NPPs Don’t Cause Cancer

Posted by AQG On May - 12 - 2010

[Approx. Read Time: 9 minutes]

Myth:  Nuclear Power Plants Cause Cancer

Few words in the English language invoke feelings of unrest and controversy as the word “nuclear”.  Historically, the word has been associated with feelings of uncertainty, fear or danger, and understandably so, as nuclear technology made its debut in the mainstream media by way of its use in weapons of mass destruction.  But as the general public becomes more aware and educated on the subject, many are finding that nuclear has nothing more than a bad rap.

As an illustration, let me pose this question:  When you think of gasoline, does your mind initially wander to Napalm?  Or better yet, does the use of fertilizer lead to thoughts of home made bombs?  There are a slew of atrocious myths circulating about nuclear power which are perceived as fact by many for this very reason.  One common misconception is that nuclear power plants emit substantial levels of radiation leading many to believe that operating nuclear power plants are surrounded by disfigured wildlife or that nearby residents are at a higher risk of contracting cancer or growing a third arm.
The truth is that the highly regulated nuclear industry takes the safety of the general public as its primary initiative through many stringently enforced radiological safeguards.  Among the physical barriers incorporated into the design of the plants, the U.S. Nuclear Regulatory Commission (NRC) enforces a number of requirements and expectations on the industry.
Take, for example, the policy statement issued by the NRC in 1986 which established safety goals and expectations with respect to an acceptable level of risk to public health and safety from the operation of nuclear power plants. According to the policy statement, the following goal was implemented as follows:

“ . . . the risk of cancer fatalities to the population near a nuclear power plant should not exceed 0.1% of the sum of cancer fatality risks from all other causes.”

As reported by the Center for Disease Control and Prevention, 180.7 cancers (i.e. malignant neoplasms) related deaths occurred per 100,000 people in 2006.  Taking this value into account with the NRC’s expectations discussed above, for a population of 100,000 people living near a nuclear power plant the risk of cancer fatalities should not exceed 0.001 x (180.7 / 100,000) = 0.000181% – still concerned?

One might argue that NO cancer related deaths should be tolerated – agreed!  Studies show that this is in fact the case and that plants exceed the NRC’s expectations (discussed further below).

The reality is, however, that we live in a radioactive world – this has been true since the beginning of time – and everyone is exposed to varying levels of radiation on a daily basis.  Take for example bananas and brazil nuts, which naturally contain higher levels of radiation than other foods.  Similarly, brick and stone homes have higher natural radiation levels than homes made of other building materials such as wood. Heck, our nation’s Capitol, which is largely constructed of granite, contains higher levels of natural radiation than most homes.  JunkScience.com once measured the radiation emanating from granite statues in the U.S. Capitol Building and discovered that a person standing in statuary hall near the Senate Chamber would absorb 5 times more radiation than would be absorbed by standing at the fence line of a nuclear power plant.

The chart below provides a comparison for doses from everyday radiation sources relative to living near a nuclear power plant, which exposes residents to an average annual dose of less than 0.001 rem.  In comparison, Title 10, Part 20, of the Code of Federal Regulations (10 CFR Part 20) dictates that the total effective dose equivalent to individual members of the public from a licensed operating plant is not to exceed 0.1 rem in a year.

relativeradiationdoses

For additional consideration, the pie chart presented is from the NRC’s website and provides a percentage breakdown between natural background radiation and artificial sources.  I believe the numbers speak for themselves.

webchart-low1

The NRC similarly limits the amount of radiation that a nuclear plant worker can receive in one year.  Title 10, Part 20, of the Code of Federal Regulations (10 CFR Part 20), establishes the does limits for radiation workers. Although the limits vary, depending on the affected part of the body, the annual total effective dose equivalent for the whole body is 5 rem, although many plants go even further to restrict employees to 2 rem per year.  In contrast, the Federal Aviation Administrations recommended occupational exposure limit for ionizing radiation is a 5-year average effective dose of 20 mSv (2 rem) per year, with no more than 50 mSv (5 rem) in a

single year (nearly the same standard).

Regulations imposed on nuclear power plants ensure that both the surrounding population and the workers within plants are exposed to only low levels of radiation.  The fact of the matter is that the biological effects due to low levels of radiation exposure are so small that they may not even be detectable.  The exact effect, however, depends on the specific type and intensity of the radiation exposure.

