Hybrid Energy Systems

Transcription

1 IAEA Workshop on Small Modular Reactor Safety and Licensing, held in Hammamet, Tunisia December 2017 Hybrid Energy Systems David Shropshire Planning and Economic Studies Section Head Division of Planning, Information and Knowledge Management Department of Nuclear Energy

2 Talk Outline Energy policy drivers Applications of SMRs Load following requirements Power management options for load following Challenges with reactor power maneouvering Hybrid system Case-study courtesy of NuScale Power

3 Energy Policy Energy Security Fuel Supply Independence Energy Security Meeting the Generation Gap Climate Change Meeting CO2 Reduction targets Economics and Affordability 3

4 Applications SMRs have been designed for the following applications: Electricity Generation Portable Water Production District Heating Hydrogen Production Process Heat Application Designed for flexibility including load following 4

5 Load Following Large reactors lack flexibility to change output over short timescales and role has been to provide base-load electricity Technical and safety issues make it difficult to load following unless adapted to do so with complicated procedures and thermally tolerant components Gas powered plants are very flexible and can vary outputs in order to meet shortcomings in electricity demands coming from renewables 5

6 Need for Load-following 6

7 EPRI User Requirements Rev. 13 (SMR) Description 24 hour load cycle: 100%>20%>100% Ramp rate of 40% per hour Capable of automatic frequency response Step change of 20% in 10 minutes Frequency variation tolerance 7

8 Regulatory Requirements Many reactors were designed for load-following and have automatic grid control features In the US some load-shape In France large reactors load follow because they produce 75% of electricity SMRs are designed to load follow but then so are many larger reactors So what do the vendors need to do to satisfy the safety regulator and operator? What would be the requirements that an SMR would have to meet to operate as part of a hybrid energy system? 8

9 Challenges with Reactor Power Manoeuvring Fuel design - resilient to frequent thermal cycling Capacity factor thermal and operational cycling accelerate component degradation Reactivity control continued low power requires boron adjustment Waste heat rejection turbine by-pass requires additional cooling tower capacity Refueling schedule affected by low power Staffing routine power manoeuvring affects workload 9

10 Light water nuclear/renewable hybrid system 10

11 Load-following requirements Predictability hourly, daily and weekly is important to make it economic Long term predictions can be planned for by supplying to other utilities or for cogeneration Short term shortages require excess capacity or the ability to divert electricity from other customers Smart grid and control is essential Operating an SMR close to 100% is key 11

12 Case Study courtesy of NuScale Power Integrating NuScale Power SMR (50MWe per module) with Horse Butte Wind Farm (<60MWe) Deployment of clean base-load electrical power to replace coal fired generation Use for Cogeneration 12

13 Horse Butte Wind Farm 13

14 12-module NuScale plant 14

15 Power Management Options for Load Following Operations Take one or more modules off-line Manoeuvring reactor power for hourly changes in demand By-passing module s steam generator directly to condenser for rapid responses Allow power changes by control rod movement down to 40% power Beginning of life modules offer greater flexibility 15

16 NuScale load-following 16

17 Load-following Options 17

18 Economic Perspective Not reduce power output or dump steam Sell excess electricity to other utilities through Excess Imbalance Market Require Automatic Generation Control Use electricity or heat for other purposes such as desalination, chemical production (cogeneration) Hybrid Energy System can be optimised to meet grid demand and other valued products without varying nuclear plant output 18

19 Decision to Load-follow Economics large capital investment so plant needs to operate 100% Regulatory requirements these have yet to be defined but will need to be informed by research on the behaviour of the plant and components Policy mandates strategic approach to operation so that it integrates with renewables and also has a range of products so as not to waste heat 19

20 For inquiries on SMR, please contact: IAEA Nuclear Power Technology Development Section Thank you!