Watts Bar Research Articles

Fishing along the Clinch River arm of Watts Bar Reservoir adjacent to the Oak Ridge Reservation, Tennessee: behavior, knowledge and risk perception

Catching and eating fish is usually viewed as a fun, healthy and safe activity. However, with continuing increases in fish consumption advisories due to the contamination of our environment, anglers have to decide whether or not to eat the fish they catch. The Clinch River arm of Watts Bar Reservoir is under a fish consumption advisory because of elevated PCB concentrations in striped bass ( Morone saxatilis), catfish ( Ictalurus spp.) and sauger ( Stizostedion canadense) due in part from contaminants released from the US Department of Energy's (USDOE's) Oak Ridge Reservation (ORR) in East Tennessee. To obtain information about the demographics, fishing behavior, knowledge, fish consumption and risk perception of anglers, a survey was conducted of 202 people actively fishing either on land or by boat along the Clinch River arm of Watts Bar Reservoir adjacent to the ORR from Melton Hill Dam to the Poplar Creek confluence or on Poplar Creek within ORR boundaries from mid-March to early November 2001. Even though 81% of people interviewed knew about the fish consumption advisories for the study area, 48% of them thought the fish were safe to eat, while 38% ate the fish that they caught from the study area. Approximately 36% of anglers who had knowledge of the fish consumption warnings ate fish from the study area. Providing confirmation that people fish for many reasons, 35% of anglers interviewed did not eat fish at all. The majority of anglers interviewed knew about the fish consumption advisories because of the signs posted throughout the study area. However, few people knew the correct fish advisories. Significantly fewer blacks had knowledge of the fish consumption warnings than whites. Information resulting from this study could be used to design a program with the objective of reaching the people who may be most at risk from eating fish caught from the Clinch River arm of Watts Bar Reservoir.

TVA TO MAKE TRITIUM FOR ATOMIC WEAPONS

Tritium gas for nuclear weapons will be made in Tennessee Valley Authority (TVA) electricity-producing nuclear reactors under a plan announced on Dec. 22, 1998, by Energy Secretary Bill Richardson. Richardson's decision will expand a 15-month-old Department of Energy pilot project at TVA's Watts Bar reactor in Spring City, Tenn., in which special lithium rods inserted into reactor fuel elements produce and capture tritium. DOE's plan also holds open the option of using TVA Sequoyah's two light-water reactors in Soddy Daisy, Tenn., to produce tritium, if needed. The Watts Bar plan is the cheapest of several proposals DOE was considering for producing the gas, a radioactive hydrogen isotope that decays at a rate of 5.5% per year. It is used to increase the power of nuclear weapons (CE ...

Long-Term Simulation of Fine-Grained Sediment Transport in Large Reservoir

A 30-year simulation of fine-grained, cohesive sediment transport in Watts Bar Reservoir, located in Tennessee, demonstrated that the SEDZL model realistically predicts overall patterns of erosion and deposition throughout this large reservoir. Good qualitative agreement was achieved between the predicted and observed trends in the net sediment-bed-elevation change during the model-calibration period, from 1961 to 1991. Quantitative comparison of predicted and measured bed elevation changes indicated that the model was generally able to accurately simulate local erosion and deposition within Watts Bar Reservoir, yielding a median absolute relative error or 46% in the cohesive sediment bed areas of the reservoir. The model predicted that 76% of the incoming sediments during this 30-year period would be trapped in the reservoir, which is in excellent agreement with the observed trapping efficiency of 72±6% (95% confidence interval).

