Commercial Nuclear Power Fact Fiction and Perception 1

Commercial Nuclear Power Fact, Fiction and Perception 1

First Things First… Forget everything that you’ve learned about nuclear power from this guy 2

About Me: Larry Reynolds 30 Years Experience in Nuclear Power 3

• I entered into the nuclear power field when I enlisted in the US Navy. • I served aboard the USS Pogy (SSN 647) as a Nuclear Mechanic and Reactor Plant Operations Supervisor. 4

• I came to Illinois to work at the Braidwood Nuclear Station in Southwest Will County. • I first worked at Braidwood writing instructions for Mechanical Maintenance tasks. • I later provided oversight of their Preventive Maintenance Program. 5

• I then worked as a ‘Work Week Manager’ to provide overall scheduling and coordination of all work in the plant for a given week (5 week rotation). • I retired from Exelon (Braidwood Station) last August. • I currently work at Hydro. Aire in Chicago at their Nuclear Pumps Division. 6

Part 1: Theory 7

The Theory? - How Does it Work? At it’s simplest, nuclear power plants use the heat created by the nuclear fission of U 235 (Uranium) to make steam. The steam is used to spin a turbine which is coupled to a generator. This produces electricity. 8

The Theory - How Does it Work? 9

Definitions: • Core: The area of the reactor that houses the fuel assemblies • Fission: The process of splitting atoms (usually U 235) • Fission Product: smaller molecules created by the fission of Uranium – these are often unstable (radioactive) • Fusion: The process of combining atoms (usually H 2) • Free Neutron: A neutron that is not part of a molecule – it’s by itself • Fast Neutron: A free neutron that has most of the original energy that it gained from the fission process • Thermal (or slow) Neutron: A free neutron that has lost most of its energy to the moderator 10

Definitions: • Poison: A material placed in a reactor to absorb neutrons so that the fission reaction can be controlled or stopped (Usually Boron or Hafnium) • Control Rod: A rod that is made from a Reactor Poison and is located in the middle of most fuel bundles. They are raised or lowered to control reactor power. They can also be rapidly inserted into the fuel bundle during an automatic shutdown of the reactor. • SCRAM: Slang for an automatic or manual shut down of the reactor. This is performed by causing a rapid insertion of control rods. The term originated at the first test reactor at Fermi Lab in Chicago (Safety Control Rod Ax Man) • Moderator: A substance with a low molecular weight used to slow neutrons (common moderators are water, helium and graphite) 11

The Theory So what heats up the water? The Fission Process for U 235 12

Keff= number of neutrons in one generation number of neutrons in preceding generation keff =ϵ • Lf • p • Lth • f • n keff = the effective multiplication factor of neutrons in the core If keff is greater than 1, the chain reaction is supercritical, and the neutron population will grow exponentially. If keff is less than 1, the chain reaction is subcritical, and the neutron population will exponentially decay. If keff = 1, the chain reaction is critical and the neutron population will remain constant. ϵ = Fast fission factor total number of fission neutrons from just thermal fission Lf = Fast neutron non-leakage probability The probability that a fast neutron will not leak out of the system p = Resonance escape probability Fraction of fission neutrons that manage to slow down from fission to thermal energies without being absorbed Lth = Thermal neutron non-leakage probability The probability that a thermal neutron will not leak out of the core f = Thermal utilization factor Probability that a neutron that gets absorbed does so in the fuel material n = Thermal Fission Factor The number of fission neutrons produced per absorption in the fuel 13

WHAT THE WHO!!!? ? A reactor that is ‘critical’ simply means that it is neither gaining or losing ‘free’ neutrons in the core. In other words, the power level is stable – neither increasing or decreasing. 14

Part 2: The Perception 15

The reality is that there is a lot of misinformation about Nuclear Power. What does a Nuclear Plant look like? Like this, Right? 16

This is actually a Coal Burning Power Plant These large cooling towers are used in many different types of power plants. 17

Perception • Three Mile Island was the worst incident at a commercial US plant, yet no radiation was released. Public outcry after this incident was responsible for many utilities abandoning plans for construction of new plants. Some of these plants were already in the process of being constructed. • The Chernobyl accident released large amounts of radiation in Russia and caused many deaths. Many people assume that an accident like Chernobyl could happen here. US Regulations prohibit a design like that used at Chernobyl and also prohibit the type of testing that was being performed that led to the accident. 18

Part 3: Practical Application 19

Application • Nuclear Power is unique: – People tend to be frightened of what they don’t understand, and nuclear power is complicated. – The US Government and US Nuclear Plant Licensees (owners) both have roles in the safe operation of Nuclear Power Plants in the US. – The NRC must approve the design of any nuclear plant prior to start of construction. 20

