4-1. Neutron Flux

Page 2

16 July 2007 (time arrow pointing in downwards direction)

ch switchover

10:13 earthquake occurs

effect of aftershock

ch switchover

19:40 cold shutdown

10-1 1 10 102 103 104 105 106 (cps)

SRM(A),(C) (red): standard

SRM(B),(D) (green): about 10 minutes delay

Reactor 2 SRM A,B,C,D

Page 3

16 July 2007 (time arrow pointing in downwards direction)

10:13 earthquake occurs

Record of APRM(A)(B)

APRM(A) (red): standard

APRM(B) (green): about 10 minutes ahead

Record of IRM(B)(F)

IRM(B) (red): standard

IRM(F) (green ): about 10 minutes ahead

effect of aftershock

APRM 0 25 50 75 100 125 (%)

IRM 0 10 20 30 40 (%)

Reactor 3 APRM(A)(B)/IRM(B)(F)

Page 4

16 July 2007 (time arrow pointing in downwards direction)

10:13 earthquake occurs

Record of APRM(C)(D)

APRM(C) (red): standard

APRM(D) (green): about 10 minutes ahead

Record of IRM(C)(G)

(Switch object of recording from APRM to IRM)

IRM(C) (red): standard

IRM(G) (green ): about 10 minutes ahead

effect of aftershock

23:07 cold shutdown

APRM 0 25 50 75 100 125 (%)

IRM 0 10 20 30 40 (%)

Reactor 3 APRM(C)(D)/IRM(C)(G)

Page 5

16 July 2007 (time arrow pointing in downwards direction)

10:13 earthquake occurs

Record of APRM(E)

APRM(E) (red)

Record of IRM(A)(E)

(Switch object of recording from APRM to IRM)

IRM(A) (red): standard

IRM(E) (green ): about 10 minutes ahead

effect of aftershock

23:07 cold shutdown

APRM 0 25 50 75 100 125 (%)

IRM 0 10 20 30 40 (%)

Reactor 3 APRM(E)/IRM(A)(E)

Page 6

16 July 2007 (time arrow pointing in downwards direction)

10:13 earthquake occurs

Record of APRM(F)

APRM(F) (red)

Record of IRM(D)(H)

(Switch object of recording from APRM to IRM)

IRM(D) (red): standard

IRM(H) (green ): about 10 minutes ahead

effect of aftershock

23:07 cold shutdown

APRM 0 25 50 75 100 125 (%)

IRM 0 10 20 30 40 (%)

Reactor 3 APRM(F)/IRM(D)(H)

Page 7

16 July 2007 (time arrow pointing in downwards direction)

10:13 earthquake occurs

Record of APRM(A)(B)

APRM(A) (red): standard

APRM(B) (green): about 10 minutes ahead

Record of IRM(B)(F)

(Switch object of recording from APRM to IRM)

IRM(B) (red): standard

IRM(F) (green ): about 10 minutes ahead

effect of aftershock

APRM 0 25 50 75 100 125 (%)

IRM 0 10 20 30 40 (%)

Reactor 4 APRM(A)(B)/IRM(B)(F)

Page 8

16 July 2007 (time arrow pointing in downwards direction)

10:13 earthquake occurs

Record of APRM(C)(D)

APRM(C) (red): standard

APRM(D) (green): about 10 minutes ahead

Record of IRM(C)(G)

(Switch object of recording from APRM to IRM)

IRM(C) (red): standard

IRM(G) (green ): about 10 minutes ahead

APRM 0 25 50 75 100 125 (%)

IRM 0 10 20 30 40 (%)

Reactor 4 APRM(C)(D)/IRM(C)(G)

Page 9

16 July 2007 (time arrow pointing in downwards direction)

10:13 earthquake occurs

Record of APRM(E)

APRM(E) (red)

Record of IRM(A)(E)

(Switch object of recording from APRM to IRM)

IRM(A) (red): standard

IRM(E) (green ): about 10 minutes ahead

APRM 0 25 50 75 100 125 (%)

IRM 0 10 20 30 40 (%)

Reactor 4 APRM(E)/IRM(A)(E)

Page 10

16 July 2007 (time arrow pointing in downwards direction)

10:13 earthquake occurs

Record of APRM(F)

APRM(F) (red)

Record of IRM(D)(H)

(Switch object of recording from APRM to IRM)

IRM(D) (red): standard

IRM(H) (green ): about 10 minutes ahead

APRM 0 25 50 75 100 125 (%)

IRM 0 10 20 30 40 (%)

Reactor 4 APRM(F)/IRM(D)(H)

Page 11

16 July 2007 (time arrow pointing in upwards direction)

1: SRNM(A) change measurement range

(intermediate range to neutron source range)

Record of SRNM(A) (intermediate range)

(Automatic switch of object of recording from APRM to SRNM)

SRNM(A) (red)

Period (green )

Record of APRM(A)

APRM(A) (red)

MRBM(A) (green)

10:13 earthquake occurs

APRM 0 25 50 75 100 125 (%)

SRNM 10-1 1 10 102 103 104 105 106 (cps)

(neutron source range)

Reactor 7 APRM(A)/SRNM(A)

Page 12

16 July 2007 (time arrow pointing in upwards direction)

1: SRNM(B) change measurement range

(intermediate range to neutron source range)

Record of SRNM(B) (intermediate range)

(Automatic switch of object of recording from APRM to SRNM)

SRNM(B) (red)

Period (green )

Record of APRM(B)

APRM(B) (red)

MRBM(A) (green)

10:13 earthquake occurs

APRM 0 25 50 75 100 125 (%)

SRNM 10-1 1 10 102 103 104 105 106 (cps)

(neutron source range)

Reactor 7 APRM(B)/SRNM(B)

Page 13

16 July 2007 (time arrow pointing in upwards direction)

1: SRNM(C) change measurement range

(intermediate range to neutron source range)

Record of SRNM(C) (intermediate range)

(Automatic switch of object of recording from APRM to SRNM)

SRNM(C) (red)

Period (green )

Record of APRM(C)

APRM(C) (red)

MRBM(A) (green)

10:13 earthquake occurs

APRM 0 25 50 75 100 125 (%)

SRNM 10-1 1 10 102 103 104 105 106 (cps)

(neutron source range)

Reactor 7 APRM(C)/SRNM(C)

Page 14

16 July 2007 (time arrow pointing in upwards direction)

1: SRNM(D) change measurement range

(intermediate range to neutron source range)

Record of SRNM(D) (intermediate range)

(Automatic switch of object of recording from APRM to SRNM)

SRNM(D) (red)

Period (green )

Record of APRM(D)

APRM(D) (red)

MRBM(A) (green)

10:13 earthquake occurs

APRM 0 25 50 75 100 125 (%)

SRNM 10-1 1 10 102 103 104 105 106 (cps)

(neutron source range)

Reactor 7 APRM(D)/SRNM(D)