ancillary and balancing services provided by npps under ... · • neutron flux (reactor power) can...

1Flexible nuclear power and ancillary services – Tatiana Salnikova – April 2019

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Ancillary and balancing services provided by NPPs under new political and economic conditions in Germany

Dr. Tatiana Salnikova, Framatome GmbHAdvisor Flexible operation of NPPs

Stockholm, April, 2th 2019

Free distribution



Challenges and needsin Germany



Power Mix in Germany

The installed capacity of photovoltaic and wind power units together already adds up to ~ 105 GW (of a total 207 GW) and generated 157 TWh (24 % of a total gross electricity generation)

Total renewables share of Germany’s gross electric power generation reached in 2018 ~ 35% (goal for 2020). Goal for 2025 ~ 40 – 45% -> Intermittency increases!

https://www.bmwi.de/Redaktion/DE/Dossier/erneuerbare-energien.html/

12%

53% 24%11%35%

Nuclear

OtherconventionalWind + Solar

Other RES



Negative/Low Prices in Germany

Since 1991, renewables obligation and feed-in tariff - “undispatchable energy”Since 2008, European Energy Exchange allows “negative prices”Since 2016, New „Electricity Market Act“ (July, 2016), integration of renewables into the market: Balance group management, imbalance settlement, capacity reserves assisting security of supply

0

20

40

60

80

100

120

2010 2011 2012 2013 2014

[MEU

R]

Volume of neg.Energy [MEUR]

https://www.erneuerbare-energien.de/Flexibilization of NPP avoids production for negative and low prices!



Activationtime Duration Pro-

curedRefund

Pay-as-bid

Primary balancing 30 s < 15 min weekly capacity

Secondary balancing 5 min < 15 min weekly capacity+ energy

Tertiary reserve 15 min

> 15 min, up to few h daily capacity+ energy

The intermittency of renewables increases the price levels on the reserve and balancing markets

Reserve and Balancing MarketsGerman Example

Reserve and balancing markets, together with redispatch and additional interday trading provide increased opportunities

0

200

400

600

2010 2011 2012 2013 2014 2015

M[E

UR]

p.a

.

Tertiary

Secondary

Primary

Market size by segment

http://neon-energie.de/



Reserve and Balancing MarketsEU electricity balancing Guideline

Further harmonization and development of the European Power Market ->EU electricity balancing Guideline -> GL-EB Goal: Effective competition, non-discrimination and transparency!Establishment of EU-wide balancing platforms for the exchange of balancing energy

• IGCC, PICASSO, MARI, TERRE, FCR cooperationHarmonisation of balancing products & settelment rules

• Imbalance Netting (IN)• automatic Frequency Restoration Reserve (aFRR)• manual Frequency Restoration Reserve (mFRR)• Replacement Reserve (RR)• Frequency Containment Reserve (FCR)

Implementation start ~ 2019, time ~ 2 - 4 years

Planned energy market harmonization is not only a great challenge, but an opportunity for a flexible NPP as well!



• Neutron flux (reactor power) can be controlled fast (±1% / sec (ref. to rated power)) by variation of coolant flow rate in a range from ≈ 60 – 100 % without affecting the relative power distribution in the core (recirculation control with speed controlled recirculation pumps)

• Further power control is possible by maneuvering of control rods in a range from ≈ 20 – 60 % power (gradient up to 10 % / min)

• Original power controller enables automatic frequency control and automatic switch between recirculation control and rod control mode. Typical power band 95 ± 5 % (using recirculation control)

• Mechanical design of the components allows frequent load follow

Design characteristics in German BWRsBWR for Flexible operation

Nordic BWRs can benefit from Framatome’s design and operational experience, transferring various concept features to their specific design and operational requirements

Framatome’s BWRs were originally designed for the flexible operation



Framatome (former KWU) PWRs were originally designed for the flexible operation with a gradients up to 5 and 10 % / min (ref. to rated power).

