Fukushima accident

According to the Nuclear Energy Act the authorities shall have sufficient expertise and other

facilities at their disposal, which has been ensured by national research programmes since

1990.

The nuclear facility operators are obliged to participate in financing and they fulfil the

obligation by paying an annual fee into the Finnish State Nuclear Waste Management Fund

(VYR).

SAFIR2018: THE FINNISH NUCLEAR POWER PLANT SAFETY RESEARCH

PROGRAMME 2015-2018

What is new in SAFIR2018?

SAFIR2018 general objectives

• Maintenance and development of know-how, education of new experts

• Internationally high level research

• Development and renewal of the research infrastructure

Three major research areas with 6 technical reference groups:

1. Plant safety and systems engineering;

2. Reactor safety;

3. Structural safety and materials.

SAFIR2018 Research Areas

Plant safety and systems

engineering

• Wide interdisciplinary research area

covering the interfaces between

operations and technologies

• Operation of the plant as a whole

• Design principles, defence-in-depth

• Operating processes, information

model and documentation of safety

justification

• Human and organisational

performance, I&C, PRA applications

etc.

Reactor safety

• Goal to ensure the experimental

facilities, computational

methods, and skilled experts

• The methods should enable

independent assessment of the

supplier’s and licensee’s

proposals

• Thermal hydraulics, reactor

dynamics, severe accidents , PRA,

electric systems etc.

Structural safety and materials

• Safe long term use of the plants

• Research on the management of

the ageing of materials and

structures

• New materials, manufacturing,

and structural engineering

• Life cycle management and

extension

• Probabilistic and deterministic

design (RI-ISI)

RG1 Automation, organisation and human factors

Three projects in 2015:

• CORE - Crafting operational resilience in nuclear domain – VTT, Finnish Institute

of Occupational Health (FIOH)

• MAPS - Management principles and safety culture in complex projects – VTT,

Aalto University, University of Oulu, University of Jyväskylä

• SAUNA - Integrated safety assessment and justification of nuclear power plant

automation – VTT, Aalto , Finnish Software Measurement Association (FISMA),

Risk Pilot, IntoWorks

RG2 Severe accidents and risk analysis

Seven projects in 2015:

• EXWE - Extreme weather and nuclear power plants – Finnish Meteorological

Institute (FMI)

• PRAMEA - Probabilistic risk assessment method development and applications –

VTT, Aalto University, Risk Pilot

• CASA - Comprehensive analysis of severe accidents – VTT

• CATFIS - Chemistry and transport of fission products – VTT

• ESPIACS - Experimental studies on projectile impacts against concrete structures

– VTT

• FIRED - Fire risk evaluation and defence-in-depth – VTT, Aalto University

• NEST - Numerical methods for external event assessment improving safety – VTT

EXWE - Extreme weather and nuclear power plants

Background and objective

Extreme weather and sea level events affect the design

principles of nuclear power plants and might pose

external threats to the plants. In addition, geomagnetic

effects of extreme solar storms may reduce the reliability

of the external power transmission grid.

The aim is to enhance scientific understanding of the

environmental conditions of the NPPs’ sites and to

predict how they may change. The work is focused on

four topics:

1) extreme weather incidents

2) extreme sea level events

3) solar storm occurrence & effects

4) atmospheric dispersion modelling of accidental

releases.

Results exploitation and effect on safety

The results can be used to improve the design of future NPP

units and the safety of existing units against the effects of nature

phenomena.

Project manager: Kirsti Jylhä, Finnish Meteorological

Institute (FMI)

Thunderstorm measurements can be used

as a source of information for extreme

convective weather cases. The figure shows

the average annual number of cloud-to-

ground lightning flashes per km2 in 2002-

2013. EXWE involves mainly detailed

analysis of measured and model-simulated

data, but also modelling runs.

CASA - Comprehensive Analysis of Severe Accidents

Background and objectiveDespite of nearly 40 years of research in the area of severe accidents there are still plenty uncertain issues. This is partly because large scale experiments with real materials are extremely difficult, if not impossible, to execute. Information obtained from separate effect tests has to be linked together by simulations.

This project focuses on enhancing simulation expertise and also tools bringing together a large spectrum of phenomena related to the thermal hydraulics of severe accidents. Analyses are extended evaluating the environmental consequences of a hypothetical severe accident.

Results exploitation and effect on safety Knowledge of the different phenomena and awareness of the remaining uncertainties, as well as their managementstrategies, forms the basis for decision making concerning severe accident management.

ResourcesProject manager: Anna Nieminen, VTT

State of the Fukushima Dai-ichi Unit 3 reactor at 43 h 34 min and 45 h after the earthquake as analysed with MELCOR.

CATFIS – Chemistry and transport of fission productsBackground and objectiveCATFIS project is focused on to reduce the uncertainties associated with the behavior and speciation of FPs in a severe accident.

The objective is to experimentally study the chemistry and transport of fission products, especially iodine and ruthenium, in primary circuit and containment conditions.

As a result, new models based on the experimental data will also be derived. The models of phenomena, which could not be previously considered in the accident analysis, can be included in SA analysis codes.

Results exploitation and effect on safety

The experimental data can be used for PSA level 2 analysis of the existing nuclear power plants. A complete experimental database will be finalized end of 2018.

