System Makeup Research Articles

Suppression pool testing at the SIET laboratory: experimental investigation of critical phenomena expected in the Fukushima Daiichi suppression chamber

In the unlikely event of a nuclear power plant long duration station black-out, as in the Fukushima Daiichi (1F) severe accident (SA), it was recognized that the suppression chamber (S/C) functions of heat sink and fission product (FP) scrubbing will degrade, resulting in the S/C pressure increase, reduction of the scrubbing efficiency and subsequent necessity of venting operations. Consequently, a relatively large amount of FPs, in particular highly volatile elements (e.g. CH3I), is likely to be dispersed into the environment. As a method to evaluate the degradation of the pool characteristics under discharge of steam and non-condensable gases through vent pipes and steam through different quencher geometries of make-up systems, an experimental campaign was recently started at the SIET research laboratory in Italy. Two different quencher geometries, representing vent pipes and the reactor core isolation cooling (RCIC) exhaust pipes in 1F2 and 1F3, were adopted. Several combinations of steam and air mass flow rates were tested to scale down the main conditions occurred during the 1F SA. Measurements of pool water temperature in different locations and visualization with high-speed camera represent the main outcome of the experimental activity. The preliminary results have demonstrated that a relatively small concentration of air in the steam flow is able to suppress the occurrence of chugging of the steam, with reduced mixing in the pool. Both RCIC quenchers adopted induced large chugging at the bottom of the pool which are effective to avoid temperature stratification, thanks to the large water recirculation and vertical mixing within the pool. At decreased subcooling, mixing in the pool ceases and the quenchers with holes disposed in the vertical direction, as in the RCIC exhaust pipe of the 1F unit 3, introduce intense stratification that drastically reduces the condensation efficiency of the S/C pool. Quencher of 1F2 RCIC does not present stratification possibly dependent on the distance of the pipe outlet to the pool floor. Given the reduced size of the pool compared to the plant scale, the observed phenomena should not be extrapolated for the whole S/C. The objective of the ongoing experimental activity is to construct a database based on the high-speed filming, measurements of major quantities such as water temperature, steam pressure and FPs concentration to foster the development of physical models for both lumped parameter SA codes and detailed computational fluid dynamics software, in an effort to enhance the understanding of the complex phenomena following the 1F accident.

Analyses of Beyond Design Basis Accident Homogeneous Boron Dilution Scenarios

Abstract Homogeneous boron dilution scenarios in a VVER-440 reactor were analyzed using the coupled KIKO3D-ATHLET code. The scenarios are named “homogeneous” because of the very slow dilution caused by a rupture in the heat exchanger of the makeup system. In the case of the presented Beyond Design Basis Accident (BDBA) scenarios, it was supposed that after 30 min the operator doesn't stop the dilution, violating the prescriptions of the Limits and Conditions document. Without the presented analyses, a significant contribution of the homogeneous boron dilution to the Core Damage Frequency (CDF) had to be assumed in the Probabilistic Safety Analyses (PSA). According to the combined results of the presented deterministic and probabilistic analyses, the final conclusion is that boron dilution transients don't give significant contribution to the CDF for the investigated VVER-440 NPP.

Improvement of the Thermohydraulic Operating Regimes of Deaerators in the Makeup and Boron Regulation System with Packed Columns

One of the main pieces of equipment in the makeup and boron regulation system for the first loop of an NPP is the deaerator, whose functions is to degas the coolant removed from the first loop of a nuclear reactor in different operating regimes. Operating experience has shown that a deaerator design with packing columns does not give the requisite margin to flooding. Deaerator calculations suggesting further ways to solve the problem are presented.

