ML20052B764

Rept on NRC IE Bulletin 79-27,Loss of Non-Class IE Instrumentation & Control Power Sys Bus During Operation.

ML20052B764
Person / Time
Site:	Grand Gulf
Issue date:	04/19/1982
From:	MISSISSIPPI POWER & LIGHT CO.
To:
Shared Package
ML20052B759	List: ML20052B758 ML20052B764
References
REF-SSINS-6820 IEB-79-27, NUDOCS 8205030543
Download: ML20052B764 (33)

Text

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REPORT ON NRC IE BULLETIN 79-27, LOSS OF NON-CLASS 1E INSTRUMENTATION AND CONTROL POWER SYSTEM BUS DURING OPERATION April 19, 1982 82050306%)

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Table of Contents IE Bulletin 79-27 Report I. Introduction II. Scope III. Method of Review IV. Summary of Findings Attachments

1. System Reviews & Recommendations 1

2. Power Supply Lists

3. Procedure Review

4. Re-review of IE Bulletin 79-02 i

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l CGNS STUDY FOR IE BULLETIN 79-27

1. INTRODUCTION This study constitutes MP&L's written response to NRC IE Bulletin 79-27, transmitted in a November 30, 1979, letter from James O'Reilly to N. L. Stampicy and GGNS Safety Evaluation Report (SER), NUREG 0831, as License condition 1.11(9).

IE Bulletin 79-27 requires a review of all plant electrical busses powering safety and non-safety related instrumentation and control devices to identify those busses that would prevent the ability to attain a cold shutdown condition if de-energized, and to ensure that emergency procedures are adequate to address the loss of such busses.

Additionally, the IE Bulletin requires a re-review of IE Circular 79-02, FAILURE OF 120-VOLT VITAL AC POWER SUPPLIES (January 11, 1979),

r to include both IE and non-class 1E safety related power supply inverters.

This report contains the scope of the GGNS IEB 79-27 study the review method utilized, and a summary of findings.

II. SCOPE The scope of this IEB 79-27 study includes the systems required to place and maintain the plant in a cold shutdown condition:

Nuclear Boiler Instrumentation (pressure, level, temperature, core flow)

High Pressure Core Spray Residual Heat Removal Standby AC Power System (Diesel Generators)

Standby Service Water Automatic Depressurization System Low Pressure Core Spray (LPCS) l Reactor Core Isolation Cooling Containment Instrument and Control System The indication and control functions of the following systems, directly 1

involved in bringing the plant to cold shutdown, were also included in the evaluation.

Control Rod Drive System Feedwater Control System Reactor Recirculation System Neutron Monitoring System Turbine Control and Bypass Systems ,

Condensate and Feedwater System These systems are predominantly fed from class 1E Division I, II, and III 4.16 KV busses 15AA, 16AB, and 17AC, each with a diesel generator as backup power, and the class IE Division I, II, and III 125 VDC busses 11DA, 11DB, and 11DC. A limited number of components fed from non-class 1E sources were also reviewed. '

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These systems, in whole or in part, are used to achieve cold shutdown under worst-case loss-of-power conditions including a loss-of-coolant accident. Independent of the event that initiates plant shutdown (whether a normal plant shutdown or a forced plant shutdown), the reactor is normally brought to approximately 100 psig using either the main condenser or, in the case of loss of offsite power or other conditions where the main condenser is unavailable, the RCIC and HPCS systems, together with either the steam condensing mode of the RHR system or the nuclear boiler pressure relief system.

For the purposes of this study the worst-case failure is assumed to be loss of of fsite power and one ESF power Division. It should be noted that operation of either Divisions I and III or II and III can be completely lost without affecting safe shutdown capability. Operation of-Division I (only) or operation of Division II (only) is sufficient to achieve safe shutdown. For failure of Divisions I or II, the following systems are assumed functional:

a. Division I Fails, Division II and III Functional:

Failed Systems Functional Systems RHR Loop A HPCS LPCS ADS RHR Loops B and C

b. Division II Fails, Division I and III Functional:

Failed Systems Functional Systems RHR Loops B and C HPCS ADS RHR Loop A LPCS For a failure of Division III (HPCS) (only), all the above systems except HPCS would be functional, again providing adequate cooldown capability.

The ADS, HPCS, and RHR systems have suitable redundancy in components such that they can routinely perform their functions for both normal and forced plant shutdown-even assuming an additional failure of power-source, offsite or onsite. Since the ADS, HPCS, and RHR systems are divisionally separated, no single failure, together with the loss of offsite power, is capable of preventing attainment of cold shutdown using these systems.

Accordingly, this study contains a review of the power supplies for-these systems' instrumentation and controls, assesses the operational effects of loss of power (Attachments 1 and 2), and addresses the E24rg2

adequacy of the plant emergency procedures used upon loss of power to the busses feeding the above systems (Attachment 3).

Finally, documentation of a review of IE circular 79-02 is included which address IEB 79-27, item 3 (Attachment 4).

III. METHOD OF REVIEW A. All instruments and equipment connected to the major busses were enumerated on drawings initiated specifically for the IE Bulletin 79-27 review. Attachment 5 is an example of one of the 438 drawings.

Using these drawings and drawings from which these were developed, each of the eight major plant systems listed in Part II above was reviewed for:

1) Power Source and Loss-of-Power (LOP) indications Using the latest revised drawings, each component's power source was determined, aa .g with indications of power failure available to control room operators. Alarms, loss of status or indication, or other effects were reviewed to determine if the loss of power would go undetected or compromise achievement of cold shutdown.

2) Power Source Diversity (for Redundant Components)

For redundant components, power sources were reviewed for diversity to assure that a single bus or breaker failure would not disable redundant systems or components.

3) Operational Effect on the System For each component subjectqd to LOP, the operational effect on its system and other interfacing systems was evaluated to determine if an unknown or undetected condition would result.

B. Emergency procedures to be used upon loss of power to the busses supplying power to the systems in II above were reviewed for:

1) Diagnostics / alarms / indicators / symptoms resulting from the evaluation in A above.