95/01513 TVA announces the end of the line for Watts Bar 2, Bellefonte 1 & 2

95/01513 TVA announces the end of the line for Watts Bar 2, Bellefonte 1 & 2

Reservoir riparian zone characteristics in the Upper Tennessee River Valley

Impoundments in the upper Tennessee River Basin have inundated historic river riparian and mesic valley slope habitats. Fifteen major Tennessee Valley Authority (TVA) reservoirs, upstream of Chattanooga TN, have effected 50,000 ha of modern reservoir riparian zones on formerly mesic terrain. These zones were defined here as winter mudflats between winter pool shores and summer pool shores and summer riparian habitats with diminishing soil saturation from summer shores up to flood zone boundaries. Watts Bar (WB), the largest of these 15 projects in terms of area, was chosen for background and field analyses of the consequential reservoir riparian processes and expressions. WB, at the median age of areal TVA reservoirs, was closed in 1942. Transects were taken in the WB summer riparian forest after consideration of topoedaphics, species composition, and the level of contemporary disturbance. Regional bottomland forests were compared. Coefficients of species similarity showed 70% compositional similarity. The basal area (BA) density of WB summer riparian forests was not similar as was composition in regional bottomland stands. Four (of twelve) subjectively selected WB transect BA densities were compared nonparametrically and were the same (90% confidence) as other bottomland stands of like chronology. Overall however, WB stands averaged 19.6 m2/ha BA to 30.0 + for regional comparisons. Stocking was low, but measured litterfall was relatively high, resulting in similar biomass productivity corrected on a unit area basis. The winter mudflats showed expanding development of phenologically distinct herbaceous and graminoid communities under a five to six month drawdown exposure regime. Thermal modifications from the winter pool heat sink were determined to alter the mudflat microenvironment. A recent shortening of the drawdown period has interrupted the adapted life history strategy of the counter-seasonal plants, and seed maturity has been restricted. Erosion of the summer shore has been increasing the extent of the mudflats at the expense of the hydrologically influenced summer riparian habitat foreslope. The discernable trend of summer riparian stand succession over mesic expression will be limited by the height and hydric avoidance occasioned by an abrupt slope to mesic, unsaturated profile, conditions. Approximations of biomass production potential pre- and post impoundment have shown a 12∶1 diminution from historic carbon detention, on a seasonal basis, within normal pool shore boundaries. Further approximations comparing the WB summer riparian forest carbon retention and detention to historic forest compartments highlighted the importance of a relatively copious, non-lignified, litterfall in the seasonally available carbon budget.

Estimation of appropriate background concentrations for assessing mercury contamination in fish

One goal of environmental restoration at contaminated industrial or hazardous waste sites is the prevention of any further release of contaminants. As a consequence of successful remediation, it is hoped that elevated contaminant concentrations in biota will return to levels characteristic of environments uncontaminated by point sources. To evaluate the efficacy of such an environmental cleanup, it is necessary to know what background contaminant concentrations would typify uncontaminated conditions in the systems of interest. An accurate estimate of an appropriate background mercury concentration in fish is needed to determine the extent to which industrial mercury discharges produce elevated mercury concentration in fish in receiving waters, and to determine the concentration in fish that would represent restoration to uncontaminated status. Losses of large quantities of mercury in the 1950s at the U.S. Department of Energy (DOE) facilities in Oak Ridge, Tennessee resulted in continued chronic contamination of several small streams and the downstream river/reservoir system. mercury concentrations in axial muscle of fish exceed 1 [mu]g/g wet wt. near the source, and decline to much lower concentrations 20 km downstream in Watts Bar Reservoir. Although remedial efforts are underway, the facility remains a continuing source of mercury contamination to the downstream waters.more » This study measures mercury concentration in bluegill and redbreast sunfish from streams and reservoirs near Oak Ridge, TN that are presumed to be relatively unimpacted by anthropogenic point sources of mercury to determine appropriate background levels in fish to apply in evaluating local contaminated streams and reservoirs. 16 refs., 1 fig., 1 tab.« less

Acoustic emission/flaw relationships for inservice monitoring of LWRs : Pacific Northwest Laboratory, Richland, Washington (United States), NUREG/CR-5645, PNL-7479, 120 pp. (Oct. 1991)

The program concerning Acoustic Emission/Flaw Relationships for Inservice Monitoring of LWRs was initiated in FY76 with the objective of validating the application of acoustic emission (AE) to monitor nuclear reactor pressure-containing components during operation to detect cracking. The program has been supported by the US Nuclear Regulatory Commission, Office of Nuclear Regulatory Research. Research and development has been performed by Pacific Northwest Laboratory, operated for the Department of Energy by Battelle Memorial Institute. The program has shown the feasibility of continuous, on-line AE monitoring to detect crack growth and produced validated methods for applying the technology. Included are relationships for estimating flaw severity from AE data and field applications at Watts Bar Unit 1 Reactor, Limerick Unit 1 Reactor, and the High Flux Isotope Reactor. This report discusses the program scope and organization, the three program phases and the results obtained, standard and code activities, and instrumentation and software developed under this program.

