ML18018B112

Scram Summary 91-01 Relating to an Event on August 13, 1991 Concerning a Turbine Trip and Automatic Reactor Scram When the Main Transformer Phase B Developed an Internal Fault

ML18018B112
Person / Time
Site:	Nine Mile Point
Issue date:	01/18/2018
From:	Niagara Mohawk Power Corp
To:	Office of Nuclear Reactor Regulation
References
Download: ML18018B112 (56)

Text

SCRAM

SUMMARY

91-01 At 0548 on August 13, 1991, Nine Mile Point Unit Two experienced a turbine trip and automatic reactor scram when the Main Transformer Phase B developed an internal fault (Main Transformer fault details discussed in separate report). The transformer fault created an electrical disturbance throughout the normal electrical distribution system. This electrical disturbance caused UPS 1A-D and G to trip off, de-energizing their respective loads. (Details of UPS trips and electrical system response are discussed. in separate reports)

Initially the operators lost most BOP instrumentation and all control room annunciation which created several conflicting indications of reactor status. The SSS ordered the mode switch be placed in shutdown and the crew began to respond to the scram. The crew recognized that feedwater pumps had tripped and initiated Reactor Core Isolation Cooling (RCIC) to control a lowering reactor water level. Reactor systems responded to the turbine trip as expected including a EOC-RPT Recirc pump downshift. Two safety relief valves lifted to limit, reactor pressure to 1070 psig. The Redundant Reactivity Control System initiated an Alternate Rod Insertion and Recirc Pump downshift signal on high reactor pressure. Post Accident Monitor recorders shifted to fast speed and continued to provide reactor pressure and water level indication.

When reactor water level reached Level 3 (159.3 inches), operators entered the Emergency Operating Procedures (EOPs) for RPV control.

Due to lack of control rod position information, operators also entered C5, Level/Power Control. In accordance with C5, automatic ADS operation was inhibited. Because RCIC was running, operators placed RHR loop A in Suppression Pool cooling. Per EAP-2 the SSS/SED declared a Site Area Emergency due to loss of control room annunciators with a plant transient in progress. Reactor water level was recovered using RCIC. The lowest level reached was approx. 145 inches, well above any ECCS injection setpoints. When water level returned to the normal band, RCIC was realigned to pump CST to CST. As water level continued to rise, operators recognized that reactor pressure was below the discharge pressure of condensate booster pumps and tripped them off. Reactor water level at that time was approximately Level 8 (202.3 inches). The cold water expanded and water level continued to rise. One CRD pump was left running to support control rod insertion. Water level was offscale high on the only operating recorders for approximately 8 minutes. During this interval water level was conservatively estimated to reach a maximum of 243 inches (9 inches below the main steam lines).

At approximately 0622, operators restored power to the UPS buses.

With power restored to Reactor Manual Control System, the Full Core Display, Rod Worth Minimizer, and Rod Sequence Control System gave some conflicting information on control rod position.

Using RPV control, section RQ, operators installed RPS jumpers and reset the scram. At that point all rods indicated full in.

With RCIC running CST to CST and condensate booster pumps secured, reactor water level decreased. Condensate Booster Pump P2A was restarted to control water level however the feedwater pump suction valves (CNM-MOV84) would not reopen presumed at the time due to high dp. Operators could not manually equalize pressure across the valves due to the SSS restricting access to the turbine building.

Operators used the low pressure/low flow valve (CNM-LV137) to control level. Water level dropped to Level 3 (159.3 inches) again and EOPs were reentered. Water level lowered to a minimum of approx. 124 inches (approx. 15 inches above an ECCS injection setpoint) before returning to the normal band.

At 0950 UPS 1C and 1D were restored to their normal power supplies UPS 1A and 1B had to be left on maintenance supply due to equipment failures. During the shutdown, several equipment failures created additional burden on the control room staff. These equipment problems are described in the Sequence of Events and the Deficiencies list.

In evaluating this transient against the USAR transient analysis the following conclusions were made:

1) Reactor pressure rise as shown on both Post Accident Monitoring recorders is much less severe than the pressure rise shown on Figure 15.2-1 of the USAR (Generator Load Rejection with Bypass) 1070 vs 1150.

2) Reactor water level as shown on both Post Accident Monitor recorders is slightly lower than the USAR, however this discrepancy was due to all feedwater pumps tripping off.

3) Neutron flux was not recorded however, the conditions used in the USAR which influence the flux spike such as pressure rise, scram speed and void fraction are all more severe than actual conditions. In addition N2-ISP-NMS-W9007 "APRM Functional Test" was performed on 8/14/91, and verified proper operation of APRM flux scrams.