2) The use of alternate indication or control circuits that may be

. powered from other busses.

3) Methods of restoring power to the bus.

IV.

SUMMARY

OF FINDINGS A. This review of the class IE and non-class 1E busses supplying equipment, instrumentation, and control power to systems used to place the plant in a cold shutdown condition has confirmed the  ;

reliability, diversity and redundancy of the systems referenced in I Part II. Automatic indication is provided in the control room to E24rg3

inform the operator that a system or part of a system is inoperable. General examples of indications of inoperability are listed below:

- If any circuit breaker of the referenced systems (required to place and maintain the plant in cold shutdown) is racked out, indication is provided in the control room.

- All motor control circuits related to the referenced systems are individually monitored. If control voltage is lost as a result of tripping of a motor-start feeder breaker or removal or a control circuit fuse, indication is provided in the control room.

- All the referenced systems which contain a control switch with test mode capability, or which may be put into a test mode by the insertion of a test jack, provide continuous control room indication that the test mode has been selected.

- Individual status indicators for each system are arranged together on the control room panels to indicate what function of the system is out of service, bypassed, or otherwise inoperable.

All bypass and inoperability indicators, both at a system level and component level, are grouped only with items that will prevent a system from operating if needed. Indication of pressures, temperatures, and other system variables that are a result of system operation are not included with the status indicators. In addition to the indication, annuniciation is provided for each ESF system train. A bypass of one or more components within a system train actuates a corresponding annunciator to alarm the fact that a given system is out of se rvice.

- The syraem of status lights for bypass indication, other display information available to the operator, and periodic testing provide assurance that the operator will be constantly aware of the status of these systems. The indication system (described previously) assures that frequent or routine bypass operations with control circuits or control power failures, which could affect system performance, are made obvious.

- All status indicator circuits for the systems in each ESF division are physically and electrically separated. This maintains independence of the systems which perform safety functions. The annunciator circuits are physically and electrically isolated from safety circuits so that no credible failure of the annunciator circuits will have an adverse effect on safety.

- Kany status indicators are provided with dual lamps as indicated in AECM-82/86, dated March 11, 1982 (Human Factors Engineering Review). Dual lamps can be tested by depressing the indicators.

Annunciators can be tested by depressing the annunciator test switches in the control room.

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- The diversity of alarms and indications associated with the loss of the class IE (and non-class 1E) instrumentation and control circuits assures that in no case can the ability to place the plant in a cold shutdown condition be compromised.

Consequently, no design modifications resulting from this review are required.

B. The review of the emergency procedures used by operators indicated that some revision and updating was required. GCNS Operations have updated emergency procedures to-agree with IEB 79-27 study results as further explained in Attachment 3.

C. The documentation referenced in Attachment 4 in response to IE Circular 79-02 indicates no further action is required or warranted.

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IEB 79-27 Attachment 1 Page 1 of 6

1. SYSTEM REVIEWS AND RECOMMENDATIONS I. NUCLEAR BOILER INSTRUMENTATION The primary Nuclear Boiler parameters required to determine if cold shutdown is being achieved are reactor vessel level and pressure.

Additionally, indication of in-vessel temperatures and core coolant flow provide confirming evidence of approach to and attainment of cold shutdown.

The power sources for these parameter measurement channels which are displayed in the Control Room are listed in Attachment 2.

A. RV LEVEL / PRESSURE INDICATIONS Nuclear Boiler Instrumentation System B21 provides diverse redun-dant indications of RV level and pressure. Two post-accident-monitor recorders 1B21-UR-R623A and B provide continuous indica-tion and trend of these key reactor parameters. Recorder A is fed from ESF Division I and recorder B from ESF Division II - provid-ing indication to the control room operator under worst-case conditions of loss of offsite power and one ESF division. Addi-tional RV level indication is provided by wide-range level indi-cator IB21-LI-R604, powered from ESF Division I through RPS MG Set A; and fuel zone level recorder IB21-LR-R615, fed from inverter 1Y80 (Non-ESF) backed up by Division I MCC 15B42. All but one of the above devices are located on control room panel 1H13-P601:

IB21-LI-R604 is located on 1H13-P680.

Loss of power to a single 1E (or non-1E) bus will not deprive the control room operators of reactor vessel level or pressure instru-mentation. Sufficient diversity and redundancy of power supplies exists to assure that under worst case loss-of-power conditions, these key reactor parameter indicators will be available to verify that the plant is being placed in a cold shutdown condition.

Primary indications of loss-of-power to these system B21 channels is a downscale reading on the indicators; failure of power supply to the recorders is evidenced by loss of motion of the indicator /-

, pen and non-movement of the chart.

B. REACTOR VESSEL TEMPERATURES Nuclear Boiler System temperature instrumentation available to the Cc trol Room operator for achieving cold shutdown consists of reactor vessel temperature measured at the bottom head, vessel top head flange, and the recirculation pump suction temperatures.

Attachment 2 lists the power source for these temperature recorders in the Control Room. Although these recorders, 1B21-TR-R643 and IB33-TR-R604, are located in one cf the "back" cabinets, 1H13-P614, which is not directly viewable from the operating consoles, the secondary importance of these parameters does not require continuous -

operator surveillance.

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IEB 79-27 Attachmsnt 1 Paza 2 of 6 The power for these recorders is fed from inverter 1Y80, backed up by automatic switchover to ESF Division I MCC 15B42. This power source and backup is considered adequately reliable to assure that

-these indicators will be available under worst case loss of power conditions. Primary indications of lors of power to these instru-ment channels is evidenced by loss of motion of the point printer and non-movement of the chart.

C. CORE FLOW INDICATIONS Under normal cool down conditions (eeactor recirculation system in operation), heat removal from the reactor core is proportional to coolant flow. Since total core coolant flow passes through the jet pumps, indication of total jet pump flow and core differential pressure (dP) will provide the control room operator additional verification of approach to cold shutdown.