Part-load diagram (PWR) with ACT = constant in upper load region Special control rod maneuvering program Axial power distribution control

• Continuous fast incore detectors for power distribution measurement and their precise calibration using Aero-ball flux measuring system

• Dynamic limitation values e.g. for softening of Pellet Cladding Interaction

Automatic boration / dilution control Closed boric acid treatment system Mechanical design of the components

allows frequent load follow

Load cycle (%) Number (design)10 (step change) 100.000

100 – 80 – 100 100.000

100 – 60 – 100 15.000

100 – 40 – 100 12.000

100 – 20 – 100 1.000

Design Characteristics of German NPPPWR for Flexible Operation

Nordic PWRs can benefit from Framatome’s design and operational experience, transferring various concept features to their specific design and operational requirements



Framatome (KWU) NPPs were originally designed to compensate load changes over a large power range with a high gradient. But were used mostly in base load. Since decade large-scaled integration of the fluctuating renewables forced German NPPs to frequent flexible operation.First, optimization projects for PWR were carried out related to the improvements of the turbine and reactor control

• Introduction of the digital technology in the filed of I&C was very beneficial; • Fully automated control processes for all types of flexible operation was achieved introducing

ALFC (Advanced Load Follow Control), further improved by Predictive Reactivity Management for PWRs

Due to build-in advanced flexible features of BWR only some minor adaptations were needed to take into account the operation experience e.g. actualization of dynamic parameters

Flexible Operation of NPPs Optimizations in Germany

NPPs are further developed to provide ancillary services in advanced automatic way for the increased power level ranges for higher profitability and enhanced safety



Operational Experience in

Germany



Operating experienceLoad follow, PWR/BWR, 1 year

Elec

trica

l Pow

er ,%

Time, month

GKN1 (PWR)

KKP1(BWR)

Source: atw, http://www.kernenergie.de/kernenergie-wAssets/docs/service/602atw-betriebsergebnisse-kkw2009.pdf

http://www.kernenergie.de/kernenergie-wAssets/docs/service/602atw-betriebsergebnisse-kkw2009.pdf



Operating experienceExample (E.ON, Fleet, 1 day)

M. Fuchs E.ON, Atoms for Future 2013, Paris,“Load follow from operator point of view“

Power Ramp typically ~ 20 MW/min No influence of load follow on maintenance activities• Inspection intervals of some components

were reducedExpected wear and tear not notable yet

NPPs belong to the most flexible plants in the German grid and can cope with the grid requirements and provide additional services in a favorable manner



Upgrades for fully automated flexible operation

in Germany



Introducing of load governor incl. load schedule (PWR)Modernization of turbine control PWRs/BWRs

• primary and secondary frequency controlModernization of reactor control in PWRs

• e.g. Advanced Load Follow Control (ALFC)Modernization of control rod control in BWRs Variable recirculation speed

• typically for BWRs (USA, Switzerland)

“Advanced Load Follow Control (ALFC) with Visualized Reactivity” A. Kuhn (Section Safety management)

Implemented upgradesControl optimizations

Load Governor

Turbine Control

Reactor Control



Turbine Controller

Time (s)

Requirement

Output

Pow

er (M

W)

Requirement

Output

16 s delay!

Grid Activation time Duration Δ PG(jump)

Continental Europe 30 s 15 min ± 2%

Great Britain 10 s 20 s -Ukraine 30 s 15 min ± 2 %Framatome 30 s 1 h up to ± 14%

Implemented upgradesExample 1: Turbine Control optimization

Pow

er (M

W)

before upgrade

after upgrade



Implemented upgrades in PWRsExample 2: Reactor control by ALFC

Advanced load following control (ALFC)

PD,W/cm

H, m Limit Values:

DNBLOCAPCI

LOCAPCI

PD = Power Distribution (in-core instrumentation)

Fully automated flexible operation• Incl. power increase back to 100% without stops

Automated core power distribution monitoring and control• greater margins for flexible operation• avoiding Xe-oscillations • Higher core loading flexibility

Automated reactivity management• Online Xe-calculation, prediction and visualization via Process

Computer Diagram• Self-Adaptation to “fuel burn up”- dependent PD-change

ALFC enables full automation of the grid-related operation modes. Together with the appropriate optimization concept for the whole plant the flexibility of NPP operation can be significantly improved.



Implemented upgrades in PWRsALFC references

ALFC implemented in: Philippsburg 2 in 2008 Isar 2 in 2014 Brokdorf in 2015 Grohnde in 2015 Gösgen in 2017 Borssele (partly) in 2017

ALFC-Predictor implemented in: Isar 2 in 2017 Gösgen in 2020 (planned)

Philippsburg 2

Grohnde

Brokdorf

Isar 2

Gösgen (CH)

Borssele (NL)



Worldwide first time: Visualization of the predictive Reactivity Management for the reactor operator

Increased Nuclear Safety through visualization of potential performance limits during flexible operation!



