Class 1E Research Articles

가우시안 포락선 선형 첩 신호의 순시 주파수 추정을 통한 원전 내 계측 케이블의 고장점 진단 연구

Integrity of the control and instrumental cables in nuclear power plant is important to maintain the stability of the nuclear power plants. In order to diagnose the integrity of the cables, the diagnostic methods based on reflectometry have been studied. The reflectometry is a non-destructive method and it is applicable to diagnose the live cables. We introduce a Gaussian enveloped linear chirp reflectometry to diagnose the cables in the nuclear power plants. In this paper, we estimate the instantaneous frequency of the Gaussian enveloped linear chirp signal by using the weighted robust least squares filtering to localize the impedance discontinuities in the class 1E instrumental cable.

On-site power system reliability of a nuclear power plant after the earthquake

Abstract Continuous and reliable sources of electrical energy are required during all modes of operation of a nuclear power plant in order to assure the safety of the plant. The electrical energy to the safety systems of the nuclear power plant is provided from the on-site power system. The objective of this paper is to analyze the nuclear power plant on-site power system reliability during normal operation and after the earthquakes with given intensity. The obtained results show the importance of the on-site power system reliability in general and battery supported section of the Class 1E power system in particular for the safety of the nuclear power plant. High level of reliability is obtained for the Class 1E and Non-1E power system during normal operation and safe shutdown earthquake. Obtained results show high level of reliability of a Class 1E power system after the earthquake with peak ground acceleration equal to the one measured at the Fukushima Daiichi nuclear power plant. Recommendation for revision of the current guideline for assessment of the acceptable station blackout duration capability is recommended considering the results of the analysis and identified deficiencies in the current guideline.

KEEFEKTIFAN PEMBELAJARAN MATEMATIKA BERBASIS KONTRUKTIVISME PADA MATA KULIAH MATEMATIKA DASAR

This research aims to improve mathematics learning achievement of first semester student majoring biology at IKIP PGRI Semarang using mathematics learning based on constructivism in basic mathematics courses. This type of study is a research of Quasy Experimental. The population is the first semester of students majoring in biology education IKIP PGRI Semarang which consists of five classes. By random sampling technique we choose two classes, class 1A as a class experiment and class 1E as a control class. Variables in this research are the process skills (X) as the independent variable and learning achievement (Y) as the dependent variable. Data collection had been done by observation and learning achievement tests and for analyzing by comparison and influence tests. The results showed that completeness test has average 70.20 . It means that completeness had been and there is a achievement difference between the experimental class and control class. Beside that, we find that variable of process skill has a positive effect to the learning achievement by regression equation and the effect is 20.3%. It is shown that learning at experiment class is effective.

A STUDY ON THE AGING DEGRADATION OF ETHYLENE-PROPYLENE-DIENE MONOMER (EPDM) UNDER LOCA CONDITION

The aging degradation and lifetime assessment of a domestic class 1E Ethylene-Propylene-Diene-Monomer (EPDM), which is a popular insulating elastomer for electrical cables in the nuclear power plants, were studied for equipment qualification verification under the Loss of Coolant Accident (LOCA) conditions. The specimens were acceleratively aged, underwent a LOCA environment, as well as tested mechanically, thermo-gravimetrically, and spectroscopically according to the American Society of the Testing of Materials (ASTM) procedures. The tensile test results revealed that the elongation at break gradually decreased with an increasing aging temperature. The lifetime of EPDM aged isothermally at 140℃ was 1,316 hours and reduced to 1,120 hours after experiencing the severe accident test. The activation energies of the elongation reduction were 1.10 ± 0.196 eV and 0.93 ± 0.191 eV before and after the LOCA condition, respectively. The TGA test results also showed that the activation energy of the aging decomposition decreased from 1.35 eV to 1.02 eV after undergoing the LOCA environment. Although the mechanical property changes were discernibly observed during the aging process, along with the LOCA simulation, the FT-IR analysis showed that the spectroscopic peaks and their intensities did not alter significantly. Therefore, it can be concluded that the degradation of the domestic class 1E EPDM due to aging can be tolerable, even in severe accident conditions such as LOCA, and thus it qualifies as a suitable insulating material for electrical cables in the nuclear power plants.

Development of Diesel Generator Excitation System in the Nuclear Power Plant

Because diesel generator excitation systems in the nuclear power generating station are included among safety related c1asses(and Class 1E), they have been supposed to apply in the nuclear power generating stations through equipment qualification by nuclear law and so on. So, they has been controlled and assured completely by quality assurance throughout the total development journey. This paper looks into the journey of development of diesel generator excitation systems in the nuclear power generating station.

Questionable system grounding practices at nuclear power plants

A number of questionable system grounding practices have been identified at nuclear power plants. These practices could result in unforeseen degradation of the ac Class 1E Power System. (Class 1E is the safety classification of the electrical systems and equipment utilized to mitigate accidents at nuclear power plants.) The paper provides an overview of system grounding with emphasis on the challenges faced with ungrounded and high-resistance grounded systems. It explains how design deficiencies are to be treated with respect to the single failure criterion, then gives a few examples of questionable system grounding practices that have been observed at nuclear power plants in the United States, categorizing these as potential design deficiencies.

