DECONTAMINATION & DECOMMISSIONING

1 February 1998

BECHTEL JACOBS WINS $2.5 BILLION DOE CONTRACT AT OAK RIDGE, PADUCAH AND PORTSMOUTH

Bechtel Jacobs Company has been awarded a five and a half year, $2.5 billion Management and Integration contract by the US Department of Energy for environmental restoration at DoE facilities in Oak Ridge, Tennessee, Paducah, Ohio, and Portsmouth, Ohio.

Under this performance-based contract, Bechtel Jacobs will be responsible for managing, planning, subcontracting, integrating, expediting, and co-ordinating tasks for the Oak Ridge Environmental Management Program. Actual work in the field will be performed primarily through competitively selected subcontractors. Bechtel Jacobs will also invest in the four-country region around Oak Ridge as part of the contract’s requirement to diversify the regional economy to help offset the impact of changing DoE missions.

Bechtel Jacobs Company LLC was formed by Bechtel National Inc and Jacobs Engineering Group Inc to bid on and execute the Oak Ridge contract. The scope of work under this contract is presently being performed by Lockheed Martin Energy Systems. Bechtel Jacobs will assume full responsibility for the work on 1 April 1998, after a phasing in period.

Joseph F Nemec will be President and General Manager of Bechtel Jacobs, and Dr James Thiesing will be Vice President and Deputy General Manager. Nemec said that significant progress had been made on environmental clean-up at Oak Ridge under the leadership of DoE and Lockheed Martin. Bechtel Jacobs will build on that success to “move the Oak Ridge Environmental Management Program to the next level of performance.”

The new contract marks a shift away from the old “Management & Operating” scope at Oak Ridge to the new “Management and Integration” concept – in fact Lockheed Martin’s Oak Ridge contract was one of the last of the old style M&O type remaining in force.

Both Bechtel and Jacobs have strong track records in the DoE defence site business. Among Bechtel’s previous awards are: an $800 million contract to manage the clean-up of Hanford; a $1.5 billion contract to take the lead in managing the Nevada Test Site; a prominent subcontracting role in a $6 billion contract to manage the Savannah River site; and management of the clean-up of radioactive and chemical contamination at former Manhattan Project sites in 14 states under the Federal government’s Formerly Utilized Sites Remedial Action Program (FUSRAP). Jacobs has been involved in US DoE environmental restoration projects at Oak Ridge, Weldon Spring and Fernald, as well as the Uranium Mill Tailings Remedial Action Program in the western USA.

GOODBYE NUMATEC, HELLO COGEMA TECHNOLOGIES INC

Cogema Inc (the Cogema Group’s US flagship company responsible for its development in the USA) and SGN (the Cogema Group engineering company) have launched Cogema Technologies Inc. This new entity supersedes Numatec Inc, Cogema’s previous US nuclear engineering arm, with the aim of providing an expanded portfolio of Cogema Group technologies and SGN engineering capabilities. Building on Numatec’s previous track record in the marketplace, Cogema Technologies Inc will focus on radioactive waste management, remediation, and engineering.

Also changing its name and ownership structure is Eurisys Corp, the holding company for Cogema operating subsidiaries at USDoE’s Hanford site, Numatec Hanford Company and SGN Engineering Corp. (formerly SESC), as well as Envitco Inc. Full ownership of the holding company has been transferred to SGN and its name changed to Cogema Services Inc.

Cogema emphasises there is no change in the missions of its subsidiaries. Numatec Hanford will continue its role as a member of the Management & Integration Contractor team led by Fluor Daniel, SGN Engineering Corp will continue to expand its off-site activities “as the most successful ‘enterprise company’ established at Hanford,” while Envitco continues to develop and apply its vitrification process to low-level radioactive wastes. In a further step to give a higher profile to the Cogema connection SGN Engineering Corp will change its name to Cogema Engineering Corp.

EPRI DFD CLEANS UP AT BIG ROCK POINT

The first full system decontamination with the EPRI DFD process has been completed at the Consumers Energy Big Rock Point BWR in Michigan USA. The plant shut down for the final time after 35 years of successful operation in August 1997. The EPRI DFD Process, which was developed by Bradtec Ltd under contract to the Electric Power Research Institute (see Nuclear Engineering International, November 1997, p12 ), was applied at Big Rock Point by PN Services. The process removes radioactive deposits from the plant’s internal surfaces for the purpose of reducing radiation exposure during future decommissioning of the plant. The process application was completed on 14 January 1998, within the planned schedule and budget. Preliminary measurements indicate that radiation dose rate reduction targets have been met. Over 400 curies of radioactive nuclides were removed from the plant by the process.

