SIZE REDUCING ZION UNIT-2 FOR WASTE DISPOSAL

Vandellos 1 N.P.P. Caisson

TruPro® is a unique and patented decommissioning and radwaste management sampling and characterization technology used to attain rapid representative sampling and characterization of sub-surface matrices at nuclear facilities. By utilizing this new and efficient profiling approach, activity and volume reduction of various segregated waste streams is achieved, which leads to a basis for controlled disposal and release of concrete, soil and rock at reduced cost, time and risk.

The TruPro® technology provides a smart solution and approach to concrete or bulk material sampling and analysis. There is a need to profile materials for radioactive and non-radioactive contaminants of concern at depth within the waste material matrix in near real-time (in-situ) in order to support the evaluation of waste levels, and to allow for immediate response to contamination and increased worker safety awareness. This enhances project manager decision-making capabilities and decommissioning strategy.

By utilizing portable calibrated Liquid Scintillation Counters and Gamma Spectrometers, analysis is performed in close proximity to sampling operations in a low background area, minimizing the number of samples submitted to the accredited laboratory. The results acquired from the samples of building materials using TruPro® are used to develop a more detailed subsurface radiological contamination profile from which a strategy of clean-up action can be derived. An initial activity report is generated for each sample volume in near real-time, taking five to 60 minutes. Sampling areas determined to be of actionable value and concern are sampled rapidly and incrementally to acquire “dry” representative samples, which are then quantitatively analyzed in close proximity to the sampling operations.

This specialized characterization approach features a drill with a specialized cutting and sampling head, drill bits, a sample collection unit, a vacuum pump and calibrated portable radiometric instruments. The equipment produces a profile of radiological or chemical contamination through the material being studied in near real-time at any angle or direction. The drill head is used to penetrate hard surfaces which causes the bulk material to be pulverized as the drill travels through the radioactive media, efficiently transmitting a representative dry sample of bulk material to the specially designed, two-stage vacuum sample retrieval unit that prevents cross contamination of the clean retrieved samples.

No circulation medium is required with this profiling process, therefore no spreading of contamination occurs; the only by-product from drilling is the sample. Samples are analyzed quantitatively in the field in near real-time producing actionable data. This allows dynamic confident decisions to be made to affect project focus and direction.

TruPro® accelerates facility clean out and demolition by:

• Eliminating historical unknowns;

• Minimizing lifecycle risks by applying creative and innovative real-time deployable solutions;

• Implementing effective sampling and characterization;

• Identifying program risks for problem areas, enhancing PM approaches and principles;

• Ensuring adequate radiological controls of work areas;

• Improving site upfront understanding and planning; and

• Better allocation of resources, raw materials & highly skilled labor.

CASE STUDIES

Mound Plant Sw-17 & Sw-19 Old Cave Facility Advanced Subsurface Sampling & Characterization

NMNT International was contracted by CH2M HILL of Ohio with the Advanced Sampling and Analysis of Tritium Facilities, SW-13/1B Building and the Old Cave facility at Mound Plant using TruPro®. The objective of the Mound Tritium Facilities Project was to deploy a concrete sampling and profiling tool that had been developed. This sampling and profiling technology was deployed for the U.S. Department of Energy Mound Environmental Management Project (DOE-MEMP) Office, as well as BWXT of Ohio Inc.

The subsurface profiling technology penetrated many locations and layers of materials to depths of 9 feet obtaining 97 separate samples, including powdered concrete and metal fine shaving samples from the Old Cave facility structures. Sampling took place in the vertical and diagonal directions downward into the floors and subsurface building structures to acquire representative samples of buried subsurface metal objects, including: cave shielding doors, end shield plates, crane rails, portions and buried sections of the cave structure, cave structure concrete footer base, and subsurface bedrocks and soils.

A summation of radionuclide activity was performed by extrapolating concentrations over all Old Cave entombment structural materials. This resulted in a significant 150 fold reduction to previously estimated radionuclide inventories. A similar reduction in radiological hazard was therefore anticipated for the removal of the Old Cave entombment during demolition of the Miamisburg Closure Project’s SW Building. Rather than using remotely-operated demolition equipment for the entombment under tightly controlled, contained and monitored conditions, less restrictive demolition became feasible. This resulted in a cost savings of approximately $550k and a time savings of approximately four months in schedule.

Southern California Edison (SCE) SONGS Unit 1: Collection & Characterization of Samples from the Reactor Bioshield, Concrete Slabs and Containment Walls

Objective: to deploy a concrete sampling and profiling tool developed by NMNT to San Onofre Nuclear Generating Station (SONGS) Unit-1. The site’s concrete structures were to be sampled, radiological analyzed and profiled at numerous locations in support of cost-effective waste minimization and safe removal of contaminated material for the SONGS-1 Decommissioning Project.

NMNT provided materials and labor to obtain 377 separate samples, including concrete and metal powdered samples, with one or two water samples at depth, from the SONGS Unit 1 containment facility. Included in this sampling activity were associated site evaluations, day-to-day sampling plans and documented reporting.

Sampling was performed in horizontal directions (i.e., through walls) and vertical directions (downward into the floors and up into ceilings), as well as at angles from a perpendicular orientation to a wall or floor surface (to obtain samples from depths within structures). To achieve these sampling angles, drill guides and mounting equipment were used. SCE provided the gantry platform and rigging to ensure safe operations and lifting systems throughout the congested and intricate process metal work of the containment structure. Retrieved powdered samples were initially assessed semi-quantitatively by handheld probe and measured quantitatively for specific radionuclide activities of interest, specifically fission products and activation products.