As shown in Attachmenc 2, core flow and dP indications are displayed on panel Ill3-P680. 'The power for this instrumentation is provided by inverter 1Y80, backed up by automatic switchover to ESF Division I MCC 15B42. This power source and backup is considered adequately reliable to assure that these indications will be available under worst-case loss of power conditions. Primary indications of loss of power to the flow indicator is a downscale reading; the recorder fails downscale.

It should be noted that loss of these control room fluw indications (blown fuse, etc.) does not deprive the operator of this parameter; local dP indicators are available for remote verification of core flow.

Under loss of offsite power conditions, the reactor rec';culation system does not operate, hence core flow indication would be of minimal use -- the operator must use vessel level and pressure as-primary indication of cooldown.

D. RECOMMENDATIONS - Nuclear Boiler Instrumentation Required Changes - None II. IIIGil PRESSURE CORE SPRAY (llPCS)

A. The liigh Pressure Core Spray (llPCS) System is self-contained except for its initiation signal source and connection to offsite power through the plant AC power distribution system. All system instruments and controls are fed from ESF Division III AC and DC buses. Loss of plant power to Division III 4.16KV bus 17AC initiates an llPCS diesel-generator start and all Division III loads are then carried by the diesel-generator.

4.16KV bus 17AC feeds MCC 17B01, which in turn feeds MCC 17B11.

I.oss of power to MCC 17B01 removes the llPCS system from service, but numerous alarms and indications of such a loss are available to the control room operator. Loss of MCC 17B11 removes HPCS DG fuel oil and service water controls, with consequent alarms alerting the control room operator to these losses also.

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m.s... e -- M .i.41

- i IEB 79-27 Attachment 1 Page 3 of 6 System process indications in the control room consist cf HPCS pump discharge pressure and flow; inboard and outboard test valve position indications; and various AC/DC power supply indications and alarms. Sufficient indications are available to enable the operator to quickly assess the nagnitude of a power loss in the

- HPCS controls and instrumentation.

B. RECOMMENDATIONS - HPCS Required Changes - None III. RESIDUAL HEAT REMOVAL (RHR)

A. The Residual Heat Removal System (RHR A, B/C) power supplies are

- adequately divided to preclude total loss of the systems due to a i single failure. RHR A components, instruments and controls are fed from ESF Division I bus 15AA; RHR B and C are fed from ESF l Division II bus 16AB. Numerous loss of power alarms and indication are available to the control room operator -- both for major bus losses and for AC/DC control power losses.

System process indications in the control room consist of pump flow, heat exchanger level and pressure controls, valve position indicators, standby service water flow indication, and heat exchanger outlet water conductivity (Attachment 2). Loss of power to these devices is indicated by a downscale reading. Loss of power to the RHR multipoint temperature recorder is evidenced by loss of motion of the point printer and non-movement of the chart.

B. RECOMMENDATIONS - RHR Required Changes - None IV. STANDBY AC POWER SYSTEM (Diesel Generators) 3 A. The onsite class IE AC power source of each of the three ESF buses is a diesel generator connected exclusively to that bus. The diesel generator starts automatically on a LOCA signal or following i the loss of the offsite power source feeding the respective ESF bus. All AC and DC control and instrumentation power for circuit breakers, DG controls and instruments, and annunciators for a given ESF power Division are fed exclusively from the respective ,

ESF sources. The diesel generator sets for Unit 1 are identified

, as:

(1) Set 11 for ESF bus 15AA - Division I (2) Set 12 for ESF bus 16AB - Division II (3) Set 13 for ESF (HPCS) bus 17AC - Division III (discussed in Part II of this Attachment)

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l IEB 79-27 Attachment 1 Page 4 of 6 Controls and instrumentation available to the control room operator include:

a) AC bus voltage, frequency, and amps for incoming power and the diesel generator; ESF DC bus voltage; breaker status indicators b) syncroscope c) fuel oil tank level indication d) system status indications All the above instruments fail downscale on loss of power.

Attachment 2 contains a list of the instruments and their power supplies.

The DG cranhcase fans are powered from ESF buses. Additionally, sufficient redundancy is incorporated into DG standby support systems so as not to compromise the ability of the diesel generators to start upon loss of offsite power. Most of the functions of these systems are performed by the DG set when it is operating; i.e., lube oil heating, jacket water heating, etc. L.oss of power to buses feeding these DG standby support systems is alarmed in the control room.

B. RECOMMENDATIONS - Standby AC Power Systems Required Changes - None V. STANDBY SERVICE WATER (SSW)

A. The Standby Service Water (SSW) system, containing the plant ultimate heat sink, is designed to remove heat from plant auxilia-rics that are required for safe reactor shutdown. It is designed to perform its cooling function following a LOCA, automatically and without operator action, assuming a single failure or passive failure coincident with loss of offsite power.

The SSW system power supplic's are adequately divided to preclude total loss of the system due to a single failure. SSW loop A components, instruments, and controls are fed from ESF Division I bus 15AA; SSW loop B is fed from ESF Division II bus 16AB.

Several loss of power alarms and indications are available to the control room operator--both for major bus losses and for AC/DC control power losses.

System process indications in the control room consist of pressure and flow recorders and basin level recorders. HPCS service water pressure and flow are indicated also. (See Attachment 2.) All indicators and recorders fail downscale on loss of power to the instrument.

B. RECOMMENDATIONS Required Changes - None E27tg4

l IEB 79-27 Attachment 1 Page 5 of 6 VI. AUTOMATIC DEPRESSURIZATION SYSTEM (ADS)

A. The Automatic Depressurization System (ADS) serves to provide reactor depressurization in case of HPCS system failure. In the event of a small line break in the reactor coolant system, ADS depressurizes the reactor allowing the Emergency Core Cooling System to flood the core. In all cases, it is one of several alternate methods of achieving cold shutdown under accident or off-normal conditions.

The ADS is an ESF Division I (ADS A) and Division II (ADS B) system, except that only one set of relief valves is provided.

. Each relief valve can be actuated by either of two solenoid-operated pilot valves--one operated by trip system A and the other by trip system B. Logic relays, manual controls, and instrumentation are mounted so that Division I and Division II separation is maintained.