The next application is scheduled for Maine Yankee PWR in February 1998.

OXY-GASOLINE DEMONSTRATES A CLEAR-CUT ADVANTAGE

Thanks to the pro-active efforts of the US Department of Energy Office of Science and Technology, a number of new and effective technologies are being added to the decommissioner’s tool box. One recent example is Petrogen’s oxy-gasoline torch, which exhibits a number of advantages relative to conventional oxy-acetylene.

Recent purchasers of the oxy-gasoline torch include: Defence Nuclear Agency, Kazakhstan; AEA Technology, UK; Bechtel (Hanford); Mason & Hanger (Pantex); Lockheed Martin (Oak Ridge); Foster Wheeler (Fernald); B&W NESI (also Fernald).

Interest in the technology has grown considerably since October 1996, when the US Department of Energy Fernald Environmental Management Project Office and Fluor Daniel Fernald completed a demonstration which verified that oxy-gasoline cutting technology is safe, reliable and cuts faster and more cleanly than the acetylene torch. The exercise was part of the Fernald Large Scale Technology Demon-stration Project (STDP). The segmentation of piping and thick-walled vessels is a key part of the Fernald clean-up effort.

Cutting through thick metal with an acetylene torch is time-consuming and complicated by a tendency for molten metal from the resulting “rough” cut to flow back together and re-fuse. While oxy-gasoline technology has been around for more than 40 years, it is not well known and suffers from the perception that use of gasoline is unsafe due to a potential for backflash, which could cause an explosion.

The Petrogen oxy-gasoline torch system consists of a three-gallon fuel tank (ASME coded), an extremely durable gasoline

supply hose, a cutting torch and an oxygen supply from conventional bottles. The entire system has been Underwriter’s Laboratory (UL) approved.

The design of the cutting torch allows gasoline delivery to the tip of the torch in the form of a confined liquid. The expansion of the gasoline from a liquid to vapour, and the mixing of oxygen, occurs in the tip. This eliminates backflash down the fuel line and keeps the torch head cool.

When cutting thick metal with an acetylene torch, the molten metal/slag is not totally removed from the cut. This results in re-solidification and the need to go back over the initial cut and cut again. This type of re-bonding did not occur with the oxy-gasoline torch. The oxy-gasoline torch cut thick metal significantly faster and more effectively than the acetylene torch. For example, the oxy-gasoline torch took 13 minutes to cut a two-inch thick steel plate, while the acetylene torch took 27 minutes.

The oxy-gasoline torch system costs about $500 more than an acetylene system, but it uses significantly less fuel. When cutting thick steel, about $3 worth of gasoline (2.5 gal) lasted all day, compared with $32 for acetylene. Also, the three-gallon gasoline tank is easier to handle, move around and set up, than an acetylene bottle.

Representatives of B&W NESI, a decontamination and decommissioning subcontractor working at Fernald at the time of the demonstration, were so impressed that they purchased an oxy-gasoline torch of their own for use on a thick-walled storage tank (pictured below) – even before the demonstration was completed.

The oxy-gasoline torch is one of a number of D&D technologies that have been assessed under the LSTDP programme. These will be subject of a future article in Nuclear Engineering International.

SAVANNAH RIVER: IN A GLASS OF ITS OWN

As of 20 January the Defense Waste Processing Facility (DWPF) – the world’s largest radwaste vitrification plant – had produced 76 canisters of vitrified waste this financial year (ie since 1 October). If this rate can be maintained the plant’s operator, Westinghouse Savannah River Company, is on target to collect performance based payments, which are only paid on canister 101 onwards (and up to canister 250).

This kind of incentivisation is typical of the new commercially orientated approach that US DoE is aiming to follow in the clean-up of former weapons sites (see pp 12-15). Last year Westinghouse operated under a slightly different performance based incentive scheme, under which a bonus was paid once 150 canisters had been produced (the eventual total was 169 canisters for the 1996/97 financial year).