4) Based on personnel interviews and review of as found conditions, we believe that all plant systems designed to mitigate the severity of this event, (ie EOC-RPT, Turbine bypass valves, SRVs, ARI) functioned as required.

Based on the above conclusions, the results of this transient were within the bounds of current transient analysis.

Scram Evaluation Team:

Team Leader: Tom Tomlinson (SRO)

Dorry Crager Brian Wade John Baudanza Jerry Helker (SRO)

Various System Engineers

Nine Mile Point Unit 2 Reactor Pressure and Water Level vs Time 210 1500 200 1400 190 180 1300 Water Level 17Q 160-150 140 I

I I

I 5'PV I I

1200 1100 I 1000 130 1 120 900 110 CL Vl lg 800 100 PP oJ I 700 90 g a I (0 g U. RPV Pressure i 80 0 I I 600 70 60 500 10 20 30 40 50 60 0 80 90 1 0 1 0 (oS-~S)

Time minotes irom 05:48 Data from August 13, 1991 Site Area Emergency

8E UENCE OP EVENT8 SCRAM 91 01 The attached Sequence of Events is a reconstruction of the events that occurred on August 13, 1991. Due to the loss of Uninterruptible Power Supply (UPS) power, normal means of recording the event were initially unavailable. Control Room meters and recorders, powered from the affected UPSs, were inoperable during the first 34 minutes of the event. The Plant Process Computer was unavailable an additional 49 minutes. This Sequence of Events is based on operator interviews and written statements, operator logs, Post Accident Monitor (PAM) recorded plots, Turbine/Generator flags, and crew debriefs. Significant effort was made to ensure the validity of the event sequence and times of occurrences.

However, due to the above-mentioned conditions, this Sequence of Events is essentially a "best approximation" of the actual event sequence.

PAGE 1 TIME INDICATIONS/PROBLEMS/ACTIONS REASON/iYUSTZPZCATION 0548 Loss of Transformer 1B due to Under Investigation Fault Customer Trip of Main Turbine, See attached list of TSV/TCV shut. relay flags.

Reactor Scrams. TSV/TCV fast closure.

Turbine bypass valves open.

Automatic to control pressure.

Fast Transfer from Normal Station'ower to See attached list of Reserve relay flags.

Power.

Failure of UPS 1A-D,G, failed UPS Failure to maintain a power supply to Under Investigation.

non-safety vital buses.

Resulting from Loss Loss of Radio Leaky Mire of UPS.

Antenna System.

Loss of Control Room Annunciators.

CÃS-MOG 52s Cooling Tower Bypass Valves went open.

Loss of Computers (Process, SPDS/ERFg GETARSg GEMS/

DRMS, 3D-Monicore) .

Loss of Gaitronics.

Loss of BOP Instrumentation.

Loss of Essential Lighting.

Off Gas Isolation.

P603 panel Recorders Fail as is.

FWS-LV10s Lockup in open position.

Loss of Drywell Cooling.

Loss of Rod position indication.

Feedwater and Condensate Booster Pump minimum flow valves fail open.

1 As shown by Scriba Oscilloscope

PAGE 2 TIME INDICATIONS/PROBLEMS/ACTZONS REASON/JUSTIFICATION ARI and PAM to fast speed at 1050 PSIG. Normal response to hi pressure due to 2 SRVs lift at 1070 PSIG. Turbine trip from high power.

After pressurization event PAM Recorders Used as reliable on P601 are used for Reactor level and indication with Pressure Indication. Level 175" redundant sources.

Pressure 920g Observed Scram Pilot lights .are out. Due to Auto Reactor Scram.

APRM Meters and LPRM Lights on back Operators used panels are Downscale, Scram Logic Lights various methods to are out, Scram Discharge volume is full. determine reactor power.

Operators dispatched to verify scram air Backup indications.

header pressure and monitor reactor pressure and water level on local indicators.

Recirc pumps Downshifted due to EOC RPT As designed.

and RRCS Hi Reactor Pressure.

Observed Feedwater pumps and Condensate Minimum flow valves Booster pump 2A tripped. Condensate failed open see Booster pump 2C Auto Starts. attached memo.

Division II H2/02 Sample Pump Trips Off. Spurious trip unrelated to UPS problems 0549 Mode switch is placed in shutdown. Ordered by SSS as conservative action.

0555 Manually initiated RCIC due to lowering Ordered by SSS to Reactor vessel level and no feed pumps control water level.

running. Experienced flow, speed and pressure oscillations while in Auto Control, therefore transferred to Manual control.