In order to truly wrap your mind around the risks associated with radiation exposure, it is useful to evaluate those risks relative to the risks associated with everyday life.  For example, a 3-millirem exposure imposes the same chance of death — 1 in a million — as each of the following common life experiences:

  • Spending 2 days in New York City (because of the air quality)
  • Riding 1 mile on a motorcycle or 300 miles in a car (because of the risk of collision)
  • Eating 40 tablespoons of peanut butter (because of aflotoxin) or 10 charbroiled steaks
  • Smoking 1 cigarette

Dr. Bernard L. Cohen of the University of Pittsburgh has extrapolated this approach in his book “The Nuclear Energy Option”.  In Chapter 8 of the book, Understanding Risk, Dr. Cohen instructs that the most logical procedure for minimizing risks is to quantify all risks and then choose those that are smaller in preference to those that are larger.  He then goes on to provide a framework for that process and applies it to the risks in generating electric power.  Chapter 8 presents various everyday activities or occurrences and their associated risks.  These risks are quantified then in terms of the loss of life expectancy (LLE); which is the average amount by which one’s life is shortened by the risk under consideration.  The figure below shows some of the activities or occurrences investigated.  It is clearly shown that living near a nuclear power plant ranks at the bottom.

lossoflifeexpectance

Further substantiating his findings, Dr. Cohens work is also published by the NRC in Regulatory Guide (RG) 8.29.  RG 8.29 offers further indication that:

“. . . the health risks from occupational radiation exposure are smaller than the risks associated with many other events or activities we encounter and accept in normal day-to-day activity.”

As mentioned earlier, countless studies have shown that populations in close proximity to a nuclear power plant receive negligible levels of radiation exposure relative to general population and are no more susceptible to cancer than the average person.

It is impractical to discuss every study ever conducted by any organization or individual regarding this matter.  Instead I have listed a few additional determinations or studies from non-bias organizations concluding such.

  • The American Cancer Society blatantly backs this notion on their website with the following statement:

“Ionizing radiation emissions from nuclear plants are closely controlled and involve negligible levels of exposure for communities near the plants. Reports about cancer case clusters in such communities have raised public concern, but studies show clusters do not occur more often near nuclear plants than they do elsewhere.”

  • A survey conducted by the National Cancer Institute and published in the Journal of the American Medical Association showed no general increased risk of death from cancer for people living in 107 U.S. counties containing or closely adjacent to 62 nuclear facilities. The facilities in the survey had all begun operation before 1982. Included were 52 commercial nuclear power plants, 9 Department of Energy research and weapons plants, and 1 commercial fuel reprocessing plant. The survey examined deaths from 16 types of cancer, including leukemia. In the counties with nuclear facilities, cancer death rates before and after the startup of the facilities was compared with cancer rates in 292 similar counties without nuclear facilities.

The results of the survey, per John Boice, Sc.D.(who was chief of NCI’s Radiation Epidemiology Branch at the time of the survey), showed that “From the data at hand, there was no convincing evidence of any increased risk of death from any of the cancers we surveyed due to living near nuclear facilities”.

  • In a response to ongoing public concern over the risk of people living near nuclear facilities, a publication of the Illinois Department of Public Health examined the pediatric cancer risk in relation to the proximity of nuclear power plants in Illinois.  Evaluations were conducted at both the county and ZIP code levels. Age-adjusted cancer incidence and mortality rates for children aged from 0 to 14 for years 1990 to 2002 were calculated for nuclear facility county group and nuclear facility ZIP code group, respectively, and then compared with those for the matched non-nuclear facility county group or non-nuclear facility ZIP code group.

The results of the publication The results indicate that pediatric cancer incidence and mortality rates for the nuclear facility county group and nuclear facility ZIP code group were not significantly different from those for their comparison groups. In addition, there was no evidence of increased trend in cancer incidence rate after startup of nuclear power plants.

  • The accident at Three Mile Island 2, what is considered the worst nuclear related accident ever to occur in the United States, caused no injuries to workers or the public.  At least a dozen epidemiological studies conducted since 1981 have found no discernible direct health effects to the population in the vicinity of the facility. Studies of the consequences of the accident were conducted by the NRC, the Environmental Protection Agency, the Department of Health, Education and Welfare, the Department of Energy and the state of Pennsylvania. The average dose to about 2 million people in the area was only about 1 millirem, according to the results of these and independent studies.  The public’s average dose from natural radiation is 100-125 millirem per year for that area.

