XYLENE POWER LTD.20190 Kennedy Road, Sharon, Ontario LOG 1VO
June 11 J 2014
Dr. Stella Swanson Chair, Joint Review Panel
Deep Geologic Repository Project
C/O Canadian Nuclear Safety Commission 280 Slater Street
Ottawa, Ontario KIP 5S9
Re: Deep Geologic Repository Project for Low and Intennediate Level Waste SUSTAINABLE NUCLEAR POWER AND NUCLEAR WASTE DISPOSAL Dear Dr. Swanson:
Due to rapid accumulation of carbon dioxide in the Earth's atmosphere mankind will need to increasingly rely upon nuclear energy. Hence the entire nuclear energy cycle, including both energy production and waste disposal, must be made sustainable. Further, the amount of installed nuclear generation on Earth may easily increase by two orders of magnitude and may run for over 20,000 years, so over that period the background radiation contribution due to long lived nuclear waste may increase by five orders of magnitude. Hence dilution of radio isotope waste is not a sustainable solution to radio isotope pollution.
The issues that must be faced are:
1) Safe and economical interim storage of the present inventory of nuclear waste. In this respect recent events at Fukushima Daiichi have clearly demonstrated that the existing inventories of radio toxic materials should be moved to dry storage locations that are far from any large body of water and that are high above local water tables;
2) Change in nuclear reactor design from slow neutrons to fast neutrons so that the prime energy source is the relatively plentiful uranium isotope U-238 instead of the relatively rare uranium isotope U-235;
3) Recycling of spent CANDU fuel to convert the highly toxic long lived trans uranium actinides into short lived radio isotopes that rapidly decay into stable non-toxic isotopes;
4) Recycling of irradiated nuclear reactor materials such as nickel, zirconium and carbon to both reduce the cost of new nuclear reactors and to minimize the mass and volume of radio toxic material in storage;
5) Recovery oftritium/helium-3 for sale to third parties to both earn income and to reduce the mass and volume of radio toxic material in storage;
6) Development of safe, economic, accessible and reliable storage for radio isotopes with halflives less than 30 years such that after 300 years the stored material, storage containers and storage space can all be reused;
7) Development of a safe, economical and reliable methodology for concentration, isolation and storage of long lived low atomic weight isotopes such as Ca-41 and CI-36 that have no present or foreseeable future value for recycling. The storage methodology should recognize that dilution is not a solution to pollution and that these isotopes are highly mobile in water. eg Dry storage in triple sealed porcelain containers;
8) Modification of nuclear generating station designs to minimize future production of long lived low atomic weight isotopes such as Ca-41 and CI-36.
Unfortunately, the present NWMO and OPG plans for the Bruce DGR fail to address the aforementioned issues and are implicitly based on three false assumptions.
FALSE ASSUMPTIONS BY NWMO/OPG:
1) The first false assumption is that future nuclear reactors will be assembled by skilled tradesmen using the same methodology as was used three to four decades ago for assembly of the the existing CANDU reactors.
2) The second false assumption is that non-accessible burial of unprocessed nuclear waste is a sustainable activity and is acceptable to the Canadian population; 3) The third false assumption is that the electricity rate payers are indifferent to: a) the cost of DGRs,
b) the cost of labor in nuclear reactor construction and
c) the cost of expensive non-recycled nuclear fuel and nuclear reactor materials.
INVALID CONCLUSIONS FLOWING FROM FALSE ASSUMPTIONS BY NWMO/OPG:
1) For worker safety the materials used in nuclear reactor construction need to initially be non-radioactive;
2) When a nuclear reactor reaches the end of its useful working life its radio active components are not recyclable;
3) All radioactive waste material should be permanently consigned to a DGR; 4) The DGRs should be inaccessible after closure and hence should to be located far
below the surrounding water table.
5) The DGRs should rely primarily on the character of the surrounding rock to minimize the rate of diffusion of water soluble material from the DGR into the surrounding environment;
6) Dilution of radio toxic material is considered by NWMO/OPG to be an acceptable solution to pollution.
