“development of a technology to investigate inside the reactor
TRANSCRIPT
“Development of a technology to investigate inside the Reactor Primary Containment Vessel (PCV)”
April 13, 2015Tokyo Electric Power Company
The content of this material includes the output of the International Research Institute for Nuclear Decommissioning (IRID)
<Reference>
‐‐ Site test “Investigation B1” on grating around the pedestal inside Unit 1 PCV ‐
[For April 10]
1. Investigation overview
1
Access points (Planned)
C0, C11,
B0, B18,～～
X‐100B
CRD rail
PLR pump
HVH MS pipe
PLR pipe
HVH
Pedestal Opening
B1, B2,
B3, B4,B5,
B6,
B7,
B8,
B9,B10,
B11,
B12,
B13,
B14,
B18,
B0,
B17,
B16,
B15,
C2,C3,
C4,
C5,
C6,
C7,
C8,
C9,
C10,
C11,
C1,
C0,
Counterclockwise access route(Conducted on April 10)
Investigation device
: Access route (counterclockwise) : Access route (clockwise)
Purpose: For Unit 1, conducting an investigation in order to collect information on “the 1st floor grating inside the Primary Containment Vessel (PCV)” from the robot inserted through X‐100B penetration pipe.
Clockwise route
Counterclockwise route
Opening to access Basement floor
2. Access route (performance result)
Actual investigation route
Original route
2
Fallen objectsX100B penetration pipe
B0,B1,
B2,
B3,
B5,
B6,B7,
B8,
B9,B11,
B12,
B14,
B15,
B16,
B17,
B18,
B10,
B13,
B4,
Where the robot stuck
The investigation was conducted taking on a different route as some objects were found to be fallen on the original access route planned. The robot was stuck on the route between B14 and B15.
Approx. 20 mm
Approx. 20 mm
Approx. 20 mm
Approx. 20 mm
3. Investigation results
3
No. Location Investigation results
①
Opening to access
basement floors
・B2 investigation* will be conducted next time.TEPCO confirmed there is an opening accessible to the basement as well as no obstacles around it.
② CRD rail
・Yet to be reached at CRD rail.・Images have been taken with a camera facing towards CRD rail from the place where the robot reached at, which is now under evaluation.
③On the access
route
・No significant damages were found on the existing facilities. (such as HVG, PLR pipe, the wall of Pedestal)・Information on the temperature and radiation levels has been obtained at each investigation point.
The following information were obtained for items ① to ③ of this investigation.
* B2 investigation: Investigation on basement floor excluding the pedestal.
B10,
X‐100B Penetration
pipe
PLR pump
HVH
PLR pipe
Pedestal Opening
HVH
CRD rail
HVH
Opening to access basement floors
B0,
B1, B2,
B3, B4,B5,
B6,
B7,
B8,
B9,
B11,
B12,
B14,
B13,
B10,
X‐100B Penetration pipe
PLR pump
HVH
Pedestal Opening
HVH
HVH
Opening to access Basement floor
B0,B1, B2,
B3, B4,B5,
B6,
B7,
B8,
B9,
B11,
B12,
B14,
B13,
4‐1. Images (Opening to access the basement)
B４
Spot where the robot can be inserted.
4
With B2 investigation to be conducted next time, TEPCO confirmed there is an opening accessible to the basement as well as no obstacles around it.
Appri. 20 mm
Approx. 50 mmPLR Pipe
B10,
X‐100B Penetration pipe
PLR pump
HVH
PLR pipe
Pedestal Opening
HVH
HVH
B0,B1, B2,
B3, B4,B5,
B6,
B7,
B8,
B9,
B11,
B12,
B14,
B13,
PLR pipe
B7
4‐2. Images (PLR pipe)
5
Approx. 20 mm
・No significant damages were found on the PLP pipe (for heat retention).
・It was found that a part of the shield has been fallen off.
B10,
X‐100B Penetration pipe
PLR pump
HVH
PLR pipe
Pedestal Opening
HVH
HVH
B0,B1, B2,
B3, B4,B5,
B6,
B7,
B8,
B9,
B11,
B12,
B14,
B13,
4‐3. Images (Equipment hatch and exterior of pedestal)
Exterior of the outer wall of the pedestal
No significant damages were found on the outer wall of the pedestal.
B３
6
Exterior of the equipment hatch.No significant damages were found on the equipment hatch.
B2
Outer wall of the pedestal
HVH（In the center at the bottom) HVH（At the edge of the bottom)
7
No significant damages were found on HVH (D).
B10,
X‐100B Penetration pipe
PLR Pump
HVH
PLR pipe
Pedestal Opening
HVH
HVH
B0,B1, B2,
B3, B4,B5,
B6,
B7,
B8,
B9,
B11,
B12,
B14,
B13,
B1
Approx. 20 mmApprox. 20 mm
4‐4. Images (HVH (D) )
5. Investigation results (Temperature/ dose rate)
Dose rate（Sv/h）
Temperature （℃）
B3 7.4 17.8B4 7.5 19.2B5 8.7 19.4B7 7.4 19.5B11 9.7 19.2B14 7.0 20.2
Temperature and dose rate were measured at the following points.
B10,
X‐100B Penetration
pipe
PLR pump
HVH
PLR pipe
Pedestal Opening
HVH
HVH
B0,B1, B2,
B3, B4,B5,
B6,
B7,
B8,
B9,
B11,
B12,
B14,
B13,
8
9
6. Investigation robot stuck on route
Object was found to be fallen on the planned route between B 14 and B 15 where was the narrowest part of it. Following the procedures, the investigation continued by choosing an another route avoidable the objects.
After that, although the robot stuck at a narrow point, it captured some images facing to the direction of CRD rail. (currently the images are under evaluation)
Actual investigation route Original route planned
Where the robot stuck
B15,
Existing pipeB14,
Fallen object
★
Possible cause and measures:
The robot got stuck with an existing pipe and some shut parts of the grating or uneven part at the joint, which resulted in making the route hard to run on.
Measures to be taken are under study.
April 2015１０ １１ １２ １３ １４ １５ １６ １７
Fri Sat Sun Mon Tue Wed Thu Fri
1. Investigation on counterclockwise route
2. Investigation on clockwise route
7. Schedule
10
Robot collection review
Under examination for the implementation period for the investigation on clockwise route.
Investigation
Dose rates were obtained below 10 Sv/h. A knowlege was obtained that with the same amount of dose rates in “investigation on clockwise route”, the investigation camera which installed into the robot could tolerate two or three days without any problems .As for the case of an investigation on clockwise route, the plan is currently reviewed based on the knowledge obtained above.
Reference: Mock‐up
11
Spot where the robot stuck
Reference: Mock‐up
12
Spot where the robot stuck
CRD rail