Separation from Division III is similarly maintained.

All the power for ADS initiation is fed from the 125 VDC system--

ADS channel A through IDAl breaker 72-llA23; ADS channel B through IDB1 through breaker 72-llB34. Sufficient alarms are provided to alert the control room operator of loss of DC power to either channel. Additionally, loss of power to any one solenoid valve or its actuation logic train is indicated on the control panel.

The only AC power supply associated with the ADS is the power supply for the SRV downstream temperature recorder (Attachment 2).

Failure of the power supply to the recorder is evidenced by loss of motion of the point printer and non-movement of the chart.

B. RECOMMENDATIONS Required Changes - None VII. LOW PRESSURE CORE SPRAY (LPCS) SYSTEM The Low Pressure Core Spray (LPCS) system is a safety system not normally used to achieve cold shutdown. This system, in conjunction with the ADS, is capable of cooling the core, independent of any other core cooling. It is included in'this report as a system capable of placing the plant in a cold shutdown condition--especially under Design Basis Accident line break condition. It is functionally backed up by RHR-A/LPCI mode (Division I), which is further backed up by RHR-B and C (Division II) and HPCS (Division III).

The LPCS system power supplies are exclusively fed from ESF Division I AC and DC sources. Adequate loss of power alarms and indicators are available to alert the control room operator of loss of power to system controls and instrumentation.

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l IEE 79-27

-Attachment 1 Page 6 of 6 System process indication in the control room consists of a system flow indicator.

(See Attachment 2.) The indicator fails downscale on '

loss of power.

B. RECOMMENDATIONS

• Required Changes - None

'VIII. REACTOR CORE ISOLATION COOLING (RCIC) SYSTEM The Reactor Core Isolation Cooling system maintains reactor water level by providing makeup water in the event the reactor becomes c isolated from the main condenser, isolated in hot standby, or if a complete plant shutdown occurs with loss of normal feedwater flow (and 4

preceding depressurized shutdown cooling). The RCIC AC and DC powcr sources are separated into ESF Division I and. Division II. Conse-quently, the system can only be used if both ESF Division I and Division II are available.

There are numerous alarms and indications to alert the operator to loss of power to instruments and control circuits. System process indication in the control room consistslaf RCIC turbine pressures and flow and RCIC pump pressures and flow. (See Attachment 2.) All control room RCIC instruments fail downscale on loss of power.

B. RECOMMENDATIONS

Required Changes - None I

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l IEB 79-27 l Attachment 2 Page 1 of 11 )l l

2. POWER SUPPLY LISTS I. NUCLEAR BOILER INSTRUMENTATION RV LI'lI*./ PRESSURE INDICATIONS

• REC /IND. SENSOR FAILURE REC /IND. POWER SUF?LY SENSOR POWER SUPPLY MODE IB21-LR-Rt15 08-lY71-22 IB21-LT-N044C Same as Downscale RPV Fuel Z:ne via Inverter Recorder Level *** lYS0*

llH13-P5X)

IB21-LI-R51] Same as Sensor I B 21-LT-N044 D 08-1Y74-22 Downscale 1X Level via Inverter uel Zone =* lYS0*

1H13-?5Z )

IB21-UR-1523A 52-IP56119 1B21-LT-N091A 125 VDC Bus As Is Post Ac:ident (Div. I) llDA, Bkr.

Monitor (27.. IB21-PT-N062A 72-IIA 18 Press & Level)

(1H13-?501) 1321-UR-15233 52-IP66117 IB21-LT-N0913 125 VDC Bus As Is Post Accident (Div. II) llDB, Bkr.

Mon i to r " .b:. IB21-PT-N062B 72-llB14 Press & Level)

( I H 13-P 5 '. ' )

IB21-LI-15]i Same as Sensor 1321-LT-N081C 52-lC71108** Downscale RPV Water Level Wide Ran;e (lH13-P5sJ)

IB21-LI-R5 35 Same as Sensor IB21-LT-N027 08-lY74-22 Downscale RPV Level via Inverter Shutdown Range *** 1Y80*

(11113-P6 G1)

• Backup fron Div. I MCC 15352 (Automatic Switchover)

• Div . I through RPS MC Set A

• • • Calibra:ed for use under depressurized conditions only.

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,' l IEB 79-27 i j l Attachment 2 l Page 2 of 11l

1. NUCLEAR BOILER INSTRUMENTATION (Con't)

RV TEMPERATURE INDICATIONS IND./ REC. TRANSMITTER FAILURE IND/ REC. PO*..'E R S UPPLY SENSOR POWER SUPPLY MODE 1321-TR-R643 08-lY74-24 IB21-TE-N029A,B 03-lY74-22 As Is Reactor Vessel Temp. via Inverter via Inverter Monitoring lY30* IB21-TE-N030A,B lY80*

(1H13-P614) 1333-TR-R604 08-lY74-30 IB33-TE-N023A,B Same As As Is

~.ecirc. A&B via Inverter Recorder

'ater Temperature 1Y80*

IH13-P614)

CORE FLOW INDICATIONS IND./ REC. TRANSMITTER FAILURE IND/ REC PO*iER SUPPLY SENSORS POWER SUPPLY MODE IB33-UR-R613 08-lY74-26 IB33-PT-N037** Same As Downscale Core DP/ Total via Inverter Recorder Jet Pump Flow lY80*

(1H13-P680)

IB33-FI-R611A,B,C,D Same as above IB33-PT-N038A, Same as above Downscale Cal. Jet Pump Flow B,C,D (1H13-P680) 1333-FI-R612A,3 Same as above IB 3 3-PT-N031*

• Same as above Downscale

. Loop A, B Jet Pump Total Flow (lH13-P680)

• Backup from Div. I MCC 15B42 ( Automatic Switchover)

• • Summed inputs from 24 Jet Pump dP transmitters

• a ,

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l IEB 79-27 l l

[ Attachment 2 l Page 3 of 11l II. RICH PRESSURE CORE SPRAY CONTROL ROOM INDICATIONS - Panel lH13-P601-16B REC./IN3. SENSOR FAILURE R F.C / I N D . POWER S*C??LY SENSOR POWER SUPPLY MODE lE22-PI-R601 125 VDC ISF lE22-PT-N051 Same as Pump Disch. downscale IIDC indicator Press IE22-FI-R603 125 VDC ISE lE22-FT-N005 HPCS Flow Same as Downscale llDC indicator IE22-ZI-R606 125 VDC ISF lE22-2T-N008 Same as Downscale NBD Test Valve llDC indicator 011 Position

~.22-ZI-R604 125 VDC ISF lE22-ZT-N010 Same as Downscale JUTBD Test Valve llDC F010 Position ~

indicator IP81-LI-R600 52-1P71125 IP81-LT-N001 Same as Downscale DG13 Fuel Oil Stg Tk indicator (on panel IH13-P870-5B.