In the decades following the accident, several studies were conducted by the Pennsylvania Department of Health, all showing conclusive evidence that no negative health effects on the population surrounding the plant. In addition to the Pennsylvania Health Department studies, several other studies have examined the health impact of the TMI accident on the population and yielded similar results.

The key to dispelling this myth is to acknowlege that, as demonstrated:

  1. Any increased risk of cancer around an operating nuclear power plant relies primarily on the adverse effects resulting from any small amount of radiation it might release.
  2. No single person can go through life without experiencing some level of radiation dose on a daily basis.
  3. The levels of radiation emitted at or near a nuclear power plant, and the associated level of risk, are negligible in comparison to that experienced in commonly occurring events and activities experienced by most on a day-to-day basis.

Once you are able to come to terms with these facts (and I hope that this article is of some help) it becomes painstakingly obvious that, contrary to popular belief, nuclear power plants do NOT cause cancer, and in fact pose no more threat to an individuals health than 365 Tbsps of peanut butter.

Myth Busted!

Next Wednesday, Adam Johnson will address the myth that as nuclear power plants age, they become more risky.

What is an “Outage?”

Posted by Carrington Dillon On May - 10 - 2010

[Approx. Read Time: 4 minutes]

st_lucieThings may be slowing down a bit here at Clean Energy Insight over the next month or two.  Currently, it is outage season for the nuclear power industry.  Many of our contributors will be supporting outage work on-site at nuclear power plants.

In the nuclear power industry, an “outage” does not primarily refer to a power outage or blackout.  Every Spring and Fall, when power demand is at its lowest, the nuclear industry shuts down some of their plants for maintenance and repair.

This could mean packing up and going to a nuclear power plant for the next three months, or staying at their home office and working the night shift.  We will try our best to keep you updated on nuclear news and interesting nuclear power facts.  However, all of our focus will be on our work in order to be as safe as possible and as productive as possible during these critical outages.  Plus, working on an outage can help an engineer gain priceless experience in the field and in the industry, which will make Clean Energy Insight better equipped to bring you voices of experience.  So…

What is an “Outage?”

In the nuclear power industry, an “outage” is a period of time in which a nuclear power plant shuts down (stops producing power)  in order to perform routine maintenance, replacements, and/or re-fuel the reactor.  During this time, the power utility ramps up power production at other plants, or purchases additional electricity from neighboring utilities to make up for the power production from a reactor that is scheduled for an outage.

Depending on the type of outage, it can last from one and a half to two months.  Additionally, outage staff works in 12 hour shifts in order to keep things moving and to provide 24 hour support.

A nuclear plant would be able to tout a 100% capacity factor if it weren’t for these scheduled outages.  Because of these necessary outages, nuclear power plants achieved an energy industry best capacity factor of 91.8% in 2008.

Some of the components that are replaced or maintenanced include but are not limited to: reactor heads, steam generators, pumps, motors, turbines and fuel.

Re-Fueling

Re-fueling outages average about 35 days in length, some have been done in 15-20 days, and are done every 18-24 months.  This means that a nuclear reactor doesn’t need to be re-fueled but every 18-24 months, setting nuclear power apart from other energy sources such as coal that need to be refueled on a daily basis.

Fuel Rods

Fuel Rods

Pumps and Motors

Pumps and motors must also be replaced or maintenanced during outages in order to service the plant and lengthen its service-life.

Reactor Coolant Pump

Baby Pump

Reactor coolant pump motors are the largest pump/motor assembly in a nuclear power plant.  These can be about 28 feet in height, weigh over 100,000 lbs, roll at 9,000-12,000 horsepower, and spit out 88,000 gallons of water per minute.

Reactor Coolant Pump for the Westinghouse AP-1000 Reactor

Reactor Coolant Pump for the Westinghouse AP-1000 Reactor

Turbines

Here’s a great video from National Geographic on the turbine replacement at Susquehanna Nuclear Power Plant.

