Tuesday, August 4, 2015

South Australia Nuclear Prospects Q1-4

Subtitle:  Nuclear Power For South Australia Not Justifiable

South Australia's Royal Commission on the Nuclear Fuel Cycle requested written responses to 17 questions on the topic of nuclear power reactors.  see link The reactors are but one of four topic areas, with the others being 1) uranium mining, 2) uranium enrichment into civilian power fuel, and 3) nuclear waste management and storage.  I was unable to submit answers to the questions for formal consideration by the Royal Commission, however, the answers are below for the first 4 questions.  Answers to the remaining questions will appear in separate posts.   The conclusion is that a nuclear power plant cannot be justified.  A small nuclear reactor would be required, which suffers from reverse economy of scale and is, therefore, very expensive for the amount of power produced.   The usual safety concerns also apply: operating upsets and radiation releases, population evacuation plans, spent fuel storage or reprocessing, and sabotage and terrorist attacks, to name a few.

The background parameters for the South Australian power grid, the NEM or National Electricity Market, are as follows. 

1. SA has peak demand of approximately 1400 MW, at times soaring to 2400+ MW in Winter; recently has hot summer peaks of 3000+ MW in January.  (Figure 4, Issues Paper 3)
2. Typical peak demand is 1400 MW, see Figure 4, Issues Paper 3.  
3. Typical minimum demand (nights) is 1000 MW, with lows in Spring of 700 to 800 MW. ( ibid, Figure 4) 
4. Generation total capacity is 5,000 MW on the NEM. 
5. Demand growth has slowed, and demand has decreased in the past few years.  The decrease is attributed to deliberate conservation measures, solar on rooftops, and demand removal via industry closures. 
6. Commission concludes that SA has 600 MW of excess, surplus, generation that could be removed from the grid without difficulties arising.  
7. There is some fraction of wind energy in the generation mix.  The balance is coal and natural gas. 
8. The grid is connected at high voltage to other Australian grids via the National Electricity Market, NEM.  A spot market exists on the NEM.  Export or import capacities are 650 MW and 220 MW, both to Victoria.
9. Some off-grid generation and demand exists, presumably in remote locations such as farming, mines, and desalination. 
10. Background information correctly identifies earthquakes as a concern, also requirement for adequate cooling water, and accessibility to power transmission lines. (No information yet on evacuation plans, tsunami threats, grid loss from other forces such as wildfires, storms, cyclones, sabotage, and large aircraft crash.)  

The Commission's Questions and Responses  (1-4)

3.1  Are there suitable areas in South Australia for the establishment of a nuclear reactor for generating electricity? What is the basis for that assessment?

Nuclear plants have been built on a variety of sites, including ocean coasts (e.g. Diablo Canyon and San Onofre in California, USA, Fukushima Dai-Ichi and Dai-ini in Japan), lake shores (Perry in Ohio, USA on the shore of Lake Erie), on islands in rivers (Three Mile Island on the Susquehanna River in Pennsylvania, USA, and South Texas near the mouth of the Colorado River in Texas, USA), and in a desert (Palo Verdes near Phoenix, Arizona, USA).  Cooling for Palo Verdes is provided by treated waste water from the nearby city of Phoenix and other towns.  It is probable that suitable sites exist in South Australia, however many factors must be considered as discussed below. 

Factors that are required to provide a meaningful answer on site selection include the size and type of nuclear reactor.  This impacts several aspects for site selection including cooling water required, infrastructure for building the plant and ongoing work, reliability of the grid at that location, probability of natural forces that impact the reactor and other parts of the plant, such as earthquakes, floods, tsunamis, ice storms, droughts, heat waves, wildfires, any other site-specific natural events, and size of population downwind of the site that must be evacuated in and when a major radiation event occurs.  

3.2  Are there commercial reactor technologies (or emerging technologies which may be commercially available in the next two decades) that can be installed and connected to the NEM? If so, what are those technologies, and what are the characteristics that make them technically suitable? What are the characteristics of the NEM that determine the suitability of a reactor for connection? 

