ML20151K276
| ML20151K276 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 10/28/1983 |
| From: | SCIENCE APPLICATIONS INTERNATIONAL CORP. (FORMERLY |
| To: | |
| Shared Package | |
| ML20151K225 | List: |
| References | |
| 1-147-08-492-00, 1-147-8-492, NUDOCS 8406270400 | |
| Download: ML20151K276 (162) | |
Text
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/ DESIGilATO '
- 3 ORilL #62B-13619C/62X-30 bi ^{gt( '[b W .;4 57 SAI #1-147-08-492-00 igi,aut; + -
FAILUBE h0 DES AND EFFECTS JRALISIS FOR THE OCONEE 1 RUCLEAR POWER STATION MAKEUP AND PURIFICATION SYSTDI Prepared for the Instrumentation and Controls Division Union Carbide Corporation, Nuclear Division by Science Applications, Inc. ,
Eystems Anrlysis Division October 28, 1983 8406270400 840424 PDR ADOCK 05000269 p PDR
ORNL #62B-13819C/62X-30 SAI #1-147-08-492-00 FAILURE MODES AND EFFECTS ANALYSIS FOR THE OCONEE 1 NUCLEAR POWER STATION MAKEUP AND PURIFICATION SYSTEM Prepared for the Instrumentation and Controls Division Union Carbide Corporation, Nuclear Division P.O. Box X Oak Ridge, TN 37830 by Science Applications, Inc.
Systems Analysis Division Jackson Plaza Tower 800 Oak Ridge Turnpike Oak Ridge, TN 37830 October 28, 1983
i TABLE OF CONTENTS Section fagg LIST OF TABLES vii LIST OF FIGURES vii
1.0 INTRODUCTION
1
! 2.0
SUMMARY
OF RESULTS 3 30 SYSTEM DESCRIPTION 9 3.1 Makeup and Purification System Overview 9 32 Subsystem Descriptions 15 3.2.1 Letdown Subsystem 15 3 2.2 RC Pump Seal Return Subsystem 16 3.2 3 HPI Pump Subsystem 17 3 2.4 RC Pump Seal Injection Subsystem 18 3 2.5 Reactor Coolant Makeup Subsystem 18 3 2.6 Chemical Processing Subsystem 19 33 Support Systems 22 4.0 FAILURE MODES AND EFFECTS ANALYSIS 25 4.1 Technical Approach 25 4.2 System Level Results 26
, 4.2.1 Functional Failures 27 4.2.2 Discussion of System Level Results 30
- 4.3 Subsystem Level Results 40 431 Letdown Subsystem 41 432 RC Pump Seal Return Subsystem 42
- 433 HPI Pump Subsystem 43 434 RC Pump Seal Injection Subsystem 45 l
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TABLE OF CONTENTS (Continued) i Section ERER j
, 435 Reactor Coolant Makeup Subsystem 46 4.3.6 Chemical Processing Subsystem 47 j
5.0 REFERENCES
109 l
APPENDICES A - Component Level FMEA of the Letdown Subsystem B - Component Level FMEA of the RC Pump Seal Return i Subsystem C - Component Level FMEA of the HPI Pump Subsystem
! D - Component Level FMEA of the RC Pump Seal Injection Subsystem E - Component Level FMEA of the Reactor Coolant Makeup Subsystem F - Component Level FMEA of the Chemical Processing
! Subsystem 1
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LIST OF TABLES Table fagt 1 Summary of Significant Effects of MU&P Component 7 and Support System Failures 2 Functional Failures and Potential Precipitating 51 Component Failures 3 Pressure Boundary Failures in the Makeup and 57 Purification System 4 Flow Blockages in the Makeup and Purification System 67 5 Flow Increases in the Makeup and Purification System 75 6 Loss of Chemical Addition, Coolant Purification 79 j Capability in the Makeup and Purification System 7 Effects of Control Instrumentation Malfunctions 81 on the Makeup and Purification System 8 Effects of Cooling Water Failures on the Makeup 89 j and Purification System 9 Effects of Instrument Air Failures on the Makeup 93 and Purification System 10 Effects of AC Electric Power Failures on the Makeup 95 and Purification System 11 FMEA Summary for Subsystem 6.0: Chemical Processing 101 Subsystem LIST OF FIGURES Figure Eggg 1 Makeup and Purification System Flow Sheet, 11 Subsystems 1.0 - 5.0 2 Makeup and Purification System Flow Sheet, Subsystem 6.0 13 4
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i 1.0 IETRODUCTION The implications of failures of safety systems on nuclear power plant safety have been studied extensively. Currently, the safety implications of control system failures in nuclear power plants are being investigated by the Oak
- Ridge National Laboratory. A major task in this effort is the preparation of I Failure Modes and Effects Analyses (FMEA) of plant systems to aid in the analysis of control system malfunctions and identification of possible 4
consequences to safety. Specifically, the studies are directed at identifying failures contributing to reactor coolant overcooling, reactor coolant undercooling or degradation of the ability of safety systems to respond on demand.