Reactor Heads

Reactor vessel closure heads must be replaced at a plant periodically as well.  These are pretty heavy components as well.  Usually around 200,000 lbs.  It’s quite a feat to be able to move an object this heavy so precisely.  Here’s a great document from Bechtel on the process they use to replace reactor heads in a safe and efficient manner. Link: Bechtel Detail Design.

Reactor Head

Reactor Head

Reactor Head being put into place

Reactor Head being put into place

Steam Generators

Steam generators are one of the biggest components in a nuclear power plant and can weigh around one million pounds.  Moving these things is big business.  It is also an art. The coordination and precision of this type of operation is impressive and intricate.  The only way to give it justice is to see it in person.  Although, I hope these images will help you understand the scope of this type of project.

tmi_rsg

Steam Generator

Here is a news clip from Lancaster Online showing two steam generators moving through rural Pennsylvania a couple of weeks ago on their way to Three Mile Island for the outage there slated to start October 26th.  The generators will be installed and the reactors will be back online by January 1st.

The delivery route must go through multiple levels of planning including coordination with local law enforcement and structural qualification of roads and bridges along the route since the steam generators are so heavy.  The steam generators that are currently running at Three Mile Island will be removed and placed in a building called an Original Steam Generator Storage Facility (OSGSF).  This facility is designed and rated to prevent the release of low-level radiation to the public and environment.

These aren’t the only activities that are performed during outages.  Some include modifications that will increase the life and power output of existing plants.  Others may include increasing fire protection safety measures in the plant.  There are many different modifications that a utility performs during outages that will increase quality and performance at their nuclear plants.  Hopefully, this post provides a high-level overview of a nuclear power industry outage.  For more detailed information, feel free to ask any questions in the comment section below.

Wednesday Fact Series: Greenhouse Emissions

Posted by Jonny Abendano On September - 16 - 2009

[Approx. Read Time: 3 minutes]

Myth: Nuclear Power Emits Massive Amounts of Greenhouse Gases

coreI have heard many times before that Nuclear Power emits a lot of greenhouse gases. In all actuality Nuclear Power emits NO greenhouse gases while producing electricity, but if you look at the entire life cycle of nuclear (mining, construction, etc.) you will see that it does emit a minimal amount of CO2 because of the labor involved in manufacturing and the construction of the units. This is the same for all other forms of energy producing sectors as well, including wind, solar, and hydro.

Yes–you read that correctly, all forms of energy production releases some sort of greenhouse gases in their life cycle. If you think about it for a minute, this statement makes total sense. Humans release CO2 into the atmosphere, we even breathe out CO2, and since we have to work at these facilities all facilities will release some CO2.   Manufacturing and construction of the facilities will also emit CO2.  The truth of the matter is, we can’t possibly have 100% CO2 free energy, but we should produce large amounts of energy while keeping our CO2 emissions to a minimum. Luckily, we have that technology available to us today and that is nuclear power!

Lets look at the graph below, it illustrates the amount of CO2 energy the US has avoided by the use of nuclear power production.

net_avoided_emissions_nuclear

How about the rest of the energy industries you ask? Well lets look at the graph below to see how much energy is avoided by other energy producing industries. You can see that nuclear power far exceeds the amount of avoided CO2 by the top “renewable” energy productions.

net_avoided_emissions_electric

Nuclear power accounts for 73.6 percent of all the energy production methods considered to be CO2 free. The graph below shows you how much energy is produced by nuclear power compared to other CO2 free emitting energies. This is one of many reasons why we should have a big portion of our energy come from nuclear power, but this is not to say that we should not keep using the other forms of clean energies. In fact, in order for the US to have the greatest benefit, the US will need to use all forms of CO2 free emitting energies, but for the most part the main producer and base power producer should be nuclear power.

green_energy_shares1

This is great information to have but one might ask, “How much CO2 is released by nuclear?” Great question! The answer is in the graph below. It illustrates the amount of CO2 that is released during the life-cycle of energy production from 8 different energy industries. As you can clearly see nuclear power is a close 3rd place but is very comparable to both Wind and geothermal. Now lets combine the information above with the amount of energy produced from nuclear and you have a clear winner of where our country needs to get their base power from…Nuclear Power!

life_cycle_emissions_comp

Wednesday Fact Series: Are NPPs Becoming Risky With Age?