I suggest to the Joint Review Panel that the aforementioned implicit assumptions by
NWMO/OPG are all wrong and that the related conclusions are also all wrong.
CORRECTED ASSUMPTIONS AND RESULTING CONCLUSIONS:
1) I have worked on both advanced microprocessor based equipment control systems and on the design of liquid sodium cooled fast neutron reactors, as described at www.xylenepower.com/FNR%20Design.htm and surrounding Nuclear related web pages. The assumption that the cores of new nuclear reactors will be assembled by skilled tradesmen is not valid because during the last thirty years there have been major advances in robotic assembly technology and because during the same period a sufficient inventory of radioactive material has accumulated to justify radioactive material recycling.
2) With robotic assembly it does not matter if the reactor materials are initially radio active. New fast neutron reactor modules are intended for robotic assembly; 3) Hence neutron irradiated nickel, uranium, plutonium, zirconium, and trans
uranium actinides can all be recycled.
4) Hence the DGRs should remain permanently accessible to permit on-going safety inspections, risk mitigation and material recycling. The DGRs will use robotic technology developed by and for the mining industry;
5) In order to inexpensively exclude water from an accessible DGR the elevation of the DGR storage vaults should be high above the local water table;
6) The DGR should use engineered containers, gravity drainage to sumps, access for risk mitigation and remote monitoring, in addition to the quality of the
surrounding rock, to prevent stored radio isotopes entering the surrounding environment;
7) The DGR storage vaults should be about 400 m below grade to provide certain containment of long lived radio isotopes through numerous glaciations;
8) The DGR should be formed in stable high density granite to provide a combination of durability, water exclusion, and safe access for thousands of years;
9) Recycling of spent CANDU fuel involves trans-uranium actinide fission in a fast neutron reactor. As compared to the present CANDU process the spent fuel toxicity lifetime is reduced 1000 fold and the energy per kg available from natural uranium is increased 100 fold;
10) The fast neutron reactor fuel cycle allows for major material, labor and DGR cost savings for the benefit of the electricity rate payer;
11) A potential supplier of liquid sodium cooled fast neutron reactors is GE-Hitachi; 12) Recent political polls indicate that at least one third of the Ontario voters are
opposed to the present projected electricity price increases and are seeking electricity price mitigation;
in that community. The majority of witnesses from the Bruce area before the Joint Review Panel are opposed to the present NWMO/OPG Bruce DGR plans.
14) Any location that is naturally sufficiently dry for safe storage oflong lived nuclear waste does not have sufficient ground water to support a permanent conununity.
Specifically I state that:
1) As fossil fuels are phased out most of the energy requirements that fossil fuels presently meet must be met by nuclear energy;
2) As a result of this increased dependence on nuclear energy the public will become less tolerant of present technical incompetence and wasteful practices at OPG and the NWMO;
3) The public will insist, if only as a cost saving measure, that expensive materials such as nickel, zirconium, and uranium, that contribute significantly to the overall cost of nuclear energy, be recycled. Hence for worker safety nuclear reactor modules will be robot assembled;
4) The informed public will demand fission of trans-uranium actinides to prevent long term pollution of drinking water;
5) In the future mankind will have no practical alternative to liquid metal cooled fast
neutron reactors operating with U-238 for fossil fuel displacement, due to depletion of the U-235 resource. Note that the deuterium-tritium-lithiurn fusion fuel cycle is also a liquid metal cooled fast neutron process.
6) The relatively high coolant temperature of a liquid metal cooled fast neutron reactor allows heat dissipation via evaporation of water instead of by direct lake water cooling, and thus greatly reduces the impact of nuclear power on marine species.
7) Nuclear reactor designs should be modified to minimize formation of Ca-41, CI 36 and C-14;
8) With respect to existing CANDU reactors reasonable efforts should be taken to recover tritiumlhelium-3 for resale.
