The tests are scheduled to continue for 17 months and will be broken up into two main stages. The purpose of the first stage, which includes 3 "steps" and 2 "hold points", is to confirm safety and performance of equipment and facilities. The purpose of the second stage, which includes 2 "steps" and no "hold points", is to test the whole plant by operating it in a manner similar to real operations.
Date (period during which activity began 1)
|
Activity / Incident
|
Comment
|
| 10 September 2010 |
Start up date deferred for 2 years to October 2012. |
The reason for the postponement is the continuing problems with the vitrification furnace. This is the 18th time that the schedule has been delayed. Originally it was supposed to begin operations in December 1997. |
| 2 August 2010 |
Small leak of high-level radioactive liquid waste from the concentration equipment. |
Leaked liquid was found in a stainless steel protective pipe around a thermometer that is installed inside the equipment to measure the temperature of the liquid waste. |
| 17 June 2010 |
A fire resistant brick that had fallen from the ceiling of the vitrification furnace was finally retrieved. |
The brick was retrieved on the 18th attempt. See entry for 24 December 2008 below. |
| 22 October 2009 |
Leak from a pipe which feeds high-level radioactive liquid waste to the vitrification kiln (furnace) in the Vitrification Facility. |
An estimated 20cc leaked from a flange into a tray below. The concentration of cesium-137 was 8.1x109 Bq/m.
A chain suspended from a crane bumped the flange causing the leak. (See 21 January 2009 for a similar though much larger leak.) |
| 12~13 September 2009 |
On September 12 cleaning of the vitirification cell was resumed for the first time since March, but problems immediately arose with the power manipulator and the operation was stopped the following day. |
The vitrification cell is contaminated because of a leak of highly radioactive fluid (see entry for January 21). There has been a series of problems with the power manipulator. |
| 31 August 2009 |
JNFL announced that it had postponed the target date for completion of the plant to October 2010. |
This is the 17th time the target date for completion of the plant has been postponed. In January 2009 the target was set at August 2009. |
| 2 April 2009 |
Nuclear Industrial and Safety Agency (NISA) determined that a leak from a pipe which feeds high-level radioactive liquid waste to the vitrification kiln in the Vitrification Facility was a breach of safety regulations. (See entry for 21 January 2009 below.) |
|
| 21 January 2009 |
Leak from a pipe which feeds high-level radioactive liquid waste to the vitrification kiln (furnace) in the Vitrification Facility. The flow was supposed to have been stopped, because repairs were being carried out, but JNFL says the flange was not closed properly. |
16 liters of liquid were caught in a tray under the pipe, but up to 150 liters may have leaked. JNFL mentions that some of the liquid evaporated, but clearly evaporation does not account for all the unaccounted for liquid. The concentration of cesium-137 was 1.6x1010 Bq/m. |
| 24 December 2008 |
JNFL reported that a camera inserted into melting kiln A revealed that some of the fire resistant bricks in the ceiling had been damaged. |
The causes of this problem and of the bent stirring rod problem referred to in the entry for 11 December are still being investigated |
| 11 December 2008 |
The stirring rod inserted into the melting kiln of the vitrification facility was found to be bent (refer 29-30 November 2008). |
JNFL acknowledged the possibility that the kiln could have been damaged as a result. (JNFL Press Release, 11 December 2008) |
| 29-30 November 2008 |
The level of the molten glass / high level waste mixture in the glass melting kiln was lowered by draining out some or all of the mixture. |
JNFL has had major problems with the vitrification facility. It came up with the primitive idea of inserting a rod through a window into the kiln in order to stir the mixture, but this just caused more problems. The window wouldn't open, then the rod could not be operated properly. JNFL plans to insert an ITV camera to see what is going on, but in order to do this it has to lower the level of the mixture. |