Operating experience with ALFC: Primary frequency control, 30 s - responce

World record for NPPs: Successful qualification test of -14 %- PG-jumps (= -200MW)

PG = 100 %



Operating experience with ALFC: Remote secondary control, 1 month

30 MW/min !

The long term reactivity effects are compensated automatically

PG = Generator Power

946 MW

27 days

∆PG =approx.550 MW 30 MW/min

PG

946 MW

1508 MW

Xenon



Advanced Load Following Control (ALFC)Operational experience

∆PG =approx.500 MW

1 day

1 month

∆PG =approx.600 MW


BOC

PG

EOCStretch Out

1 year



Improvement of Core Power Distribution MonitoringInstallation of Fatigue Monitoring Systems e.g. FAMOSi and applying appropriate Fatigue Analyses Concept (AFC)

Execution of Flow-Accelerated Corrosion Analyses with Framatome COMSY Tool e.g. for ELPO - Calculations incl. maintenance optimization Installation of Vibration Monitoring Systems (MSR, Condenser, etc.) based on e.g. Framatome Vibration Monitoring ToolboxOnline chemical monitoring e.g. Intelligent Monitoring of NPP Water Chemistry with DIWA™ + Continuous Measurement of Boron Concentration – COMBOSurveillance concept for secondary side (HW+SW)

Implemented upgradesMonitoring – Diagnostic

Proactive monitoring and diagnostics is essential for safe and economical long term operation of NPP in flexible operation mode



Global Framatome Approach to NPP Flexible Operations



NPP Flexible OperationsOur Solutions – Technical Background

Load Follow (LF)• Low power period: power level, duration• Power range rate (slope): slow, fast• Load ScheduleFrequency Control (FC)• Primary (PFC): automatic (amplitude, slope)• Secondary (SFC): remote control (amplitude

slope); possible superimposition of PFC and SFC

Follow unexpected grid requests• Ramps (amplitude, slope)• Instantaneous return to full power (slope)• House Load Operation

Extended Low Power Operation (ELPO)• Reduce the power level during significant

periods (number of occurrences, duration)

Adaptation todaily demand variation

Adaptation toreal-time frequency

variation

Adaptation to Grid disturbances

Adaptation to longer term forecasted

demand

All flexible modes can be implemented from semi manual to fully automated mode!

Potential Grid Requirements

Potential NPP Operation Modes

50%, > 24 h

100% 100%

Example



Plant Systems

FunctionsPlant Components

FUEL performance

Compatible to all customer requirements which can occur regarding all flexible operations modes (implemented, singly or in combination)Framatome global approach is based on overall experience from reliable, safe and competitive flexible operations of Framatome-designed NPPs in France and Germany over many decades.

Step 1: Feasibility study “from the Reactor Core to the Grid” Step 2: Optimisation and implementation packages „from Low to High flexibility Demand“

GO

Optimization andImplementationFeasibility StudyCustomer Requirements

NPP Flexible OperationsKey features

Load Follow

Primary and Secondary

Frequency Control

Unexpected grid requests

Extended Low Power Operation

System Evalu-ation

Licensing

Upgrade analyses

Program-matic

uprades

Optimi-zations

andModificati

ons

Stake-holder

Interfaces



Fuel Behavior and transition analysis

• Neutronic and TM Justifications

• Power maneuvering guidelines (PCI)

• Optimization of Fuel management strategies

• Fuel transition global package, if required

Chemistry issues

• Primary side - Boric Acid/ Alkalisation management (pH-value) and treatment

• Secondary side - BOP optimizations (pH -value), SG (cleaning strategy)

• Feedwater quality (e.g. O2 content) (BWR)

Life-time issues

• Wear e.g. control rod system wear

• Fatigue• Flow-accelerated corrosion• Vibrations • Impact on Design Transients File

Control issues

• BoP and BNI I&C incl. control rod maneuvering program - automated reactivity management (Boration / Dilution) (PWR)- axial power distribution control - Xe transient management

• Optimized coordination between pump and control rod controller (BWR)

• Pressurizer level and pressure control channels (PWR)

