fuel assembly

VII) Preparations for startup

Taking generator off the

₇ i) Reactor opening

grid

works

I Synchronization

V vili) Integrated load test

Critical path (reactor works)

• Removal of [ PCV & RPV ) upper heads

•Removal of dryer & separator

• Installation of main steam line plug

Irradiated

insnection fl icl pool sidel

& i i) Fuel Q

transfer ¹

tO

LPRM,<

CR L

iii) Remo /al, overhaul

inspcctioi s & installation of ¹

crd r '

IV) Fuel exchange & shuffling

v)Reacto: restoration works

RPV uppertend installatioC

Core checkf. Dryer separ tor installation

O')’ Draining &

[ reactor well

!■ RPV upper

lead installation

Control drive system (CRD)

Main steam isolation valve (MSIV)

From line plug installation

j. MSIV

A, leak test

] [ Removal r i installatii i ',0

overhaul inspections & n of CRD i o

MSIV leak test ( (removal of line plug)

i CRD func ional test ] Air vent, c rive test, i scram test

Insp :ction of MSIV

VI) pcv upper head Qf ’

installation & \

leak test i

d

RPV hydrostatic test

System tests Integrated functional test Integrated functional test

Fla it startup

Main steam safety/relief valve

(MS S«V)

In-service inspection Q—

(ISI) Reactor water clean-up system (CUW) Reactor recirculation

system (PLR)

Main turbine

Q-

5

o

^Inspection &. fu ictional test of Mi S/RV i

Ih-service inspection

Inspection of CUV⁷ pump (one train alway; in service)

o':

Inspection of reactor

: recirculation pump mecl anical seal

Disassembl y of main turbine

Opening of HP ar 1LP stage casings

XD

Lubricating oil syste n. flashing

- - ■

Inspection

of main turbine

rOOv

‘O 0/

Disassembly of major valves

Main turbine valves Q

Main steam stop t alve

Steam control val

Combined interne jt valve

Turbine bypass v;

Ive

o

o

Rotor, blade, nozde, I caring,

shaft coupling, labyrii th packing,-jj'

control device, tuminj;

equipment, etc.

Maintenance of major

Assembly of ma

n turbine

valves

Valve lap] img

Inspfecti mi

Assembly of ma or valves

—c/

Ad i

(inclu ling pressure control systeri)

ustment of major valves i ling pressure control >

Vacuum-up test

Turbine turning

Figure 4.2.2 Standard work sequence of periodic inspection

(3) Removal of RPV upper head

(1) Preparations for reactor shutdown /cooling (preparations to cany in equipment/for work place)

(2) Removal of well cover and slot plug Removal of reactor c ontainmenl upp er he a d

(4) Removal and transfer of dryer

Figure 4.2.3 (1 )-(4) Schematic diagram of major jobs related to reactor

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NSRA, Japan

(5) Water fill-up of reactor well and diyer/separatorpit Removal of pool gate

Removal and transfer of separator

(J) (J) Fuel transfer

@ Taking-out and maintenance of MSIV (MS line plug in place)

■® Taking-out and maintenance of MS relief-safety valve (MS line plugin place)

(6) Main steam line plug

(with support ring for reverse pressure)

Drainage of main steam line

Leaktest and maintenance of MSIV Maintenance of main steam relief-safety valve

(8) Overhaul inspection of control rod drive mechanism

(after fuel transfer)

'J ^{CRD handUn}S ^devicfl _< . 1 CRD automatic exchanger

® CRD reinoval/instaxation device J

(|) CRD cart

(j) CRD repair room

Figure 4.2.3 (5)-(8) Schematic diagram of major works related to reactor

NSRA, Japan

4-20

At this point, the main steam line plugs are attached to the main steam nozzles of the RPV, enabling inspection and maintenance works on the main steam isolation valves and main steam safety­relief valves in parallel with works on the core.

2. Fuel transfer and replacement of local power monitors

After opening the RPV, the spent fuel assemblies to be replaced with fresh fuel assemblies during the periodic inspection and the fuel assemblies around the control rods for which drive mechanisms are to be inspected, the control rods (CRs) to be replaced, and the local power monitors to be replaced are taken out and transferred to the spent fuel pool. After these tasks, local power monitors and CRs are replaced as required.

In handling fuel assemblies (both fresh and spent), the provisions to provide safety measures (placards and preventive measures against criticality, etc.) are observed.

2. Inspection and maintenance of control rod drive mechanisms, and inspection of irradiated fuel assemblies

According to the long-term periodic inspection program, control rod drive mechanisms (CRDs) scheduled to be inspected in the fiscal year of concern are removed from the RPV, undergo their overhaul inspections, and are installed again into the RPV (they may be replaced with spare CRDs).

In parallel with this work, visual inspections are conducted in the fuel pool on some of the irradiated fuel assemblies to be reused or treated as spent fuel to confirm their integrity.

2. Fuel replacement, shuffling, and core inspection

When overhaul inspections of CRDs have been completed and CRs are operable, the taken-out fuel assemblies are reloaded together with fresh fuel assemblies according to a new fuel loading pattern. Fuel shuffling is carried out in order to make fuel burnup as uniform as possible.

After reloading fuel, it is confirmed using an underwater TV etc. that fuel assemblies have been loaded correctly in the specified locations.

2. Reactor restoration work and hydrostatic pressure test of the reactor pressure vessel When jobs involved with the core have been

completed, the RPV is closed in reverse sequence to the RPV opening. Then, a hydrostatic pressure test

of the RPV is performed to confirm the integrity, focusing on the parts (mainly flanges) which were removed from the pressure boundary of the pressure vessel and reinstalled during the periodic inspection.

For this reason, jobs on the components to undergo overhaul inspections among those related to the reactor must be completed by the time of the hydrostatic pressure test of the pressure vessel except for those of the RCCV.

2. Installation of RCCV upper head and leak rate tests

After the hydrostatic pressure test of the pressure vessel, the RCCV upper head is installed, and all the penetrations and hatches are restored and closed and the local leak rate tests are also performed.

Then, the whole containment vessel is pressurized with nitrogen gas, and the total leak rate test is conducted to confirm the containment integrity.

2. Preparations for startup

With completion of the total leak rate test of the RCCV, all the periodic inspection work activities centering on overhaul inspections are completed and preparations for plant startup are begun. Preparations include confirming completion of the periodic inspection jobs and lining up each system so that it is appropriate for plant operation. Also, by performing functional tests and performance tests between systems in an integrated manner at this time, it is confirmed that the plant can be operated safely.

When the predetermined inspections and maintenance and tests during shutdown have been completed, the plant is started and its power is increased to the rated power for performing the test operation.

2. Integrated load test

When the plant is at the rated power under stable operating conditions, the integrated load test is performed to confirm that the plant is stably operating with the predetermined performance. In the case that the overhaul inspection of the turbine was performed, its load and performance tests are performed at the same time.

With completion of the integrated load test, the periodic inspection and licensee’s periodic inspection are complete.

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NSRA, Japan