| 25 November 2008 |
|
JNFL announced that the date for completion of active tests had been postponed a further two months to February 2009. |
| 10 October 2008 |
Testing of the Vitrification Facility resumed. |
See entry for 2-3 July 2008 below. |
1 -2 October 2008
(-17:20pm) |
12 BWR spent fuel assemblies sheared and dissolved. |
With this batch, JNFL has sheared and dissolved its full quota of spent fuel allowed during active testing of the Rokkasho Reprocessing Plant. However, until the problems with the vitrification facility are resolved, the tests will not be complete and approval to begin commercial operations cannot be given. |
30 September -1 October 2008
(-17:20pm) |
14 BWR spent fuel assemblies sheared and dissolved. |
|
29-30 September 2008
(-17:20pm) |
22 BWR spent fuel assemblies sheared and dissolved. |
|
28-29 September 2008
(-17:20pm) |
21 BWR spent fuel assemblies sheared and dissolved. |
|
25-28 September 2008
(-17:20pm) |
60 BWR spent fuel assemblies sheared and dissolved. |
|
24-25 September 2008
(-17:20pm) |
3 BWR spent fuel assemblies sheared and dissolved. |
|
18-21 September 2008
(-17:20pm) |
4 BWR spent fuel assemblies sheared and dissolved. |
|
17-18 September 2008
(-17:20pm) |
20 BWR spent fuel assemblies sheared and dissolved. |
|
16-17 September 2008
(-17:20pm) |
22 BWR spent fuel assemblies sheared and dissolved. |
|
15-16 September 2008
(-17:20pm) |
22 BWR spent fuel assemblies sheared and dissolved. |
|
15 September 2008
(-17:20pm) |
5 BWR spent fuel assemblies sheared and dissolved. |
|
28-29 July 2008
(-17:20pm) |
13 BWR spent fuel assemblies sheared and dissolved. |
Stopped shearing and dissolving on July 29 when problems arose opening and closing a door in the hull and end piece drum measuring cell in the Head End Building. |
| 28 July 2008 |
|
JNFL decided to extend the planned completion date of active testing of the plant to November 2008.
Yomiuri Shimbun 29 July 2008 |
27-28 July 2008
(-17:20pm) |
20 BWR spent fuel assemblies sheared and dissolved. |
|
24-27 July 2008
(-17:20pm) |
26 BWR spent fuel assemblies sheared and dissolved. |
|
| 2-3 July 2008 |
More problems with the vitrification facility. This time the problem is said to relate to a nozzle at the bottom of the melting furnace. It is classified as an A-class problem (most serious). |
The government approved the resumption of vitrification on 30 June, after the vitrification facility had been out of operation for 6 months. (See articles in Nuke Info Tokyo for details.) On July 2, vitrification resumed, but problems began that same day. |
1-2 July 2008
(-17:20pm) |
12 BWR spent fuel assemblies sheared and dissolved. |
|
30 June - 1 July 2008
(-17:20pm) |
3 BWR spent fuel assemblies sheared and dissolved. |
|
| 30 June 2008 |
|
The Tooh Nippo (local Aomori newspaper) reported that the total cumulative amount of "plutonium product" produced at Rokkasho by the end of May 2008 was:5,417kg. "Plutonium product" was defined as MOX minus oxygen, so it includes both uranium and plutonium. Half of this, or about 2.7 tons, is plutonium.
518kg of "plutonium product" was produced during the month of May 2008.
|
19-22 June 2008
(-17:20pm) |
14 BWR spent fuel assemblies sheared and dissolved. |
|
18-19 June 2008
(-17:20pm) |
20 BWR spent fuel assemblies sheared and dissolved. |
|
17-18 June 2008
(-17:20pm) |
20 BWR spent fuel assemblies sheared and dissolved. |
|
16-17 June 2008
(-17:20pm) |
22 BWR spent fuel assemblies sheared and dissolved. |
|
15-16 June 2008
(-17:20pm) |
21 BWR spent fuel assemblies sheared and dissolved. |
|
12-15 June 2008
(-17:20pm) |
24 BWR spent fuel assemblies sheared and dissolved. |
Shearing and dissolving resumed on 14 June for the first time since 13 April (see below). |
| 29 April 2008 |
|
JNFL President announced that the planned completion date of active testing of the plant had been delayed from February 2008 to July 2008.