• Human Machine Interface

Technical specifications

• Plant operating conditions• Operational technical

specifications• Other current documentation

Safety analyses

• 3D power and burn up distributions

• Impact on the Safety Analyses Report / PSR (Events; Core and plant initial conditions before accidents)

Training issues

• Operator training • Simulator

NPP Flexible Operations: potential impacts

Framatome provides a full range of customized solutions to address all possible impacts with a single point of accountability to maximize profit and improve safety



Summary and Outlook



NPP Flexible Operations Summary and Outlook

NPPs all over the world were originally optimized for Base Load Operationas flexible operation was not required for NPPs

main design challenges typically are e.g. I&C issues, fuel integrity and special need for secondary side surveillance and fatigue monitoring -> proactive acting is essential especially for a long term operation of the NPP, taking into account flexible operation mode

Overall approach capitalizes on experience feedback Reliable, safe and competitive flexible operations of Framatome-designed

NPPs in France and Germany over many decades

Identify needs

Compare needs and capabilities

Evaluate impact

Propose optimizations & upgrades

Validate & Implement



Future of nuclear energy isflexible

… Framatome has the solution tailored to meetyour needs



Any reproduction, alteration, transmission to any third party or publication in whole or in part of this document and/or its

content is prohibited unless Framatome has provided its prior and written consent.

This document and any information it contains shall not be used for any other purpose than the one for which they were

provided. Legal action may be taken against any infringer and/or any person breaching the aforementioned obligations



Chemistry issues for primary and secondary side pH control through Boric Acid / Alkalization management and Balance of Plant

optimizations to reduce corrosion product transport Zinc Chemistry for dose rate minimization Steam Generators: Application of Filming Amines for minimization of deposit load and

SG cleanness strategy (SG Fouling Index Toolbox)Fuel Behavior and Transition Analysis For Framatome Fuel, power manoeuvring guidelines preventing Pellet Cladding

Interaction (PCI) were established Over many years, successful application in France and Germany Currently, FUEL justification analyses in another countries (e.g. China, Belgium, South

Africa, UK, USA)

Chemistry and Fuel related topics



Flexible operation modeswith Advanced Load Following Control (ALFC)

ActivationTime,

Duration

PowerGradient, MW/min

RangeΔPG, MW

Activated by

Frequencycontrol

Primary 30 s;max. 15 min

Jump,back to full

load within 30 s

up to-200

asymmetric ↓

Automaticly: linked directly to turbine power controller

Remote secondary

5 min, typically 15

min

30 - 40 ≈ 600 Automaticly: setpoint of turbine load (load dispatcher),

gradient (reactor operator)

Load follow Tertiary 15 min, > 15 min till

1h/incident

up to 40 ≈ 1000 telephone contact with load dispatcher/ load ramp

(gradient, target load, often incl. duration)

Fully automated flexible operation for the increased power ranges



BWR Optimizations for load follow operation

PID

Optimized coordinationwith Grid operator• Remote controlled reactor

power (in certain limits)

Optimized recirculationcontrol• Variable frequency drives

Optimized reactorpower control• automatic grid frequency

control (primary control)• Reactor power control• Optimized coordination

between pump- and control rod controller

• Instrumentation

Optimized surveillance• Thermal fatigue monitoring e.g. Famosi• Assessment based on existing system

instrumentation• Vibration monitoring• Advanced thermal load determination

Optimization in steamfeedwater cycle• Condensate drain control• Preheater degassing• Feedwater degassing• Water chemistry• Flow induced corrossion• Control valves• Mechanical design, thermosleeves

Optimized core design• Control rod pattern• Fuel economy• minimize fuel load with e.g. Xedor



Advanced Load Following Control (ALFC)Commissioning test “100% - 30% - 100%”

100% REO

6h at 30%

100%

40 MW/minCondition

limitations related to PD

Reactor PowerXe-reactivitygradientsin upper/lowercore half

Xe-Max.

Permitted Reactor Power

REO = Rated Electrical Output

No axial Xenon oscillation; no manual interventions required



ALFCPrimary frequency control

Delivery 15 min

Delivery 15 min

Break 15 min

Activation <30 s

Activation <30 s

Deactivation <30 s

Deactivation <30 s PG

(measured value)

PG setpoint(frequency dependent change)

-200MW = -14%

PG = 100 %


World record: Successful qualification test of -14 %-PG-jumps (= -200 MW)

ancillary and balancing services provided by npps under ... · • neutron flux (reactor power) can...

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