Reactor Recirc Runback at L4 (178.3"). Auto response.

PAGE 3 TIME INDICATIONS/PROBLEMS/ACTIONS REASON/JUSTIFICATION Groups 4 and 5 Isolations at L3 (159.3")

0556 Entered RPV control EOP. Reactor Vessel Water level <159.3" and lowering.

Entered C5. No rod position indication.

ADS inhibit switch to on. .Required by C5.

Initiated suppression pool cooling Ordered by SSS due to using RHS*PlA. RCIC operation.

0600 Declared Site Area Emergency. EAP-2, Loss of all control room annunciators with plant transient in progress.

Operators dispatched to verify UPS Ordered by SSS due to operation. diagnosis of control room indications.

0607 Commenced logging cooldown. EOP-RPV, verify cooldown.

0608 Notified State and local authorities. EPP-20 0612 Initiated NRC Contact EPP-20 0612 Controlling Reactor Vessel Water As directed by C5.

level with RCIC in manual. Reactor level rising. Reactor Pressure lowering.

0614 Secured RCIC injection, started Maintaining level pumping tank-to-tank. control.

0615 LS (202.3) is reached, Condensate Maintaining level Booster pumps are secured. control.

Operator reports that. series UPS 1A-D,G have tripped.

0620 Secured condensate pumps except for Standard operating P1A. Reactor Vessel Water level is practice.

lowering.

0622 Restore UPS 1A-D,G by manually As directed by SSS.

transferring to maintenance bus.

Annunciator Power and other indications are restored.

PAGE 4 TIME INDICATIONS/PROBLEMS/ACTIONS REASON/JUSTIFICATION Group 9 Isolation Restoration of Power to UPSs FWS-LV10s closed.

0630 All rods in except 6 which Loss of power. See have no indication on Pull attached memo.

Core Display (Rod 14-31 has no indication on RWM, and 15 without full-in indication on RSCS) .

CNM-MOV84s closed. OP-3 prerequisite for starting a condensate booster pumps Restored Drywell Cooling Per Operating Highest Temperature -165'F. procedures.

Lowest Temperature -120'P 0640 Started Condensate Booster Level steadily Pump P2A to maintain Reactor lowering.

Water level 165" 180".

Attempted to open MOV 84A & B Under Investigation.

after booster pump running.

Received dual indication.

Opened FWS-LV55A in an attempt to establish feed flow to vessel. No flow due to CNM-84S closed.

Re-entered RPV EOP on level.

Using LV-137 to control Reactor Vessel Water level.

0645 Reset Rod Drive Control RDCS not scanning System. due to loss of power.

0650 Installed RPS jumpers per To enable resetting EOP-6 Att. 14. scram.

0653 Reset scram. EOP-RPV, Section RQ 0700 All rods indicated full in.

Controlling Reactor Press on bypass valves.

0711 Process computer restored.

PAGE 5 TIME INDICATIONS/PROBLEMS/ACTIONS REASON/JUSTIFICATION Division II H~ O~ Sample Pump Pound tripped by restarted. operator.

0729 Started mechanical air removal pumps. Maintain condenser No Auxiliary Steam to Clean Steam vacuum.

Reboilers. Started Aux Boiler. Had to pin open AOV-145.

0732 Main Turbine would not go on turning See attached memo.

gear.

0738 Started Condensate Pump P1B. To clear high stator temp on P1A due to high flow.

0740 RCIC Shutdown to standby. No longer needed.

0750 SPDS restored.

0758 Hydraulic Power Units Reset. Normal response.

0805 Stack Gems reported Inop. Computer Computer did not restore department started rebooting system. itself properly after power was restored.

0806 RCS Plow Control Valves full open. N2-OP-29 0810 Completed restoring RHR Loops B and C B and C loops were marked to operable. up prior to the event for corrective and preventative maintenance on various valves and instruments.

0821 ADS inhibit switch to Normal, RPS EOP Recovery.

jumpers removed.

0847 Stack Gems computer restored.

0937 RCIC INOP AOV156 did not. indicate Technical Specifications shut, MOV126 de-energized shut per 3/4.6.3 Technical Specifications.

0950 UPS 1C & 1D restored to Normal Power, Per SED could not restore 1A & 1B to Normal Power, left selected to maintenance.

1006 Drywell vacuum breaker operability Had just determined that test was performed as required by two SRVs had lifted at'.

Tech Specs. the beginning of the event.

PAGE 6 TIME INDICATIONS/PROBLEMS/ACTIONS REASON/JUSTIFICATION 1020 UPS 1G restored to normal Per SED.

power.

