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Shimomura, Yusuke; Sato, Takuya; Fukui, Yasutaka; Kudo, Kenji; Yoshioka, Tatsuji
JAEA-Review 2018-023, 220 Pages, 2019/01
JAEA-Review-2018-023.pdf:15.6MB
On September 11, 2015, leaky traces of bituminized wastes were confirmed from four drums filled with bituminization in waste packages storage yard (II) of waste management facility in Oarai Research and Development Center. Moreover, even after the subsequent investigation, a leakage trace was found from one bituminous drum on November 10, 2015. Furthermore, on December 2, 2015, there was no a leakage trace in one bituminous drum, however the upper lid was found to be intensely corroded. To investigate the causes and the countermeasures for leakages of bituminized wastes from the drums, we have set up a Work Group to investigate the causes and the countermeasures to leakage traces from the drums. This report is based on "Report on Cause Investigation and Countermeasure of Leakage Trace from the Drum" summarized by this working group, the report was reconstructed including the contents clarified in the subsequent document investigation.
; Kondo, Toshiyuki; *
JNC TN8440 2001-024, 210 Pages, 2001/08
JNC-TN8440-2001-024.pdf:24.99MB
In order to make this book reflect in the investigation which turned the bitumen solidification object to maintenance of the abandonment object technical standard on condition of carrying out subterranean disposal in the future - solidification - it created for the purpose of utilizing as precious sources of information, such as a nuclide inventory in the living body, group-izing of the past campaign required for typical solidification object selection, and information offer at the time of disposal examination. A development operation history collected so that histories including the shift action in an institution of the formation of discharge reduction of the characteristic of solidification object manufacture outlines, such as composition of the process of an institution and a solidification object and a storage actual result, the contents of an examination of the past campaign, and the solidification object manufactured based on topics or radioactive iodine and radioactive carbon etc., such as the past contents of an examination / operation, may grasp comprehensively in creation, and it carried out as the composition stared the trend of future disposal fixedly. It was a period (for 16 years) until an bituminization demonstration facility processing institution will start a cold examination from April (Showa 57), 1982, and it starts a hot examination from May 4, it starts solidification processing technical development operation from october 6 and it results in the fire explosion accident on March 11 (Heisei 9), 1997, and low level radioactivity concentration waste fluid was processed 7,438 m
, and 29,967 bitumen solidification objects were manufactured. According to the accident, it is necessary to hand it down to future generations with processing technology while the bitumen solidification object manufactured in 15 years although the bituminization demonstration facility processing institution came to close the mission holds information precious ...
Fukumoto, Masahiro; Nishikawa, Yoshiaki*; Kagawa, Akio; Kawamura, Kazuhiro
JNC TN8400 2001-002, 23 Pages, 2000/12
JNC-TN8400-2001-002.pdf:0.55MB
The soluble organic compounds generated by radiological degradation of asphalt (
ray) were confirmed as a part of influence of the bituminized waste degradation in the TRU waste repository. Especially, the influence of the nitrate was focused on. As a result, the concentration of the soluble organic compounds generated by radiological degradation of asphalt (10MGy, ray which is correspond to absorbed dose of asphalt for 1,000,000 years) were lower (each formic acid : about 50mg/dm, acetic acid : about 30mg/dm and oxalic acid : about 2mg/dm) than that of the formic acid, the acetic acid and the oxalic acid which Valcke et al. had shown (the influence of the organic at the solubility examination which uses Pu and Am). Moreover, the change in the concentration of TOC and the soluble organic compounds (formic acid, acetic acid and oxalic acid) is little under the existence of nitrate ion. That is, the formic acid and acetic acid which can be organic ligands were generated little by oxidative decomposition of asphalt in the process that nitrate ion becomes nitrite ion by radiation. The influence of the soluble organic compounds by the radiological degradation of the asphalt ( ray) on adsorption and solubility by the complexation of radionuclides in the performance assessment can be limited.
Noda, Kimio; Shinohara, Kunihiko; Kanamori, Masashi
JNC TN8410 2001-010, 35 Pages, 2000/10
JNC-TN8410-2001-010.pdf:3.85MB
We, the radiation control section of JNC have had two important experiences on the JCO critical accident and the JNC fire-explosion accident. Especially, at the critical accident in JCO, it was essential to take an action on the radiation protection activities for the evacuated neighboring inhabitants to the safety area. During the accident, we carried out the radiation protection activities, at the beginning of the accident, environmental monitoring of the surrounding area. Especially for the JCO accident, we took an action to terminate criticality, radiation shielding and monitoring, environmental monitoring, radiation survey of the residents, radiation monitoring of exhaust air.