Although the objectives of the broad study are generic, specific nuclear power
, plant systems' designs are required for the preparation of a detailed FMEA.
For this reason, the FMEA is being performed on the systems of the Oconee l
Nuclear Power Station. This report documents the results of the FMEA of the Makeup and Purification (MU&P) system.
To achieve the program objectives, the FMEA of the MU&P system included detailed consideration of the equipment associated with reactor coolant letdown, the HPI pumps, makeup, chemical addition and processing, RC pump seal return and seal injection. In addition, the analysis included consideration of failures of interfacing support systems including control instrumentation,
, cooling water, instrument air and AC electric power distribution systems.
The major results of the study are summarized in Section 2, Summary of Results. The design of the MU&P system and interfacing support systems are described in Section 3, System Description. The FMEA methodology and the analysis results are described in detail in Section 4, Failure Modes and l Effects Analysis. For convenience, the lengthy tables of results have been
! placed at the end of each section.
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2.0 SUBGEABY OF RESULTS A detailed FMEA of the MU&P system has been performed to evaluate the extent to which MU&P component failures or interfacing support system failure contribute to reactor coolant overcooling, undercooling or degradation of safety functions.
Due to the complexity of the MU&P system, the FMEA was performed in two steps.
A component level FMEA was performed first to evaluate the effects of component failures on its subsystem and subsystem interfaces. The results of the component level FMEA are presented in Appendices A through F.
The major subsystem effects, including pressure boundary failures, flow blockage failures, flow increase f ailures and loss of chemical addition or coolant purification capability, then were considered as postulated functional failures to evaluate system and plant level effects. The relationship of component failures to functional failures and the detailed system level FMEA results, including the effects of interfacing support system failures are discussed in Section 4.2.
The detailed FMEA results have been reviewed to identify those functional failures and effects which are judged to have a significant impact on safety.
For the specified effects of significance, the key contributing component failures for the initiating functional failures then were identified. The affects of MU&P component failures and functional failures of support systems judged to be significant are listed in Table 1.
- Pressure boundary failures in the high pressure letdown piping are significant due to the simultaneous initiation of an isolatable small LOCA and draining of the LST possibly leading to failure of HPI pump A and/or B. Pressure boundary f ailures in other subsystems would contribute to HPI pump failure but not initiate an RC leak or small LOCA. In addition to pressure boundary cracks such as LD Cooler tube failure, pressure boundary failures could occur follouing maintenance on redundant components such as the LD coolers. If, 3
following maintenance, LD cooler C1 A remained isolated with a drain path open, the plant could be started-up and operated us11g the cooler, C18. The failure condition could remain undetected until cooler CI A isolation valves were opened creating the LOCA.
This functional failure potentially contributes to either overcooling and undercooling conditions. A LOCA with inadequate emergency injection would result in undercooling. An isolatable LOCA also is a pressurized thermal shock (PTS) transient of interest since the RCS would initially be reduced in temperature during depressurization and subsequently repressurize following isolation of the leak path.
Flow blockage and flow increase failures, possibly caused by control instrumentation failures, could result in draining the LST or directly blocking flow to the HPI pumps. Either condition could result in failing the operating HPI pump. Low LST level is alarmed and the operator can be expected to provide an alternate supply of water to the HPI pump with reasonably high probability. Closure of the isolation valve in the LST outlet line, however, would result in a rapid pump failure due to cavitation. In addition, the high indicated LST level and low indicated makeup and seal injection flowrates may induce the operator to start a secor.d HPI pump possibly resulting in its failure.
The postulated failure of interfacing cooling water systems, although unlikely, was found to have potentially significant effects. Failure of the CC system results in termination of cooling water flow to the RC pump seals and LD cooler, automatic isolation of letdown flow on high letdown temperature and a resulting slow decrease in LST level. If the operator allowed the LST to drain resulting in failure of the operating HPI pump, RC pump seal failure could occur followinst the loss of seal injection flow. The small LOCA (pump seal failure) and degraded emergency HPI due to common cause is considered significant.
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- Although the LPSW system performs a safety function in its emergency mode of i operation, it also aust function during normal plant operation to support f
control system functions. For this reason, failure of this interfacing i support system was included for completeness. Failure of the LPSW, in ,
- eddition to causing loss of CC function discussed above, results in loss of j cooling water to the HPI pump actor bearing and most other emergency systems. '
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The significance of this event is increased since the LPSW system failure j
affects both Unit 1 and Unit 2 systems.