IP81-LI-R601 52-IP71125 IP81-LT-N004 Same as Downscale DG13 Fuel Oil Day Tk indicator (on panel 1H13-P870-5B, IE22-SI-R612 Incoming Frequency All electrical Midscale IE22-EI-R611 instruments fed Incoming Voltage from respective Downscale IE22-SI-R613 AC or DC source (Syncros: ope)

N/A lE22-EI-R614 Running '.'altage

, Downscale

. IE22-ST-R615 Running Frequency Midscale IE22-EI-R610 4.16KV Bus 17AC Downscale IE22-EI-R617 480 MCC 17B01 Downscale IE22-EI-R618 125 DC Bus llDC Downscale IE22-II-R622 152-1706 Amps Downscale IE22-II-R619 152-1704 Amps Downscale IE22-II-R620 152-1705 Amps Downscale IE22-II-R621 MCC 17B01 INCM FDR 152-1703

~

Downscale IE22-II-R616 HPCS Pu p Motor Amps Downscale 1E22-II-R607 DG 13 A ps Downscale IE22-JI-R608 DG 13 Vars Midscale IE22-JI-R609 DC 13 Watts n~ aa--1a

. .h..- -

j IEB 79-27 ) l l Attachment 2 i Page 4 of 11l III. RESIDUAL HEAT RE>t0 VAL (RHR-A) (DIV. I)

CONTROL R0051 INDICATIONS - Panel lH13-P601 REC . /I ND . SENSOR FAILURE REC /IND. PO'.JER SUPPLY SENSOR POh'ER SUPPLY MODE lE12-ZI-R609A 7211A31 1E12-ZT-N133A Same as Dawnscale Mx A Vnt Viv Off 125 VDC indicator F074A Posn Bus llDA 1E12-ZI-R608A Same as above IE12-ZT-N134A Same as Downscale Hx A Vnt Viv indicator F073A Posn IE12-ZI-R611A Same as above IE12-ZT-Nil 7A Same as Downscale x A Outlet indicator 003A Posn 6E12-ZI-R612A Same as above IE12-ZT-Nil 8A Same as Downscale Hx A Bypass indicator F0adA Posn -

IE12-CI-R610A 52-lP53104 lE12-CE-N001A Same as Downscale Hx A Out indicator Conductivity lE12-PI-R605-1 52-lP56120 lE12-PT-N023 Same as Downscale RHR to indicator RCIC Press

• IE12-PI~R606A-1 52-lP56120 lE12-PT-N026A Same as Downscale RHR Hx A indicator Steam Press **

IE12-LI-R604A-1 52-IP56120 lE12-LT-N008A Same as Downscale

. RHR Hx A indicator Level ***

IE12-FI-R602A 52-lP56120 lE12-FT-N007A Same as Downscale RHR Ex A indicator SSh' Flow IE12-FI-R603A 52-lP56120 IE12-FT-N015A Same as Downscale RHR Pump A indicator Disch Flow Controller IE12-PK-R605 on same power supply

• • Controller IE12-PK-R606A on s'ame power supply

• • • Controller IE12-LK-R604A on same power supply

- . A, . ._ ._ ___ "

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--l IEB 79-27 l d 1 Attachment 2 l Page 5 of 11[

III. RESIDUAL HEAT ' REMOVAL (RHR B/C) DIV. II ' L CONTROL ROOM INDICATIONS - Panel 1H13-P601

-REC./IND. SENSOR FAILURE.

~ REC /IND. POWER SUPPLY SENSOR -POWER SUPPLY MODE p IE12-ZI-R609B 72-IIB 38 IE12-ZT-N1333 Same as

' Downscale Hx B Vnt Viv Off~125 VDC indicator F074B Posn Bus llDB -

~

-lE12-ZI-R6083 Same as above 1E12-ZT-N1343 Same as Downscale Hx B VntsVlv indicator p F073B Posn i

E12-ZI-R611B> Same as above IE12-ZT-Nil 73 Same as Downsca le

'x B Outlet indicator 003B Posn

[ 4E12-ZI-R612B Same as above 1E12-ZT-Nils 3 Same as Downsca le Hx B Bypass indicator F048B Posn IE12-CI-R610B 52-1P63103 lE12-CE-N0013 Same as Downscale

" Hx B Out - indicator Conductivity s

IE12-TR-R601 08-1476-18 See Drawing N/A - As Is e

RllR ~ Of f inverter E-1181 Sh. 66 Temperature Temperatures' lYS2* for list elements

, 'IE12-FI-R6023 52-IP66111 lE12-FT-N0073 Same as Downsca le RHR llX B indicator

.SSW Flow

! IE12-FI-R603B 52-1P66111 lE12-FT-N0153 Same as Downscale i . RilR' Pump B indicator s

Disch Flow 1

i IE12-FI-R603C 52-IP66111 lE12-FT-N015C Same as Downscale i' RilR Pump C indicator i- Disch Flow 4

IE12-PI-R606B-1 52-IP66111 1E12-PT-N026B- Same as Downscale RilR lix B indicator j Steam Press **

IE12-LI-R604B-1 52-IP66111 1E12-LT-N00S3 Same as Dawnscale RilR lix B- indicator Leve1***

i

• ~ I Backedfup-by'Div. II MCC 16B42 (Automatic Switchover)