Mine, Tatsuya*; Mihara, Morihiro; ; *; *
JNC TN8430 2000-003, 33 Pages, 2000/04
On the geological disposal system of the radioactive wastes, the activities of the microorganisms that could degrade the asphalt might be significant for the assessment of the system performance. As the main effects of the biodegradation of the asphalt, the fluctuation of leaching behavior of the nuclides included in asphalt waste has been indicated. In this study, the asphalt biodegradation test was carried out. The microorganism of which asphalt degradation ability was comparatively higher under aerobic condition and anaerobic condition was used. The asphalt biodegradation rate was calculated and it was evaluated whether the asphalt biodegradation in this system could occur. The results show that the asphalt biodegradation rate under anaerobic and high alkali condition will be 300 times lower than under aerobic and neutral pH.
Fukunaga, Sakae*; Yokoyama, Hidekazu*; Arai, Kazuhiro*; Asano, Hidekazu*; Senjyu, Takafumi*; Kudo, Akira*
JNC TJ8400 2000-030, 54 Pages, 2000/02
JNC-TJ8400-2000-030.pdf:1.69MB
It is easy to assume from the past data that microbial transport do not find at 100%-sodium bentonite. Microbial transport do not find at 100%-calcium bentonite too. There are no effects to distribution ration (Kd) of Neptunium (Np) and Plutonium (Pu) with bentonite by sterilizing on low Eh condition (Eh= -500mv). Kd values of Np and Pu show behavior, which are increasing on the hard acidic and alkali conditions. Especially, Kd values of Pu shows one of Kd value is about 100 ml/g on pH=3
6, but the other of Kd value is about 400,000 ml/g on pH=13. Precipitating plutonium hydrates occurred the large Kd value on alkali condition.
Fukunaga, Sakae*; Yokoyama, Hidekazu*; Arai, Kazuhiro*; Asano, Hidekazu*; Senjyu, Takafumi*; Kudo, Akira*
JNC TJ8400 2000-029, 36 Pages, 2000/02
JNC-TJ8400-2000-029.pdf:1.28MB
It is easy to assume from the past data that microbial transport do not find at 100%-sodium bentonite. Microbial transport do not find at 100%-calcium bentonite too. There are no effects to distribution ration (Kd) of Neptunium (Np) and Plutonium (Pu) with bentonite by sterilizing on low Eh condition (Eh = -500mv). Kd values of Np and Pu show behavior, which are increasing on the hard acidic and alkali conditions. Especially, Kd values of Pu shows one of Kd value is about 100 ml/g on pH = 36, but the other of Kd value is about 400,000 ml/g on pH = 13. Precipitating plutonium hydrates occurred the large Kd value on alkali condition.
Koyama, Tomozo; ; Omori, Eiichi; ; ; Shibata, Atsuhiro; Shigetome, Yoshiaki
JNC TN8410 99-027, 423 Pages, 1999/12
The bituminization demonstration facility of Tokai Reprocessig Plant had a fire and explosion incident. The cause of the incident was investigated. Also, the facility condition and release of radioactive materials were evaluated. The cause of the fire and subsequent explosion was determined in a two year investigation. The main cause of the fire was that the temperature of the bituminized product rose to an unusually high temperature by a physical heating phenomena inside the extruder, which was caused by the lowering the feed rate of liquid waste. A moderate chemical reaction in the bituminized product continued and consequently the bituminized product overheated and ignited. The cause of the explosion was the accumulation of flammable gases generated from insufficiently extinguished bituminized product in the filling room in which the ventilation system had been shut down. The flammable gas was ignited by another bituminized product that overheated to the flash point temperature. This report details the condition of the facility before and after the incident, cause of the incident, and an evaluated amount of released radioactive materials.
Miura, Akihiko;
JNC TN8410 99-046, 35 Pages, 1999/10
Judging from several evidences which are operators' testimony, observation result, and so on, the "Committee for an Investigation into the Fire and Explosion Incident at the BDF of the Reprocessing plant of Tokai Works" concluded another fire incident occurred in the filling room (R152) after the explosion (hereafter called second fire incident). This report explains the simulation result of second fire incident. Calculated air temperature and radiation intensity are used another calculations that indicate the thermal influence from the fire name to the extruder or neighboring drums. About second fire incident, calculated result indicates first fire occurred from the No.30104 drum that was produced in 30B or several drums including No.30104 drum. It is estimated that temperature and thermal runaway reaction was not due to fire of neighboring drum because the drum doesn't receive large influence thermally by radiation from the neighboring fire name. Each result suggests the all burnt 29B and 30B drums were filled at higher temperature than usual.
