542 Gas Analyzers for Monitoring Nuclear Reactor Coolant Removal

Introduction

The task of decommissioning of nuclear reactors is not just a matter of safe dealing with radioactivity issues, it is equally challenging to remove non-nuclear contamination economically and safely. NNC is presently developing a system for removal of alkaline metal coolant contamination from the Dounreay Fast Breeder Reactor (DFR) that has been kept carefully under maintenance since its shutdown in 1977.

Methods of Decommissioning Nuclear Reactors

As potassium and sodium are both air and water sensitive, the mixture of potassium and sodium metal in alloy form does not just have a high level of radionuclides but also poses a fire risk. This potassium-sodium mixture is used as a coolant. One way of decommissioning nuclear reactors is to drain the bulk NaK from the reactor and deal with the remaining residues using the Water Vapour Nitrogen (WVN) process.

The coolant residues that remain after draining form a surface coating and small pools over the exposed steel surfaces in both the cooling system and the reactor vessel. The issue that needs to be solved is to remove these residues without generating excess hydrogen off-gas concentrations or pressure pulses from unstable reactions and to convert the entire residue to hydroxide. It is then possible to flush the hydroxide with a water rinse after which final dismantling can commence.

Measurement Methods

Measurement of hydrogen off-gas is done with the help of a Systech 542 programmable hydrogen gas analyzer. The development process by NNC passes low-concentration water vapour that is carried by nitrogen over the contaminated surfaces to react with the alkaline metals. Hydrogen off-gas is produced by the reaction. The first Systech 542 programmable analyzer was acquired by NNC in 1994. From then, a number of design changes have been made by Systech design engineers to meet the specific needs of the development program.

The method followed is detailed below:

• Hydrogen-off gas is measured by two Systech 542 programmable hydrogen gas analyzers that indicate remaining contaminant levels.
• The coolant and water vapour react to produce sodium hydroxide and potassium hydroxide as well as hydrogen off-gas.
• Two Systech 542 programmable hydrogen gas analyzers measure the amount of hydrogen-off gas produced, which indicates the amount of remaining contaminant.
• The gas analyzers have two alarms that can be set to high or low level. The alarms on both the analyzers were used by NNC as a high-level and an extremely high level such that if there is high or very high hydrogen off-gas concentration, it is possible to set automatic trip levels.
• Analogue outputs obtained from the Systech 542 hydrogen gas analyzers provide data for logging.
• The Systech 542 hydrogen gas analyzer is provided with settable analog outputs that are recorded on a data logging system. As NNC is normally interested in low hydrogen off-gas levels, but also the high levels need to be recorded, the analog output ranges of both the instruments are different, one high and the other low-sensitivity.
• It is essential that Systech 542 hydrogen gas analyzers are precise and stable at both high and very low concentrations of hydrogen off-gas.

The Warrington Test Rig Experiment

NNC is presently running a test rig at its Warrington facility to evaluate the effectiveness of the process under operating conditions and to determine operational parameters that can be transferred to a full-scale unit. It is important that Systech 542 hydrogen gas analyzers used for monitoring the decontamination process progress and monitor safe venting are stable and reliable at both low and high concentrations of hydrogen-off gas.

The Systech 542 hydrogen gas analyzer, the most critical application for the decontamination process is used to measure low levels of 10 ppm hydrogen in nitrogen. At these low concentrations, instrument drift can pose to be a major problem. It was observed at Warrington that there was a drift of 20 ppm because of changes in ambient environmental conditions between day and night. The impact of instrument drift has been minimized in the NNC rig by running the 542's auto-zero program at predetermined intervals.

Conclusion

Systech 542 programmable hydrogen gas analyzers are critical in developing a process for safe decontamination of reactor system components. The consultant engineer of NNC has described the Systech 542 programmable hydrogen gas analyzers as the most important element in the system and it is proving to be a key component in the development of the process for the safe decontamination of reactor system components from the Dounreay Fast Breeder Reactor.

