None

; ; Tanabe, Hiromi; ; ; ;

PNC TN9080 92-009, 24 Pages, 1992/04

PNC-TN9080-92-009.pdf:0.94MB

None

None

; ; Tanabe, Hiromi; ; ; ;

PNC TN9080 92-007, 113 Pages, 1992/04

PNC-TN9080-92-007.pdf:3.26MB

None

None

; ; ; Miyakawa, Shunichi; ; ; Ito, Hideaki

PNC TN9080 92-005, 70 Pages, 1992/04

PNC-TN9080-92-005.pdf:1.39MB

None

Design study of large FBR plant (5); The Development of the analysis code for thermal transients of FBR plant

; *; ; ;

PNC TN9410 91-109, 83 Pages, 1991/02

PNC-TN9410-91-109.pdf:2.46MB

Many studies for the 600MWe large FBR plant design began at April 1990 in our section. In order to evaluate the thermal transient for this plant, the analysis code, by which we can easily find the proper design parameters, is under development. The program of this code is based on Super-COPD. As the first step of the development, a simple model of Super-COPD was constructed, and the thermal transients of this plant were calculated. These results showed as follows; (1)The thermal transient characteristics were easily calculated when the primary and secondary flows were input conditions, (2)The results of this calculation showed the similar characteristics to those of 'Monju' plant except for the AC outlet sodium temperature that changes much in small differences in its flow characteristics, (3)The thermal transients of this large FBR plant transport the response much quicker than those of 'Monju'. It is supposed that this plant has shorter loops than 'Monju'. Another calculations of this plant and 'Monju' plant are scheduled in order to verify this model.

Development of remote maintenance technology; Trial fabrication of sodium handling robot

*; *; *; *; *

PNC TN9410 87-046, 62 Pages, 1987/04

PNC-TN9410-87-046.pdf:8.3MB

Sodium Handling Robot was trially fabricated, in order to develop the manipulation technology which was one of the key technologies for Remote Maintenance in FBR Plant. The robot was fabricated by the following three steps. (1)1st step (1984). Trial fabrication of Handling manipulater (2)2nd step (1985). Trial fabrication of Control unit (3)3rd step. Trial fabrication of Uiecle. This report describes the outline and specification of sodium handling robot. The robot has 7 freedom as same functions as a human arm, to be used for sodium cleaning of components by steam. The manipulater of the robot was controlled by master-arm. The test was carried out to confirm and investigate the functions for actual use.

MONJU Primary prototype pump test

*; *; *; *; *

PNC TN941 85-79, 157 Pages, 1985/05

PNC-TN941-85-79.pdf:3.61MB

In-sodium test was carried out for MONJU primary prototype pump, having a new hydrostatic bearing and convection suppressing fin. The test parameters were sodium level in the pump and flow of the seal gas. The test results are summarized as follows. (1)The pump operated satisfactorily on each condition of low sodium level with and without seal gas and normal sodium level without seal gas. This shows the pump has the soundness even in the cases of primary piping broken and the seal gas stopped. (2)It was obtained from the low sodium level test that each time of radial temperature difference for both inner and outer casings was its maximum and stable respectively. (3)It was approved that the maximum radial temperature differences for both inner and outer casings were increased with the time passing and sodium level falling, and also approved that the time which the temperature differences became their maximum were short with sodium level falling. (4)Maximum displacement of outer casing was smaller than the approved value at the lowest sodium level test, so it seems there is no problem on the real pump operation. (5)The test showed that convection suppressing fin was useful why the displacement of the casings were suppressed, because the times of the maximum radial temperature differences of the casings were late and displacement of outer casing was increased slowly. (6)It was approved that the pony motor of the pump was stopped and started again satisfactorily at the lowest sodium level.