• • Controller-lE12-PK-R606B on same~pouer supply

• • • Controller IE12-LK-R6043 on same power supply

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n. \ IEB 79-27 1 -l

.,< l Attachment-2 l Page 6 ot 11[L IV, STASDBY'fCPO',fERSYSTEM(DieselGenerators)

, . ', NT. .,

CONTROL ROOM INDICATIONS - DU's ll,and 12, pa nei lH13-P864 Fuel Oil Levels x -

A B FAILURE INDICATOR- '

POWER SUPPLY cPOWER SUPPLY SENSOR MODE-

.1P75-LI-R607A(B)- 72-IIA 29 11B23 iP75-LT-N004A(B) Downscale c: Fuel Oil Level- , o{t 125 VDC off 125 VDC ,

NDay. Tank [A(B);, Bus 1IDA ' Bus 1IDB' ,-

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2 i

I P'75-L1-P,608

' AtB ); 52-IP56125 52-IP66123 IP75-LT-N001A(B) Downscale Juel 05 b level-

• tor Tank. ACB)

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,Electriedl FAILURE

_Ind ic a t'b r . -

LLabel MODE

'm ** h  :

1R21-EI-R610\(B) 'INCOMINO VOLTS DIV ,1 (DIV II) Downscale 2-iR21bXI-R611A(B) SYNCROSCOPE

Full scale "+" or

i IR21-EI-612A(B)

' RUl1N NG ' VOLTS DIV I (DIV II)

Downscale IP75-EI-R600A(B) ^

DIESEL GEN 11 (12) AC VOLTS Downscale IP75-SI-R601A(B)

DIESEL GEN 11 (12) FREQUENCY Midscale IL21-EI-R603A(B). 125 VDC SUS llDA (llDB) Downscale

. lP7 5-II-R604A(B ) v . DIESEL GEN 11 (12) AC AMPS- Downscale.

IP75-EI-R605A(B) DIESEL GEN 11 (12) FIELD DC VOLTS Downscale c .

IP75-II-R606A(B)

+

DIESEL'.'CEN 11 (12) FIELD DC AMP Downscale IP75-JI(R602A(B) DIESEL GEN 11 (12) WATTS Downscale IP75-JI-R603A(B). ,

l>IESEL GEJ 11 (12) VARS Downscale

• 1R 21-I T,-R613A( B )-

-ESF 'XF.'G P12 BUS 15AA (16AB) INCM FDR ~

Downscale r

152-1511 (1611) 3 l 1R21-EI-R615A(B) 4.16 KV Bus 15AA (16AB) q Downscale IR21-II-R616A(B)' ESF XD3"#21 BUS 15AA (16AB) INCM FDR Downscale 152-1501;(1601) N 1R21-II-R617A(B) y ESF'XD3%11 BUS 15AA (16AB) INCM FDR

• Downscale

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- lkEB79-2_7_._ i l l_ Attachment 2 l Pa::e 7 of 11l IV. STANDBY AC POWER SYSTEMS (Con't)

DIVISION I Failure Indicator Label Mode IR20-II-R627A LCC 15BA4 INCM FDR 52-15401 Downscale IR20-EI-R628A 480V LCC 15BA4 Downscale IR20-II-R629A LCC 15BA2 INCM FDR 52-15201 Downceale IR20-EI-R630A 680V LCC BUS 15BA2 i

Downscale 1*t20-II-R64BA LCC 153A6 INCM FDR 52-15601 Downscale 320-EI-R647A 480V LCC 15BA6 Downscale R20-II-R631A LCC 15BA5 INCM FDR 52-15501 Downscale IR20-EI-R632A 480V LCC 15BA5 Downscale IR20-II-R633A LCC 15BA1 INCM FDR 52-15101 Downscale IR20-EI-R634A 480V LCC 15BA1 Downscale IR20-II-R635A LCC 15BA3 INCM FDR 52-15301 Downscale IR20-EI-R636A 480V LCC 15BA3 Downscale DIVISION 11 1R20-II-R6273 LCC 163B4 INCM FDR 52-16401 Downscale IR20-EI-R6283 480V LCC 16BB4 Downscale

, 1R20-II-R6293 LCC 16BD2 INCM FDR 52-16201 Downscale IR20-El-R6303 480V LCC 16B32 Downscale IR20-EI-R6483 LCC 16BB6 INCM FDR 52-16601 Downscale IR20-EI-R6473 480V LCC 16BB6 Downscale IR20-EI-R6313 LCC 16BBS INCM FDR 52-16501 Downscale IR20-EI-K6323 480V LCC 16BB5 Downscale IR20-II-R6333 LCC 16 bbl INCM FDR 52-16101 Downscale IR20-EI-R6343 480V LCC 16 bbl Downscale IR20-II-R6353 LCC 16BB3 INCM FDR 52-16301 Downscale IR20-EI-43633 480V LCC 16BB3 Downscale i

+ l Y-

• l IEB 79'--27 { l i

[ Attachment 2 i Page 8 of 11l V. STANDBY SERVICE WATER (SSW)

CONTROL ROOM INDICATIONS - Illl3-P870 REC./IND. SENSOR FAILURE REC /15D. POWER SUPPLY SENSOR POUER SUPPLY MODE IPtl-LR-R604A 52-IP56125 IP41-LT-N004A Same as Downscale SSW 3asin A indicator Level I P ' l-i'R-R6 06 A 52-lP56125 IP41-FT-N018 A Same as Downscale SSW Loop A IP41-FT-N020A indicator Tiov/?ress IP41-FT-N016A l

IP41-PT-N009A '

3L1-LR-R6043 52-IP66123 IP41-LT-N004B Same as Downscale 3W Basin B indicator

_evel IP41-UR-R6063 52-IP66123 IP41-FT-N018B Same as Downscale '

SSW Loop B Ficw/?ress IP41-FT-N020B indicator IP41-FT-N0163 1P41-PT-5009B IP41-PI-R602 Same as sensor IP41-PT-N009C 52-lP71125 SSW Loop C Downscale IP41-FT-N016C Press I?il-FI-R601 Same as sensor IP41-FT-N018C 52-lP71125 SSW Loop C Downscale IP41-FT-N016C Flow

. . s I.IEB 79-27 I l l Attachment 2 l Page 9 of 11(

VI. AUT051ATIC DEPRESSURIZATION SYSTEM TADS)

CO:: TROL ROO:! INDICATIONS - 1H13-P614 I I

l REC./IND. 1 REC /IND. FJWER SUPPLY SENSORS  !! DE $

1321-TJR-R614 03-lY 71-25 1321-T2-N004A I ADS As Is i off inverter thru N004W  !