Posted by Adam Johnson On September - 2 - 2009

[Approx. Read Time: 3 minutes]

Myth: As Nuclear Power Plants Age, They Become More “Risky”

callawayA generality that the 104 commercial U.S. Nuclear Power Plants (NPPs) commonly fall victim to is that as things age, they are at a greater risk for potential failure.  The more miles on your car, the more time you usually spend at the repair shop.  The longer you live in your house, the more trips you have to make to the nearby home improvement store.  Although this is common with most things that we encounter in our everyday lives, this is not the case for NPPs.

The Nuclear Regulatory Commission (NRC) initiated the Industry Trends Program (ITP) to monitor trends of industry performance indicators to ensure safety at NPPs is maintained.  If any adverse trends are detected in the performance indicators, the NRC will evaluate the issue and take appropriate regulatory action to address it.  Each year these performance indicators are reviewed by the NRC as part of the Agency Action Review Meeting (AARM).  Any statistically significant adverse trends are included in the NRC’s Performance and Accountability report to Congress.

“No statistically significant adverse trends have been identified through the end of fiscal year (FY) 2008, based on the ITP indicators and the Accident Sequence Precursor (ASP) program.” – NRC website, Industry Trends page

Full details of the trends monitored by the NRC as part of the ITP can be found in the current ITP report, SECY-09-0048.  Definitions and descriptions for performance indicators can be found in the NRC Inspection Manual Chapter (IMC) 0313, Appendix A.  Below you can find several of the Fiscal Year 2008 Long-Term Industry Trends Results from the most recent ITP report along with a brief description of the indicator.

Significant Events

Definition: Significant Events are defined as —

  1. A Yellow or Red Reactor Oversight Process (ROP) finding or performance indicator
  2. An event with a Conditional Core Damage Probability (CCDP) or increase in core damage probability (ΔCDP) of 1×10-5 or higher
  3. An Abnormal Occurrence as defined by Management Directive 8.1, “Abnormal Occurrence Reporting Procedure”
  4. An event rated two or higher on the International Nuclear Event Scale

sig-events

Forced Outage Rate (FOR)

Definition: The forced outage rate is the number of forced outage hours divided by the sum of unit service hours and forced outage hours.

forced-outage-rateSafety System Actuations (SSA)

Definition: Safety system actuations are manual or automatic actuations of the logic or equipment of either certain Emergency Core Cooling Systems (ECCS) or, in response to an actual low voltage on a vital bus, the Emergency AC Power System.

safety-system-actuationsAutomatic Scrams While Critical

Definition: The number of unplanned automatic scrams that occurred while the affected reactor was critical.  A Scram is an emergency shutdown of a nuclear reactor.

auto-scrams

Opponents to the industry trending rationale may state that NPPs are subject to negative aging effects, such as equipment failures.  My response to this claim is that you are exactly correct.  Every plant does experience some form of equipment aging or failure, but being realistic, nothing is made to last forever.  Equipment aging begins as soon as a piece of equipment is operated for the first time.  The important issue is how the utilities manage the aging effects and also how they identify and mitigate the risks associated with the operation of their plants.  NPPs are designed to sustain equipment aging and failures through redundancy and dedicated systems that are capable of and dedicated to maintaining public safety.

Along with the ITP, there are also measures to evaluate the ability of NPPs to maintain safety on an individual basis.  INPO routinely sends teams to evaluate plant operations, processes and personnel.  INPO then assigns a score to the plant based on observations during the assessment.  Negative ratings from the assessment generally warrant more demanding requirements to maintain safety by the NRC and can even lead to a NPP being shut down.

The information presented in the annual ITP report confirms that the safety of operating nuclear power plants is being maintained.  The decreasing trends can be attributed to the dedication of the individuals in the commercial nuclear power industry to deliver safe and reliable power to the public, as well as:

  • Regulatory guidance (NRC)
  • Industry organization involvement (INPO, EPRI, etc.)
  • Improved processes and procedures
  • Evaluation and incorporation of operating experience and lessons learned
  • Advances in technology / Plant modifications
  • Predictive and preventive maintenance capabilities
  • Economic benefit to maintain a plant

Another intriguing subject that comes up when discussing the safety of NPPs is the potential for a plant to become a terrorist target.  Mike Bullard will be addressing this issue in two weeks.  Next Wednesday, Jonny Abendano will take on the myth that nuclear energy emits greenhouse gases.

Fact Sheet 2010 NEI Quiz