due to water decomposition, after the 
reactor is placed in service. 
8. When the pressurizer temperature 
reaches 400° F, a steam bubble is 
formed in the pressurizer by reducing 
coolant pressure to approximately 200 
psig. During subsequent steps, the 
pressurizer level is maintained within 
the prescribed limits by discharging 
or adding water as required. 
9. The reactor control-rod system is 
then energized and rod withdrawal be- 
gun to continue the warm-up of reactor 
coolant. During rod withdrawal, the 
neutron level and the level-change-rate 
instruments are closely observed to in- 
sure that the level-change rate is below 
the specified values. As the point of 
predicted criticality is approached, con- 
tinuous rod withdrawal is stopped, and 
the rods are withdrawn in small steps 
until criticality is reached. Protective 
devices are provided to limit the speed 
of approach to criticality. If the level- 
change rate should exceed a predeter- 
mined value, rod motion will be stopped 
automatically. 
10. When the reactor is critical, the 
control-rod position is adjusted to pro- 
duce a power level equivalent to 1-2% 
of full power, or as required to heat 
reactor coolant at a rate of 100° F per 
hour. To maintain this power level, 
the rods must be further withdrawn at 
intervals to compensate for the nega- 
tive temperature coefficient, which will 
reduce power level as temperatures in- 
crease unless reactivity is added. 
11. The pressurizer heaters and 
spray-valve control are then placed on 
automatic. 
Turbine-Plant Start-Up 
While proceeding with the warmup 
of the reactor plant, the turbine-gener- 
ator plant will be placed in service as 
follows: 
1. The condenser circulating water 
flow is established, and the condensate 
system is placed in service, circulating 
water from the condenser hotwell 
through the air-ejector condenser and 
other heat exchangers back to the 
hotwell. 
2. The turbine glands are sealed, and 
the air ejector is placed in service to 
evacuate the condenser. 
3. The drum vents are closed when 
pressure reaches approximately 20 
psig, and the free drains on the steam 
leads and the header are checked to 
insure that they are free of water. 
4. The turbine high-pressure aux- 
68 
iliary oil pump is started, and the 
various drains on the turbine are 
opened in preparation for placing the 
turbine on ‘‘steam slow roll.” 
5. When steam pressure is approxi- 
mately 75 psig (reactor-coolant tem- 
perature 300° F), and the condenser 
vacuum is at least 10 in. of Hg, the 
throttle valves are opened, and steam 
is admitted to the turbine to place it 
on ‘‘steam slow roll.’”” When steam is 
admitted to the turbine, the free drains 
on the steam leads and the header are 
closed. 
6. If the turbine is free of rubs, the 
speed is- increased to approximately 
150 rpm, and the shaft eccentricity is 
checked. 
7. If the shaft is true (eccentricity 
less than 0.001 inches), the turbine 
speed will be increased to 1,800 rpm at 
a uniform rate in approximately 25 min. 
8. The boiler feed system is placed 
in service when required, and the drum 
level is controlled manually. 
9. As the turbine speed approaches 
1,800 rpm, the governor controls are 
observed to insure that speed is prop- 
erly controlled. 
10. The overspeed trip mechanism 
is checked by increasing turbine speed 
slowly to the trip point, and the throttle 
valves are immediately reopened. 
11. Excitation voltage is applied to 
the generator field and is adjusted as 
necessary to match generator voltage 
with system voltage. 
12. The generator is synchronized 
and loaded to 5-10 Mw, and voltage 
control is placed on automatic. 
13. Half of the station service load 
is switched to the generator-lead sta- 
tion service transformer. 
Final Steps 
During this period, the reactor plant 
warmup will have continued at a rate 
of 100° F per hour, and the reactor 
coolant temperature will have risen to 
approximately 400° F. During the 
loading of the station and the comple- 
tion of the reactor coolant system 
warmup, the following steps are taken. 
1. The turbine-generator and auxil- 
iaries are set up for normal running 
operation, and the generator is. loaded 
at specified rates in accordance with 
system requirements. 
2. The boiler-feedwater system is 
placed on automatic control when flow 
conditions permit. 
3. When average reactor coolant 
temperature reaches 525° F, the rod 
control system is placed on automatic 
control. 
4. The reactor coolant is sampled 
and analyzed for oxygen content, and 
hydrogen is added as required. 
The Station is now capable of accept- 
ing its share of load swings as required 
for system regulation (determined by 
consumer demand). To be specific, it 
will be required to follow daily system 
load changes at an average rate of 3 
Mw per minute, and to accept load 
swings of 20 Mw maximum at a rate of 
24 Mw per minute. It must also han- 
dle a proportional part of the load 
swings imposed on the various stations 
by casualties on the system. 
The output of the reactor will follow 
all but the largest load changes without 
immediate control-rod movement, due 
to the negative temperature coefficient 
of reactivity inherent in the core, which 
permits it to produce only that power 
which is taken from it. However, sub- 
sequent changes in control-rod position 
are required to maintain average tem- 
perature constant due to the change in 
xenon concentration in the core follow- 
ing load changes. Xenon, which is a 
fission product, absorbs neutrons. Its 
change in concentration with power 
level causes changes in reactivity. 
With the type of startup described 
here, the time required to reach the 
normal operating range (20-100% of 
full power) from a cold condition would 
be approximately 8 hr. This is con- 
siderably longer than the 51¢ hr re- 
quired for a similar startup of a con- 
ventional station of this size, but as was 
mentioned earlier, this startup will be 
used infrequently. The most frequent 
startup is one where the reactor coolant 
and associated systems have been main- 
tained at or near operating temperature 
during the shutdown. In a startup 
from this condition, the hydrazine 
treatment would not be necessary, and 
the delay introduced by the require- 
ment for heating reactor coolant would 
be eliminated. This would reduce the 
time required for startup to approxi- 
mately 114 hr as compared to 214 hr 
required for the hot startup of a con- 
ventional station. As these compari- 
sons of startup times indicate, the 
reactor plant will be as flexible and, in 
some instances, more flexible than 
a coal-fired boiler plant. Also, the 
startup procedure shows that the actual 
mechanics of reactor-plant operation 
are no more difficult than conventional 
plant operation. 