Source: http://www.azom.com/article.aspx?ArticleID=7086

Air Quality in Europe — 2012 report

'Air pollution is bad for our health. It reduces human life expectancy by more than eight months on average and by more than two years in the most polluted cities and regions. Member States must comply with EU air quality standards quickly and reduce air pollutant emissions,' Janez Potočnik, EU Commissioner for the Environment (EU, 2010a).

Emissions of air pollutants derive from almost all economic and societal activities. In Europe, emissions of many air pollutants have decreased. Much progress has been made in tackling air pollutants such as sulphur dioxide (SO2), carbon monoxide (CO) and benzene (C6H6) while other pollutants still present a serious threat to the health of Europeans and their environment.

Indeed air pollutant concentrations are still too high and harm our health and the ecosystems we depend on. A significant proportion of Europe's population lives in areas, especially cities, where exceedances of air quality standardsoccur. Particulate matter (PM) and ozone (O3) pollution are particularly associated with serious health risks.

Air pollutants released in one European country may contribute to or result in poor air quality elsewhere. Moreover, important contributions from intercontinental transport influence the O3 and PM concentrations in Europe.

Greater international cooperation, also focusing on links between climate and air pollutionpolicies, is required more than ever to address air pollution. Reducing air pollution and improving air quality therefore remains a key priority.

Purpose and scope of this report
This report presents an overview and analysis of the status and trends of air quality in Europe based on concentration measurements in ambient air and data on anthropogenic emissions and trends from 2001 — when mandatory monitoring of ambient air concentrations of selected pollutants first produced reliable air quality information — to 2010.

This report has been published annually since 2011 and updates regularly the information given in the five yearly report 'the European environment — state and outlook' (SOER) of the European Environment Agency. The analysis covers up to 38 European countries (1), including the EU Member States and the EEA-32 member countries.

According to Directive 2008/50/EC on Ambient Air Quality and Cleaner Air for Europe, the Commission shall review in 2013 the provisions related to certain pollutants. This report aims to inform this review and the review of the European Commission's Thematic Strategy on Air Pollution.

More info here: http://www.environmental-expert.com/articles/air-quality-in-europe-2012-report-316918

ATIs F12 Gas Transmitter

ATIs F12 Gas Transmitter is designed to measure toxic gas in hazardous locations requiring an Intrinsically Safe (IS) device. A non-IS version is also available for non-hazardous locations. Each version utilizes a digital communications protocol. For many toxic gases, ATI offers a unique sensor response testing system unmatched by any competitive transmitter. Even outdoors in high wind conditions, the Auto-Test system provides reliable response checks to insure system integrity. Sensor response is verified with an actual gas sample, generated on demand. Generators store run time information accessible to operators, and are automatically tested for compatibility with the installed sensor. F12 transmitters provide useful features that simplify installation, operation, and maintenance. The 4-button keypad is used to configure the menu-driven setup pages. The display also provides alarm indication and complete menus for setting up operating parameters. The IS version of the transmitter is available with HART™ communications. The HART™ protocol supports the HART™ Universal and Common Practice Commands at 1200 baud using the Bell 202 FSK modem standard. The non-IS version of the transmitter is available with MODBUS™ communications. The MODBUS™ protocol supports 9600 baud access to concentration and status information, and supports alarm setup and many other functions on either RS485 or RS232 (software selectable). More information at: http://www.analyticaltechnology.com/public/product.aspx?ProductID=1024

Chlorine spill evacuates Jewish Center in Clifton

The Clifton Fire Department's Hazmat unit was dispatched to the Jewish Family Service Children's Center on Scoles Avenue early Wednesday morning after 75 gallons of chlorine began leaking in a storage room near the Olympic-sized pool.

Clifton Fire Chief Vincent Colavitti said a worker moving materials accidentally hit and broke off the chlorine valve, causing 75 gallons of sodium hypochlorite, a liquid, to spill on to the floor.

Colavitti said the worker was by himself and initially attempted to stop the leak with his hand. As the fire department was alerted, the worker received alternate transport to St. Joseph's Regional Medical Center after complaining about burns on his hands, ankles and face.