PERFORMANCE ANALYSIS OF HELIUM INVENTORY CONTROL OF RGTT200K COOLING SYSTEM

RGTT200K is a power reactor, designed based on HTGR tech-nology having capability to operate at high temperatures. RGTT200K features are 200 MWth power, helium-cooled, graphite moderator and reflector, pebble fuel type, and uses the Brayton direct cycle. Helium Inventory Control System (HICS) is one of its safety system which maintains the pressure, the helium coolant quality and quantity to meet safety requirements. The HICS consists of 3 subsys-tems, namely: Inventory Control System (ICS), Helium Purification System (HPS), and Helium Make-Up System (HMS). All of the systems have the function to maintain pressure, helium quality and quantity so that the reactor can operate reliable and safely. This paper discusses the performance of the ICS, which is integrated to the reactor coolant. The research objective was to determine the helium storage tank response rate, when primary coolant is overpressured and depressurized. The methodology used in this research is modeling and simulation by using ChemCAD. In previous re-search, the HPS, ICS and HMS have been modeled but have not been integrated yet in to the primary coolant. The simulation results showed that the time required for the injection tank back to the cool-ant normal pressure of 52 bars, due to depressurization up to 5 % was 160 seconds. While the time required for bleeding / blowdown to the storage tanks due to overpressurization up to 5 % was 186 seconds.

ICONE23-1216 Simulation on Reactor Boron and Water Makeup System based on GSE

ICONE23-1216 Simulation on Reactor Boron and Water Makeup System based on GSE

Foulant characteristics comparison in recycling cooling water system makeup by municipal reclaimed water and surface water in power plant.

Due to water shortage, municipal reclaimed water rather than surface water was replenished into recycling cooling water system in power plants in some cities in China. In order to understand the effects of the measure on carbon steel corrosion, characteristics of two kinds of foulant produced in different systems were studied in the paper. Differences between municipal reclaimed water and surface water were analyzed firstly. Then, the weight and the morphology of two kinds of foulant were compared. Moreover, other characteristics including the total number of bacteria, sulfate reducing bacteria, iron bacteria, extracellular polymeric substance (EPS), protein (PN), and polysaccharide (PS) in foulant were analyzed. Based on results, it could be concluded that microbial and corrosive risk would be increased when the system replenished by municipal reclaimed water instead of surface water.

Sensitivity analysis on inverse characteristics of directional over current relays using differential evolution algorithm

Protection relays in a power system makeup to pairs, one as main protection relay and the other as a backup protection relay. Directional over current relays (DOCR) have been using for backup protection mainly in distribution system. Coordination of these DOCRs is an optimization problem that is being solved using various types of optimizing algorithms by the researchers in the field. This paper attempts this problem in different direction which analyzes different inverse characteristics of DOCR and their sensitivities to different faults. Optimal values for time dial and plug settings for the DOCRs are obtained by using a recently developed algorithm: Opposition based chaotic differential evolution algorithms. IEEE 4-bus system has been taken as a test model and the algorithms are implemented in it for different types of characteristics based on the degree of inversion i.e., normally inverse, very inverse, extremely inverse and long-time inverse characteristics.

Diagnostic Analysis of Boiler Make-Up Water Treatment System in Taishan Power Plant

The boiler make-up water pretreatment system and desalination system of 2×1000MW units in Taishan power plant were investigated and analyzed,and their corrosion risk were assessed . The results showed that the change of seasons had no effect on the dosage of coagulate in boiler make-up water pretreatment system and the system had advantages of economic operation, simple maintenance, however, corrosion risk might exist in equipment; for desalination system, carbon remover could be omitted and it had a large cycle water production, and the water quality of the mixed bed is good, however, the effect of iron removal and high efficiency filter backwashing is poor, In addition, corrosion existed in both acid and alkali regeneration system as well as in drainage system, steam turbine and effluent treatment equipment.

Exploration and determination of the principles of rotary-percussive underground slimhole drilling

A possibility of the efficient use of rotary percussive drilling to provide drilling smaller diameter holes (40–70mm) both in mining and prospecting is disclosed herein. A new construction designed for the nipple thread connection is described. The relative amplitude variation, change of power pulse time and energy in their propagation throughout the drilling tool are determined. A possibility of the efficient power pulse transfer along the drill string to the rock destruction tools with new nipple connections which allow automating the make-up and breakout system of drill pipe was supported by experiments.

