DOE: DECON & DECOMMISSIONING

Columbus Laboratory Chooses MOOSE
Pentek's MOOSE scabbling robot was leased, along with a trained operator, to remediate radiologically contaminated concrete floors at a Columbus-based nuclear research laboratory where DOE work had been conducted. The floors-14,600 square feet (1,300 square meters) in total-were in two former metallurgical process buildings. Areas in a former machine shop were covered with an adhesive tar residue that increased the difficulty of the project. "We tried several methods-solvents, scraping, vacuum blasting-to remove the residue and concluded that Pentek had the only system that could effectively do the job," said Dave Siefert, the owner's operations manager. "The MOOSE was attractive because it can clean a large area in a single pass. Pentek's methodology was also a plus because, since no extra wastes are produced with their equipment, it is much easier to manage the contaminated material."

As the scabbling process completely contains airborne particulates within an evacuated shroud, daily activities proceeded normally in other areas of the building. "Pentek offered us the most time and cost savings of any approach. This is important for a government-sponsored project," Siefert said.

Lockheed Martin Idaho Technologies: Pentek Scores High in Scoping Tests
With the shift in mission due to the cessation of reprocessing activities, maintenance decontamination at the Idaho National Engineering Laboratory's Chemical Processing Plant (ICCP) gave way to full decommissioning. As a result, ICPP's contractor, Lockheed Martin Idaho Technologies (LMIT), sought safer, more efficient removal methodologies that could decontaminate concrete to higher levels of cleanliness while also reducing secondary waste generation.

ICPP conducted a scoping study on contaminated concrete samples to test the dry mechanical method embodied by the Pentek system. Pentek technicians were called upon to clean 24 square feet (2 square meters) of radioactively contaminated concrete lids. Study goals were to achieve no airborne contamination, no toxic chemicals, no liquid wastes, and capability to decon the bulk concrete for free-release.

Pentek's all-mechanical system removed 1/8-inch (3 mm) of concrete from the entire lid surface in a little under an hour using a single operator. According to the final report, Concrete Decontamination Scoping Tests, "The VAC-PAC system was dustless. The dust and debris created by the [CORNER-CUTTER] needle scalers and SQUIRREL scabblers were captured by shrouds covering the tool surface and then transported through a vacuum hose by a VAC-PAC HEPA filtered vacuum and waste packaging system...The entire system was very flexible and easy to operate." The report continued: "The system generated very little waste; the lid surface after cleaning was level and did not have any peaks or valleys."

"Worth mentioning is the ease in decontaminating the stainless steel equipment following project completion," added Decon Development Engineer Kip Archibald. The report concludes that Pentek's dry scabbling is a safe and effective technique for the removal of contaminated concrete. ICPP followed through with the subsequent purchase of two Pentek systems. For a copy of the complete report, contact Pentek's Nuclear & General Decontamination Department at pentekusa@aol.com.

Bechtel Hanford: Pentek System Supports Decon of Solar Basins
Bechtel Hanford, Inc. (BHI), a DOE Environmental Restoration contractor, recently evaluated concrete decontamination methods for a 183-H Solar Basin project at the Hanford Site in Washington State. Four large basins, used as evaporation areas for a variety of hazardous and irradiated wastes, roughly 37,000 square feet (3,400 square meters) in total area, required the removal of a uniform 1/4-inch (6 mm) surface layer of concrete. "We had some problems related to the vacuum blasting equipment we initially used due to the need to repeatedly replace internal components," said Rod Griffin, BHI's construction supervisor. BHI reviewed alternate remediation processes after the downtime began to seriously impact their project schedule.

"Blasting is pretty good for coatings removal on flat surfaces, but is simply not designed for aggressive concrete decontamination," said Rod Griffin.

"Pentek, on the other hand, provides a dry, effective system specifically designed for radiological concrete remediation."

A demonstration at Pentek's Pittsburgh training facility resulted in BHI's decision to procure a complete Pentek system, including the SQUIRREL-I, a recent addition to Pentek's integrated dustless decontamination equipment. This single piston, air-driven scabbler with localized exhaust is designed to aggressively remove 1/4-inch (6 mm) of concrete in a single pass. According to BHI, the SQUIRREL-I scabblers aggressively culled concrete from the vertical and horizontal basin surfaces without creating worrisome airbmemorne or safety concerns. The tools were later used to chase down "hot spots" and crevices after the uppermost 1/4-inch (6mm) stratum was removed.

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