(JNFL President's monthly press conference, 29 May 2008) |
| 18 April 2008 |
JNFL announced that on two occasions an IAEA seal in the uranium oxide storage building was damaged while checking a crane. |
The damage was first caused on 15 March and again on 10 April 2008. Apparently the seal was located on the rail along which the crane ran. |
| 13 April 2008 |
Oil leaked from a pressure control unit in the shearing machine in the Head End Building. It is similar to the accident that occurred on 1 January 2008. |
Shearing and Dissolving has been stopped. |
10-13 April 2008
(-17:20pm) |
34 BWR spent fuel assemblies sheared and dissolved. |
|
| 10 April 2008 |
An IAEA seal in the uranium oxide storage building was damaged while checking a crane. |
See 18 April 2008. |
9-10 April 2008
(-17:20pm) |
12 BWR spent fuel assemblies sheared and dissolved. |
|
8-9 April 2008
(-17:20pm) |
23 BWR spent fuel assemblies sheared and dissolved. |
|
7-8 April 2008
(-17:20pm) |
22 BWR spent fuel assemblies sheared and dissolved. |
|
6-7 April 2008
(-17:20pm) |
19 BWR spent fuel assemblies sheared and dissolved. |
|
3-6 April 2008
(-17:20pm) |
57 BWR spent fuel assemblies sheared and dissolved. |
|
2-3 April 2008
(-17:20pm) |
12 BWR spent fuel assemblies sheared and dissolved. |
|
1-2 April 2008
(-17:20pm) |
12 BWR spent fuel assemblies sheared and dissolved. |
|
31 March - 1 April 2008
(-17:20pm) |
8 BWR spent fuel assemblies sheared and dissolved. |
|
| 15 March 2008 |
An IAEA seal in the uranium oxide storage building was damaged while checking a crane. |
See 18 April 2008. |
| 25 February 2008 |
|
JNFL President announced that the planned completion date of active testing of the plant had been delayed from February 2008 to May 2008.
(JNFL President's monthly press conference, 25 February 2008) |
| 14 February 2008 |
JNFL declared that it had commenced Step 5. |
In practice JNFL will not recommence shearing and dissolving spent fuel until it fixes problems with the glass vitrification process. That is not expected until the end of March 2008.
(JNFL President's monthly press conference, 25 February 2008) |
14 January - 15 January 2008
(-17:20pm) |
6 BWR spent fuel assemblies sheared and dissolved. |
|
10 January - 14 January 2008
(-17:20pm) |
52 BWR spent fuel assemblies sheared and dissolved. |
|
| 1 January 2008, 18:00 |
750 liters of oil leaked from a pressure control unit in the shearing machine in the Head End Building. |
Shearing and Dissolving has been stopped. |
| 27 December 2007 |
From 27 December, over the new year, scrape out glass from the melting furnace in the Vitrification Facility. |
Due to high viscosity, |
27 December 2007 - 3 January 2008
(-17:20pm) |
104 BWR spent fuel assemblies sheared and dissolved. |
|
26-27 December 2007
(-17:20pm) |
19 BWR spent fuel assemblies sheared and dissolved. |
|
25-26 December 2007
(-17:20pm) |
18 BWR spent fuel assemblies sheared and dissolved. |
|
24-25 December 2007
(-17:20pm) |
13 BWR spent fuel assemblies sheared and dissolved. |
|
20-24 December 2007
(-17:20pm) |
42 BWR spent fuel assemblies sheared and dissolved. |
|
19-20 December 2007
(-17:20pm) |
22 BWR spent fuel assemblies sheared and dissolved. |
|
18-19 December 2007
(-17:20pm) |
17 BWR spent fuel assemblies sheared and dissolved. |
|
17-18 December 2007
(-17:20pm) |
