40OP-9ZZ05 Power Ops

Question 1

When must chemistry be notified of a power change and why?

Answer 1

Chemistry must be informed when thermal power is changed greater than 15% RTP in one hour. This allows Chemistry to sample to verify compliance with the LCO 3.4.17 SR that requires Dose Equivalent I-131 to be verified less than or equal to 1.0 uCi/gm.

Question 2

What operator response is required for Main Turbine Vibration?

Answer 2

1. Immediately trip the Turbine if FILTERED journal vibration readings exceed 10 mils and is abruptly trending toward 12 mils.
2. Trip the turbine if FILTERED vibration exceeds 10 mils and is trending toward 12 mils over a 15 minute period.
3. Auto Trip = 12 mils
4. During a NORMAL power reduction ending with a PLANNED reactor shutdown, the reactor shall be tripped if either of the following conditions develops: [Ref 2.2.6; CRAI 3334065]
   • A sudden step increase in turbine vibration of 2 mils.
   • Vibration has increased to 10 mils

Question 3

What are the operational limits of Condenser vacuum in regards to the Main Turbine?

Answer 3

1. During Turbine startup, most limiting shell shall be maintained greater than 2” HgA and less than 4” HgA, but as close to 4” HgA as possible. ‘C’ Shell shall be maintained below 5” HgA.
2. Main Turbine shall not be operated less than or equal 410 MW with Condenser backpressure greater than 4“ HgA and less than or equal to 5” HgA for greater than 1 hour.
3. Main Turbine shall not be operated less than 40% load with backpressure greater than 5” HgA. (This may result in Turbine Damage).

Question 4

Why are Cooling Tower Fans operated when Circulating Water is in service?

Answer 4

To ensure the site environmental license is not violated, anytime a Circulating Water pump is operating, a sufficient number of Cooling Tower Fans should remain operating on each inservice Cooling Tower to prevent spillage past the concrete liner.

Question 5

When Feedwater Heaters are removed from service, why must Turbine load be lowered?

Answer 5

To prevent undue loading or overstressing of any turbine part, the maximum permissible kilowatt output which can be generated with various combinations of feedwater heaters out of service must be reduced in accordance with the table, Appendix C, provided in 40OP-9ZZ05.

Question 6

Describe the reason for maintaining proper D/P across the Economizer Feed valves.

Answer 6

1. At 100% power, maintain greater than 100 psid by adjusting the BIAS on the MFP speed controllers.
2. Sufficient D/P to feed Steam Generators through normal transients.
3. Avoid excessive D/P that could result in Economizer Valve oscillations.
4. Maintain D/P as low as possible to improve MW output.

Question 7

What are the values and operational actions required for certain values of ASI and ESI?

Answer 7

1. IF the most limiting CPC point ID 0187, Hot Pin ASI indicates a value outside the limits of (-)0.45 and (+)0.45, AND is trending to the CPC AUX Trip value of + or -0.5, THEN initiate a manual reactor trip.
2. Greater than 20% power, ASI shall be maintained + or - 0.05 of Full Power ESI.
3. Greater than 50% power, ASI shall be maintained = or - 0.01 of Full Power ESI.
   Insert CEAs or Dilute if top peaked (negative ASI)
   Withdraw CEAs or Borate if bottom peaked (positive ASI)

Question 8

What are necessary actions to dampen ASI oscillations?

Answer 8

If the boration or dilution method of ASI control is used, and RCS temperature cannot be maintained within (±) 1°F of the normal value of Tcold, then the CEAs will be used to control ASI. In this case, insertion of Group 5 or PSCEAs as ASI crosses ESI towards the top of the core, stopping insertion when ASI stabilizes at ESI is the method to use. Then, as ASI changes direction and moves toward the bottom, the same CEAs are withdrawn back to ARO (or to appropriate positions), which will serve the dual purpose of pulling the ASI toward the top, in effect dampening it again, and returning the CEAs to the desired position.

Question 9

What CEA positions will have maximum effect of forcing power to the bottom of the core?

Answer 9

Group 4 and 5 overlap may be modified for ASI control if the core is heavily top peaked due to burnup or xenon oscillations and power is less than 70% (55% with COLSS out of service). Aligning PSCEAs to 75 inches, Group 5 to 75 inches, and Group 4 to 85 inches will provide maximum effect in forcing power to the bottom of the core.

Question 10

Describe Axial Offset Anomaly and what are the potential affects on operations?

Answer 10

1. An axial shape trend that indicates a shift in power production toward the bottom of the core is generally known as Axial Offset Anomaly (AOA).
2. The cause of AOA is most likely crud buildup on fuel assemblies in the upper portion of the reactor core.
3. As a result of the reduced fissioning in the upper core, the power distribution shifts toward the bottom of the core. The resulting shift in power causes a reduction in SDM and an increase in local peaking factors.

Question 11

Describe behavior of ASI response to power changes as the core ages.

Answer 11

As the core approaches end of cycle (EOC), the oscillations are expected to become more unstable (divergent). Frequent dilutions or CEA manipulations are required to control the oscillations.

Question 12

Describe the procedural power limits and how to determine whether power is below the Licensed Power Limit.