ResourcesProject manager: Teemu Kärkelä, VTTCollaboration with IRSN, JRC-ITU, Chalmers, NUGENIA

The number concentration of the formed IOx particles after the exposure of gaseous CH3I precursor to beta radiation in an oxygen atmosphere at 20 °C. The irradiation period ranged from 1 day to 4 days.

RG3 Reactor and fuel

Five projects in 2015:

• KATVE - Nuclear Criticality and Safety Analyses Preparedness at VTT – VTT

• MONSOON - Development of a Monte Carlo based calculation sequence for

reactor core safety analyses – VTT

• NEPAL15 - Neutronics, burnup and nuclear fuel – Aalto University

• PANCHO - Physics and Chemistry of Nuclear Fuel – VTT

• SADE - Safety analyses for dynamical events – VTT

RG4 Thermal hydraulics


• COVA - Comprehensive and systematic validation of independent safety analysis

tools – VTT

• INSTAB - Couplings and instabilities in reactor systems – Lappeenranta University

of Technology

• INTEGRA - Integral and separate effects tests on thermal-hydraulic problems in

reactors – Lappeenranta University of Technology, VTT

• NURESA - Development and Validation of CFD Methods for Nuclear Reactor

Safety Assessment – VTT, Aalto University, Lappeenranta University of

Technology

• USVA - Uncertainty and sensitivity analyses for reactor safety – VTT, Aalto

University

RG5 Structural integrity


• FOUND - Analysis of fatigue and other cumulative ageing to extend lifetime –

VTT, Aalto University

• LOST - Long term operation aspects of structural integrity – VTT

• MOCCA - Mitigation of cracking through advanced water chemistry – VTT

• THELMA - Thermal ageing and EAC research for plant life management – VTT,

Aalto University

• WANDA - Non-destructive examination of NPP primary circuit components and

concrete infrastructure – VTT, Aalto University

RG6 Research infrastructure

Three projects in 2015:

• INFRAL - Development of thermal-hydraulic infrastructure at LUT –

Lappeenranta University of Technology

• JHR - JHR collaboration & Melodie follow-up – VTT

• REHOT - Renewal of Hot Cell infrastructure – VTT

http://safir2018.vtt.fi


EVOLUTION OF THE NUCLEAR SAFETY RESEARCHPROGRAMME SAFIR2014 > SAFIR2018

Change in the SAFIR programme 2014 > 2018 has been successfully implemented:

• from 9 technical areas to 3 research areas with a wider scope and

intensive information exchange

• more responsibility to the research areas – before in the steering

group > motivated technology based research areas

• work shop practices for the steering group:

• strategy process during the programme

• road map process > where do we want to go in 5 years, what should be

available, how is the working environment changing?

• work shop practices for the reference groups/research groups >

wider topics to be discussed and new project ideas identified.

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TOWARDS COMPREHENSIVE SAFETY APPROACHES ?• Orientation of ongoing research projects: both experimental and

modelling based ones should be included and in co-operation• Initiating new projects during the programme not only maintaining the

research topics.• Planning of projects with a +3 – 5 years perspective

To be prepared for the unknown or unexpected – aim of the programme:

• Not all the detailed data can be available?

• The approaches to tackle the new questions, to fill the knowledge or data gaps and to combine different approaches should be presented and practized?

• Is it important to take into account all the “3S” or even all the “5S” and understand the relationships of these?

• The highest requirements / safety – are we focusing on the right issues and do we see the big picture while improving the individual items ?

• Do we need both the generalists and the specialists – and their communication?

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COMPLETE NUCLEAR WASTE MANAGEMENT ON ONE ISLAND, OLKILUOTO

FINAL DISPOSAL FACILITY FOR SPENT NUCLEAR FUELUnderground research facility ONKALO under construction

INTERIM STORAGE FOR SPENT NUCLEAR FUELIn operation since 1987

FINAL DISPOSAL REPOSITORY FOR DECOMMISSIONING WASTETo be built for decommissioning of plant units

OPERATING WASTE REPOSITORYIn operation since 1992

Final disposal of spent fuel

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FORTUM POWER & HEATFORTUM POWER & HEAT

POSIVA OYPOSIVA OY

TEOLLISUUDEN VOIMA OYJTEOLLISUUDEN VOIMA OYJ In the future

Final disposal of spent nuclear fuel

Operating wasterepository

Operating wasterepository

Olkiluotopower plant

Interim storage ofspent nuclear fuel

Interim storage ofspent nuclear fuel

Loviisapower plant

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40 years’ effort

Studies into geologic disposal started

Site selection research

Selection of Olkiluoto

Construction of ONKALO and site confirmation studies in Olkiluoto

Construction of disposal facilities

Test operation,commissioning

Start of disposalin 2020’s

Application for the operation license

Application for theconstruction license

Decision in prinsiple by the Government and the Parliament

Government’s decisionon time table

1978

1983

2001

20122015

Construction licence

2.12.2015 Pietilä Susan 33

Final disposal facility in 2020’s

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R&D NEEDS AND POST- FUKUSHIMA SAFETY IMPROVEMENTS - NUCLEAR SAFETY RESEARCH · PDF...

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