ML072970053

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July-August Exam 50-325, 324/2007301 Final Simulator Scenarios (Scenario 2 of 4) (Section 4 of 4)
ML072970053
Person / Time
Site: Brunswick  Duke Energy icon.png
Issue date: 01/31/2007
From:
- No Known Affiliation
To:
Office of Nuclear Reactor Regulation
References
50-324/07-301, 50-325/07-301 50-324/07-301, 50-325/07-301
Download: ML072970053 (12)
v • d • e


Text

SCRAM CARD

  • ENSURE SCRAM VALVES ARE OPEN BY MANUAL

~C*RAM OR ARlTRIP"

\\

  • CONT~QL REACTOR PRESSURE BETWEEN 800 AND 1000 PSIG
  • CONTROL REACTOR VESSEL LEVEL BETWEEN +.170 AN-D +200 INCHES
  • INSERT NUCLEAR INSTRUMENTATION
  • PLACE RECIRC PUMP SPEED CONTROLLERS TO 10%
  • ENSURE HEATER DRAIN PUMPS ARE TRIPPED
  • ENSURE TURBINE OIL SYSTEM OPERATING
  • PLACE SULCV IN SERVICE

(

(

(

\

  • STEP RC/Q-15

"",I PERFORM "ALTERNATE CONTROL ROO INSERTION" (EOP* 01* LEP* 02)

RC/Q-15 I

STEP BASES:

Concurrent execution of this step with the remainder of this procedure optimizes efforts to achieve reactor shutdown. EOP-01-LEP-02 (Alternate Control Rod Insertion) addresses alternate methods of control rod insertion.

Reactor shutdown on control rod insertion alone is preferable to injecting boron for the following reasons:

a. Boron injection contaminates the primary system, requiring extensive cleanup and subsequent inspection before continued plant operation is possible.
b. If a leak occurs below the elevation of the reactor water level being maintained, boron injection may not be successful in shutting down the reactor.
c. A reactor shutdown on boron is not necessarily a stable condition; if boron is subsequently diluted or displaced by a leak or an operational error, the reactor could return to criticality.

Several alternate methods for inserting control rods are presented in EOP-01-LEP-02.

See the Step Discussions for EOP-01-LEP-02 for a detailed discussion of these methods.

  • 1001-37.5 Rev. 8 Page 87 of 90 I
  • STEPS RCtO-OS through RCtO-10 (continued)

The Boron Injection Initiation Temperature is defined to be the greater of:

a. The Suppression Pool temperature at which initiation of a reactor scram is required by Technical Specifications, or
b. The highest Suppression Pool temperature at which initiation of boron injection using SLC will result in injection of the Hot Shutdown Boron Weight of boron before Suppression Pool temperature exceeds the Heat Capacity Temperature Limit.

Criterion b is a function of reactor power; a higher reactor power level causes higher integrated heat energy to be rejected to the Suppression Pool thus requiring a lower Suppression Pool temperature for initiation of boron injection if the Heat Capacity Temperature Limit is not to be exceeded before reactor shut down is achieved.

At Brunswick, a single value is used for Boron Injection Initiation Temperature (110°F) for procedure simplification.

  • 1001 -37.5 Rev. 8 Page 82 of 90 I

STEPS RC/O-OB through RC/O-10 NO YES RClQ*10 STEP BASES:

If reactor power is above 2%, the operator is directed to inject boron. This is a conservative action because with power above 2%, Suppression Pool temperature will steadily increase towards 110°F. This also allows sufficient time for the Hot Shutdown Boron Weight of boron to be injected. The extra time may be needed since the alternate systems used for boron injection require significantly more time to inject boron should the SLC System fail. The SLC system is initiated to shut down the reactor.

As long as the core remains submerged (the preferred method of core cooling), fuel integrity and reactor vessel integrity are not directly challenged even under failure-to-scram conditions. A scram failure coupled with an MSIV isolation; however, results in rapid heatup of the Suppression Pool due to the steam discharged from the reactor vessel via SRVs. The challenge to containment thus becomes the limiting factor which defines the requirement for boron injection.

If Suppression Pool temperature and reactor pressure cannot be maintained below the Heat Capacity Temperature Limit, rapid depressurization of the reactor vessel will be required. To avoid depressurizing the reactor vessel with the reactor at power, it is desirable to shut down the reactor prior to reaching the Heat Capacity Temperature Limit, thus minimizing the quantity of heat rejected to the Suppression Pool. The Boron Injection Initiation Temperature is defined so as to achieve this when practicable.

1001-37.5 Rev. 8 Page 81 of 90 I

.* STEP RC/L-29 CAN REACTOR YES WATER LEVEL BE RESTORED ANO MAINTAINED ABOVE LL*4 RCIL*~

NO

  • STEP BASES:

When reactor water level cannot be restored and maintained above the LL-4, emergency depressurization is required for the purpose of maximizing injection flow from high head pumps and to permit injection from low-head pumps. Prior to emergency depressurization, high reactor pressure may have precluded injection from low-head pumps.