Questionable System Grounding Practices at Nuclear Power Plants

A number of questionable system grounding practices have been identified at nuclear power plants. These practices could result in unforeseen degradation of the ac Class 1E Power System. (Class 1E is the safety classification of the electrical systems and equipment utilized to mitigate accidents at nuclear power plants). This paper provides an overview of System Grounding with emphasis on the challenges faced with ungrounded and high resistance grounded systems. It explains how design deficiencies are to be treated with respect to the single failure criterion, then gives a few examples of questionable system grounding practices that have been observed at nuclear power plants in the U.S., categorizing these as potential design deficiencies.

Safety system augmentation at Russian Nuclear Power Plants

This paper describes the design and procurement of a Class 1E DC power supply system to upgrade plant safety at the Kola Nuclear Power Plant (NPP). Kola NPP is located above the Arctic circle at Polyanie Zprie, Murmansk, Russia. Kola NPP consists of four units. Units 1 and 2 have VVER-440/230 type reactors: Units 3 and 4 have VVER-440/213 type reactors. The VVER 440 reactor design is similar to the pressurized water reactor design used in the US. This project provided redundant Class 1E DC station batteries and DC switchboards for Kola NPP, Units 1 and 2. The new DC power supply system was designed and procured in compliance with current nuclear design practices and requirements. Technical issues that needed to be addressed included reconciling the requirements in both US and Russian codes and satisfying the requirements of the Russian nuclear regulatory authority. Close interface with ATOMENERGOPROEKT (AEP), the Russian design organization, KOLA NPP plant personnel, and GOSATOMNASZOR (GAN), the Russian Version of US Nuclear Regulatory Commission was necessary to develop a design that would assure compliance with current Russian design requirements. Hence, this project was expected to serve as an example for plant upgrades at other similar VVER-440 nuclear plants. In addition to technical issues, the project needed to address language barriers and the logistics of shipping equipment to a remote section of the Former Soviet Union.

Prealbumin in nutrition evaluation

We compressed 16 test-pattern classes of albumin (ALB), cholesterol (CHOL), and total protein (TPR) in 545 chemistry profiles to 4 classes by converting decision values to a number code to separate malnourished (1 or 2) from nonmalnourished (NM) (0) patients, using as cutoff values for nonmalnourished (0), mild (1), and moderate (2): ALB 35, 27 g/L; TPR 63, 53 g/L; CHOL 3.9, 2.8 mmol/L; and BUN 9.3, 3.6 mmol/L. The BUN was found to have too low an S-value to make a contribution to the compressed classification. The cutoff values for classifying the data were assigned prior to statistical analysis, after examining information in the structured data. The data was obtained by a natural experiment in which the test profiles routinely done by the laboratory were randomly extracted. The analysis identifies the values for the variables used that best classify the data and are not dependent on distributional assumptions. The data were converted to 0, 1, or 2 as outcomes, to create a ternary truth table (each row is nnnn, the n value is 0 to 2). This allows for 3 4 (81) possible patterns, without the inclusion of prealbumin (PAB). The emerging system has much fewer patterns in the information-rich truth table formed (a purposeful, far from random, event). We added PAB, coded, and examined the data for 129 patients. The classes are a compressed truth table of n-coded patterns with outcomes of 0, 1, or 2 with protein-energy malnutrition (PEM) increasing from an all-0 to all-2 pattern. Pattern class (F = 154), PAB (F = 35), ALB (F = 56), and CHOL (F = 18) were different across PEM class and predicted PEM class (R 2 = 0.7864, F = 119, p < E −5). Kruskal-Wallis analysis of class by ranks was significant for pattern class (1E −18), PAB (6.1E −15), ALB (1E −16), CHOL (9E −10), and TPR (5.3E −13). The medians and standard error (SEM) for PAB, ALB, and CHOL of all four PABCLASSES (NM, mild, moderate, severe) are: PAB = 209, 8.7; 159, 9.3; 137, 10.4; 72, 11.1 mg/L, ALB = 36, 0.7; 30.5, 0.8; 25.0, 0.8; 24.5, 0.8 g/L; CHOL = 4.43, 0.17; 4.04, 0.20; 3.11, 0.21; 2.54, 0.22 mmol/L. PAB and CHOL values show the effect of nutrition support on PAB and CHOL in PEM. Moderately malnourished patients receiving nutrition support have PAB values in the normal range at 137 mg/L and at 159 mg/L when the ALB is at 25 g/L or at 30.5 g/L.

