<Reference>“Development of a technology to investigate inside
the Reactor Primary Containment Vessel (PCV)”- Results of follow up check after the site test -[For April 18 and 19, 2015]
April 20, 2015
Tokyo Electric Power Company

The content of this material includes the output of the International Research Institute for Nuclear Decommissioning (IRID)

1. Check items
The following items were checked on the counterclockwise route.
■ Route of remaining cable,■ Degree of interference of remained cables at the opening to access the basement,■ Status of the investigation device blocked in the vessel, and■ Access route to the CRD rail.
CRD rail
HVH

C11,
C10,

B14,
B13,

C9,

B12,

C8,

Spot where the investigation device
blocked on the counterclockwiseroute. (Apr. 10)

B11,

C7,

PLR pump
B9,

C6,

PLR pipe

C5,

B8,

C4,
C3,

B3,
C2,
B1,
C1,
C0, B0,

B4,

B5,

B6,

B7,

B10,

The opening to accessthe basement.

B2,

X-100B12. Status of the cable remained■ The route of remaining cables is shown as below.
■ It was confirmed that the remaining cable around the opening to access the basement will be noobstacle to B2 investigation.

X-6 Penetration

Pedestal
Opening

Spot where theinvestigation
device blocked.

PLR pipe

HVH（Ｄ）

X-100 B penetration
pipe

Opening to accessthe basement: the part the cable attached on floor..
: the part the cable is floating.

23. Status of the investigation device blocked
The situation of the investigation device blocked is shown as below, which is almost compatible with what has been assumed.

Structural object
Gap at the wide point(Space with one step lower)

B14,
B13,
B12,

Grating

B11,

PLR pump
B9,

PLR pipe
B3, B4,

B8,
B5,
B6,

B1,
B0,

B2,

B7,

B10,

Crawler onright side wasstuck andcontacted
with thestructuralobject.

Investigation device(Final position )Images captured by the investigation device

The investigation device blocked
Structuralobject

33

4. Check on the access route to CRD rail
It was judged that the suggested access route to CRD rail would be too narrow to get the device pass through between
the two structural objects.

Suggested
access route

B14,
B13,

Structural object

B12,
B11,

Structural object

PLR pump
B9,

PLR pipeB3, B4,

B10,

B8,
B5,

B7,

Investigation
device blocked

Shooting range

B6,
B1,

B2,

B0,

Images captured by the investigation device

Investigation
deviceSuggested
access route4

5. Collection of the investigation device
 Earning information inside the reactor primary containment vessel, which is the main purpose of thisinvestigation, has been achieved.
 Due to the deterioration of the monitoring camera with radiation, it became disabled to perform adeformation check on the device. Accordingly, the collection of the device to outside the reactor primarycontainment vessel has been judged as risky. (*1)
PCV

Bellows part of guide pipe
Guide pipe

X-100B penetration*1 Having found that there is a slight
unevenness at the bellows part ofguide pipe when inserting theinvestigation device, there is a riskthat the device might get stuckwhen its passing though thebellows.

Bldg. concrete
CRD Support beamDevice hatchmonorailMonitoring camera
In order to collect the device
from the grating floor, checkthe deformation degree ofthe device.

Investigation device

1F Grating5

6. Leaving the investigation device Locations where the devices are left are shown as below. Those are places that are able to retain thedevices in a stable state.
 The remaining devices will be no obstacle to B2 investigation.
CRD rail
HVH

MS pipe

Spot where the device
is left on the
counterclockwiseroute.

: Access route investigated (counterclockwise route)Pedestal Opening: Access route investigated (clockwise route)
C11,

B14,

C10,

B13,

C9,
B12,
C8,
B11,

PLR pump

C7,

B9,

C6,

PLR pipe

B8,

C5,
B3,

C4,

HVH

C3,
C2,

B1,

B2,

B5,
B4,

B7,
B6,

C1,

Spot where the device isleft on the clockwiserouteC0,B10,Opening toaccess thebasement

B0,

X-100B penetration pipe

6

(Reference) Measurement on temperature/ dose rate
Temperature and dose rate were measured at the following points.

HVH

CRD rail

Measurement taken: April 19, 2015

Pedestal opening

Around B14

B14,
B13,
B12,

HVH

B11,

Around B7

B10,

Final point(around C3)

PLR pump
B9,

PLR pipe
C5,

B8,
B5,

C4,

B3,

C3,

B4,

B7,

Around B11

Dose rate（Sv/h）

Temperature
（℃）

4.4
5.7

17.9
18.7

5.9
4.1

19.1
20.4

B6,
C2,

B1,

B2,

C1,
C0,

B0,

X-100B
7