Fission & Activation Products, Cs-137 and Co-60 needed to be detected at depth within the SONGS Unit 1 Bioshield concrete matrix in near real-time to support the evaluation of shipment and clean-up goals for concretes of Cs-137 and Co-60, and to allow for immediate response to contamination and increased worker safety awareness. The accepted method for detecting Cs-137 and Co-60 is gamma spectrometry.

Profiling the concretes of the site area to depth included the following desired capabilities and design features of the equipment:

• Powered by a facility electric supply or mobile diesel electric power generator unit coupled to 200-foot power cables;

• Removal of 377 concrete samples, using a specialized tungsten carbide drilling technology;

• Removal, at incremental depths, of potentially contaminated concrete from predetermined sampling points sequentially (to depths of ½-inch to 8 feet by 3 inches in any direction);

• Collection of all concrete particulate from sampling operations into specialized filter units; and

• Produce representative samples in a powdered form for optimal counting by gamma spectrometry.

The result was a cost savings of $300k for every 3 inches of annulus concrete proven to be LLW before shipment to ENVIROCARE meeting Waste Acceptance Criteria (WAC).

Material Sample Collection with Tritium and Gamma Analyses at the University Of Illinois’s TRIGA Nuclear Research Reactor

The University of Illinois in Champaign-Urbana has an Advanced TRIGA reactor facility. Scientech, LLC was tasked with fully characterizing the facility. Part of this characterization involved the collection and analysis of samples by NMNT of the various solid media, including concrete, graphite, metals and sub-slab surface soils, for immediate analysis of Activation and Tritium contamination well below the easily measured surfaces. Performing quantitative volumetric concrete or metal radioanalyses without lab intervention was a key objective of this dynamic characterization approach.

Currently, concrete core bores are shipped to certified laboratories where the concrete residue is run through a battery of tests to determine the contaminants. The existing core boring operation volatilizes or washes out some of the contaminants (such as Tritium) and oftentimes cross-contaminates the area around the core bore site. The volatilization of the contaminants can lead to airborne problems in the immediate vicinity of the core bore. Cross-contamination by the use of large amounts of water can increase the contamination spreading throughout the area, and thereby increase the amount of waste generated that needs to be treated and stabilized before disposal. The goal was to avoid those field activities that could cause this type of release.

TruPro®, in conjunction with radiometric instrumentation, was utilized to produce contamination profiles through the material being studied. All samples (except metals) on-site were analyzed within 10 minutes for Tritium using calibrated portable liquid scintillation counters (LSC), and analyzed for gamma activation products using a calibrated ISOCS. Improved sample collection with near real-time analysis, along with greater awareness of the historical hazards and liabilities, significantly enhanced the understanding of the depth distribution of contaminants of concern. By sampling and characterizing complex slab, sub-slab and reactor bioshield annulus locations, the site characterization and decommissioning plan were validated, developed and refined.

Characterization of Vandellós 1 N.P.PCaisson, Spain

The purpose of the project was to provide the necessary radiochemical fingerprinting to properly identify and quantify radiological activities of concretes and metal in cross sectional profile at the Vandellos graphite-gas N.P.P. Unit 1, located at the Empresa Nacional de Residuos Radioactivos S.A. (ENRESA) Reactor Site ENRESA Instalacion Vandellos I, Hospitalet de L’Infant. The characterization of the caisson ascertained the quantities of activated and non-activated materials of the reactor caisson.

NMNT obtained 173 separate samples, including powdered concrete and metal fine powdered samples, with a water sample at depth from the Vandellos 1 N.P.P. Sampling was in the horizontal direction (i.e., through walls). The company used drill guides and mounting equipment to achieve these sampling profiles; ENRESA provided radiological protection on the gantry platforms and rigging to ensure safe operations and lifting systems throughout the congested work environment of the containment structure. All of the retrieved powdered samples were measured quantitatively for specific radionuclide activities of interest, specifically fission products and activation products.

NMNT also characterized the Jose Cabrera N.P.P Caisson in Spain.

Satisfying International Decommissioning Sampling and Characterization Needs

The ability of TruPro® to identify the boundaries of activation or define activity contamination migration and the limits of material activation at depth beyond the easily measured surfaces, addresses many nuclear reactor decommissioning characterization needs. A clear picture of the extent of building activity concentrations are obtained by using the TruPro® system in conjunction with the use of deployed on-site radiometric instruments. This approach and technology allows the quantitative characterization of the nuclear site building materials within 60 minutes of representative sample acquisition. The compact and mobile, near real-time, focused sampling effort implements a dynamic decision-making approach for the facility characterization project’s derivation of a suitable decommissioning strategy, toward ultimate waste segregation.

About the Authors:

Dr. Sue Aggarwal is president and CEO of New Millennium Nuclear Technologies (NMNT) International. She currently manages and coordinates all aspects of NMNT’s radiation program. Dr. Aggarwal is also an elected Executive Committee Member of the DDRD of the American Nuclear Society. To contact Dr. Aggarwal,call 303-984-5788, or email saggarwal@nmnuclear.com.

Grant Charters is the managing director at NMNT. Mr. Charters provides nuclear radioactive waste management expertise, technical field and laboratory managerial operations for D&D, environmental restoration and other radiation projects. To contact Mr. Charters, call 303-984-5788 or email gcharters@nmnuclear.com.