Acoustic emission system calibration at Watts Bar Unit 1 nuclear reactor

An acoustic emission system has been installed on TVA's Watts Bar Unit 1 reactor to monitor selected areas of the pressure boundary during hydrostatic testing, hot functional testing, and ultimately, during reactor startup and operation. This is a part of a cooperative effort between TVA and NRC Research to test and demonstrate AE technology. This technology has been developed under an NRC Research program to validate the application of AE techniques for continuous, on-line monitoring of reactor pressure boundaries to detect cracking. This report discusses the performance of and results from a special calibration test of the AE system using simulated AE signals to evaluate the accuracy of signal source location by the system.

Poor Reproductive Success of Striped Bass from a Reservoir with Reduced Summer Habitat

Abstract Reproductive success (spawning, egg production, fertilization, hatch, larval survival) of striped bass Morone saxatilis from Cherokee Reservoir, Tennessee, was less in most years from 1979 to 1984 than that for stocks from two other Tennessee reservoirs, Norris and Watts Bar, when captured individuals from all three stocks were spawned in a hatchery. Reduced reproductive performance was expressed largely as reduction in percentage of females that spawned successfully and as poor embryo survival within 1 d postfertilization. Reproduction by Cherokee stock was best in years following those when the reservoir flushing rate was high. Reduced reproductive competence may be related to a decrease in the amount of summer habitat with suitable temperatures and dissolved oxygen concentrations, which stresses fish most severely in Cherokee Reservoir compared with the other two reservoirs. Rigorous testing of this hypothesis is recommended to guide management of striped bass and water quality in fresh and es...

Evaluation of methods for leak detection in reactor primary systems

No currently available, single leak-detection method combines optimal leakage detection sensitivity, leak-locating ability, and leakage measurement accuracy. Technology is available to improve leak detection capability at specific sites by use of acoustic monitoring. However, current acoustic monitoring techniques provide no source discrimination (e.g., to distinguish between leaks from pipe cracks and valves) and no leak-rate information (a small leak may saturate the system). Seven cracks, including three field-induced IGSCC specimens and two thermal-fatique cracks, have been installed in a laboratory acoustic leak detection facility. The IGSCC specimens produce stronger acoustic signals than the thermal-fatigue cracks at equivalent leak rates. Despite significant differences in crack geometry, the acoustic signals from the three IGSCC specimens, tested at the same leak rate, are virtually identical in the frequency range from 300 to 400 kHz. Thus, the quantitative correlations between the acoustic signals and leak rate in the 300–400 kHz band are very similar for the IGSCC specimens. Also, acoustic background data have been acquired during a hot functional test at the Watts Bar PWR. With these data, it is now possible to estimate the sensitivity of acoustic leak detection techniques.

Threadfin shad, Dorosoma petenense Günther, mortality: causes and ecological implications in a South‐eastern United States reservoir

Cold stress was identified as an important factor influencing both reservoir‐wide mortality and impingement of threadfin shad, Dorosoma petenense, during the period October 1976 to April 1977 in Watts Bar Reservoir, Tennessee. Relative numbers and size frequency of impinged threadfin shad were similar to the relative numbers and size frequency of shad preyed upon by sauger, Stizostedion canadense, and skipjack herring, Alosa chrysochloris. This relationship implies that the factor mainly responsible for impingement, low temperature, also influences prey vulnerability. Threadfin shad made up 99% of the combined diet of sauger and skipjack herring from November until the threadfin shad disappeared in January. These predators did not readily switch to alternative prey in the short term, but by the next autumn 25–100% of the diet was alternative prey. Reappearance of threadfin shad the year following mass mortality and ability of the predators to vary their diet emphasize the resilient nature of some predator‐prey systems.