None

; Onuki, Osamu;

Donen Giho, (53), p.36 - 62, 1985/03

https://jopss.jaea.go.jp/pdfdata/PNC-TN134-85-01.pdf

None

Sodium boiling detection by acoustic method

*; *; *; Haga, Kazuo*; *; *

PNC TN941 84-59, 49 Pages, 1984/03

PNC-TN941-84-59.pdf:1.62MB

Sodium boiling experiments were conducted with the out-of-core sodium loop in order to establish the acoustic detection method of sodium boiling in FBR reactor core. The following results, which are informative to the design of the sodium boiling boiling acoustic detection system were obtained concerned about the characteristic of sodium boiling sound, the method of signal processing and the change of acoustic sensor performance. (1)Acoustic pressure by sodium boiling increases according to the boiling grade, but boiling period becomes longer conversely. The maximum acoustic pressure reached about 1000 Pascal, and the period decreased until about 0.7 second. (2)Acoustic spectrum extends from a few kHz to a few tens kHz, but by in-sodium sensor, lower frequency components and by on-wraper tube sensor, higher frequency components were obtained mainly. And the latter sensor had peculiar acoustic signals which didn't appear in the former sensor. (3)Smooting processing of acoustic signals was found to be necessary for the cross correlation method in order to obtain the time lag between the signals of two sensors. (4)Detecting sensitivity of piezo electric acoustic sensors (LiNbO) decreased about 20 dB and recovered to 5 dB after used in sodium for long time. But the resistance between electrodes of sensors continued to decrease with the operation time in sodium due to lack of oxygen. (5)On the detection of early stage sodium boiling, some methods which utilizes the boiling periodicity and cross-correlation between two sensors would be necessary in order to distinguish that was caused by boiling from the flow noise. Some studies are still necessary in future for the establishment of the detection method of early stage boiling under the real level of flow noise, and the localization method of boiling sourse. Besides these efforts, the development of magnetic distortion probe which doesn't need oxygen is also expected.

In-sodium test of long length level-meter

*; *; *; *

PNC TN941 84-04, 103 Pages, 1984/01

PNC-TN941-84-04.pdf:2.82MB

It is planed that induction type level-meter of effective measurement length about 5m is installed for monitoring of sodium level in reactor vessel of "MONJU" Plant. Length of level-meters made so far were less than 2m. So long length level-meter which had same length for real plant was fabricated, and in-sodium tests for confirmation of performance as "MONJU" plant instrument were conducted. From these tests, it was found that "MONJU" plant require ment on measurement accuracy (4%) was satisfied, and prospect of design and fabrication for real plant was obtained. And some propositions were given which were about improvement design of the level-meter property and caution at the installation into the reactor vessel.

Experimental study of local sodium boiling detection by use of temperature and flow fluctuations at the outlet of subassembly

*; *; Haga, Kazuo*; Yamaguchi, Katsuhisa; *

PNC TN941 83-97, 71 Pages, 1983/06

PNC-TN941-83-97.pdf:2.53MB

Out-of-pile local boiling experiments were carried out with a wire spacer type 91-pin bundle. A half edge part of its cross-sectional area was blocked by a 5mm thick stainless-steel plate. The purpose of the experiments is to study the feasibility of detecting coolant boiling accident within a LMFBR fuel subassembly using the temperature and flow fluctuations at the outlet of individual subassembly. Initial conditions of the experiment are as follows: (1)Bundle inlet temperature : 400 500 C (2)Heat flux : 72 93 W/cm (3)Coolant flow velocity at the normal bundle section : 0.64 1.13 m/s. Local boiling was generated immediately behind the blockage by increasing heat flux gradually, with inlet sodium temperature and coolant flow rate being held to be constant. Specifications of the instrumentation system for measuring temperature and flow fluctuations are listed below: (1)Thermocouples Chromel-Alumel thermocouples, Grounded-type (O.D. 0.3mm) and ungrounded-type (O.D. 4.8mm) Time constant (63.2%) 10 msec and 2.14 sec respectively (2)Flowmeter Eddy-current type temperature and flowmeter Exciting frequency : 425 Hz (3)Fluctuation measuring circuit : Maximum gain : 60 dB Frequency characteristics : flat in the frequency range from 0.01 to 15 Hz, 20 dB/dec attenuation slope below 0.01 Hz and 200 dB/dec attenuation slope above 15 Hz. The following subjects have been studied. (1)To investigate how boiling informations are transferred. (2)Anomaly detection methods by use of the temperature and flow fluctuations. (3)Feasibility of detecting local boiling accident by fluctuation signals. These studies yielded the following conclusions. (1)Spectral peak arround 4 Hz in the power spectral density functions of the temperature fluctuations was observed at the downstream bundle section of the blockage. This frequency peak is consistent with that of void formation and collapse and may ...