1031 Group 9 Isolation Reset. Normal Recovery.

1055 Started Reactor Water Cleanup For chemistry and Pump PlB for full reject. water level control.

1056 Reactor Water Cleanup Pump P1B Root cause in trips when Reactor Water progress. No Cleanup Isolates due to Delta equipment damage.

Flow. See Engineering memo.

1158 Secured RHS Pump PlA. Needed to stroke MOU40A for PMT. Two loops of shutdown cooling are required by Tech Specs.

1217 Reset RHR shutdowwn cooling, RWCU, and Group 4 Isolations.

1415 Shut Condensate AOV109 For chemistry (condensate bypass) . concerns.

1458 Shutdown RCS Pump P1B for OP-3 1 shutdown cooling.

1508 Started RHS Pump P1B in OP-101C/31 shutdown cooling mode.

Experienced difficulty in Initially unable to controlling Reactor Uessel properly throttle Water Level. RHS*MOV142, RHR Discharge to Radwaste, from Control Room.

Opened locally.

1519 Shutdown Condensate Booster OP-101C Pump P2A.

1520 Shutdown Condensate Pump P1A. OP-101C 1807 Shut 2FWS-MOV21A & 21B. OP-101C 1846 Reactor is in Cold Shutdown.

1943 Terminated Site Area Emergency. Per SED.

Deficiencies Noted durin the Event and 0 en Items

1) Reactor Water Chemistry Excursion

~ Yang Soong of Nuclear Technology has analyzed the chemistry excursion. His recommendations to Chemistry were that 1) this startup ocur at a slower rate that normal .in order to minimize the effect of any remaining chemical species in the vessel, and 2) Maximum RWCU flow be maintained throughout startup.

2) Water hammer in WCS

~ Engineering evaluation memo SM2-M91-0213

~ Inspection of WCS piping was performed on August 13, 1991, at approximately 1950 hours0.0226 days <br />0.542 hours <br />0.00322 weeks <br />7.41975e-4 months <br /> by Engineering and Radiation Protection. This inspection revealed no abnormal conditions and Engineering has no reservations regarding return of WCS back to-service.

3) 2ASS-AOV145 had to be pinned open

~ WR 178843'R 164466'R 193588

~ ASS-AOV145, Aux Boiler Steam Inlet Control to Reboilers, has an air leak at its control block. The leak causes a loss of air to the valve and subsequent valve closure.

Once opened, the valve had to be pinned open.

4) Water hammer in RHR

~ Engineering Evaluation memo NMP77864

~ Inspection of the RHR ",Piping System was performed on August 13, 1991, at approximately 1350 hours0.0156 days <br />0.375 hours <br />0.00223 weeks <br />5.13675e-4 months <br /> by Engineering and Radiation Protection. This inspection revealed no abnormal conditions and Engineering has no reservations regarding return of RHR back to service.

This inspection was performed while the loop was warmed up for the second time. No procedural problems were identified.

5) Friskall on Reactor Building Exit

~ WR 192659

~ During the Site Area Emergency, two of the three Friskalls at the Reactor Building were initially not available. One was reset by 0700 and the other required a Work Request. The WR was completed August 17, 1991.

6) 2CNM-MOV84s couldn'5 be open WR 192891, WR 192892, WR 194591, Engineering Evaluation

~ Attempts to open the feedwater suction valves were unsuccessful due to differential pressure (approximately 500 psig) across the valves. WRs were submitted to check torque settings. Investigation is continuing.

7) Chemistry Sampling and Analysis Chemistry Evaluation The normal sample tap was not available due to the WCS isolation, requiring operator action to valve-in the alternate sample tap. The Loop A tap is not normally valved into service as a result of an engineering assessment of flex hose failure. Chemistry is to submit a DER to request Loop A sample tap continuous service.

Loss of power to chiller caused the temperature switch to trip. The local thermal reset was required to be depressed and held for five seconds. The Chemistry Technician did not wait the required time and the temperature switch didn't reset.

This delayed the sample approximately 15 minutes. An Operator Aid has been developed to identify the five second time requirement.

The gamma spectrometer was in use for the stack sample analysis. The spare gamma spectrometer in under repair.

The unit is to be repaired consistent with department priorities.

~ Communication was sometimes confusing between lab, OSC, and TSC. Emergency Planning is to revise OSC to facilitate control of Chemistry Sample teams.

~ Ion Chromatographic analysis dilution and contamination problems were encountered. All chem techs qualified in ion chromatography will be requalified by September 5, 1991.