Safety Valves lY79*

Temperature s

Backed up by Div. I MCC 15342 (Autocar.ic Switchover) 1 i

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, l YEB 79-27 ) [

j Attachment 2 lPate 10 of 11l V II . LOW PRESSURE CORE SPRAY (LPCS)

CONTROL ROOM INDICATIONS - Panel 1H13-P601 REC./IND. SENSOR FAILURE REC /IND. POWER SUPPLY SENSOR POWER SUPPLY MODS lE21-FI-R600 52-IP56120 IE21-FT-N003A Sane as Downscale.

LPCS Pump indicator Disch Flow i

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' l IEB 79-27 I l

] Attachment 2 (Page 11 of 11l VIII. REACTOR CORE ISOLATION COOLING (RCIC)

CONTROL R00:1 INDICATIONS . Panel IE13-?601 INDICATOR SENSOR FAILURE INDICATOR POWER SUPPLY

• SENSOR P0h'ER SUPPLY MODE lE51-PI-R602 72-IIA 32 IE51-PT-N007 Same as Downscale Inlet Press indicator RCIC Turbine IE51-SI-R605 72-IIA 24 On ~urbine Self powered Downscale RCIC Turbine Speed IE51-PI-R603 72-IIA 18 IE31-PT-N056A Same as Downscale RCIC Turbine Exh indicator Pressure IE51-PI-R604 72-IIA 18 1E51-PT-N052 Same as Reads "0" RCIC Pump Suction indicator Pressure IE51-PI-R601 72-IIA 13 IE31-PT-N050 Same as Downscale RCIC Pump Disch indicator Pressure IE51-PI-R606 72-IIA 32 lE51-FT-N003 Same as Downs ca le RCIC Pump Disch Flow indicator IE51-FK-R600 72-IIA 32 IE51-FT-N003 Same as Downscale RCIC Flow indicator

, Control

• All fed from 125 VDC Bus llDA 9

, o IEB 79-27 Attachment 3 Page 1 of 2  ;

3. PROCEDURE REVIEW IE Bulletin 79-27 directed licensees to review their emergency procedures that are used by control room operators upon loss of power to buses feeding power to instrument and control system used for achieving cold shutdown. ,

i This applies to the Alarm Response Instructions (ARI's) for the ESF Division I, II, and III buses which provide power to the systems listed in Section II.

Additionally, selected safety-related Emergency Procedures (EP's) and Off-Normal Event Procedures (ONEP's) were reviewed.

The ARI's which address loss of power to the ESF buses are as follows:

ESF Division I AC and DC 04-1-02-1H13-P864-1A-Al thru H4 ESF Division II AC and DC 04-1-02-1H13-P864-2A-Al thru H4 ESF Division III AC and DD 04-1-02-1H13-P601-1A-Al thru H5 (HPCS)

The ARI's have been reviewed and revised by CGNS Operations. Some alarm panel window engravings have been changed and some windows have bece moved to other panels in response to human factors requirements. The ARI review is now complete. The ARI review addressed the items contained in paragraph 2a, b, and c of IE Bulletin 79-27 and assured that the procedures included the referenced requirements.

Emergency Procedures (EP's) and Off-Normal Emergency Procedures (ONEP's) which 1

may be used (in whole or in part) to place the plant in a cold shutdown condition were reviewed for effects of power loss in accordance with the requirements of IEB 79-27. The procedures reviewed were:

Procedure Number Title 05-S-01-EP-1 Level Control 05-S-01-EP-2 Cooldown 05-S-01-EP-3 containment Control 05-S-01-EP-4 Level Restoration 05-S-01-EP-5 Rapid RPV Depressurization 05-S-01-EP-6 Core Cooling Without Injection 05-S-01-EP-7 Core Cooling Without Level Restoration 05-S-01-EP-8 Alternate Shutdown Cooling 05-5-01-EP-9 RPV Flooding

~05-S-01-EP-10 Reactivity Control 05-S-02-II-1 Shutdown from Remote Shutdown Panel 05-S-02-III-9 Loss of HPCS 05-S-02-III-10 Loss of RCIC 05-S-02-V-2 Loss of TBCW E28rgl

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IEB 79-27 Attachment 3 Page 2 of 2 Results of the procedure review and the revised procedure status are:

Annenciator Response Instructions ARI's 04-1-02-11113-P864-1 A, P864-2A, & P601-16A revised Off-Normal Event Procedures All ONEP's revised - Revision 10 status Emergency Procedures Procedure revisions continuing.

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l IEB 79-27 l l l Attachment 4 IPage 1 of 1 l RE-REVIEW OF IE CIRCULAR NO. 79-02 FAILURE OF 120 VOLT VITAL AC POWER SUPPLIES, DATED JANUARY ll, 1979 P

IE Bulletin 79-27 directed licenseees to re-review IE Circular 79-02 to include both class IE and non-class IE safety-related power supply inverters. In response to this item, reterence is made to the to11owing documents (copies attached):

a) CGNS Comment Control Form dated 12 March 1979, P. H. Skinner to A. S. McCurdy b) Letter, dated 25 May, 1979, A. Zaccarta (Bechtel) to L. F. Dale (MP&L) c) Memo, dated 11 April 1980, R. A. Ambrosino to C. K. McCoy The reterenced documentation provides the response to IE Circular 79-02 requested in Bulletin 79-02. No further action is required.