POTENTIAL NUCLEAR WASTE STORAGE LOCATION:
From a geophysical perspective by far the best nuclear waste storage location in Canada is Jersey Emerald. Jersey Emerald is a 5 million square foot naturally dry depleted
Canadian hard rock mine with about 10 km of main access truck tunnels, 12 foot to 60
foot high internal storage vaults and geology that is uniquely suitable for storage of radio isotopes and/or other highly toxic material. The Jersey Emerald workings are 200 m to 600 m below grade but are more than 300 m above the surrounding water table. The lower portions of Jersey Emerald are in extremely dense water tight granite. Jersey Emerald was a critical source of zinc, lead and tungsten during WWII but was closed in
1972 due to low commodity prices. Today Jersey Emerald is likely the most safe and secure facility in North America for nuclear material storage.
In 2013 Jersey Emerald and the surrounding property and mineral rights were available for purchase at a price that is a small fraction of the projected cost of the Bruce DGRs. In August 2013 both the NWMO and OPG failed to even inspect Jersey Emerald when it was available to them, free and clear, complete with 4000 hectares of assembled
surrounding property, including both surface and mineral rights, for $67.5 million. For an estimated additional $100 million NWMO/OPG could have acquired an additional
16,000 hectare exclusion zone, giving NWMO/OPG title to everything within an 8 kIn radius of Jersey Emerald. The failure of both NWMO and OPG to place a $2 million dollar purchase deposit on the Jersey Emerald property prior to December 13, 2013 will likely go down in history as the worst ever management decision in the Canadian nuclear power history. This matter appears to be indicative of incompetence and/or corruption within the senior managements of both OPG and the NWMO.
NUCLEAR WASTE CATEGORlES:
The Joint Review Panel is presently charged with making decisions relating to disposal of Low Level Nuclear Waste (LLW) and Intermediate Level Nuclear Waste (ILW). The NWMO presently has responsibility for disposal of High Level Waste (HLW), which in Canada is spent CANDU reactor fuel. However, if a fast neutron reactor is used to convert spent CANDU reactor fuel into LLWand ILW then it appears that the Joint Review Panel will also be responsible for disposal of that waste. The issue of who is responsible for HLW while it is in the process of being converted to fast neutron reactor fuel remains to be resolved.
Low level waste (LLW), consisting of isotopes with half lives of less than 30 years, is from an engineering perspective simple to deal with. The LLW can be safely isolated in engineered containers that are stored for 300 years in a gravity drained depleted hard rock mine that is high above the local water table. Thus stored the LL W will spontaneously decay into stable isotopes.
High level waste (HLW), which in Canada is spent fuel from CANDU reactors, is highly radio toxic due to its plutonium and trans-uranium actinide content. The NWMO
currently plans to bury untreated HL W in copper containers.
In my view the present NWMO plan is complete foolishness. Using proven technology HLW can be converted into fuel for liquid sodium cooled fast neutron breeder reactors. Such reactors fission the HLW atoms so that they become LLW atoms which are simple to deal with from a disposal perspective. Furthermore, fast neutron reactors multiply by
100 fold the useful energy obtainable per kg of natural uranium as compared to a CANDU reactor.
The existing inventory of HLW could be interim stored at Jersey Emerald and then
chemically processed at Trail, BC which is about 40 km away. Trail has a long history of bulk chemical processing of highly toxic materials.
All nuclear power technologies produce some intermediate level waste (ILW). The main source of this ILW is exposure of reactor component materials to the intense particle and radiation fluxes present inside a nuclear reactor. This ILW is the most difficult nuclear waste to deal with in the long term and deserves the full attention of the Joint Review Panel on an element by element basis.
I refer to a letter dated May 30, 2014 from Allen Webster ofOPG to the Chair of the Joint Review Panel. His letter has about 235 pages of attachments. I refer to attachment #1 pages 3, 4, 5, 6.
The identified ILW problem isotopes are Ni-59, Ni-63, Cl-36, Ca-41 Zr-93INb-93m, Nb 94, and C-14.