Application • Because of the severe consequences of a nuclear accident, the nuclear industry is highly regulated. • Prior to start of operation, each plant must receive a license to operate from the NRC that has the force of law and covers design, maintenance, testing and operations of the plant. 21

Application • Because of the severe consequences of a nuclear accident, the nuclear industry is highly regulated. • Nuclear workers have FBI background checks and drug screening prior to being allowed unescorted access to a nuclear plant. Random checks are required as long as access is allowed. • Every year each nuclear plant employee must complete training on emergency procedures, security protocols, radiation safety and other topics important to nuclear safety. • The NRC requires positive ID of each employee prior to entry into the plant (security badges and hand scanners). • All employees and packages are screened prior to entry in the plant (similar to airport screening). 22

Application • Because of the severe consequences of a nuclear accident, the nuclear industry is highly regulated. • Drills that simulate various emergency scenarios are held on a regular basis to test the communication, response and coordination between each Nuclear Plant, Response Centers, State and Local Governments. 23

Application • Nuclear industry regulations (continued): • Fences, key-carded doors and an armed security force are all used to enforce security. Each plant has a unique Security Plan based on it’s location and plant geography. Each plan must be approved by the NRC and includes the design of the permanent structures as well as number of guards on staff, the type of weapons on-site, etc. • Periodic drills are performed to test plant security staff response to a simulated attack. A ‘ninja force’ simulates an attempt to enter the plant and damage the reactor with both sides using laser tag rifles. 24

Application • Nuclear industry regulations (continued): • Almost every activity at a nuclear plant is performed using a procedure or set of work instructions that is reviewed against the plant’s operating license prior to approval to ensure that all regulations are met. • Every component (and sub-component) that is important to nuclear safety has been evaluated in detail to ensure that it can be relied upon to perform as required. This includes detailed analysis of breaking strength, resistance to corrosion, and other pertinent material attributes. All parts used must have traceability and documentation of all phases of manufacture and testing. 25

Application USS Thresher: Poor materials and construction caused sinking of this submarine. As a result, the US Navy implemented SUBSAFE program to ensure quality of materials used in submarines. This method was also adopted at nuclear plants shortly thereafter. 26

Application – In addition to careful selection, testing and documentation of replacement parts, all maintenance must be planned and scheduled to ensure that: • Removal of equipment from service will not violate any part of the operating license due to loss of redundancy • Procedures and work instructions are used to ensure work is performed correctly • Radiation and contamination exposure are minimized (Time, Distance, Shielding) • Equipment is scheduled to be operated (or exercised) at periodic intervals to prove to the NRC that it could operate as designed in an emergency. 27

Application – As a result of all of these processes and regulations, the majority of workers at a nuclear plant spend a great deal of their time performing engineering analysis, work planning, scheduling or documentation tasks. – Most nuclear workers receive very little radiation. An airline pilot receives more radiation in a year than most nuclear plant workers. – Major repair work, and all repair work inside of the containment building is performed during a refueling outage. This is when the reactor is shut down to allow for replacement of fuel bundles. This is also a key to lowering radiation dose rates to workers performing maintenance. 28

Application • INPO (Institute for Nuclear Power Operations) was formed shortly after the nuclear incident at Three Mile Island in December 1979. • INPO Mission. . . to promote the highest levels of safety and reliability – to promote excellence – in the operation of commercial nuclear power plants. • INPO conducts evaluations of Plants to ensure that they are operated in a safe and reliable manner. These evaluations also establish and communicate ‘best practices’ across the nation (and world - by participation in WANO). • Provides an independent assessment of the quality of operations at a power plant. INPO allows the nuclear industry to ‘self-police’ itself. 29

Part 4: Comparisons 30

Comparisons: • Nuclear – Larger Nuclear plants have capacities of 1200 Mw and can generate an average of 20, 000 Mw. Hr in a year (2 unit site). – Power plants (not just nuclear) can kill fish in large numbers due to the heating of river, lake and sea water. 31

Comparisons: • Nuclear – Nuclear plants generate low level waste as well as spent fuel. The government has agreed to take on the responsibility for disposal of spent nuclear fuel. 32

Comparisons: A single uranium fuel pellet the size of a pencil eraser contains the same amount of energy as 17, 000 cubic feet of natural gas, 1, 780 pounds of coal or 149 gallons of oil. 33

Comparisons: Nuclear energy data • A typical nuclear power plant generates 20 tons of used nuclear fuel in a year. This used fuel is stored on site in spent fuel pools or NRC approved storage units. • About 95 % of LLRW decays to background levels within 100 years or less. • Low-level radioactive waste is stored in special disposal facilities across the nation. These disposal facilities also store Low-level radioactive waste from medical and industrial sources. 34