8) Trouble with getting turbine on turning gear

~ System Engineer Evaluation, DER 2-91-Q0868

~ Following turbine coastdown, the turning gear motor tripped on overcurrent and allowed the rotor to come to a complete stop. Subsequent attempts to put the turbine on the turning gear resulted in motor overloads due to the thermally induced bowing of the rotor. The rotor cooled for approximately eight hours and was then placed on the turning gear. A subsequent walkdown revealed no unusual conditions.

occasionally trips on It is known the turning gear overcurrent during coastdown and there are no special recommendations for turbine startup or shutdown as a result of this event. A DER was initiated to address this recurring problem.

9) ICS Outboard check valve 2ICS-AOV156 indication

~ WR 193343, WR 194584

~ With the ICS system secured, testable check valve AOV156 indicated full open on PNL601. During performance of WR 193343 for correction of the indication problem, it was noted the valve packing was leaking. Performance of WR 194584 corrected the packing leak.

10) Two sumps on Rx 175'lightly overflowed

~ WR 193371

~ All Equipment Drain Sumps on Rx 175'verflowed to Floor Sumps with only DER Tank 2A (at ramp) exceeding boundary area. Walkdown on August 26,,1991, showed leakage to be from DFR TK2A discharge hose within the sump.

11) MSIV AOV6D Dual Indication

~ WR 193349

~ 2MSS*AOV6D indicated dual position when taken to close.

The WR is complete.

12) No Aux Main Steam to Clean Steam Reboilers due to PV113

~ WR 193207

~ 2ASS-PV113, Clean Steam Reboilers Control Valve, does not control steam pressure when 'ASS-STV112 is open.

Scheduled for work August 27 and 30, 1991.

13) LOCA Bypass Switches do not work without UPS (Black) Power

~ Plant Change Request .PC2-0258-91

~ Request for LOCA override switches and logic to be able to function without (Black) UPS power.

14) 2CNM-AOV101 Open

~ Procedure Change Evaluation

~ PCE submitted to add reclosure of AOV101, bypass around low pressure feedwater heaters, and AOV109, bypass around condensate demineralizers, after scram to OP-101C.

AOV109 was closed to address potential chemistry concerns. AOV101 was closed after cold shutdown.

15) ODI 5.16 Skills of the Trade

~ Procedure Change Evaluation

~ PCE submitted to add manual breaker operation for 600V and less. This change has been completed.

16) Reactor Vessel Upset range not available on Process Computer and not powered from Safety Related Bus

~ Plant Change Request PC2-0257-91

~ Request that Reactor Vessel Upset range instrumentation be powered from a Safety Related bus and recorded on the process computer in order that level may be recorded during transients that involve power failure.

17) RHS*MOV142, RHR Discharge to Radwaste, would not initially open from PNL601

~ WR 193350

~ The throttle discharge to radwaste would not open from the control room and had to be manually opened at the valve. The WR was completed on August 13, 1991.

0

18) Cooling Tower Bypass Gates fail open on loss of power to temperature instruments.

~ Plant Change Request PC2-0288-91

~ Loss of UPS power caused the temperature instruments in the basin to fail downscale, sending a signal for the bypass gates to open. This could have caused an overflow of the basin (in this event the basin did not overflow) and a loss of the circulation water heat sink. The plant change request was submitted to change the logic so that the bypass gates fail closed.

19) Transformer 1B Fault

~ Root Cause being investigated Transformer being removed. Spare Transformer to be used.

20) UPS1A-D and G failed to transfer

~ System Engineer Evaluation continuing

21) Feedwater and Condensate Booster Pumps trip off

~ System Engineering Evaluation

~ Loss of UPS1A and 1B resulted in loss of flow signals to the minimum flow valves for both the feedwater and condensate booster pumps. This caused the system flow to exceed the supply capacity of the condensate system, causing system pressure to decrease.

The operating "B" and "C" feed pumps and "A" condensate booster pumps tripped on low suction.

22) Control Rod position indications not consistent

~ System Engineering Evaluation

~ During two verifications the following conditions were noted:

a) RSCS indicated that 15 rods were not full in.

b) The Full Core Display (DMM) indicated that 6 rods were not full in.

c) The RWM indicated that all rods were full in.

The operation and indications produced by the Reactor Manual Control System are different for each of the three indicating sub-systems.

a) RSCS

-"Full-In" and no "Data Fault".

b) -"Full-In" c)

DMM RWM -(Tens, Units 0,0) or "Full-In" or Latch Function.

The solutions could be to use RWM and DMM for full-in rod position verification or change the data fault data-bit... on the Probe Data Processor III Card. Use of the RWM in conjunction with the Full Core Display and RSCS vise RSCS alone is highly recommended.