The worker was gone as the Hazmat team entered the facility and secured the sodium hypochlorite, Colavitti said, explaining its concentration was relatively low at 12 percent, adding a higher concentration may cause serious bodily burns and injuries.

As the Hazmat Unit took care of the leak, firefighters evacuated about 75 people from the building. Colavitti said there were no other injuries to firefighters or civilians. The status of the worker is unknown at this time and center officials were unavailable for comment.

After the Clifton Fire Department secured the scene, it was turned over to the center for cleanup with supervision by a Passaic County Health Department official.

Source: http://www.northjersey.com/news/170394876_Chlorine_spill_evacuates_Jewish_Center_in_Clifton.html

Q45N Dissolved Ammonia Monitor

Continuous monitoring of ammonia in water and wastewater streams is becoming increasingly important for plant operations and process control. Unfortunately, on-line ammonia monitors are generally very expensive, complex, and labor intensive instruments. Most are automated versions of ammonia selective ion electrodes methods better suited to laboratory measurements. Others are automated colorimetric devices or instrumental methods that are difficult to justify on a cost basis.

ATI has developed a completely new approach to on-line monitoring of ammonia that is far less expensive and much simpler than conventional monitoring equipment. The Q45N Dissolved Ammonia Monitor uses reaction chemistry that converts ammonia in solution to a stable monochloramine compound equivalent in concentration to the original ammonia level. The chloramine concentration is then measured with a unique amperometric sensor that responds linearly to chloramines while eliminating interference from excess free chlorine in solution.

Q45N Dissolved Ammonia monitors (Analyzers, Transmitters)  are available in two versions, one that includes all components conveniently integrated into a Nema 4X fiberglas enclosure, and a second that separates the monitor from the chemistry system for applications where a more convenient display location is desired. A sample inlet filter assembly attached to the side of the enclosure allows filtered sample to be drawn from the inlet flow. Sample must be pumped to the inlet assembly at a rate high enough to insure the desired response time for the measurement system. Excess sample is bypassed to any convenient drain location.

ATI’s Q45N Dissolved Ammonia monitoring package for dissolved ammonia provides the measurement stability needed to avoid complicated automatic calibration systems. Unlike typical ammonia SIE sensors subject to significant drift problems, the amperometric sensor provides excellent repeatability long periods of time. And because the measurement utilizes chloramine conversion for measurement, the sample is inherently subjected to biocidal conditions, eliminating long term biofouling on the sensor.

More information at: http://www.analyticaltechnology.com/public/product.aspx?ProductID=1048

What are ozone depleting substances?

In 1974, the world was alerted to the possible catastrophic depletion of stratospheric ozone by chlorofluorocarbons (CFCs), which were then emitted from domestic and commercial refrigeration and from air conditioning equipment, plastic foams and aerosol cans. Before 1974, CFCs were thought of as harmless chemical artifacts in the atmosphere, useful as tracers of the movement of air between countries and hemispheres.

In order to assess this threat to stratospheric ozone, which absorbs most of the harmful solar ultraviolet radiation impinging on the Earth’s atmosphere, scientists needed accurate information on the amounts and accumulation rates of CFCs in the global background atmosphere. Several nations, in particular Australia, the UK and the USA, responded quickly to this challenge. They established CFC-monitoring facilities in a number of strategic, clean-air locations around the world, in part funded by the global CFC industry.

CSIRO established the first Southern Hemispheric CFC measurement laboratory at Aspendale, Victoria, in 1975, and commenced in-situ measurements at Cape Grim, Tasmania, in early 1976. The Cape Grim station, funded and managed by the Australian Bureau of Meteorology, monitors and studies global atmospheric composition in a science program led by CSIRO and the Bureau.

By the early 1980s the atmospheric data, coupled with the industry estimates of global CFC production and emissions, proved that CFCs were long-lived, lasting more than 50 years in the atmosphere. This long life meant they could reach the stratosphere, where they broke down, releasing reactive chlorine species that catalytically destroyed ozone.