Cumulative stress-induced mortality of gizzard shad in a southeastern U.S. reservoir

Starvation was apparently responsible for a large die-off of gizzard shad, Dorosoma cepedianum, in several east Tennessee reservoirs during the spring of 1983. Condition indices, calorific equivalents, lipids, and blood parameters of electrofished (control) shad from Watts Bar Reservoir were significantly higher than these parameters for recently dead shad and for stressed shad, indicating that the stressed and dead fish were at similar levels of physiological condition. We hypothesize that mortality due to starvation resulted from a year-long series of unusual environmental conditions beginning with an abnormally warm spring in 1982 which delayed spawning for some shad, a mild winter in 1982–1983 which increased metabolic demands, and an unusually cool spring in 1983 which delayed food availability. These events may have acted in a cumulative fashion, with each inducing additional increments of stress until lipid stores were depleted to a nonrecovery level, which appears to be about 4% of dry body weight. At least 10% of the adult gizzard shad died of starvation. Most predators were probably not adversely affected by the die-off because of the high availability of shad smaller than 16 cm (total length) and the vulnerability of stressed shad to predation.

Acoustic emission for on-line reactor monitoring: Results of intermediate vessel test monitoring and reactor hot functional testing

This article discusses a program designed to develop the use of acoustic emission (AE) methods for continuous surveillance to detect and evaluate flaw growth in reactor pressure boundaries. Technology developed in the laboratory for identifying AE from crack growth and for using that AE information to estimate flaw severity is now being evaluated on an intermediate vessel test and on a reactor facility. A vessel, designated ZB-1, has been tested under fatigue loading with simulated reactor conditions at Mannheim, West Germany, in collaboration with the German Materialprüfungsanstalt (MPA), Stuttgart. Fatigue cracking from machined flaws and in a fabrication weld were both detected clearly by AE. AE data were measured on a US nuclear reactor (Watts Bar, Unit 1) during hot functional preservice testing. This demonstrated that coolant flow noise is a manageable problem and that AE can be detected under operational coolant flow and temperature conditions.

Influences of Water Quality on Distribution of Striped Bass in a Tennessee River Impoundment

Abstract Telemetry techniques were used to evaluate relationships between water quality and distribution of adult striped bass Morone saxatilis during an 18-month period in Watts Bar Reservoir, Tennessee. Distribution and movements of fish were influenced by water temperature and dissolved oxygen concentration. During winter and early spring, temperature was vertically and horizontally uniform, and striped bass were relatively mobile and occurred in both tributary arms as well as in the main body of the reservoir. As the reservoir warmed in summer, fish were less mobile and progressively limited to areas in the tributary arms where temperature was less than 24 C and dissolved oxygen exceeded 4 mg/liter. Parts of the tributary arms of Watts Bar Reservoir provided such areas due to hypolimnetic discharges from upstream impoundments and groundwater inflows. Striped bass were restricted to these areas until late fall, when the entire reservoir cooled and again was nearly isothermal. Knowledge of relationships...

Assessment Methodology for the Detail Control Room Review

Following the Three Mile Island Unit 2 (TMI-2) incident, the U.S. Nuclear Regulatory Commission promulgated requirements for detailed control room design reviews (DCRDR) of all nuclear power plants. As a result, Tennessee Valley Authority (TVA) planned a DCRDR for each of its nuclear power plants: Bellefonte, Browns Ferry, Sequoyah, and Watts Bar. A DCRDR seeks to identify and correct sources of manmachine error in nuclear power plant control rooms. There are five phases of a DCRDR: (1) preparation and planning, (2) survey (which includes operational experience review, checklist, and task analysis), (3) assessment, (4) implementation, and (5) reporting. This paper will focus on the assessment phase of TVA's Bellefonte Nuclear Power Plant DCRDR. The paper will first give the methodology and then the results obtained.

Habitat Preferences and Food Habits of Young-of-the-Year Striped Bass, White Bass, and Yellow Bass in Watts Bar Reservoir, Tennessee

Abstract Resource sharing among stocked striped bass (Morone saxatilis), young-of-the-year white bass (Morone chrysops), and yellow bass (Morone mississippiensis) in Watts Bar Reservoir, Tennessee, was evaluated by determining distribution patterns and prey utilization. Fish were collected in 1978 by electrofishing shoreline transects near seven sites where fingerling striped bass were stocked. Electrofishing catch rates generally were positively correlated among species but preferences for substrates were not consistently detected across sample periods. Although distribution patterns were similar, the three species appeared to utilize different sizes of prey. Striped bass consumed relatively big prey such as fish larvae and large invertebrates while yellow bass mainly ate zooplankton. White bass were opportunistic, eating fish and dipteran larvae when they were abundant but consuming smaller prey at other times. Ecological segregation of the basses by food size may affect the success of striped bass intr...