Depressurizing the reactor is preferred over restoring reactor water level through the use of systems which inject inside the shroud because:

a. A large reactor power excursion may result from in-shroud injection.
b. Rapid depressurization, by itself, will reduce reactor power due to a substantial increase in voids.
c. Following the depressurization, reactor power will stabilize at a lower level.
  • 1001-37.5 Rev. 8 Page 29 of 90 I
  • STEP RC/L-29 (continued)

Emergency depressurization is not required until reactor water level cannot be restored and maintained above LL-4 because:

a. Adequate core cooling exists so long as reactor water level remains above LL-4, or even momentarily drops below LL-4.
b. The time during which reactor water level decreases to LL-4 can best be used to line up and start pumps in additional injection systems listed in Table 1, which might not yet have been placed in service.
  • 1001-37.5 Rev. 8 Page 30 of 90 I
  • STEPS RC/P-40 and RC/P-41 I

( TERMINATE AND PREVENT \

INJECTION TO THE REACTOR VESSEL FROM THE FOLLOWING SYSTEMS UNLESS THE SYSTEM IS BEING USED TO INJECT BORON:

  • CONDENSATEJFEEDWATER

\

  • ALTERNATE COOLANT INJECTION SYSTEMS J I RCIP-40 WHEN INJECTION TO THE REACTOR VESSEL FROM THE SPECIFIED SYSTEMS HAS BEEN TERMINATED AND PREVENTED, RAPIDLY DEPRESSURIZE THE REACTOR IRRESPECTIVE OF RESULTING COOLDOWN RATE AS FOLLOWS I RClP-41 L.---~--

STEP BASES:

Injection into the reactor vessel is terminated and prevented before Emergency Depressurization proceeds in order to prevent uncontrolled injection of large amount of cold water as reactor pressure decreases below the shutoff head of operating system pumps. Injection from boron injection systems and CRD is not terminated because operation of these systems may be needed to establish and maintain reactor shutdown.

Further, the injection flow rates from these systems are small compared to those of the other systems used to control reactor water level. Injection from RCIC is not terminated because the injection flow rate from this system is small, continued operation of the turbine aids in depressuring the reactor vessel, and operation during reactor depressurization is not expected to result in significant injection flow rate variations.

Only when the listed systems have been terminated and prevented is emergency depressurization allowed.

  • 1001-37.5 Rev. 8 Page 66 of 90 I

(

Manpower Required:

NOTE 1 Control Operator Special Equipment: 4 jumpers (15, 16, 17, and 18) co: 1. Unit 1 Only: ENSURE the REACTOR MODE SWITCH, C71-S1, is in *SHUTDOWN.*

co: 2. Unit 2 Only: IF steam flow is less than 3 X 10 6 lb/hr, THEN ENSURE the REACTOR MODE SWITCH, C72-S1,i"S in RSHUTDOWNR.

NOTE Steps 3 and 4 may be performed concurrently.

3. IF an automatic scram signal is present AND power is available to the RPS bus, THEN INSTALL the following jumpers to bypass the reactor scram:

co: a. Jumper 15 in Panel H12-P609, Terminal Board DD, from the right side of Fuse C71A(C72A)-F14A to Terminal 4 of Relay C71A(C72A)-K12E.

co: b. Jumper 16 in Panel H12-P609, Terminal Board BB, from the left side of Fuse C71A(C72A)-F14C to Terminal 4 of Relay C71A(C72A) -K12G.

co: c. Jumper 17 in Panel H12-P611, Terminal Board DD, from the right side of Fuse C71A(C72A)-F14B to Terminal 4 of Relay C71A(C72A) -K12F.

co: d. Jumper 18 in Panel H12-P611, Terminal Board BB, from the left side of Fuse C71A(C72A)-F14D to Terminal 4 of Relay C71A(C72A) -K12H .

  • IOEOP-01-LEP-02 Rev. 25 Page 13 of 281

Section 3 - Continued

4. INHIBIT ARI by performing the following steps; co: a. PLACE ARI AUTO/MANUAL INITIATION switch, Cll(C12)-CS-5560, to "INOP".

co: b. PLACE ARI RESET switch (spring return),

Cll(C12)-CS-5562, to "RESET" and MAINTAI~

for a minimum of five (5) seconds, THEN RELEASE.

co: c. VERIFY the red "TRIP" light located above ARI INITIATION, Cll(C12)-CS-556l is off.

co: 5. ENSURE the DISCH VOL VENT & DRAIN TEST switch is in "ISOLATE".

6. VERIFY the following valves are closed:

co: a. DISCH VOL VENT VLV Cll(C12)-V139 co: b. DISCH VOL VENT VLV Cll(C12)-CV-F010 co: c. DISCH VOL DRAIN VLV Cll(C12)-V140

  • co:

co:

co:

7.

8.

d. DISCH VOL DRAIN VLV Cll(C12)-CV-FOll RESET RPS.

IF RPS CANNOT be reset, THEN RETURN to Step C.6 on Page 2.

co: 9. PLACE the DISCH VOL VENT & DRAIN TEST switch to "NORMAL" .

10. VERIFY the following valves are open:

co: a. DISCH VOL VENT VLV Cll(C12)-V139 co: b. DISCH VOL VENT VLV Cll(C12)-CV-F010 co: c. DISCH VOL DRAIN VLV Cll(C12)-V140 co: d. DISCH VOL DRAIN VLV Cll(C12)-CV-FOll

  • IOEOP-01-LEP-02 Rev. 25 Page 14 of 281

Section 3 - Continued co: 11. WHEN the scram discharge volume has drained for approximately 2 minutes OR SDV HI-HI LEVEL RPS TRIP annunciator (A-OS 1-6) clears, THEN CONTINUE in this procedure.

NOTE IF venting control rod over piston area in accordance with Section 6, THEN the AO should be notified so venting can be secured, prior to inserting a manual SCRAM.

CO: 12. Manually SCRAM the reactor.

13. IF control rods moved inward, THEN PERFORM the following:

CO: a. IF all control rods are inserted to or beyond position DO, THEN RETURN to Step C.6 on Page 2.

CO: b. IF all control rods are NOT inserted to or beyond Position DO, THEN RETURN to Step S on Page 14 .

CO: 14. IF control rods DID NOT move inward, THEN RETURN to Step C.6 on Page 2 .

  • IOEOP-01-LEP-02 Rev. 25 Page 15 of 281
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