22 BWR spent fuel assemblies sheared and dissolved. |
Originally no BWR spent fuel assemblies were to be sheared and dissolved during Step 4. |
| 24 November |
Problems with equipment for welding lids onto vitrified high active waste canisters. |
Part must be replaced before vitrification can be resumed. |
8-11 November 2007
(-17:20pm) |
Vitrified Waste Stored in Number 1 Vitrified Package Storage Building (East) for the first time. |
|
7-8 November 2007
(-17:20pm) |
2 PWR spent fuel assemblies sheared and dissolved. |
Step 4 shearing and dissolving completed 8 November (JNFL President's monthly press conference, 28 November 2007) |
6-7 November 2007
(-17:20pm) |
4 PWR spent fuel assemblies sheared and dissolved. |
|
5-6 November 2007
(-17:20pm) |
2 PWR spent fuel assemblies sheared and dissolved. |
|
5 November 2007
(-17:20pm) |
Testing of High Active Waste Vitrification process commenced. |
Proceeding at a rate of one or two canisters per day. (JNFL President's monthly press conference, 28 November 2007) |
1-4 November 2007
(-17:20pm) |
8 PWR spent fuel assemblies sheared and dissolved. |
|
30-31 October 2007
(-17:20pm) |
4 PWR spent fuel assemblies sheared and dissolved. |
|
29-30 October 2007
(-17:20pm) |
10 PWR spent fuel assemblies sheared and dissolved. |
|
28-29 October 2007
(-17:20pm) |
11 PWR spent fuel assemblies sheared and dissolved. |
|
25-28 October 2007
(-17:20pm) |
27 PWR spent fuel assemblies sheared and dissolved. |
Shearing restarted on 25 October after fixing problems which arose on 1 October. (JNFL President's monthly press conference, 30 October 2007) |
| 1 October 2007 |
At around 22:00 problems arose with a basket for catching sheared end pieces. Shearing was stopped to address the problem. |
|
1-2 October 2007 2007
(-17:20pm) |
3 PWR spent fuel assemblies sheared and dissolved. |
|
30 September -1 October 2007
(-17:20pm) |
11 PWR spent fuel assemblies sheared and dissolved. |
|
27-30 September 2007
(-17:20pm) |
15 PWR spent fuel assemblies sheared and dissolved. |
|
20-24 September 2007
(-17:20pm) |
9 PWR spent fuel assemblies sheared and dissolved. |
|
19-20 September 2007
(-17:20pm) |
8 PWR spent fuel assemblies sheared and dissolved. |
|
18-19 September 2007
(-17:20pm) |
11 PWR spent fuel assemblies sheared and dissolved. |
|
17-18 September 2007
(-17:20pm) |
10 PWR spent fuel assemblies sheared and dissolved. |
|
13-17 September 2007
(-17:20pm) |
39 PWR spent fuel assemblies sheared and dissolved. |
|
12-13 September 2007
(-17:20pm) |
11 PWR spent fuel assemblies sheared and dissolved. |
|
11-12 September 2007
(-17:20pm) |
9 PWR spent fuel assemblies sheared and dissolved. |
|
10-11 September 2007
(-17:20pm) |
11 PWR spent fuel assemblies sheared and dissolved. |
|
9-10 September 2007
(-17:20pm) |
10 PWR spent fuel assemblies sheared and dissolved. |
|
6-9 September 2007
(-17:20pm) |
21 PWR spent fuel assemblies sheared and dissolved. |
Commenced shearing spent fuel assemblies for step 4 of the tests on 7 September, according to JNFL's President in his monthly press conference. (7 September 2007) |
| 7 September 2007 |
Of the 110 PWR fuel assemblies which will be sheared and dissolved during step 4, 100 of which will be done continuously.
Commencement of full operations of the plant delayed from November 2007 to February 2008.