(This method of verification of rod position post scram is already incorporated in current operating procedures.)

23) Stack GEMS Computer did not properly restart when power was restored

~ DER 2-91-Q-730, Chemistry Evaluation

~ The Stack GEMS was operable during and after the site area emergency although the Control Room Chart Recorder lost communication with GEMS for a brief period.

Particulate and iodine sample acquistion was continous during and after the event. Computer Control of the system was interrupted for two (2) brief periods.

24) The following ESF Actuations will be covered by LER 91-17 Scram DER 2-91-Q-708 Group 9 Isolation DER 2-91-Q-773 RWCU Isolation DER 2-91-Q-710 Group 4 Isolation DER 2-91-Q-798

25) Missed required Tech Spec Surveillance DER 2-91-Q-709, System Engineer Evaluation Tech Spec 3/4.6.4, Suppression Chamber/Drywell Vacuum Breaker, require that... operability shall be demonstrated within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> after any discharge of steam to the suppression chamber from the safety/relief valves, by cycling each vacuum breaker through at least one complete cycle of full travel". The actuation of two safety/relief valves wasn't discovered until approximately four hours after they actually lifted so this Tech. spec. was not met within the required time limit.

26) Missed required Tech Spec Action (RPS Inop due to EOP Jumpers)

~ DER 2-91-Q-74B & Section from J. Helker's report "Assessment of Operator Response"

~ Defeating of RPS interlocks is authorized by the EOPs for this particular scenario in order to,provide the ability to reset the scram and perform multiple scrams. This Tech Spec action request specifies placing at leat one trip system in a tripped condition within one hour. 'PS Using N2-EOP-6 Attachment 14 operators had defeated all RPS interlocks (except for manual) as directed by the EOPs for a period of approximately one and 'one half hours. The basis for the procedures and safety evaluations recognize the potential for this condition, thus, the action taken by the operators and direction by two procedures was appropriate.

27) DIV II H,/0, Sample Pump Trip (2CMS*P2B)

~ WR 190966 & 196053 WR 190966 (910824) is closed. Work Item

Description:

During Plant Transient on 910813 Div. II Pump (2CMS-P2B) tripped for no obvious reason. Div. I CMS and all other Div. II CMS SOVs were found in their normal positions.

Determine cause of pump trip and correct Cause of failures: None found, possibly spurious.

if required.

Following completion of the WR IEC traced the wires through the electricl downings and determined that pump

• P2B was wired to the correct power panel.

Subsequently NMP2 Operations tripped pump *P2B by opening its power panel breaker.

WR 196053 (910829) is still check the breaker for pump *P2B.

open. Work Item

Description:

28) RCIC Flow Oscillations WR 184909 and 189944 WR 184909 (910814) is still open. Work Item After several minutes of operation during the RCIC

Description:

Quarterly Surveillance the RCIC Flow Controller in auto began to hunt at approximately plus or minus 50 GPM about its set point of 600 GPM.

Need Control Loop Setting Verification per attached and troubleshoot as necessary.

WR 18994 (910627) is still open. Work Item

Description:

RCIC Turbine .Speed Exhibits hunting during surveillance test; perform applicable procedure steps (N2-IMP-ICS-9001) to tune up the RCIC Control System.

29) Drywell Temp indicator discrepancy CMS*TRX130 WR189947 WR 189947 (910819) is showing elevation still open. Work Item

Description:

Pen 307 temperature on the Drywell temperature recorder did not move during temperature transient in the Drywell.

30) Fire panels affected by transient Letter from A. Andersen dated August 15, 1991.

18 of 20 fire panels at Unit 2 maintained normal power supply. Two fire panels transferred to internal battery backup. There was no interruptions or decreases of fire protection/detection/suppression at the local fire panels.

31) Group 9 Isolation

~ System Engineering Evaluation.

~ Upon loss of UPSlA, automatic isolation of Group 9 valves was lost. Also, loss of UPS1B resulted in loss of 2GTS-RE105, causing the radiation monitor trip contacts to close. This closed contact feeds a 15 second time delay relay in the isolation logic.

When power was restored, to UPS1A, the Group 9 isolation logic was restored, causing the relay fed from the radiation monitor to time out,,which resulted in 9 isolation.

the'roup

32) WCS isolation

~ Operations Evaluation of Operating Procedure.

~ Root Cause under investigation by Operations Department.

33) Verification that EOP Actions Restored to Normal

~ Attachment 14 (Alternate Control Rod Insertions) to N2-EOP-6 which installed the RPS Jumpers has a hand written double verification of,their removal.

