Toxic Waste Disposal

“With power, comes great responsibility,” The discovery of nuclear power is one

of mankind’s greatest leap in technology, but the problems risen by it also

demonstrate our inabilities to deal with our advances, and if we do not solve the

problems, we will eventually suffer from the side effects of using nuclear power.

Nuclear power provides a great amount of energy, is environmental friendly in

terms of CO2 emission and won’t run out for at least another 200 years7. The

main source of radioactive waste nowadays comes from nuclear plants which

generates electricity by the application of nuclear fission; however, fission

reactions create byproducts unlike fusion reaction which is completely

renewable. The byproducts of nuclear energy are extremely toxic, can

contaminate the environment and cause serious health issues to humans. Hence,

finding the proper way of disposal of toxic waste is crucial for the future of

nuclear power but the solution to this problem is yet to be found even though

scientists and engineers have been working on it for years.

During the cold war, the radioactive waste problem was briefly recognized and

a great amount of radioactive waste was created in the press of create nuclear

warheads. Because of the lack of knowledge of the consequences, a huge amount

of radioactive waste was stored for future disposal.1 In addition to the

radioactive waste generated by nuclear plants nowadays, an even greater

amount of radioactive waste is waiting to be disposed. However, there are a lot

of difficulties regarding the disposal of radioactive waste. Politically, nobodies

want radioactive waste to be stored near them, which makes siting difficult.

Technologically, handling radioactive waste is still a major problem. Even though

the waste is stored safely now, it is reaching the capacity limits and we must deal

with it and find a proper way of disposal to avoid the disaster it may develop

into.

The current main strategy to dispose radioactive waste is to isolate the waste

from civilization by placing it underground so the waste will eventually decay to

normal back ground level, however, this may take millions of years. Most nuclear

waste originates from the neutron irradiation of uranium fuels or targets in

civilian and defense reactors. The waste is then encapsulated in multi-metal-

barrier waste packages for disposal in a geological repository. However, it is

predicted that the waste packages will corrode and release radionuclides to the

surrounding within a few thousands years.1 The technology for safe disposal

facilities is one of the biggest technological concerns2 which requires continuous

work from scientists and engineers to solve this problem. Yucca Mountain is a

nuclear waste repository in the U.S., and one of its concerns is that if the

radionuclides released from spent fuel containers leach into groundwater, the

whole region of U.S. may become uninhabitable. However, monitored storage is a

proven technology so there’s no immediate safety issue and in Yucca Mountain,

there is a groundwater protection standard3. Yet, in long term, we do not know

how the radioactive substances will behave in thousands of years and we cannot

predict the behavior. In order to leave future generations a maximum range of

options rather than a sealed repository4, we must find a way to safe disposal

radioactive waste so our future generations won’t be affected and suffer from the

consequences of our actions.

Vitrification is the most common way to handle radioactive waste that requires

long-term storage. Because the waste has to be stored for a long time before it

decays back to normal background level, it must be stabilized into a form which

will neither react nor degrade for an extended period of time.4 The radioactive

waste is concentrated to long-lived radionuclides, which is then washed to

remove excess aluminum and salts. It is then combined and melted with finely

grounded glass at about 1150 oC, poured into stainless steel canisters1 and

packaged to provide additional barriers to protect the environment from being

contaminated. The main reason to vitrification is to turn the waste in a relatively

insoluble, compact solid so it would be easier to store and handle. Also, due to

the low solubility, the chance of groundwater contamination is reduced greatly.

The most common form of vitrified waste is borosilicate glass because it is a

fairly robust waste form. In addition, it is chemically durable, resistant to

radiolysis, relatively insensitive to fluctuations in waste composition and easy to

process remotely. After the radioactive waste is incorporated into glass, it is

then stored in deep underground repository and monitored for many years.

For medium active waste in the nuclear industry, it is common to treat it with

ion exchange –in another word, concentrating the radioactivity into a small

volume by using ferric hydroxide floc to remove radioactive metals from

aqueous solution. After that, the radioactive metals can be made into solid form

by mixing with cement. The solid form is then stored for it to decay4.

Synroc is an emerging technology for immobilizing various forms of

intermediate- and high-level radioactive waste for disposal.8 (which is currently

under development for US military waste)4. The concept behind this technology

is similar to that behind vitrification – to stabilize the waste into a form which

will neither react nor degrade for a long period of time. Moreover, using syrnoc

has a few advantages over borosilicate glass. Instead of just bonding the

radioactive waste into the glass matrix, synroc incorporates the radioactive

waste into its crystal structures so the waste can be stored for a long period of

time. Also different type of synroc waste forms can be developed for the

immobilization of different types of waste9, while borosilicate glass may not be

suitable for all types of waste. For example, plutonium does not bind strongly to

the matrix of borosilicate glass,1 but the newly developed form of synroc can

immobilize plutonium.8 Even though synroc is still under development-phase, it

will become a more common method of nuclear waste storage because it

minimizes leaching better.

The modern technologies are capable of handling radioactive waste and there

are no immediate safety issues, but this is only a short-term solution as they are

only postponing, not solving the problem. In order to leave our future

generations an unpolluted environment, the radioactive waste must be disposed

properly and we should leave no trace behind. The most straight-forward

solution for the future is to develop a technology that can neutralize radiation.

Though it may seem absurd as it is proved “scientifically impossible”, I believe

that it will be invented one day.. In addition, there are some scientists working

on developing such technologies already. Tom Bearden is a physicist who came

up with a theory that it is possible to neutralize radiation by broadcasting the

exact same vibrational frequency of depleted uranium10. Though the theory is not

proven yet, I believe that this technology will be developed in the future. Just like

50 years ago, who would have predicted that we would have smartphones that

can carry out multiple tasks?

References:

1. Crowley, Kevin. "Nuclear Waste Disposal: The Technical Challenges." 06 1997: 31-39. Web. 21 Jul. 2013. 

2. McCombie, Charles. "Nuclear Waste Management Worldwide." 06 1997: 56-62. Web. 21 Jul. 2013. <http://scitation.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=PHTOAD000050000006000056000001

3. “Yucca Mountain nuclear waste repository” <http://en.wikipedia.org/wiki/Yucca_Mountain_nuclear_waste_repository>

4. “Radioactive Waste” Wikipedia <http://en.wikipedia.org/wiki/Radioactive_waste>

5. Thompson, Linda. Vitrification of Nuclear Waste. Diss. Stanford, 2010. Web. <http://large.stanford.edu/courses/2010/ph240/thompson2/>.

6. Department of Energy, Office of Waste Management, High-Level Waste Borosilicate Glass. A Compendium of Corrosion, Characteristics (3 vols.), Washington, DC (1994).

7. Fetter, Steve. "How long will the world's uranium supplies last?." 26 Jan 2009: n. page. Web. 21 Jul. 2013. <http://www.scientificamerican.com/article.cfm?id=how-long-will-global-uranium-deposits-last>.

8. "Synroc Wasteform." . World Nuclear Association, n.d. Web. 22 Jul 2013. <http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Nuclear-Wastes/Synroc/

9. “Synroc” Wikipedia <http://en.wikipedia.org/wiki/Synroc>10. Jayhan, Phil. "How to Neutralize Radiation by Tom Bearden." 23 Jun 2005.

N.p., Online Posting toLet's Roll. Web. 22 Jul. 2013. <http://letsrollforums.com/neutralize-radiation-tom-bearden-t6730.html?s=713866c3501fd7feef67e0edb52c89f2&>.