|
JNFL President's press conference. (7 September 2007) |
| 31 August 2007 |
Step 4 commenced |
On 4 September a one line announcement was posted on JNFL's web site. |
| 26 April 2007 |
Step 3 completed. |
JNFL President's press conference (26 April 2007) |
| 18 April 2007 |
JNFL revealed that the earthquake design standards for the number 1 channel box shearing maching and the fuel handling machine in the spent fuel pool were calculated incorrectly. |
The miscalculation was known to the person in charge at subcontracter Hitachi Engineering & Services in 1996, but he concealed the problem. |
12-15 April 2007
(-17:20pm) |
3 PWR spent fuel assemblies sheared and dissolved. |
This completed the shearing for Step 3 of the active tests (275 BWR and 44 PWR). |
11-12 April 2007
(-17:20pm) |
7 PWR spent fuel assemblies sheared and dissolved. |
|
10-11 April 2007
(-17:20pm) |
11 PWR spent fuel assemblies sheared and dissolved. |
|
9-10 April 2007
(-17:20pm) |
10 PWR spent fuel assemblies sheared and dissolved. |
|
8-9 April 2007
(-17:20pm) |
9 PWR spent fuel assemblies sheared and dissolved. |
|
5-8 April 2007
(-17:20pm) |
4 PWR spent fuel assemblies sheared and dissolved. |
|
| 11 March 2007 |
Incident in the Uranium-plutonium Co-denitration Building: Uranium-plutonium solution was poured into a tray which should have been empty, but which actually already contained a denitrated uranium-plutonium mixture. |
NGOs have raised questions about this incident from the perspective of criticality control. |
7-8 March 2007
(-17:20pm) |
15 BWR spent fuel assemblies sheared and dissolved. |
|
6-7 March 2007
(-17:20pm) |
20 BWR spent fuel assemblies sheared and dissolved. |
|
5-6 March 2007
(-17:20pm) |
20 BWR spent fuel assemblies sheared and dissolved. |
|
4-5 March 2007
(-17:20pm) |
20 BWR spent fuel assemblies sheared and dissolved. |
|
1-4 March 2007
(-17:20pm) |
60 BWR spent fuel assemblies sheared and dissolved. |
|
28 February - 1 March 2007
(-17:20pm) |
23 BWR spent fuel assemblies sheared and dissolved. |
|
27-28 February 2007
(-17:20pm) |
21 BWR spent fuel assemblies sheared and dissolved. |
|
26-27 February 2007
(-17:20pm) |
22 BWR spent fuel assemblies sheared and dissolved. |
|
25-26 February 2007
(-17:20pm) |
22 BWR spent fuel assemblies sheared and dissolved. |
|
22-25 February 2007
(-17:20pm) |
6 BWR spent fuel assemblies sheared and dissolved. |
|
7-8 February 2007
(-17:20pm) |
6 BWR spent fuel assemblies sheared and dissolved. |
|
6-7 February 2007
(-17:20pm) |
18 BWR spent fuel assemblies sheared and dissolved. |
|
5-6 February 2007
(-17:20pm) |
17 BWR spent fuel assemblies sheared and dissolved. |
|
4-5 February 2007
(-17:20pm) |
5 BWR spent fuel assemblies sheared and dissolved. |
|
| 31 January 2007 |
|
JNFL President announced that the planned completion date of active testing of the plant has been postponed by 3 months to November 2007. The reason given was that commencement of step three of the active tests was 3 months behind schedule. |
| 29 January 2007 |
Step 3 of active tests begins. |
|
6-7 December 2006
(-17:20pm) |
End of Step 2. Second "hold point". |
|
19-20 November 2006
(-17:20pm) |
10 BWR spent fuel assemblies sheared and dissolved. With this, the 57 BWR assemblies (10 tons) planned for step 2 have all been sheared and dissolved. |
|
16-19 November 2006
(-17:20pm) |
42 BWR spent fuel assemblies sheared and dissolved. |
|
| 16 November 2006 |
MOX powder (i.e. finished product) produced for the first time at Rokkasho. |
|
15-16 November 2006
(-17:20pm) |
3 BWR spent fuel assemblies sheared and dissolved. |
|
14-15 November 2006
(-17:20pm) |
For the first time during the active tests 2 BWR spent fuel assemblies were sheared and dissolved. |
|
| 2 November 2006 |
Began production of MOX (uranium/plutonium mixed oxide.) |
JNFL expects to begin recovering final MOX product by mid November. (JNFL press release, 2 November 2006) |
26-29 October 2006
(-17:20pm) |
Began receiving plutonium solution into the Uranium-plutonium Co-denitration Building |
|
| 27 October 2006 |
It is planned that 60 BWR fuel assemblies (10 tons) will be sheared and dissolved during the remainder of Step 2.