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1. . 3echte Power Corporation

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Engineers--Censtructors 15740 Shady Grove cload

, Gaitnerst:urg, Maryland 20760

, 301-948 27CO t

May 25,1979 Mr. I.. F. Dale Nuclear Project lianager

• Mississippi Power & Light Cc=pany P. O. Box 1640 Jackson, Mississippi 39205 -

Dear Mr. Dale:

Nuetear OA Is Aeolicable Middle South Energy, Inc.

Grand Culf Nuclear Station Bechtel Job No. 9645

, Tile: 0262/E-079.0/L-860.0 Re: 3F2-79/50, dated February 6, 1979 II Circular No. 79-02

=.

PJ3-79/0327 U *'e have reviewed the II Ci'rcula r "o. 79-02 entitled " Failure of 120 Volt AC

?cuer Supplies" from the NRC enclosed with your letter dated February 6,1979 and have the following co _ ents to =ake.

1. Bere is no class II 120VAC Uninterruptible power supply of the type described in the II circular No. 79-02 on the Grand Gulf Project.

F.cuever there is a 120/240VAC uninterruptible power supply (BOP) for supplying power to computers, security system etc. for this, Static Inverters supplied by Solid State Controls.Inc., are used.

2. De proble=s described in the II circular were unique to the design of Arkansas Nuclear Station (ANS) Unit 2 design and is not applicable to '

the Grand Gulf 120/240VAC systen design. We =ain d'.fferences are:

a. Dere is no Under Voltage device with fixed or adjustable ti=e delay to shut down the D.C. incoming power supply on,CCNS in-verters as was the case in ANS 2 inverters.

b. ANS 2 utill:ed an uncontrolled rectifier as the main source of pcVer to the Static Inverters. h is could have resulted in tho passing of high voltage surges on the AC system to the invertee resulting in bicen fuses. On Grand Gulf the main power source for the inverters is 125VDC 3US which in turn receives power through Battery ch.srges which h laced output.

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Bechfel Power Corporation

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+2 Mr. L. F. Dale May 25, 1979 Bechtel Job No. 9645 Mp3-79/0327

c. On Grand Culf, we 1:=edia tely annuncia te the operation of S ta tic Transfer Switch t'o preclude the possibility of con-tinued operation of 120/2407 power supplies frem the al-cerna te AC pcver sources, without the knculedge of the op-erator.

If you have any further questions, please do not hesitafe to call us.

Very truly yours,

- e

. L. &n Iaccaria g oject Engineer IDM:vr cc: J. P. McCaushy, Jr.

. Z< McCoy

," W. L. Nail

~ '

T. E. Reaves Dr. D. C. Gibbs J. N. Ward R. L. Scotr D. M. Lake H. H. Veber e

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44, s

• (*.i.p0

.* a W MEMO TO: C. K. McCoy

)

FRCM: R. A. Ambrosino

SUBJECT:

IE Circular 79-02, " Failure of 120 Volt Vital AC Power Supplies" In September, 1978, Arkansas Nuclear Cne (ANO) Unit 2 while in hot functional testing preceding initial criticality, suffered a degradation of both independent off-site power sources. This prcduced an undervoltage condition on the Engineered Safety Feature (ESF) buses and caused an inadvertent ESF acutation. It 1

was deter =ined that the ESF actuation occurred on a loss of at least two of the uninterruptable 120 volt vital AC power sources.

Investigation revealed that all four of the Solidstate Controls Inc. (SCI) inverter static switches had automatically transferred to the alternate power supply. A single conclusive cause of the undesired SCI inverter static switch transfer could not be iden-tified. However, the following prcblems were noted:

1. The setting of time delay relays for the low voltage trip, were noe verified during either preoperational testing or subsequent maintenance.

g 2. A cc fuse within the inverter component on one SCI inverter, J was found blown. This could have been due to an excessive DC voltage to the inverter ccaponent caused by a transient on the 480 volt AC input.

3. The SCI inverter static switch is designed to transfer to an alternate source on inverter overcurrent and undercurrent.

Possibly the instantaneous inductive load caused setpoints to be exceeded.

The circular recuested certain determinations be made. These ac-cc=panied by a response (from meno to ASM from PHS dated 3/12/79)

. are shown below:

1. Cetermine whether or not time delay circuitry is used in inverter units. If so, have they been adjusted to the appropriate setpoint as required by equipment and the in-tegrated system design.

Response :

A time delay is designed into the lL62 system (inverters).

II differs in that the inverters will transfer back to the normal source in less than two seconds following re-availability of power.

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. .s- w,- :. =. .=.. a::7-h.,- _termina it ena AC input voltage anc trans:or=cr tap snttings ara optirti::d to prevent ' exceeding ther inverter component nama plato maximum ratcd DC input voltage in the event of high AC input voltage transient.

Response : '

The vendor adjusted setpoints for IL62 inverter static trans-fer switches are 70% of nominal output voltage and 120% of full load output. Steps will be added during preoperational test-ing to verify these setpoints. -

3. If an alternate 120 volt source is used in your design, de-termine if the protection transfer circuitry of the inverter has been optimized within design limits to ensure =axi=um possible availability of the inverter system during transient loading conditions.

Pasponse: .

The IL62 system does not have a "nor=al" AC input. It is fed from a 125 VDC bus. .

4.

Oeter=ine if the administrative controls employed by your facility ensures operability of safety systems after its (e . g . , time delay relays, switches, etc.) have been sub-jected to maintenance or testing.

Re sponse : ,

Normal maintenance and calibration procedures will cover this task.

It should be noted that there is no class IE 120 VAC uninterruptible power supply, as mentioned, at Grand Gulf (Bechtel letter MPB-79/0327) .

However, there is a 120/240 VAC uninterruptible (SOP) pcwer supply which employs SCI static inverters.

Additionally, the problems described are unique to the design of ANO Unit 2 and are not applicable to the Grand Gulf 120/240 VAC system design.

's f M a R. AN A.~..brosino L 4-11-80 GJ/~dRP/RAA:pjc Attachments cc: L. Pentecost C. R. Hutchinson E'ile 6 *

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