Evolution of Tubular Handling Brings Big Safety, Efficiency Gain

Technology Update Safety and efficiency have long been the drivers in the evolution of tubular handling and running technology, from manual systems to highly mechanized and automated processes. As increasingly complex well construction demands have created new challenges and a heightened emphasis on well integrity, a more comprehensive approach to tubular management and running has emerged. Evolving beyond rotary table operations, today’s tubular running services also encompass an upstream focus on pipe preparation and makeup offline and a downstream emphasis that ensures high-integrity casing string installations to total depth (TD). Tubular Management Tubular management requires a comprehensive process that involves logistical planning, pipe storage, preparation, makeup, and wellsite planning to deliver pipe ready to run. A successfully executed offline process covering all of these factors yields greater consistency and reduces personnel and infrastructure requirements. Safety and efficiency gains are achievable by controlling how the pipe is handled, controlled, and run in onshore and offshore operations. Offline pipe makeup for casing, tubing, and drillpipe is done at Weatherford with advanced oilfield bucking (Fig. 1) and torque-control makeup systems that employ the same technology used on rig systems for many years. The technology, which can be positioned at permanent facilities and on remote locations, is used to build ready-to-run double or triple stands of tubulars for delivery to the rig. Delivery of rig-ready pipe to the wellsite limits the exposure of rig personnel to makeup and running operations and reduces pipe preparation cost and rig time. It also reduces openhole exposure time, which helps minimize wellbore stability issues and contributes to better casing running times. Connection integrity control, beginning with planning and preparation, reduces the chance of failure and well repairs. As with rig-based systems, the offline technology makes or breaks connections using highly accurate torque measurements that are displayed and recorded. The system ensures connection integrity and makeup parameters for API and premium thread tubing, casing, production riser, and drillpipe. Cementing accessories can also be made up and the system can be configured for subassembly of downhole equipment. Faster makeup speeds are enabled by rotational makeup and breakout technology that can be instantly reversed. Detailed pipe connection data is collected off site or on the rig with unique identifiers barcoded on the pipe. Information recorded during offline makeup is merged with data from connections made up on the rig, including torque, length, drift, and tally. This synchronized data collection and automated traceability improves research, reduces nonproductive time, and lowers costs associated with connection integrity. Efficiency and cost reductions are also achieved through streamlined tubulars selection, improved supply chain efficiency, and application of vendor and supplier management systems. For tubulars headed offshore, smooth logistics, packaging, and transportation depend on well-designed and -executed quayside operations.

BWR-4 safety systems serviceability during blackout at the Fukushima-1 NPP (Japan)

During the serious accident at the Fukushima-1 NPP (Japan), the cores of the Nos. 2 and 3 units were cooled for a long period of time by safety systems which were not designed for operation under prolonged power loss. The serviceability of BWR-4 high-head makeup systems and the reasons for their failure are analyzed. It is shown that taking dc losses in the No. 2 unit into account the makeup system remained serviceable in the unanticipated regime. The shutdown of the makeup systems in both units could have been due to the maximum backpressure being reached at the turbine outlets or by cavitation in the turbopumps. It is shown that it is important to make a realistic assessment of the depletion time of the storage batteries in the No. 3 unit.

Treatment of Wastewater to Meet the Requirements for Cooling Water Systems in Jordan’s Nuclear Plants

Scaling and corrosion associated with the use of natural hard water in cooling towers during recirculation pose great problems from both economical and technical points of view, such as decreased system efficiency and increased frequency of chemical cleaning. Treated municipal wastewater (MWW) is a promising alternative to freshwater as power plant cooling system makeup water, especially in arid regions. In this work, hybrid systems of salt precipitation (SP), nanofiltration (NF) and reverse osmosis (RO) were investigated, as potential pretreatment processes for wastewater reuse as cooling water in the planned Jordan nuclear power plants. The As-Samra wastewater was used to calculate the potential of carbonate and sulfate scale formation. The results were compared to scale potentials from Palo Verde wastewater. Four cases were investigated; SP, NF, SP-RO and NF-RO. The SP pretreatment cases showed the highest monovalent to divalent ratio because of a high removal of Ca and Mg and addition of Na from the chemicals of the SP step. The NF pretreatment cases, showed the lowest calcium sulfate scale potential and this potential decreases with the % pretreatment. The scale amount increases very slightly with concentration times when the SP and NF product is desalinated by RO step.