It is also planned to commence production of mixed uranium-plutonium oxide in November.
|
JNFL President Press Conference 27 October 2006 |
25-26 October 2006
(-17:20pm) |
Began receiving uranium solution into the Uranium-plutonium Co-denitration Building |
|
23-24 October '06
(-17:20pm) |
2 PWR spent fuel assemblies sheared and dissolved. With this, the 109 PWR assemblies (50 tons) planned for step 2 have all been sheared and dissolved. |
|
22-23 October '06
(-17:20pm) |
7 PWR spent fuel assemblies sheared and dissolved. |
|
19-22 October '06
(-17:20pm) |
25 PWR spent fuel assemblies sheared and dissolved. |
|
18-19 October '06
(-17:20pm) |
8 PWR spent fuel assemblies sheared and dissolved. |
|
17-18 October '06
(-17:20pm) |
9 PWR spent fuel assemblies sheared and dissolved. |
|
16-17 October '06
(-17:20pm) |
6 PWR spent fuel assemblies sheared and dissolved. |
|
9-10 October '06
(-17:20pm) |
1 PWR spent fuel assembly sheared and dissolved. |
|
5-9 October '06
(-17:20pm) |
27 PWR spent fuel assemblies sheared and dissolved. |
|
4-5 October '06
(-17:20pm) |
4 PWR spent fuel assemblies sheared and dissolved. |
|
3-4 October '06
(-17:20pm) |
Began storing uranium-oxide product in the Uranium Oxide Storage Building. |
|
3-4 October 06
(-17:20pm) |
10 PWR spent fuel assemblies sheared and dissolved. |
|
2-3 October 06
(-17:20pm) |
4 PWR spent fuel assemblies sheared and dissolved. |
|
| 18 August '06 |
At about 23:00 a high radiation reading was recorded about 360 meters west of the main exhaust stack. The recording was made by the monitor on the Vitrified Package Storage Building. |
The exhaust stack is 150 meters high and is meant to disperse the radioactivity that is released. Citizens' groups are asking why radioactivity was recorded so close to the exhaust stack. |
| 17-20 August '06 |
6 PWR spent fuel assemblies sheared and dissolved. |
|
| 14-15 August '06 |
Begin receiving uranium solution into Uranium Denitration Building |
|
| 12 August '06 |
Step 2 of active tests begins. |
|
| 26 June '06 |
JNFL announced that Step 1 of the active tests had been completed. Between the completion of Step 1 and the commencement of Step 2 there is a "hold point", during which JNFL says it will assess basic safety and correct any problems. |
|
| 24 June '06 |
JNFL announced that there was a possibility that a subcontractor worker in the Analysis Laboratory Building had received internal exposure to radiation.
This is the second publicly disclosed case of worker exposure (see also 19-20 May below). This time the worker was only 19 years old.
|
Alpha radioactivity of 0.7 Bq was discovered in a smear test taken from the workers nose. JNFL said on July 3rd that a bioassay revealed no internal radiation exposure. However, if radioactive material was inhaled and lodged deep inside the lungs it would not have shown up in JNFL's tests. |
| 8-11 June '06 |
19 more PWR spent fuel assemblies sheared and dissolved. A total of 67 assemblies have been sheared and dissolved, which is the number scheduled for step one of the active tests. |
|
| 7-8 June '06 |
8 more PWR spent fuel assemblies sheared and dissolved. |
|
| 6-7 June '06 |
4 more PWR spent fuel assemblies sheared and dissolved. |
|
| 1 June '06 |
Began receiving liquid waste in High Active Liquid Waste Vitrification Building |
|
| 30 May '06 |
36 of the 67 spent fuel assemblies to be processed in step one of the active tests had been sheared and dissolved by this day.
Dealing with problems that have arisen so far during the active tests has taken about two weeks, but this is not expected to affect the planned date for completion of the tests (August 2007).
|
(JNFL President's press conference, 30 May 2006) |
| 19-20 May '06 |
A subcontractor worker in the Analysis Laboratory Building was exposed to plutonium. Internal exposure was confirmed through a bioassay (see CNIC media release).
It is believed that the worker inhaled or ingested the plutonium sometime in the period 19-20 May, while handling radioactive material through a "glove box" and under a "hood" .
JNFL's manual did not originally require workers to use a mask during this operation, but JNFL responded to this incident by requiring that a mask be worn in future.
|
Plutonium was detected on the chest area of the worker's clothing on May 22nd, during a survey before the clothing was cleaned. The worker's exposure was not confirmed until May 25th.
JNFL assessed the committed effective dose to be 0.014 mSv.