Comparisons: • Wind – Most wind energy comes from turbines that can be as tall as a 20 -story building and have three 200 -footlong (60 -meter-long) blades. – The largest wind turbines being manufactured today can produce 2 Mw each with adequate wind. – Wind turbines only work when the wind is blowing (Duh!). – This would mean that to equal a nuclear power plant, a wind farm would need 600 wind turbines. Typical spacing is 7 X the rotor diameter or every 1400 feet. Placed in a single row, this would be 840, 000 feet long (or 160 miles long – or 180 square miles if placed in a grid). – DOE documents estimate bird kills from wind turbines at about 1 bird per Mw per year (or 1200 birds per year in the above example). They also estimate that in areas with bats, the bat kill would be 30 bats per Mw per year (36, 000 bats per year in the above example). 35

Comparisons: • Solar – The amount of electricity produced by a multi-reactor nuclear power plant would require more than 60 square miles of photovoltaic panels • Fossil (Oil, Natural Gas and Coal) – Carbon Dioxide emissions (acid rain) – Like nuclear plants, these plants can also result in fish kills • Conservation – Use less electricity – Buy products that have a minimal of processing (extensive processing usually means extensive electrical usage) 36

FAQ’s: 37

FAQ’s: • What is used nuclear fuel? – Used uranium fuel assemblies from commercial reactors still have 90 percent of the original potential energy. They are currently stored at nuclear energy facilities where they are used. • How is used nuclear fuel stored? – Most plants store used fuel in steel-lined, concrete vaults filled with water, which acts as a natural barrier for radiation from the used fuel. The water also keeps the fuel cool while it becomes less radioactive. The water itself does not leave the used fuel pool, rather is constantly circulated to maintain a suitable temperature. – After at least five years of storage in the used fuel pool, the rods can be moved into large, heavily shielded concrete and steel storage containers, whose designs must be approved by the Nuclear Regulatory Commission. There it awaits removal by the U. S. Department of Energy to a disposal facility. 38

FAQ’s: • What is low-level radioactive waste? – Low-level radioactive waste is a byproduct of the uses of radioactive materials. This includes waste from electricity generation, medical diagnosis and treatment, biomedical and pharmaceutical research and manufacturing. – It is solid material that is transported under strict regulations established by the U. S. Department of Transportation and the Nuclear Regulatory Commission. – Low-level radioactive waste usually consists of items such as gloves and other protective clothing, glass and plastic laboratory supplies, machine parts and tools, and disposable medical items that have come in contact with radioactive materials. 39

FAQ’s: • What is radiation? – The radiation one associates with a nuclear power plant are particles, such as alpha rays and gamma rays, emitted as a result of the fission process. • Do nuclear power plants release radioactive material? – Yes, but in small levels that are regulated by the federal government. Nuclear power plants produce radioactive gases and liquid wastes during normal operation. A plant has tanks designed to store gas and liquid radioactive materials that are generated during normal operation. The radioactive material is held for a period of time to allow for the radioactivity level to decrease before being treated and/or released in a planned, monitored way. This keeps the amount of radioactive material in releases low and well within federal limits. 40

FAQ’s: • How did the 2011 nuclear accident in Japan affect the nuclear energy industry? – In the United States, the nuclear energy industry and the NRC immediately took steps to make facilities even safer than before the accident. Most other countries took a similar approach to the United States and kept their facilities operating. Germany and Switzerland are phasing out their nuclear energy facilities. Japan shut down its plants, but has restarted one and may restart others after they make safety upgrades. – The industry quickly implemented a safety enhancement strategy to ensure that plants have the additional equipment needed to respond to extreme natural events such as the tsunami in Japan. The industry initiative will provide additional sources of water and electric power to keep the reactor and used fuel pool cool if electricity from the grid is unavailable, as it was in Japan. – Additional generators, batteries, water pumps and other emergency equipment have been purchased at each site. In addition, regional response centers in Tennessee and Arizona will maintain more emergency equipment that can be dispatched quickly to any facility that needs it. 41

QUESTIONS ? ? ? 42

Links: • • • http: //www. nei. org/Knowledge-Center/Nuclear-Statistics http: //www. hydroinc. com/ http: //www. exeloncorp. com/locations? energy=nuclear http: //environment. nationalgeographic. com/environment/globalwarming/wind-power-profile/ http: //windeis. anl. gov/guide/basics/ http: //energy. gov/eere/wind/frequently-asked-questions-about-windenergy http: //energy. gov/sites/prod/files/2015/03/f 20/AWWI-Wind-Wildlife. Interactions-Factsheet. pdf http: //www. riverkeeper. org/campaigns/stop-polluters/powerplants/power-plant-fish-kills/ http: //thebulletin. org/nuclear-energy-different-other-energy-sources/why -nuclear-power-uniquely-dangerous http: //www. cracked. com/personal-experiences-1848 -i-work-in-nuclearpower-plant-5 -insane-realities. html http: //www. nrc. gov/about-nrc. html 43