~ The ADS inhibit switch is a Control Room front panel switch on panel P601 which has been verified to be back in its normal position.

~ A Procedure Change Evaluation (PCE) will be written suggesting that all EOP-6 attachments have double verification steps after all restoration steps.

~ A second PCE will be written suggesting that the startup check list for N2-OP-101A have two additional line items.

a) Was Nine Mile Point Two in the EOPs when it was shut down?

Yes/No b) If a) above was yes verif that all EOP-6 action items have been restored.

related

LIST OF PROTECTIVE RELAY ACTUATED ON AUGUST 13 1991 Protective Rela Lockout Rela Action Ref. Dw 87-2SPMX01 86-1-2SPUX01 ~ Initiate Turbine Trip ESK-8SPUOl Main Transformer 86-2-2SPUX02 ~ Initiate Fast Transfer ESK-8SPU02 Differential to Reserve Station ESK-5NPS13 Protection Relay Transformer ESK-5NPS14 Unit Protection Alt 2 Protective Rela Lockout Rela Action 87-2SPUX02 86-1-2SPUY01 ~ Initiate Turbine Trip ESK-8SPU01 Unit Differential 86-2-2SPUY01 ~ Initiate Fast Transfer ESK-8SPU03 Protection Relay to Reserve Station ESK-5NPS13 Transformer ESK-5NPS14 63-2SPMY01 86-1-2SPUY01 ~ Initiate Turbine Trip ESK-8SPU03 Fault Pressure 86-2-2SPUY01 ~ Initiate Fast Transfer Sh. 2 Transformer to Reserve Station ESK-8SPU03 Transformer Sh. 1 ESK-5NPS13 ESK-5NPS14 Unit Protection Backu Protective Rela Lockout Rela Action Ref. Dw 50/51N 86-1-2SPUZ01 ~ Initiate Turbine Trip ESK-8SPU04 2SPMZ01 86-2-2SPUZ01 . ~

Initiate Slow Transfer ESK-5NPS13 Protection Relay After 30 Sec. ESK-5NPS14 Block Fast Transfer After 6 Cycles Generator Protection Protective Rela Lockout Rela Action Ref. Dw Gen. Phase OC During 86-1-2SPGZ01 ~ Initiate Turbine Trip ESK-8SPG01 Startup ~ Initiate Slow Transfer ESK-8SPG04 50-2SPGZ02 After 30 Sec. ESK-5NPS13 Block Fast Transfer ESK-5NPS14

SCRIBA RELAYS BUILDING Ã1 Panel 4-25 Loss Ground Line 20 Panel 3-1F STA Serv. Loss of Source 1 & or g2 Panel 3-7R Line Protection "A" Package 345 KV. Scriba Volney f20 46TTA 20 Panel 23R Line 23 67NB/L23 Inst "B" Package Nine Mile 23/DTT Xmit & Rev .

30TRB 1/L23 Trip R230 TC g2 Trip R925 TC g2 Panel 1-5R 345 NM2 Scriba 23 Dir Trans Trip Receive "A" 30 TRA-1 L23

2ENS*SWG103 XFMR. FDR. 2EJS-X3A 103-1 Undervoltage Relay Flags in ON;

1) 27BA 2ENS B24

2) 27BB 2ENS B24

3) 27BC 2ENS B24 2ENS*SWG101 XFMR. FDR. 2EJS-X1A 101-14 Undervoltage Relay Flags in ON;

1) 27BA 2ENS A24

2) 27BB 2ENS A24

3) 27BC 2ENS A24 2ENS*SWG102 HPCS METERING CUBICLE 102-7 Undervoltage Relay Flags in ON;

1) 27BA

2) 27BB

3) 27BC 2NPS-SWG002 "B" AUX. BOILER

1) ABM-B1B SWG-002-3 50/51-2-2ABM B51 (INST.) flag in

2CEC-PNL847 (EHC CABINET BAY E) 30 VDC PMG SUPPLY -HIGH LIMIT

-LOW LIMIT 30 VDC HOUSE POWER SUPPLY -HIGH LIMIT

-LOW LIMIT

-22VDC PMG SUPPLY -HIGH LIMIT

-LOW LIMIT

-22VDC HOUSE POWER SUPPLY -HIGH LIMIT

-LOW LIMIT (low limit not lit, WR154662) 24VDC PMG SUPPLY -HIGH LIMIT

-LOW LXMXT 24VDC HOUSE POWER SUPPLY -HIGH LIMIT

-LOW LIMIT OSC 1 3K HZ -HIGH LIMIT

-LOW LIMIT (WR168493)