Spatial Concentration Variation of Contaminants in a Residential Kitchen and the Effect of Makeup Air System

In this paper, the experimental data of CO, CO2 and total volatile organic compound (TVOC) concentration in a residential kitchen are presented. Based on them, a simulation software with friendly and simply operating interfaceis is developed on the platform of VC++. The distribution law of the contaminants is studied via the simulation results, and it is obvious that location of accumulation of the contaminants are highly relevant to the location of stove and closer to the walls. An addition natural air makeup system is proposed to improve indoor airenvironment in kitchens, the effection of the air makeup system is analyzed with exergy theory.

Development of HPLC with High-sensitive and Precise Electrochemical Detection Enabling Dynamic Analysis of Compounds of Biological Importance

HPLC with electrochemical detection (HPLC-ECD) is an attractive method with sensitivity and selectivity for the determination of redox compounds. However, an improper system makeup or operation is apt not to show such the intrinsic characteristics of the analytical results by HPLC-ECD in regards to biological sample assays. In this review, HPLC-ECD enabling high-sensitive and precise analysis of compounds of biological importance was developed using the following chemometric strategies: spectrum analysis of chromatographic baseline noise, standard deviation (S.D.) of area measurements in baseline noise from stochastic aspects, and optimization of HPLC conditions and method validations in HPLC-ECD using the prediction of precision based on the FUMI (Function of Mutual Information) theory. When HPLC-ECD was established using a capillary column (0.2 mm i.d.), catechins were determined at attomole levels and the present HPLC-ECD was applied to the determination of concentration profiles of catechins in human plasma after green tea ingestion. Moreover, two HPLC-ECD systems for determining acids and bases were developed by the means of the voltammetric reduction of quinone and the oxidation of trolox, respectively. Thus, the application of HPLC-ECD methods has been remarkably expanded through the development of novel ECD for the determination of acids and bases which are less active electrochemically. The present methods for determining acids and bases were applied to the pharmacokinetic studies of free fatty acids and theophylline, respectively. In conclusion, it was shown the present HPLC-ECD methods have been successfully applied to biomedical and pharmaceutical analyses.

Corrosiveness of Different Treated Municipal Wastewaters Used as Power Plant Cooling System Makeup Water: A Bench-Scale Evaluation

Corrosion of metals and metal alloys in a recirculating power plant cooling system is a major operational concern and is exacerbated when using treated municipal wastewater as makeup water, due to the degraded water quality. In this study different treated municipal wastewaters were used in a bench-scale water recirculation system, simulating cooling water conditions in power plant cooling systems. The treated municipal wastewaters used were: secondary treated municipal wastewater (SMW) with pH reduction, SMW with nitrification-filtration, and SMW with nitrification-filtration-granular activated carbon (GAC) adsorbtion. The corrosiveness of these treated municipal wastewaters to mild steel, copper and cupronickel alloys were analyzed. The efficacy of Tolyltriazole (a corrosion inhibitor) was also analyzed in this study. Results showed tolyltriazole successfully reduced the corrosion rates of mild-steel copper and cupronickel alloys in all the systems.

Pilot-scale cooling tower to evaluate corrosion, scaling, and biofouling control strategies for cooling system makeup water

Pilot-scale cooling towers can be used to evaluate corrosion, scaling, and biofouling control strategies when using particular cooling system makeup water and particular operating conditions. To study the potential for using a number of different impaired waters as makeup water, a pilot-scale system capable of generating 27,000 kJ∕h heat load and maintaining recirculating water flow with a Reynolds number of 1.92 × 10(4) was designed to study these critical processes under conditions that are similar to full-scale systems. The pilot-scale cooling tower was equipped with an automatic makeup water control system, automatic blowdown control system, semi-automatic biocide feeding system, and corrosion, scaling, and biofouling monitoring systems. Observed operational data revealed that the major operating parameters, including temperature change (6.6 °C), cycles of concentration (N = 4.6), water flow velocity (0.66 m∕s), and air mass velocity (3660 kg∕h m(2)), were controlled quite well for an extended period of time (up to 2 months). Overall, the performance of the pilot-scale cooling towers using treated municipal wastewater was shown to be suitable to study critical processes (corrosion, scaling, biofouling) and evaluate cooling water management strategies for makeup waters of complex quality.