Nickel is an essential and relatively expensive component of all steels that have useful strength at high temperatures. Nickel is a relatively rare element. It constitutes about 10% of common stainless steel alloys and constitutes as much as 70% of alloys used in construction of steam generators. When steel is recycled a primary objective is recovery of the nickel content. A nuclear generating station typically contains hundreds of tons of nickel, which accounts for a significant fraction of the total facility cost. The isotopes Ni-59 and Ni-63 arise as a result of neutron absorption by the stable nickel isotopes Ni-58 and Ni-62. Ni-59 has a tabulated half life of 80,000 years. Ni-63 has a tabulated halflife of 92 years
Future displacement of fossil fuels with nuclear power will require much more nickel. From a nickel conservation perspective it makes little sense to irradiate fresh nickel and then 60 years later to permanently bury that irradiated nickel. It makes much more sense to recycle irradiated nickel into future nuclear reactors. Such recycling may require a dedicated steel mill facility. However, the major point is that metal alloys with
significant radioactive nickel content should be interim stored in a safe, accessible, high and dry location, such as Jersey Emerald or another comparable naturally dry mine, until the inventory of these irradiated alloys is sufficient to justify the dedicated steel mill facility required to process these alloys into new nuclear reactor components.
Calcium is a substantial component of concrete and mortar. The isotope Ca-41, which has a half life of 80,000 years, arises as a result of neutron absorption by the stable isotope Ca-40. In the presence of water and carbon dioxide calcium forms water soluble
Ca(HC03)2. Isolating radioactive calcium from the environment for a million years means excluding it from water and carbon dioxide for that period. That is a daunting task.
Unless extreme care is used over a protracted period ultimately Ca-41 will find its way into the environment. With respect to the existing Ca-4l the best that we can do for now is to make suitably engineered containers that, if undisturbed and stored in a naturally dry location, such as Jersey Emerald, will likely last over 10,000 years. However, at some point in the distant future someone is going to have to deal with the stored Ca-41. Right now the only alternate solution to the Ca-41 problem is dilution. That in effect is what will happen if the Ca-41 is buried in the proposed Bruce DGR.
We should avoid producing more Ca-41. That means that new nuclear reactor designs should not rely on concrete for peripheral neutron absorption. Adding more non-concrete neutron shielding will likely increase the initial cost of new nuclear reactors, but so be it. The Joint Review Panel should recommend that the CNSC ensure that Ca-41 formation is negligible in new Canadian nuclear reactor designs.
In the CANDU reactor chlorine occurs as a component of chlorinated hydrocarbons used to in sealing and insulating materials. Neutron absorption by the stable isotope CI-35 results in CI-36, which has a halflife of 308,000 years. Fortunately, as compared to the masses of nickel and calcium, the chlorine content of a CANDU reactor is relatively small. However, chlorine has the chemical property that it forms water soluble salts with a large number of elements. The best that we can do with respect to existing Cl-36 is to chemically bind it to sodium or lithium and then encase that salt in a sealed container that is engineered to last over 10,000 years. At some time in the distant future someone will have to deal with the stored CI-36. The only alternate disposal methodology is dilution which will occur if the CI-36 is buried in the proposed Bruce DGR.
We can minimize the CI-36 formation problem in the future by changing from CANDU reactors to liquid metal cooled fast neutron reactors that do not use chlorinated materials anywhere near the neutron flux. In tills respect it would be helpful for the Joint Review Panel to recommend that the CNSC ensure that in new Canadian nuclear reactors there is no chlorine in the proximity of the neutron flux.
Zirconium is extensively used for fuel tubes and moderator isolation tubes in CANDU reactors due to its relatively low neutron absorption cross section. Zirconium has many stable and short lived isotopes. However, the troublesome isotope is Zr-93, which has a half life of about 1,500,000 years. Zr-93 arises both as a result of neutron absorption by the stable isotope Zr-92 and as a fission product. The decay product of Zr-93 is Nb-93m, which has a half life of 13.6 years. Its decay product is stable Nb-93.
The real issue with zirconium is that it is an essential alloy component of fuel for liquid sodium cooled fast neutron reactors. The zirconium prevents formation of a low melting temperature plutonium-iron eutectic. In a fast neutron flux Zr-93 becomes Zr-94 which is a stable isotope.
For this reason neutron irradiated zirconium should not be buried. It should be stored in a safe accessible high and dry location, such as Jersey Emerald, until it is required as a fuel alloy component for fast neutron reactors. That date may be only a few years hence. Under no circumstances should irradiated zirconium be stored or buried where it is not easily accessible.