Demand on NEM for SA is small at 1400 MWe typical daily maximum, and 3,000 MWe annual maximum.  Population served is approximately 1.6 million.   Night minimum demand is approximately 700 MWe.   This places NEM on the small end of utility grids, and likely unsuitable for a nuclear reactor.  It is notable that zero islands with similar power demand have nuclear power for electricity.   There are, however, commercial reactor technologies that could be installed and connected to the NEM.  The grid’s operational stability, and economics of generation, would be severely compromised.  

Determining if nuclear technologies may be commercially available in the next two decades requires prudent speculation.  One such technology undergoing research is the PRISM, or Power Reactor Innovative Small Module.  (S-PRISM Fuel Cycle Study, For Session 3: Future Deployment Programs and Issues, A. Dubberley et. al. 2003, see link)  PRISM technology would require a spent fuel reprocessing plant to extract fissile and fertile material, then react the extracted material via fission to produce power.  The plants would consist of multiple 760 MWe power blocks.  It can be seen from the above that the PRISM technology is too big to suit the NEM and South Australia.   The costs would also be prohibitive. 

In addition, PRISM technology requires ready access to spent nuclear fuel, which must be imported into South Australia.  The safe transport of spent nuclear fuel from Japan, the US, Europe, and elsewhere presents very great problems.  A ship containing spent nuclear fuel would be a prime target for terrorists and pirates.  A spent nuclear fuel ship could be held for ransom.  Also, the environmental consequences of a sunk ship would be devastating.  
The safety of a PRISM, which is a Liquid Metal Fast Reactor, LMR, is dubious at best and catastrophic at worst.  If a LMR is located underground, one then has an atomic land mine.  The liquid metal is typically sodium, which reacts furiously with air or water to produce great quantities of heat or explosive gas.  Leaks are inevitable in a process system.  

Other small reactor technologies under research include thorium-based SMR, and high temperature gas reactors.   None of these have any advantages to recommend them. 

3.3  Are there commercial reactor technologies (or emerging technologies which may be commercially available in the next two decades) that can be installed and connected in an off-grid setting? If so, what are those technologies, and what are the characteristics that make them technically suitable? What are the characteristics of any particular off-grid setting that determine the suitability of a reactor for connection?

Other than military ship and submarine nuclear power plants, none are available, and none likely to become available and economic.   A nuclear reactor in an off-grid setting must compete successfully with two alternatives: the expense of bringing reliable grid power to the off-grid load, or the expense and variable reliability of on-site generation such as diesel-powered generators, and gas-turbine cogeneration systems.  For many off-grid applications, both electricity and steam for heat are required.  A gas-fired cogeneration system may have excellent economics in such a location.  A small nuclear reactor would have unfavorable economics.  

3.4  What factors affect the assessment of viability for installing any facility to generate electricity in the NEM? How might those factors be quantified and assessed? What are the factors in an off-grid setting exclusively? How might they be quantified and assessed? 

Factors for installing any generating facility on a grid, including NEM, include infrastructure availability, capital cost, operating cost, safety, reliability, turn-down ratio, ramping rate, fuel availability, cooling requirements, transmission requirements, impact on the grid from planned and unplanned shutdowns, years required during construction before connecting to the grid, and environmental impacts from both ongoing operations and after the facility closes at the end of its useful life.  Several comparisons of multiple sources of electricity have been performed, including e.g. California’s cost study from 2010. see link

Factors for an off-grid setting also include most of the above factors for NEM, noting that infrastructure additions are almost certainly required, e.g. roads for heavy components, and reduced efficiency where the off-grid setting is far from cooling water so that air cooling must be used.  One factor for the NEM that likely will not be present for off-grid consideration is the impact on the local grid from an unplanned shutdown.  However, the load that is serviced by the off-grid power plant will certainly be impacted by any shutdown of the power plant.  
Note that an off-grid setting would almost certainly require load-following capability from a nuclear power plant, which adds to the cost of the plant, decreases safety, decreases the operating lifetime, and increases the price that must be paid for the electricity produced.

Questions 5-8 and answers, see link.
Questions 9-12 and answers, see link
Questions 13-17 and answers, see link

Roger E. Sowell, Esq.
Marina del Rey, California
copyright (c) 2015 by Roger Sowell

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