Microbiological Induced Corrosion on Brass in Recycling Cooling Water System Makeup by Reclaimed Water

The impacts of microorganism on brass corrosion were studied in static experiment in this paper. Two main factors, temperature and concentration ratio, were considered. According to the actual operation of recycling cooling water system, four temperatures (15℃, 25℃, 35℃ and 45℃) and four concentration ratios (1, 2.5, 3.5 and 4.5) were selected in the experiment. Corrosion potential, current density, average corrosion rate were measured by time. The results showed that: Microorganism often aggravated corrosion of brass during initial and final stages, but alleviated its corrosion at the middle time. With the extension of time that brass immersed in the solution, the microbes began to intensify the corrosion of the metal. When concentration ratios were 2.5 and 3.5 and temperature was 15℃, microbe promoted brass corrosion obviously and corrosion degrees.

Anticoagulation control of pharmacist-managed collaborative care versus usual care in Thailand

There has been a lack of evidence of the effects of pharmacist-managed warfarin therapy (PMWT) in developing countries (e.g. Southeast Asian countries) where the patients' characteristics, genetic make-up, clinical practice and healthcare system are different from the Western world. This study aimed to compare the anticoagulation control and clinical outcomes associated with warfarin therapy provided by PMWT to usual care (UC) in the Thai population. A 1,000-bed tertiary-care hospital in Nakornratchasima province of Thailand. A quasi-experimental study comparing PMWT and UC in patients receiving long-term warfarin therapy. For PMWT group, clinical pharmacists optimised the warfarin therapy and suggested recommendations (e.g. dose adjustment, safer alternative drugs, and follow-up time) to physicians. The UC group received the standard care. Time in therapeutic range (TTR), both actual- and expanded-TTR, bleeding and thromboembolic complications, and physician' acceptance of pharmacist suggestions. Of 433 patients enrolled, 220 and 213 were in the PMWT and UC groups respectively. At baseline, patient's characteristics of both groups were comparable. At the end of follow-up period, patients in the PMWT group had significantly higher actual-TTR (48.3% vs. 40.1%; P < 0.001) and expanded-TTR (62.7% vs. 53.9%; P < 0.001) compared to those in the UC group. Rates of major bleeding were 4.4 vs 4.5 events per 100 person-years for the PMWT and UC groups, respectively. Pharmacists performed 284 interventions with an acceptance rate of 80.3% from physicians. Pharmacist-managed warfarin therapy resulted in a significantly better anticoagulation control. This study showed that a collaborative approach in anticoagulation management can be successfully implemented in a developing country. Implementation of such care model in other developing countries should be considered.

Corrosion Control when Using Passively Treated Abandoned Mine Drainage as Alternative Makeup Water for Cooling Systems

Passively treated abandoned mine drainage (AMD) is a promising alternative to fresh water as power plant cooling water system makeup water in mining regions where such water is abundant. Passive treatment and reuse of AMD can avoid the contamination of surface water caused by discharge of abandoned mine water, which typically is acidic and contains high concentrations of metals, especially iron. The purpose of this study was to evaluate the feasibility of reusing passively treated AMD in cooling systems with respect to corrosion control through laboratory experiments and pilot-scale field testing. The results showed that, with the addition of the inhibitor mixture orthophosphate and tolyltriazole, mild steel and copper corrosion rates were reduced to acceptable levels (< 0.127 mm/y and < 0.0076 mm/y, respectively). Aluminum had pitting corrosion problems in every condition tested, while cupronickel showed that, even in the absence of any inhibitor and in the presence of the biocide monochloramine, its corrosion rate was still very low (0.018 mm/y).

Corrosiveness of Different Treated Municipal Wastewaters Used as Power Plant Cooling System Makeup Water: A Bench-Scale Evaluation

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