A recommended approach for calculating degraded voltage relay setpoints for nuclear generating stations

Determining the proper setpoint for degraded voltage relays in nuclear generating stations is a complex task which requires a complete understanding of the Class 1E power distribution system. Despite the importance of degraded voltage relay setpoint calculations, most of the available references only give clues on how not set these relays rather than provide guidance on how to determine the appropriate setpoint. This paper presents an approach for performing these calculations which attempts to ensure that all of the relevant design issues are addressed. >

Circuit by circuit power cable separation in nuclear power plants

Many nuclear power plants, designed prior to 1975 were engineered to achieve the independence of the circuits and equipment comprised of or associated with Class 1E systems; this was achieved by the means of circuit by circuit physical separation and electrical isolation rather than by unitized raceways on a train basis to a greater degree than at post 1975 designed plants. Because circuit by circuit separation results in cables from different power trains being routed in the same cable trays, a careful analysis is required to ensure that redundant Class 1E circuits are not routed in the same raceways. This paper presents the analysis done for the power cables at the Consolidated Edison Company's Indian Point 2 nuclear power plant and identifies the steps required to maintain this power cable configuration.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Loss-of-coolant accident (LOCA) testing of aged cables with application to nuclear plant life extension

Sandia National Laboratories is conducting long-term aging research on representative samples of U.S. nuclear power plant Class 1E cables. The objectives of this program are to determine the suitability of these cables for extended life (beyond 40-year design basis) and to assess various cable condition monitoring (CM) techniques for predicting remaining cable life. Twelve different cable products have been artifically aged at relatively mild exposure conditions in three test chambers to nominal equivalent lifetimes of 20, 40, and 60 years based on Arrhenius acceleration theory. After aging, the cables in each chamber were exposed to a sequential accident profile consisting of 1100 kGy of high dose rate gamma irradiation followed by a simulated design basis loss-of-coolant accident (LOCA) steam exposure. This paper presents selected results of the LOCA testing. Although some of the cables experienced electrical failures, the results of these tests indicate a good life extension potential for a number of popular U.S. cable products. Results of the CM techniques are still under evaluation and are not reported here.

Extending qualified life of Class 1E equipment

The regulatory basis, essential ingredients, and program strategies are discussed for extending the qualified life of both harsh- and mild-environment Class 1E equipment used in nuclear power plants. A nuclear power plant houses many hundreds of Class 1E components with qualified parts having 5 (or less) to 40 years of qualified life. Regulatory guidance exists on extending this equipment's qualified life and maintaining it in a qualified state as life progresses. Qualified life can be extended by monitoring environmental parameters, maintaining accurate records, and conducting meaningful surveillance tests using preaged modules. Mild-environment equipment should also be included in the life extension program.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Extending Qualified Life of Class 1e Equipment

Extending Qualified Life of Class 1e Equipment

An Uninterruptible Power System as a Safety Related Isolation Device for Nuclear Power Plants

This paper describes the test procedure and results of a program to qualify a Class 1E uninterruptible power supply (UPS) as a power circuit isolation device between Class 1E power input sources and non-Class 1E load circuits for application in a nuclear power plant. Results demonstrate that the tested equipment provides suitable isolation and that the UPS is completely self-protecting as well as providing its normal UPS functions with automatic static bypass in the event of UPS failure or externally applied overload.

An Uninterruptible Power System as a Safety Related Isolation Device for Nuclear Power Plants

This paper describes the test procedure and results of a program to qualify a Class 1E uninterruptible power supply (UPS) as a power circuit isolation device between Class 1E power input sources and non-Class 1E load circuits for application in a nuclear power plant. Results demonstrate that the tested equipment provides suitable isolation and that the UPS is completely self-protecting as well as providing its normal UPS functions with automatic static bypass in the event of UPS failure or externally applied overload.

Development and Results of a Test Program to Demonstrate Compliance with IEEE STD 384 and R.G. 1.75 Electrical Separation Requirements

The IEEE Std 384-1974, entitled ``Criteria for Separation of Class 1E Equipment and Circuits,'' contains criteria to ensure the independence of redundant Class 1E equipment when designing electrical systems in nuclear plants. The NRC, in R.G. 1.75 Rev. 2, 1978, endorses, with comments, IEEE-384, as the means of achieving independence. One method given in IEEE-384, is that of maintaining a specified separation between components; another method utilizes a combination of separation and barriers. The standard also allows alternative methods to be used when justified by test-based analyses. This paper is a report of a test program undertaken to provide a basis for analysis in the development of alternative methods of achieving separation. The test parameters developed and used, and the results obtained, should prove useful in determining alternative methods of complying with R.G. 1.75 requirements. It should be noted the results of these tests are highly dependent on the type of cable used and the fault current assumptions.

Application of a Microprocessor Based Solid State Programmable Logic System for Control of Class 1E Components and Devices

Application of a Microprocessor Based Solid State Programmable Logic System for Control of Class 1E Components and Devices

Operational Implications of Qualification Tests of Class 1E Electrical Components for Mild Environments

Operational Implications of Qualification Tests of Class 1E Electrical Components for Mild Environments

Operational Implications of Qualification Tests of Class 1E Electrical Components for Mild Environments

This paper presents information regarding a program of accelerated aging and seismic testing of electrical and electronic components used in safety related equipment which is located in mild environment areas of a nuclear power plant. The test methodology is responsive to IEEE Std. 323-1974 and IEEE Std. 344-1975 for Class 1E electrical equipment. The methods used in accelerated aging and seismic testing of the elemental components (capacitors, potentiometers, integrated circuits, etc.) are described and results are presented on a mix of such components which have been tested to various equivalent lives. The operational implications of this program are also discussed.