In CANDU reactors a small fraction of the fuel tube weight is niobium. Neutron absorption by the stable isotope Nb-93 results in Nb-94 which has a half life of about 20,000 years. The simplest way to deal with Nb-94 is to leave it alloyed with its host zirconium and to use it as a component of fast neutron reactor fuel. In a fast neutron flux Nb-94 becomes Nb-95, which has a halflife of 35 days and decays into stable Mo-95.
In nuclear reactors carbon occurs as a small component of steel, and as a component of: hydrocarbon seals, electrical insulation, thermal insulation, vibration isolators and neutron reflectors. Neutron absorption by the stable isotope C-13 results in C-14 which has a half life of about 5730 years. Natural decay of C-14 to inconsequential levels takes over 50,000 years. A basic problem is that in the presence of water carbon containing compounds gradually deteriorate into carbon dioxide (C02) gas and methane (CH4) gas. These gases are difficult to contain. The C02 gas goes into solution in surrounding water where it combines with any nearby calcium: oxide, hydroxide or carbonate to form Ca(HC03)2 which is highly water soluble and which diffuses everywhere. The CH4 gas mixes with other natural sources of CH4 and becomes natural gas. In the atmosphere CH4 combines with 02 to form more C02.
For the foreseeable future the C-14 problem can be mitigated by storing carbon
containing ILW in containers in a dry, dark and low temperature environment, such as Jersey Emerald, so that the carbon remains chemically bound to other elements and does not react with air or ground water. In the long term mankind will likely have to rely on careful containment to keep the local C-14 concentration at an acceptable level.
A challenging problem in nuclear reactors is the use of graphite (C) or boron carbide (B4C) as a neutron reflector. The carbon in the neutron reflector is exposed to an intense neutron flux which will gradually produce C-14. The alternative is to make the reactor physically twice as large and rely upon a uranium blanket for peripheral neutron
absorption. This issue of C-14 formation might in the long term become a public health issue. In my view the best interim solution is to recycle the irradiated carbon so that the
total amount of irradiated carbon is minimized and the C-14 remains chemically bound in a stable compound such as B4C from which oxygen and water are carefully excluded. If C-14 is placed in the Bruce DGR it will eventually dilute into the environment. To minimize the environmental load carbon used in neutron reflector applications should be recycled.
I have set out herein appropriate methodologies for dealing with the dominant long lived ILW radio nuclei that arise out of the operation of nuclear reactors. The current
OPGINWMO plan for the Bruce DGR does not adequately address material recycling. Of particular concern is inattention to recycling of nickel, zirconium and neutron reflector carbon. There is no mention of recovery of of tritiumlhelium-3. As of the Joint Review Panel hearing dates in the autumn of2013, the "expert" offered by the NWMO had no knowledge of the critical role of zirconium in fast neutron reactor fuel or of the related fuel processing chemistry. This issue reveals an unacceptable level of technical
incompetence in the managements of both the NWMO and OPG.
A major concern about the proposed Bruce DGR is that it is far below rather than far above the local water table, which makes long term water exclusion and long term access for safety confirmation, remedial action and material recycling prohibitively expensive. Another significant issue is lack of explicit recognition of reactor design changes that should be immediately implemented to minimize formation of problem ILW isotopes. In short it is my recommendation that the Joint Review Panel reject the proposed Bruce DGR site and instruct both OPG and NWMO to choose an alternate DGR site in granite that is high above the local water table and hence is much more suitable for storage of nuclear wastes in a manner that safely and inexpensively permits on-going inspection, risk mitigation and radioactive material recycling.
I further recommend that the Joint Review Panel address the issue of reactor design modification to minimize future formation ofCa-41 and CI-36.
I further recommend that the Joint Review Panel instruct OPG and Bruce Power to recover for resale to third parties the tritium/helium-3 that OPG currently plans to place in the proposed Bruce DGR.
Charles Rhodes. P.Eng., B.Sc., M.A.Sc., PhD. Chief Engineer