Measurements of Growth and Consumption of Sauger (Stizostedion canadense): Implication for Fish Energetics Studies

The energy budget of sauger (Stizostedion canadense), in Watts Bar Reservoir, Tennessee, was studied over a 17-mo period. Field determinations of consumption and laboratory determinations of metabolism were incorporated into the balanced energy equation of Winberg to predict growth in energy value of sauger in age-classes I+ and II+. The equation included energetic costs of specific dynamic action and the metabolic efficiency penalty of metabolizing body energy stores. Observed and predicted growth during the warm months, March through October, agreed within 2.5–9.6% for the I+ and II+ age-classes, respectively. Observed and predicted growth over the winter for the only age-class modeled, the I+, did not agree. High food consumption during winter did not result in the amount of growth expected, suggesting that the physiological assumptions of the balanced energy equation are invalid for describing the winter energetics of sauger. We emphasize the potential error in inferring consumption from growth and metabolism.Key words: sauger, Stizostedion, bioenergetics, feeding, growth, modeling

Structuring of a Predator Population Through Temperature-Mediated Effects on Prey Availability

Temperature can control the structure of a predator population by regulating the abundance and size availability of prey. Relatively small differences in winter temperatures between years can have a major influence on largemouth bass (Micropterus salmoides) population structure because of the threshold relationship between temperature and the lower lethal limits of shad. The relationship between prey availability and predator growth and mortality was established through field measurements of consumed energy. Growth and consumption of largemouth bass in Watts Bar Reservoir, Tennessee, was lower in 1979 than in 1980 as a result of lower winter water temperature in 1979, which reduced the abundance and availability of adequate-sized prey. Depending on the severity of the winter, bass that do not attain 25 ± 5 cm by the end of their first growing season do not survive to annulus I formation because of the unavailability of appropriate-sized prey in the spring and the inability of small bass to store sufficient energy reserves. Selective mortality favoring survival of larger individuals in an age-class is operating in the Watts Bar largemouth bass population. This has significant implications for predator growth in ecosystems that experience large seasonal fluctuations in prey availability.Key words: predator population structure, prey availability, reservoir temperature, energy consumption, growth, largemouth bass, selective mortality, shad

Relative Effectiveness of Two Ichthyoplankton Sampling Techniques

Two common ichthyoplankton sampling devices, a pump and a conical plankton net, were evaluated for their relative effectiveness in collecting various sizes of clupeid larvae in the headwaters of Watts Bar Reservoir in eastern Tennessee. Triplicate surface pump and towed-net samples were taken during both day and night on three dates in June 1979 to detect any diel differences in sampler effectiveness. Clupeid larvae, 4–10 mm long, were collected in numbers large enough to make meaningful statistical comparisons of the two techniques. The differences in the mean densities of most length groups between nighttime pump and tow samples were not statistically significant. During the day, however, the pump collected significantly more 4-mm larvae and the towed net collected more 5- to 10-mm larvae. Our results indicate that under conditions by which these samplers are commonly deployed in open waters, most sizes of young shad larvae exhibited a greater ability to avoid the pump sampler than the towed net during the daytime.Key words: ichthyoplankton, pump, nets, fish larvae, avoidance

Sustained Fast Valving Applied to Tennessee Valley Authority’s Watts Bar Nuclear Units

The first application of sustained fast valving for nuclear units is planned for units 1 and 2 at the Tenneseee Valley Authority’s (TVA) Watts Bar Nuclear Plant. The proposed turbine cycle and the advantages of sustained fast valving to the power system are presented. The turbine cycle simulation is discussed and the effects of feedwater heater energy storage on short term power transients are demonstrated. The mechanical reliability of the turbine and related equipment is determined from the turbine cycle simulation.