ML20204J120
| ML20204J120 | |
| Person / Time | |
|---|---|
| Site: | Millstone, Haddam Neck, 05000000 |
| Issue date: | 05/12/1987 |
| From: | CONNECTICUT YANKEE ATOMIC POWER CO. |
| To: | |
| Shared Package | |
| ML20204H467 | List:
|
| References | |
| EOP-3.1-49, NUDOCS 8810240544 | |
| Download: ML20204J120 (4) | |
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awserr-i nev. e-ei E0P 3.1-49 Rev. 3 E0P2 MAY 121987
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PLANT OPERATIONS REVIEW COMMITTEE APPROVAL Connecticut Yankee pg g _ _ *,
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Emer ency Operating Procedure No. OP 3.1-49 Op %
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hhh PARTIAL LOSS OF DC freenov 4
e 1.0 DISCUSSION O
1.1 This procedure is to be used when either DC bus voltage is lost.
1.2 The. loss of a DC bus is highly unlikely due to its two independent power sources. The loss of a DC bus is an indication of a serfous problem so the DC bus cross connect should never be used during this event because it may cause a loss of both DC busses.
1.3 Loss of either DC battery bus will cause a loss of control power and breaker position indication for half of the 4160V and 480V breakers, these breakers will stay in _the position they were in prior to the loss of the DC battery bus. ;It is recomended that plant electricians be called in to operate any Breaker that must be operated manually in the shut or open position orfan energized bus due to the extreme danger associated with performing this action.
1.4 A loss of DC does not affect motor control centers (MCCs) as their control power and breaker position indication are supplied by AC transfomers integral to the MCC.
1.5 Opening of the S/G safattes is probable because:
I 1.
Loss of the "A" battery bus deenergizes solenoids shutting the MSIVs.
2.
Loss of "B" battery bus deenergizes solenoids preventing the operation of the HP steam dump system 1.6 Loss of either DC bus will cause a reactor trip with two different and distinct indications, 1.
Loss of "A" battery bus will cause a reactor trip with no primary i
side annunciators. The turbine does not trip.
2.
Loss of "B" battery bus will cause a reactor trip and turbine trip with no secondary side annunciators.
8810240544 0010c7 PDR ADOCK 05000213 P
PDR Page 1 of 4
E0P 3.1-49 Rev. 3 E0P2 MAY121987
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1.7 On a loss of "A" or "B" battery bus, decay heat will have to be removed by natural circulation.
In the case of "A" bus, the remaining RCP will have to be tripped off due to loss of CCW cooling and on a "B" bus loss, no pump transfer causes the RCPT to stop when the 148-37-2 and 148-47-2 open.
2.0 SYMPTOMS 2.1 Loss of "A" Battery Bus 2.1.1 Reactor trip (no turbine trip) with a loss of primary side annunciation.
2.1.2 Loss of A and B vital inverters (two power range drawers failedlow).
2.1.3 Loss ut' breaker indicating lights and control power for all breakers on busses 1-1A, 1-2, 4, 5, and 8.
- 2. I'.'4 MSIV closed.
2.2 Loss of "B" Battery Bus 2.2.1 Reactor trip and tdrbine trip with a loss of secondary side annunciation.
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2.2.2 Loss of C and D vi 1 inverters (two power range drawers fail low).
E 2.2.3 Loss of breaker indicating Ifghts and control power for all breakers on busses 1-18, 1-3, 6, 7 and 9.
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3.0 AUTOMATIC ACTION l
3.1 Loss of "A" Battery Bus l
3.1.1 Reactor trip (due to loss of A and B vital inverter).
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3.1.2 Main steam trip valves closure due to loss of power to solenoid valves 1 and 3.
3.1.3 Core cooling initiates, the "B" diesel starts, and its timer sequence on its ECCS equipenent and a High Containment j
Pressure WL actuates causing containment isolation.
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3.1.4 Charging flow control valves 110 and 110A go wide open.
3.1.5 Auto auxiliary feed initiation to S/Gs 1 and 2.
i 3.2 Loss of "B" Battery Bus 1
3.2.1 Reactor trip (due to loss of C and 0 vital inverters).
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E0P 301-49 Rev. 3 E0P2 g i g gg7 3.2.2 Turbine trip.
3.2.3 Auto auxiliary feed initiation to S/Gs 3 and 4.
3.2.4 L/D orifices in auto shut (pressurizer level channel 3).
4.0 IMMEDIATE ACTIONS i
4.1 Loss of "A" Battery Bus 4.1.1 Perform imediate actions contained in E-0, Reactor Trip or Safety Injection, Steps 1 through 3, if not perfonned.
4.1.2 Locally trip the turbine.
4.1.3 Trip all reactor coolant pumps within two minutes due to the loss of the bearing oil cooling water.
- 1 and 2 RCP will have to be tripped locally.
4.2 Loss of "B" Battery Bus i
4.2.1 Perform immediate actions contained in E-0, Reactor Trip or Safety Injection, S,teps 1 through 3. if not performerl.
CAUTION: Check if SI is actdated or required.
If actuated or required, go to E-0, Step 4.
5.0 SUBSEQUENT ACTIONS
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5.1 Loss of "A" Battery Bus 5.1.1 Open all breakers on vital busses A and 8 Re-energize A and 8 vital busses from their backup power supplies, and then sequence on loads.
I 5.1.2 Verify all four steam Ifne trip valves go closed by observing that the steam header pressure is decreasing.
5.1.3 Reset $! and HCP W/L per ES-1.1 after DC power restored, or open ekt.13 8 and reset 8 SI WL, then HCP WL per ES-1.1.
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5.1.4 Re-establish nonnel charging and letdown. Maintaining i
pressurizer level greater than 25%.
5.1.5 Re-energize ekt. 138.
I 5.1.6 Notify CONVEX of loss of 12R-1T-2 primary protective relay tripping and 1772-12R-5 operating capability.
5.1.7 Place il & #2 RCP's, 309-1A and 3TIA breaker control i
switches in trip pullout to prevent inadvertent starting.
f 5.1.8 Go to step 5.3.
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E0P 301-49 Rev. 3 E0P2 NAY 121987 5.2 Loss of "B" Battery Bus 5.2.1 Place all letdown orifices to close position.
5.2.2 Open all breakers on vital busses C and D.
Re-energize C and D vital busses from their backup power supplies and then sequence on loads 5.2.3 All four RCPs will trip 52 seconds after turbf'ne trips.
5.2.4 Re-establish nonnal letdown.
5.2.5 Notify CONViX of the loss of 12R-1T-2 breaker control and 8/U protective relay tripping and the 1206-12R-5 operating capability.
5.2.6 Start the auxiliary oil pump.
5.2.7 Place f 3 & #4 RCP's, 309-1B and 2T1B breaker control switches in trip pullout to prevent inadvertent starting.
5.2.8 Go to step 5.3.
5.3 If RCS pressure is less than~1700 psig, check that core cooling has actuated and is operating. Refer to E-0, Reactor Trip or Safety Injection.
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5.4 Manually trip the breakers f6r the feed and condensate pumps associated with the affecte<fDC but as necessary.
5.5 Manually trip the breaker for the heater drains pump associated with the affected DC bus.
5.6 Close or check closed the feed ifne MOVs.
5.7 Evaluate reactor coolant pressure to detennine if it is low or decreasing in an uncontrolled manner.
If it is low or decreasing, verify that:
(a) all pressurizer spray Ifne valves are closed, and (b) all pressurizer air operated relief valves and relief isolation valves are closed.
5.8 Return to E-0. Step 3.
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