OSC 2 3K H7i -HIGH LIMIT

-LOW LIMIT OSC 3 3K HZ -HIGH LIMIT

-LOW LIMIT OSC 4 3K HZ -HIGH LXMIT II -LOW LIMIT THESE ARE LIGHTS THAT ARE LIT ON THIS PANEL THAT ARE NOT IN DURING NORMAL OPERATIONS

~s~P4- ~~~~'~+ ~<

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0 1991 ESL LISTINGS PRIOR TO TRANSIENT INFO ONLY?91-459 RHS B & C work WRs & EPMs No 91-458B SCRM "A" failed Calibration Surv In Mode 1 91-458A RMS-CAB180 Vent GEMS Surv No 91-457 GTS*FN1B (GTS Train B) Unit Cooler No Work (Div. II)91-456 SWP*CAB146A RHS SW Effluent Loop A No Rad Mon 91-455 SWP*CAB23A RHR SW "A" Rad Mon No 91-452 HVC*CAB18A & C Cont Room Air Intake No Rad Mon's y

91-451 SWP*CAB146B SW Effluent Loop B Rad Mon No 91-431 EGA-HOSE13B Connection to C2B Leaks Yes91-427 RMS*RElD Rx Bldg. ARM Inop Yes91-420 WCS-V30A Valve Backseated to stop leak Yes91-407 LPM-NBE2A & B, NBV101 Loose Parts Monitor No Recirc Loop Set Points too low & ground prob 91-374 RMS*RE111 Rx Bldg. ARM Inop w/112 oper in Mode 1 91-361 CMS*SOV25D SOV won't open Yes91-359 HVC*UC107 Repairs to SWP Valve Yes91-345 Rx Bldg. Unit Coolers - Set Points raised Yes91-278 RHS*MOV40A S/D Cooling Loop "A" Inop No until PMT performed 91-262 CPS*AOV104, 106 Hold Outs on AOVs for No LLRT Failure 91-257 Appendix "R" Valves Surv. Yes91-255 Control Rod 22-47 Indication 9 position No 48 Inop

1991 ESL LISTINGS PRIOR TO TRANSIENT (cont'd)91-214 CPS-FN1 Purge Fan Running w/ Drywell open Yes91-169 SLS-P1A/B Resolution to NRC in f91-12 No 91-'160 OFG-FT13A & B Flow Xmttr Calib No 91-083 HVR*UC413A & B Dampers shut as per Yes Pr 90-09183 91-072 ICS*PCV115 Info. Only (PCV115 Failed Open) Yes91-068 Appendix R Valves Hold Outs Yes91-024 RHS*SOV36B Isolated Yes91-016 CMS*SOV26A & C, CMS*SOV23B Deactivated Yes for Failed Surv.

RESULTS OF UPS FAILURE

1) Loss of Control Room Annunciators

2) Loss of Control Room Computers

3) Loss of Gaitronics

4) Loss of BOP Instrumentation

5) Loss of Essential Lighting

6) Loss of Drywell Cooling

7) Offgas System Isolation

8) Loss of Rod Position Indication

9) Group 9 Isolation

10) P603 Recorders fail as is

11) FWS-LV10s Lockup in open position

12) CWS-MOG52s (Cooling Tower Bypass Valves) went open

13) Loss of Radio Leaky Wire Antenna System

14) Feedwater and Condensate Booster Pump minimum flow valves fail open

0 I NEUTRONFLUX 2 PEAK FUEL CENTER TEMP 1 VFSSEL PRES RISE Ipail i

3 AVE SURFACE HEAT FLUX FEEDWATEI\ FLOW 5 VESSEL STEAM FLOW 2 SIM LINE PRES RISE lpail 3 SAFETY VALVE FLOW Iel 4 RELIEF VALVE FLOW Iti O 5 BYPASSVALVE FLOW111 6 TURBINE STEAM FLOW Ill 100 0

I Z

O 50 6 3 8 w 10 10 TIME Isecl TIME Reel I LEVEL lincheeleepekirII 2 WR SENSED LEVEL hnchecl 3 NR SENSED LEVEL Iincheel I CORE INLET FLOW III 6 DRIVE FLOW I III IO I

I O

EU IL I VOID REACTIVITY 2 DOPPLER REACTIVITY 3 SCRAM REACTIVITY 4 TOTAL RE AC 1 IV IT Y

- 100 -2 10 0 3 4 1IMF. Ine'I TIME bccl FIGURE 15.2-1 GENERATOR LOAD REJECTION WITH BYPASS NIAGARA MOHAWK POWER CORPORATION NINE MILE POINT-UNIT 2 FINAL SAFETY ANALYSIS REPORT