Plant Operating Standard

PS-09 and PE-15 Primary and Pressurizing Systems

A. Normal Operation
- 1. The pressurizer operates to maintain the primary system between 1735 and 1765 psig during the normal operation.
  - a. The normal water level for the pressurizer is 27 inches.
  - b. The water level indicated by the pressurizer level indicator is equal to the actual water level only at 617F. The attached curve (Figure 1) shows the actual level compared to the indicated level at other temperatures.
  - c. Periodically (at approximate one-hour intervals), adjust the setpoint on the pressurizer level controls, and note that the controls react correspondingly.
  - d. Daily the pressurizer is vented for approximately fifteen (15) minutes through WL-1V to remove collected non-condensible gases.
- 2. The primary loops in operation.
  - a. The following primary pumps should be in operation.
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Full Speed		Half Speed	No. of Loops		Permissible
								Power Level
	4			0		2			80 MWt
	3			0		2			68 MWt
	2			0		2			52 MWt
	0			4		2			40 MWt *
	0			3		2			32 MWt *
	1			2 in same	2			48 MWt
				  loop

* Actually limited to 20% F.P. maximum by Start-Run switch.
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    [MWt is MegaWatts thermal. The other notation you will see is MWe, which is MegaWatts electrical, which is about 1/2 the thermal rating because of losses running generators.]
  - b. Steam generators are removing sufficient heat from the primary water to maintain the average primary temperature at approximately 508F with the reactor operating up to 80MWt.
    - (1) The boiler water level is programmed from - 9.5" to +2.0" for changes in reactor power levels of 20% to 80% (These levels are based on 0" being midway between the two boiler level nozzles).
    - (2) The maximum temperature difference between the primary and steam system must be <100F in the Steam generator. (This also applies to shutdown conditions.)
    - (3) a maximum pressure of 800 psig is specified for the secondary side of the steam generators. (2)
- 3. The attached Figures II and III present temperature limitations to be observed during warmup and cooldown and operation of the Primary System.
  - a. Pressurizer (PE) temperature is plotted vertically, and Primary System (PS) temperature is plotted horizontally, In interpreting this plot, the pressurizer water temperature element is to be used including any correction for instrument error. The highest reading primary system reactor output temperature element i an operating loop is to be used including any correction for instrument error. PE temperatures are saturation temperatures and correspond to the system pressure. The cross lined and shaded areas represent the required operating areas.
  - b. The crosslined area represents an area of limited heatup operation in which the PE temperature exceeds the PS temperature by more than 225F. The following precautions shall be observed:
    - (1) Pressurizer level is to be maintained nearly constant.
    - (2) PE heaters are to be used for maintaining pressure only.
    - (3) Recirculation through the use of spray is not permitted.
  - c. The spray valves are not to be used while operating with only one pump at half speed in the starboard loop due to the inability of the pump to provide enough head to both spray and keep the level reference cup filled.
- 4. Heatup and Cooldown Rate Maximum Limits
  - a. Pressurizer: 70F/hr. avg.
  - b. Primary System: Heatup: 35F/hr. avg. Cooldown: 45F/hr. avg.
  - c. Subsequent to an extended period of normal operation (8 hours or more), the primary temperature may be varied without restriction as to rate, provided the maximum difference between primary temperature and normal operating temperature does not exceed 50F.
B. Minimum Conditions for Reactor Operations
- 1. The pressurizer is operating and is capable of maintaining the pressure of the primary water between 1585 psig and 1900 psig.
  - a. The PE level is maintained between 12 and 43 inches.
  - b. The pressurizer is vented daily for approximately fifteen (15) minutes through WL-1V. Refer to POS WL-39 for precautions for this operation.
- 2. One primary loop is capable of operating.
  - a. The following pumps are capable of operating in the one primary loop with a total minimum flow of 4000 gpm.
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Permissible Reactor Power		Pumps
	  20 MWt			2 pumps @ half speed
	* 48 MWt			2 pumps @ full speed
```
  - b. The steam generator in the one primary loop is capable of maintaining the average primary system temperature at 508F+-6F with the reactor producing 0 to 50% power.
    - (1) The boiler water level must be capable of being controlled between -9.5" and +2.0" H2O. (These levels are based on 0" H2) being midway between the two boiler level nozzles.)
- 3. A minimum of 23 gpm of cooling water supplied to each primary pump.
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NOTE:  In an emergency, any PS pump may be operated without CW flow for the following time periods:
	Full speed:	15 minutes
	Half speed:	30 minutes
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- 4. Control rod seal water and primary pump flushing water must be supplied in accordance with requirements listed in POS PP-21, SL-37.
- 5. Due to pump vendor recommendations, operation with flows above 7000 gpm is restricted. Operation with flows in the 7000 -7250 gpm range is permissible but not in excess of fourteen days continuous operation. Therefore, caution is indicated when operation is with one pump at full speed and one at half speed in different loops.
* Permissible output of Steam Generator Limited to approximately 40 MWt.
My text copyright 2020 Tommy Johnson, all rights reserved. I believe the Savannah documentation is property of MARAD or the US government.