Scientists also realised that CFCs were not the only important ozone depleting substances (ODS) being released to the atmosphere. The chlorinated solvents carbon tetrachloride, and former dry-cleaning agents methyl chloroform, were identified as significant ODS. So were the halons – bromine containing fire-fighting chemicals – and methyl bromide, an agricultural and structural fumigant. The latter chemicals were identified as particularly potent ODS because they contained bromine, even more destructive of stratospheric ozone than chlorine.

To rapidly phase out CFCs, the industry developed the already existing HCFCs as interim replacement refrigerants and foaming agents. Hydrocarbons were developed as long-term replacements for CFCs in aerosol propellants. HCFCs were themselves ODSs, but because of their relatively short atmospheric lifetimes they were significantly less potent than the CFCs they replaced.

By 1987, just over a decade after the ozone threat was enunciated, the nations of the world came together to sign the Montreal Protocol, which controlled the production and consumptions of ODSs including HCFCs. Around the same time, the industry announced that it had developed safe, ozone-friendly CFC replacements, the hydrofluorocarbons (HFCs).

Unlike the CFCs and chlorinated solvents, accurate and comprehensive measurements of HCFCs, HFCs, the halons and methyl bromide were only possible by the mid-1990s. This was thanks to the development of a suitable measurement technology – gas chromatography-mass spectrometry (GC-MS) – and reliable calibration standards.

CSIRO and the Bureau of Meteorology had an archive of clean air samples collected regularly at Cape Grim since 1978 (the Cape Grim Air Archive). In the late 1990s, CSIRO got GC-MS capability and – in partnership with international laboratories at the University of California at San Diego, USA and the University of East Anglia at Norwich, UK – were able to reconstruct the complete ODS atmospheric history at Cape Grim back to 1978. CSIRO also applied these techniques to the analysis of air samples extracted in Antarctica, extending the complete ODS atmospheric history back to the 1930s.

The Cape Grim ODS data are available at the World Data Centre for Greenhouse Gases. The Cape Grim Air Archive and Antarctic firn ODS data are available on request from the authors.

Chlorine levels rose rapidly from the 1960s, peaking in the late-1990s at about 4.4 parts per billion molar, before starting to decline, thanks to the successful implementation of the Montreal Protocol. Currently chlorine levels are falling by 6% per decade and it is anticipated they will fall to 1980s levels by about 2045 if the world continues to adhere to the Protocol. By then it is likely that the Antarctic ozone hole will be very weak or non-existent.

Source: http://theconversation.edu.au/what-are-ozone-depleting-substances-9203

Q45H/64 Dissolved Ozone Monitor

ATIs Model Q45H/64 Dissolved Ozone Monitor is the ideal choice for on-line monitoring and control of ozonation systems. Capable of measuring DO3 concentrations as low as 0-200 PPB full scale, the system provides the sensitivity needed for demanding applications such as pharmaceutical grade water or semiconductor wash water. And with the standard 0-2 PPM range, the monitor is ideally suited to water bottling systems or municipal water treatment. Even high range applications requiring 0-20 or 0-200 PPM can be easily accommodated.

Unlike on-line colorimetric and most amperometric monitors, Q45H systems utilize a membrane-covered polarographic sensor that does not require the addition of chemical reagents.  The Q45H system has no moving parts, so there are no pumps or motors that burn out or tubing breaks that create maintenance nightmares. All normal maintenance items are included with each system.

Utilizing a highly selective polarographic membraned sensor, dissolved ozone can be monitored interference-free, with little maintenance. There are no moving parts and what little maintenance is required can be done in just a few minutes.  Installation is simple and you can be up and running in a few hours.

Available in loop-powered transmitter or AC operated analyzer, the Q45H/64 is well suited for almost any DO3 measurement requirement. Even a portable data-logging version is available for temporary installation or process studies. And for even more flexibility, the instrument is available with an optional pH sensor input that allows a single unit to provide both dissolved ozone and pH analog outputs.

More information on this product can be found at: http://www.analyticaltechnology.com/public/product.aspx?ProductID=1044