Construction of the $2 billion DWPF goes back to 1983, when Dupont was manager of the Savannah River site, but delays due to changing environmental requirements, safety upgrades, improved training and the need for a waste qualification test phase to demonstrate that the glass form meets requirements for long term storage, meant that the plant did not start radioactive operations until March 1996.

Another recent vitrification development involving Westinghouse Savannah River was completion in October 1997 of a three-and-a-half-week demonstration test on the Transportable Vitrification System (TVS). Claimed to be the first such portable system, TVS was developed by Westinghouse Savannah River in collaboration with Envitco (80% Cogema, 20% Toledo Engineering), the initial application envisaged being processing of mixed low-level waste at Oak Ridge.

During the demonstration 17388 lb of radioactive glass material were produced from Oak Ridge’s mixed waste. The glass was poured into 14 specially designed cubes manufactured from recycled, radioactively contaminated stainless steel, each holding about 8ft3 of glass and sealed for transportation. Vitrifying the waste reduced the volume by about 60%. The results of the demonstration test are currently being assessed by EPA Region 4. Now that the demonstration is complete, several future missions for TVS, at Oak Ridge, Savannah River and other sites, are being considered.

Elsewhere on the Savannah River site a vitrification melter for low level waste recently went back into service following extensive repair and modification due to faster than expected wear of melter box components. GTS Duratek, vendor of the technology and operator of the privatised plant took a one-time charge of $5.9 million in the first quarter of 1997 to cover the costs and expected losses arising from the delay to the vitrification programme, which is being carried out under a $14 million fixed price contract with US DoE. This is another illustration of commercialisation in the DoE clean-up programme, illustrating the harsh realities of privatisation – where it is the contractor’s job to sort out problems without calling for any extra money from the taxpayer. GTS Duratek and its strategic partner BNFL (which has invested money in the company) sees the Savannah River job as paving the way for the much bigger Hanford Tank Waste project (see panel above).

IN-SITU GAMMA SPECTROSCOPY GETS IMMEDIATE RESULTS

ISOCS (In-Situ Object Counting System), Canberra’s portable gamma spectroscopy quantitative assay system, has proved very successful since its introduction nearly one year ago, with sales of about 40 units so far. For the first time, near-instantaneous nuclide-specific quantitative assays can be done on a wide assortment of objects.

For many decommissioning and decontamination (D&D) projects, gamma spectroscopy is an excellent tool to monitor the status of contamination and significant cost savings can be realised by closely monitoring decontamination progress. Having characterisation results available immediately allows the expensive decontamination process to be stopped at the earliest possible time. In situ gamma spectroscopy with ISOCS can also be used to verify that items or facilities are not contaminated, so that unnecessary labour and waste disposal costs can be minimised.

The ISOCS system consists of a high resolution Ge detector mounted in a 2-day or 5-day multi-attitude cryostat that is rugged enough for field applications. The detector is surrounded by a versatile set of lead shielding to allow work in the complex background environment of D&D projects. Data acquisition and analyses are performed by Canberra’s battery powered InSpector MCA, a laptop PC, and the new Windows Genie-2000 software. The product is truly innovative because efficiency calibrations can be done by the user in the field with the ISOCS software. No radioactive sources are necessary! These calibrations can be done for very large and complicated objects, like ceilings, floors, waste containers, pipes, tanks, trucks, holes through soil or concrete, etc. Any object that fits within a 50 meter radius sphere around the detector, and at any distance from the detector, can be calibrated at any energy from 50 keV to 7000 keV. The calibrations generally take a few minutes, and can be simultaneous with the data acquisition. The results are available in a few minutes after the acquisition is complete.

Typical examples of ISOCS uses are:

• Determining the nuclides and activity inside pipes without opening the pipe.

• Determining the nuclides and activity of sludge at the bottom of tanks.

• Determining the nuclides, activity, and depth distribution in concrete activated by neutrons, without sampling.

• Assaying large construction waste containers from D&D sites to prove that they do not contain contaminated material.

• Proving that an entire ceiling is not contaminated without the need to build scaffolding and employ people to take samples.

• Determining radioactivity in glove boxes without opening them up.

• Determining the activity of radioactive drums of waste inside shielded shipping casks without opening anything.