The contamination on the clothing was as follows:
Maximum alpha: 5 Bq/cm2
Maximum beta: 0.17 Bq/cm2
|
| 17 May '06 (19:00 pm) |
A leak of 7 liters of uranous nitrate solution was discovered by a worker from a subcontractor company in the Number 1 Reagent Distribution Chamber on the first floor of the Purification Building (see CNIC media release). The worker noticed a strange smell coming from the next room. The leak was stopped 8 hours later by halting the plutonium refining process. |
The solution leaked from a T joint, where uranous nitrate solution is supplied to the Plutonium Washing Mixer Settler as a reagent in the plutonium purifaction process.
According to JNFL's analysis, the leak was caused by erosion of non-metal impurities by the uranous nitrate solution. The same problem arose in July 2005 during the uranium tests. JNFL also found that other T joints from the same lot had been eroded.
JNFL said the liquid would be "recovered and delt with appropriately", though media reports said a worker wiped it up.
The concentrations were as follows:
Total beta: approx. 4.7 x 102 Bq/ml
Total alpha: approx. 6.5 Bq/ml
All uranium: approx. 21 gm/l
|
15 - 16 May '06
(17:20pm - 17:20 pm) |
4 more PWR spent fuel assemblies sheared and dissolved in this period |
|
14 - 15 May '06
(17:20pm - 17:20 pm) |
8 more PWR spent fuel assemblies sheared and dissolved in this period |
|
| 11-14 May '06 |
6 more PWR spent fuel assemblies sheared and dissolved in this period |
|
| 1-7 May '06 |
10 more PWR spent fuel assemblies sheared and dissolved in this period. |
|
| 23 April '06 (17:50 pm) |
Radioactivity discovered in a 'detection pot' in the 'active trench' which runs between the Separation Building and the Purification Building. |
JNFL checked to see whether there was a leak from tanks etc. in the area, but confirmed on 2 May that there was not. It said that there was no effect on the surrounding environment.
According to JNFL, the concentration of radioactivity for all gamma emitters was 0.52 Bq/ml. The volume was quoted simply as "a very small quantity".
|
| 18 April '06 |
Purification of plutonium and uranium begins (Purification Building) |
Residual fission products are removed. |
| 16 April '06 |
Plutonium separation process begins (Separation Building) |
Dissolved spent fuel is sent to the Separation Building and plutonium and uranium are separated from fissile products. |
| 11 April '06 (3:40 am) |
40 litres of radioactive water leaks from hull rinser vessel (Head End Building) |
Hulls are undissolved remains of spent fuel cladding. They are rinsed to remove radioactive materials.
According to JNFL, the leaked water was contained within the cell (in fact, a rather large room), recovered and reused and there was no radiation exposure to workers.
The concentrations and total quantities of radioactivity and of uranium and plutonium in the leaked fluid were as follows:
Total alpha emitters: 40 liters @ 4.1 x 105 Bq/ml = 1.6 x 1010 Bq
Total gamma emitters: 40 liters @ 3.1 x 106 Bq/ml = 1.2 x 1011 Bq
Uranium: 40 liters @ 6.5 gram/liter = 260 grams
Plutonium: 40 liters @ 0.025 gram/liter = 1 gram.
(Compare this to the annual benchmark for alpha emitters of 3.8 x 109 Bq and the annual benchmark for non-alpha emitters of 2.1 x 1011 Bq. Also compare it to the legal limit for the concentration of alpha-emitting plutonium-239 in liquid releases of 4 x 10-3 Bq/ml and the legal limit for the concentration of cesium-137 in liquid releases of 3 x 10-2 Bq/ml.)
|
| 11 April '06 |
Testing of Low Active Liquid Waste Treatment Building begins. |
|
| 8 April '06 |
8 PWR spent fuel assemblies had been sheared and dissolved by this date. |
|
| 31 March '06 (2:58 pm) |
Active tests begin.
Spent fuel is moved from the Spent Fuel Receiving and Storage Building to the Head End Building.
Step 1 involves only PWR spent fuel. The first 3 steps are to confirm safety and performance of equipment and facilities.
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Simply by commencing active tests on the last day of the 2005 fiscal year, JNFL received 52.9 billion yen. (The fiscal year in Japan runs from 1 April to 31 March.) Clearly the main motivating factor behind the final scramble to start before the end of the fiscal year was JNFL's desire to receive this payment.
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