Answer 12

1. Steady State Reactor Power is to be maintained less than or equal to 100.00% by a 12 hour rolling average of JSCALORH (Hourly average of Secondary Calorimetric Power). JSCALOR is allowed to exceed 100.00% by small amounts for short durations due to instrument fluctuation or small oscillations in Reactor Power; however, JSCALORH shall not intentionally be raised above 100.00% to increase the 12 hour rolling average. If JSCALOR is unavailable then the same guidance is applicable to the Power Limit in use.
2. From approximately 20% to 100% rated thermal power, the uncertainties in the Secondary Power Calorimetric (JSCALOR) are lower than for NKBDELT. JSCALOR should be used in this power range. However, if COLSS calorimetric power (JSCALOR/JSCALORC) is not available, NKBDELTC can still be used up to 96.6% Reactor Power.
3. If COLSS calorimetric power (JSCALOR/JSCALORC) becomes unavailable when Reactor Power is between 96.6% and 100%, Reactor Power will have to be reduced to less than or equal to 96.6% (after 4 hours of attempting to restore JSCALOR, or 96.6% established as an upper limit if power is reduced below 96.6%) as NKBDELTC has as much as 3.4% error and could cause an inadvertent overpower condition.

Question 13

What is the purpose and operational limits of the Ultrasonic Flow meter for Feedwater flow?

Answer 13

1. The purpose of the Ultrasonic Flow Meter (UFM) is to provide highly accurate flow measurement device that can provide Feedwater flow indication to the Plant Computer and Core Monitoring Computer to input to the calculation of plant power. When appropriate, the UFM is selected as the input to replace the installed venturi-based differential pressure element, which is less accurate than the UFM and is subject to fouling from corrosion and other impurities in the Feedwater, which further degrades its accuracy.
2. The UFM is not always in service. The venturi is used during startup until the plant parameters support the operation of the UFM. The UFM is calibrated for a feedwater temperature range. Feedwater temperature is 421°F to 475°F (448°F +/- 27°F).
3. To support the limits, and because the accuracy is not needed until closer to the License Power Limit, the UFM is typically not placed into service until >93% power during a power ascension.

Question 14

What are the Main Generator limits that are required to be observed?

Answer 14

1. Maintain hydrogen pressure and hydrogen cooling so that cold gas temperature does not exceed 48°C.
2. Maintain generator load, reactive power and cooling in accordance with Appendix I, Generator Capability Curve. This will prevent generator overheating.
3. Generator terminal voltage limits are 22.8kV to 25.2kV (24 + or - 5%).
4. VAR Loading - Buck = 310 MVARs Maximum. (560 Boost)
5. Switchyard Overvoltage = 535.5 kV

Question 15

When and how is a Rapid Shutdown of the Unit performed?

Answer 15

1. 40OP-9ZZ05 Section 6.5 – Rapid Shutdown/Rapid Downpower is used if the CRS has directed the unit shutdown within one hour.
2. Equipment degradation requires time critical action
3. LCO time restrictions require time critical action

Question 16

Why is it important to track the use of the Auxiliary Spray Valves?

Answer 16

1. When Auxiliary Sprays are utilized, thermal shock to the spray nozzle occurs. This can’t be avoided due to the design of the system.
2. TRM 3.4.102 has TSR 3.4.102.2 which provides the requirement… “The spray water temperature differential shall be determined for use” and the frequency of this TSR is “Each cycle of main spray when less than 4 reactor coolant pumps are operating and for each cycle of auxiliary spray operation.”
3. The limitations imposed on the pressurizer spray water temperature differential are provided to assure that the pressurizer is operated within the design criteria assumed for in the fatigue analysis performed in accordance with the ASME Code Requirements.

Question 17

Describe plant operations with both Main Spray valves isolated.

Answer 17

Steady State Operations recommendations
• Minimize plant evolutions and maintenance activities which could cause a plant upset.
• Utilize Pressurizer Heater controls as the preferred means to adjust RCS pressure.
• Auxiliary Spray valve operations should be minimized. (Log when used in 40OP-9RC01)
• Maintain Letdown in service.
• Minimize High Rate Blowdown.
• If High Rate Blowdown is in service, then consider intentionally lowering RCS pressure 15 25 psi prior to stopping High Rate Blowdown.

Question 18

How is the maximum power ascension rate determined?

Answer 18

Power increases are controlled to ensure the fuel is protected from damage. 40OP-9ZZ05 includes the ramp rate restrictions that are imposed. The loading rate limit, determined using Appendix A, is a guideline to ensure that the fuel preconditioning guidelines are not exceeded. The limit determined in Appendix A is the actual loading rate limit and it must not be exceeded. Exceeding these guidelines could result in fuel damage and cause the fuel warranty to be voided.

Question 19

How is power ramp rate monitored?

Answer 19

Monitor the power ascension using ONE of the following:

1. IF the Power Ascension Ramprate OAP is available, THEN perform the Power Ascension Ramprate OAP to monitor the power ascension during performance of this procedure.
2. IF Power Ascension Ramprate OAP is not available, THEN perform Appendix G Power Ascension Ramprate Data Sheet to monitor the power ascension during performance of this procedure.