• Finding the correct identity and activity and depth of a “lost” source buried underground, as part of a field exercise.

AUTOMATED SURFACE CONTAMINATION PRODUCES SURVEY REPORTS IN MINUTES

It has been estimated that 10% to 30% of the tens of billions of dollars it will take to clean up the legacy of the nuclear weapons complex, and that of the first generation of commercial nuclear power plants in the USA, will be spent on radiation surveys, for example to decide whether further clean-up is needed and/or whether to dispose of material in a landfill or specialised nuclear burial site.

Traditionally these surveys are performed with monitors that provide the technician with a reading of the local radiation field under the sensor and considerable time is spent slowly scanning a surface for an indication of elevated readings. Public concerns raise the cost of these surveys since the burden of proof is raised to a high standard and also dictate that considerable time be spent writing down readings and transcribing them to a formal report, taking several man-weeks.

The Surface Contamination Monitor (SCM) developed by Shonka Research Associates aims to automate the process, with consequent dramatic savings in time and money. The Surface Contamination Monitor uses a patented position sensitive proportional counter to measure beta/gamma and alpha contamination on floor surfaces. The position sensitivity of the counter means it can be made to act like an array of hundreds of single point detectors located side by side. Survey data is sampled in 5 cm square regions along the length of the monitor, which can be 5m or more. The monitor is mounted on a motorised cart with a wheel position encoder. An image of the contamination is presented to the technician while scanning and the data is also logged to a file.

The file can be further studied using the Survey Information Management System (SIMS). SIMS provides a visualisation oriented database for archiving data, reporting data, and subjecting data to visual and statistical studies. The strips of data can be aligned into larger areas with a simple Windows program that permits the user to “drag and drop” the data into the correct relative location. SIMS can also provide a common reporting system for conventional surveys that take data in a repetitive pattern or use some means of measuring the location of the reading.

In the past, reports were data intensive and aimed to provide a statistical proof that the measurements found no detectable radioactive contamination. The new system produces pictures of the surface contamination that permits characterisation of the residual contamination at levels that are more than an order of magnitude below what can be achieved using conventional methods.

Partial development funding for the technology came from a series of Nuclear Regulatory Commission Small Business Innovative Research grants. The system has been used in a laundry monitor (see Nuclear Engineering International, December 1996) and similar mathematical treatment is being applied to detectors for monitoring of buried sources of contamination.

Major applications of SCM/SIMS to date are:

• CP-5 reactor survey – December 1996.

A series of surveys was performed for the Large Scale Demonstration Project (LSDP) associated with the CP-5 reactor at the Argonne National Laboratory. The surveys were performed for the Strategic Alliance for Environmental Restoration, a consortium of utilities and contractors that ran this LSDP for the DoE’s Federal Energy Technology Center (FETC). The US Army Corps of Engineers scored the test surveys, which were over 1000 m2. The surveys took less than two days to perform, including on-site mobilisation, and SCM/SIMS proved substantially less costly and faster than conventional survey methods.

• C reactor survey – March 1997

A series of surveys was performed for the LSDP associated with the C reactor, a plutonium production reactor at Hanford. The surveys were performed for Bechtel Hanford Inc (BHI), which ran this LSDP (also for the DoE’s FETC) and the US Army Corps of Engineers again scored the tests. Surveys were performed in two days on-site for beta and alpha contamination as well as external exposure rate, collimated high-energy (137Cs) spectrometer measurements and X-ray (low-energy) measurements for transuranic nuclides. Alpha detection limits achieved in the survey showed that the system achieved an order of magnitude improvement in detection limits over conventional measurement techniques, and was cheaper and quicker.

• BONUS reactor survey – July, 1997 (first commercial application)

The BONUS characterisation survey was performed for the Jacobs Engineering Group, a subcontractor to DoE. BONUS was a power and research reactor in Rincon, Puerto Rico, that was shut down and defueled in the late 1960s. The Puerto Rico Electric Power Authority plans to convert the building into a science museum. The facility survey was performed on 4 levels in an 83 ft diameter steel hemisphere along with some other areas in adjoining buildings. Environmental conditions during the survey were harsh, with temperatures up to 140°F during the day. The 4000m2 survey was completed in two on-site weeks with an additional week for writing an executive summary and performing quality assurance on the automatically generated survey reports. Nearly 2 million measurements were recorded with 400 data points per m2.