Miura, Akihiko;
JNC TN8410 99-044, 189 Pages, 1999/10
This report includes several results that were made by calculation with several methods to clarify the cause of the fire and explosion incident. In the early times, we didn't have exact information of chemicaI property, reaction rate and any physical constants that we needed. But because the only data that indicate the cooling process of bituminized product was reported, we made heat-transporting calculation with taking this data. Based on the theory of the thermal hazard evaluation that was called Semenov theory or Frank-Kamenetskii theory, the amount of heat generation was estimated using the heat transporting calculation. Common theories were introduced in first section. In the second section, several results of heat transporting calculation were indicated. Calculations were made as follows. First, the model of bituminized product that was filled in the drum was created with the data of cooling process. Second, when the heat was generated in the drum, time-dependent temperature distribution was calculated. And last, judging from the balance of heat generation and heat radiation the critical heat rate was estimated.
; Miura, Akihiko; ;
JNC TN8410 99-043, 135 Pages, 1999/10
All result of chemical analysis and operators observation suggest non-chemical mechanism raised the filling temperature of the bituminized product at the incident. We, Tokai reprocessing plant safety evaluation and analysis team, performed the experiment using laboratory scale extruder and viscosity measurement to explain the high temperature of mixture. The result of the experiment using laboratory scale extruder showed that the phenomena of salt enrichment and salt accumulation oceured and they raised mixture temperature at the decreased feeed rate. These phenomena depend on the feed rate and they have large contribution of heat transportation and rise of operational torque due to the friction between screw and mixture. Based on the experiment result and all information, we investigated the operation procedure, operational records and machine arrangement to try to explain the behavior of the mixture in the extruder. Judging from each torque and temperature behavior, we succeeded in explaining a sequential behavior in the incident. It is estimated that mixture temperature was raised by physical heat generation in the extruder and this report explains each operation, investigated result and estimated event sequences.
Fujine, Sachio; Murata, Mikio; Abe, Hitoshi; Takada, Junichi; Tsukamoto, Michio; Miyata, Teijiro*; Ida, Masaaki*; Watanabe, Makio; Uchiyama, Gunzo; Asakura, Toshihide; et al.
JAERI-Research 99-056, p.278 - 0, 1999/09
JAERI-Research-99-056.pdf:22.73MB
no abstracts in English
Shigetome, Yoshiaki; ; ; Miura, Akihiko; Sato, Yoshihiko; Koyama, Tomozo
JNC TN8200 99-001, 128 Pages, 1999/07
None
Abe, Hitoshi; Takada, Junichi; Tsukamoto, Michio; *; Murata, Mikio
Journal of Nuclear Science and Technology, 36(7), p.619 - 625, 1999/07
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)no abstracts in English
Murata, Mikio; Takada, Junichi; Tsukamoto, Michio
KURRI-KR-30, p.5 - 11, 1998/00
no abstracts in English
; Funasaka, Hideyuki; ; Koyama, Tomozo
PNC TN8600 97-007, 109 Pages, 1997/11
no abstracts in English
; Aoyama, Makoto; ; Yamanouchi, Takamichi
PNC TN8410 97-319, 143 Pages, 1997/10
The fire and explosion incident occurred at Bituminization Demonstration Facility of PNC Tokai Works on March 11, 1997. In order to ascertain the cause of incident, the investigation has been pushed forward. During investigation, we obtained essential information from operators, such as softness of bituminized product, white smoke generated from bituminized product. This condition has never been observed comparing past normal operation. Therefore, we assumed that temperature of bituminized product had increased more than expected. In order to confirm above assumption, we made experiment for obtaining the relationship between temperature and fluidity of bituminized product. Simulated bituminized product was heated up to each temperature (210, 230, 250, 270
C) in a pot and poured down into an another pot. We observed the fluidity of bituminized product when it flowing down into a pot. The fluidity of bituminized product increased with high temperature. The fluidity of bituminized product at 270C looked similar to fluidity of bituminized product that had ignited itself at the incident. White smoke generated from bituminized product and amounts of white smoke increased with high temperature. The smoke was considered to be gas that generated through thermal decomposition or volatilization of bitumen.
Sazarashi, Masami*; *; Ikeda, Yasuhisa*; Kumagai, Mikio*; *; *
PNC TJ1564 97-002, 20 Pages, 1997/03
None
