Hennigan Engineering was called upon to be part of the mitigation and “Root Cause Analysis” for a tritium release into the groundwater that occurred at a nuclear power station in the Eastern United States.  Hennigan was a key participant in daily meetings with facility management at all levels as well as shareholders. Hennigan was responsible for drain system investigations, drain system clearing and the development of a detailed Report of Findings that was included in the facility’s Root Cause Analysis report to the NRC.

Radioactive hydrogen is called tritium (³H).  The NRC takes any release of tritium from a nuclear facility very seriously as does the Environmental Protection Agency. Naturally occurring tritium is rare and is created by the interaction of the earth’s atmosphere and cosmic rays passing through the atmosphere.  Significant amounts of tritium are generated by human activity, including the operation of nuclear power plants.  Tritium contains up to 5 times more biological change per unit of radiation than gamma radiation. The NRC closely investigates any nuclear facility tritium release incident to ensure that Operators take immediate and appropriate action to mitigate the cause of any release (or potential release).

Subsequent to the discovery of a tritium release into the groundwater from the facility; Hennigan was engaged by the facility and immediately deployed a full crew and the equipment necessary to investigate the drain systems, identify defects, clear the drain systems and perform the necessary tasks to minimize the potential for a future release due to the same “Root Cause”.  This included system mapping and the development and use of specialty tools including video inspection equipment, high pressure hydrolase tools and mechanical methods.

The final report developed and submitted by Hennigan Engineering was satisfactory to the NRC and others, such that the issuance of impending fines and / or temporary facility shut-down was avoided. Hennigan Engineering continues to support the facility on this matter by assisting with the implementation of the recommendations made by Hennigan Engineering’s “Report of Findings”

In as much as it was critical to successfully solve the problem, it was also necessary to solve the problem under the constraint of a very tight schedule while at the same time minimizing costs. Hennigan Engineering efficiently completed the work within the required schedule and also within the budget available.  Much of this work took place in very challenging conditions including high temperatures, Locked High Radiation areas and in very tight difficult spaces. Despite these challenges; the work was completed safely; without injury of any kind to any person involved with the work.

Hennigan Engineering Reveals Surprising Cost Saving Figures of Maintaining Chiller Efficiency

Facility Managers, Maintenance Personnel and Engineers recognize the problems caused by scale in water systems; increased maintenance, unplanned shutdowns, premature replacement of equipment and higher energy costs.

Thin layers of scale can form in a Chiller’s tubes, decreasing the efficiency (heat transfer) of the heat exchanger resulting in increased energy costs. The thermal conductivity of calcium carbonate is 4,000 times less than that of copper and therefore, even the thinnest coating acts as an insulator reducing the heat transfer, decreasing efficiency.

Scale in the Chiller tubes causes an increase in the head pressure, resulting in a substantial increase in energy consumption of the compressor. Chiller equipment manufacturers agree that just a 0.04inch (40 thousandths) thick scale buildup on the heat exchanger tubes of a 500 ton Chiller results in $37,000.00 extra on the electrical bill. The larger the Chiller, the more energy wasted: the same 40 thousandths scale thickness in a 1200 ton Chiller could add $90,000.00 to the electrical bill!

Most Chiller installations experience problems and have difficulty with peak demands during summer months. Unfortunately, most of these installations have no room to install a larger Chiller and therefore they have to accept that on days of high humidity, when cooling towers become less effective, the compressors are liable to trip off on high head pressure – stopping the function of the Chiller just when the need is the greatest.

Cleaning

 Historically, mechanical cleaning has been the means of tube scale removal. Unfortunately a thin layer of scale still coats the Chiller tubes and can also cause cathodic cells due to inconsistent cleaning leaving clean areas as well as dirty areas. The resulting cells cause corrosion and pitting leading to tube failure.

Solution:

 High Pressure Water Jetting (Hydrolasing) up to 20,000 psi has been shown to be extremely effective in FULL scale removal without streaking (clean area vs. dirty area) and without any damage to the tube substrate. We have seen head pressure reduction of 15psi to 20psi after cleaning with this method.

Since there is commonly only a 50psi differential between low load and full load, this pressure reduction after Hydrolase cleaning greatly reduces operating costs and increases the efficiency of the chiller.

In addition to the obvious energy savings and costs associated with inefficient Chiller operations, a substantial reduction of millions of tons of CO2 generation that is associated with refrigeration is also achieved.

With the experience and expertise of Hennigan Engineering in the utilization of Hydrolasing Chiller tubes a substantial savings can be achieved. We look forward to the opportunity to support your Chiller cleaning needs.