• C reactor final status survey – November 1997

Following the successful demonstration at the C Reactor at Hanford, a final status survey was performed. The SCM was operated by a technician from the facility’s HP staff upon completion of a 4 hour training course.

• F reactor characterisation survey – November 1997

Following the successful demonstration at Hanford C Reactor, a characterisation survey of Building 108F, a research facility located near the F production reactor, was performed. The 108F survey identified significant alpha contamination. This discovery was unexpected and resulted in modifications to the planned decommissioning.

• Idaho air support buildings final status survey – November 1997

The two large air support buildings that had been used for “dense pack” storage of Rocky Flats (TRU) waste at the Idaho National Engineering and Environment Laboratory (INEEL) were surveyed. The survey fulfilled a court ordered agreement with the EPA and the State of Idaho and had to be completed prior to the end of the 1997 calendar year. Conventional methods were incapable of meeting this schedule. The area, 12 000 m2, was surveyed once for alpha (with a 20 dpm/100cm2 detection limit) and once for beta. The system included a second “recount” detector, and nearly 20 million measurements were recorded. The survey was completed in 21 shifts and 2 weeks of on-site effort. Environmental conditions were harsh, with surveys performed at temperatures that were below 20°F at times and under dripping condensation during the warmer mid-afternoons.

• Building 301 characterisation survey – November 1997

Following the successful demonstration at CP-5, a characterisation survey for Building 301, a hot cell and TRU facility at Argonne, was performed. Rooms were measured that averaged in excess of 100 000 dpm/100cm2 with peaks greater than ten million dpm. Surveys in the loft area resulted in an observation that contamination patterns matched patterns from roof leaks, indicating that contamination was present from historic releases under present day roofing. This discovery was unexpected and resulted in modifications to the planned decommissioning.

• Connecticut Yankee turbine floor and paved area characterisation survey – December 1997

In conjunction with Millennium Services Inc, a survey for beta contamination was performed on 13000 m2 of paved exterior areas and various floors of the turbine building at the recently closed Connecticut Yankee power plant. Satisfactory performance was achieved despite the fact that the exterior surveys were performed in sub-freezing winter conditions. Detection limits of 1000 dpm/100cm2 were achieved at production rates of up to 500 m2 per hour. Eight previously unidentified discrete radioactive particles and one general area of contamination were found that exceeded survey reporting limits. The data indicate additional discrete radioactive particles present below reporting limits.

DISPIM: CREATING A BETTER IMAGE FOR ALPHA PLANT DECOMMISSIONING

BNFL announces a new generation of DISPIM (Decommissioning In-Situ Plutonium Inventory Monitor) for measuring Pu concentrations in glove boxes and process vessels and providing the operator with 3-D plots (on screen and hard copy) showing where each concentration is and how much Pu is there. The system is designed to help in the decommissioning of alpha plants, for example in supporting criticality control strategies and minimising operator dose through early removal of Pu concentrations.

Designed as a modular passive neutron coincidence counting system, the new DISPIM is easily reconfigured to do measurements on components of various shapes and sizes. It can also fit into areas where space is restricted, eg an access corridor narrower than 1m.

The incorporation of high resolution gamma spectrometry allows the Pu mass to be calculated if the isotopic composition of the plant material has not been specified.

DISPIM is available for purchase or hire using trained BNFL staff.

DRAWING UP A DECOMMISSIONING PLAN FOR LENINGRAD 1

Pacific Northwest National Laboratory of the USA has recently completed the initial study to identify a decommissioning strategy for the Leningrad unit 1 RBMK-1000, the first such commercial plant to be constructed. The study, carried out jointly by PNNL, Brookhaven and the Kurchatov Institute, analysed the factors affecting the choice of decommissioning strategy for the plant and proposed SAFESTOR as the optimal choice. The study also looked at alternative uses for the unit 1 facilities and recommended conversion to a waste processing and storage complex because there are no central waste treatment or disposal facilities available in Russia.

A follow-on study, a joint effort between PNNL and the Kurchatov Institute, started in October 1997. The aim of the new study is to provide a rough order of magnitude cost estimate for the proposed decommissioning strategy. It is due for completion in April 1998.



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