, The failure of most AC electric power buses serving the MU4P were found to a t j have small effect. However, due to the possible manual transfer of 208 VAC buses IS1 and XS2 to a single power source, one of several bus failures could l
! ofrectively block emergency HPI if required. Although this event is not a
- control system failure, it may be significant and is identified for future 3 ,
l reference. '
} In conclusion, a FMEA has been performed on the Oconee Unit 1 MU4P system to 4
j ovalute the effect of MU&P component failures. In general, most componenk, failures have small effects due to the redundancy of key MU4P components and i
j the availability of effective remedial actions. As discussed above, however,
{ several failures were found to have significant effects including the
! degradation of the emergency HPI function and/or the initiation of RC leaks or i
j small LOCA's. #
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TASLE 1. 8""mf OF CICHIPICANT BFFECTS OF NU&P CDAPOWENT AND SUPPORT CYSTER FAILDRES Functional Failure Pallure Causes Effect Significance
- 1. Pressure Boundary Pa11ures o Letdown Cooler tube o Isolatable RC Leak or Initiation ot an isolatable RC la migh Pressure Letdown failure or Small LOCA and leak or small LOCA and Piping degradation or the required o Placing the spare Rapid draining of LST and safety function, Emergency MPI, letdown cooler in possible consequential due to a common cause.
operation if its drain f ailure of operating HPI valves had been left pump (s). An attempt to open and isolation restore flow by starting valves left closed due the spare NPI pump could to improper prior result in its failure, maintenance. Pump damage can be prevented by the operator providing an alternate source of borated water to the MP3 pumps.
- 2. Plow stockage Pallures o closure of purification o Draining of LST and Degradation of the emergency in Low Pressure Letdown demineraliser or makeup possible consequential HPI safety functaon.
Piping Upstream of LST filter isolation valves f ailure of operating HPI due to valve operator, pump (s). An attempt to control instrumentation restore flow by starting or maintenance failure, or the spare HPI pump could result in its fa!!ure.
o Transfer of 3-Way valve Pump damage can be sa diverting flow from LST prevented by the operator to bleed holdup tank due removing the blockage or to valve operator or providing an alternate control instrumentation supply of borated water failure. to the RPI pumps.
- 3. Plow Blockage Pa!!ures o Closure of NPI pump o Cavitation and rapid Degradation of the emergency in Low Pressure BPI suction valve due to fa!!ure of operating HPI HPI safety function.
Pump Suction Piping valve operator or control pump (s) . An attempt to instrumentation failure, restore flow by starting the spare HP1 pump could result in its failure.
Pump damage can be prevented by tripping the HPI Famp(s) or rapidly providing an alternate source of borated water.
- 4. Pressure Boundary Failure o Placing a spare o Draining of LST and Degradation of the emergency in the Low Pressure purification possible consequential HPI safety function.
Letdown Piping demineraliser or makeup f ailure of the operating filter in operation if HPI pump (s). An attempt its drain valves had been to restore flow by lef t open and isolation starting the spare HPI valves lef t closed due to pump could result in its improper prior fa!!ure. Pump damage maintenance, or can be prevented by providing an siternate o A letdown relief valve source of borated water opening and f alling open to the HPI pumps, following a flow blockage (assumes blockage is removed otherwise see Item 2).
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TABLE 1. SUNNARY OF SIGNIFICANT EFFECTS OF NU6F CORPOWENT AND SUPPORT SYSTER FAILURES (Continued)
Functional Failure Failure Causes Effect Significance
- 5. Flow Increase Failure o Opening of makeup control o Draining of LST and Degradation of the emergency in the Makeup Piping valve due to valve possible consequential HPI safety function, operator or control failure of the operating instrumentation failure, or HPI pumps. An attempt to increase flow by starting o Opening cf HPI discharge spare HPI pump could valve due to valve result in its failure.
operator or control Pump damage can be instrumentation failure. prevented by throttling the Makeup flow or providing an alternate source of borated water to the HPI pumps.
- 6. Component Cooling Water o CC containment isolation o Loss of CC system can Initiation of an RC leak or System Failures valve closes due to result in termination of small LOCA and degradation of valve operator or control cooling water flow to RC the required safety function, instrumentation failure, or pump seals and isolation Emergency HPI, due to a common of letdown. Unless an cause, o Trip of one CC pump and alternate supply of f ailure of spare to borated water is provided start. to the operating HPI pump, 00 seal injection flow could be lost and consequential failure of RC pump seals could occur.
- 7. Low Pressure service o Common cause failure of o Loss of LPSW to the Initiation of an RC leak or Water System Failures LPSW system (e.g., all operating HPI pump (s) small LOCA (due to loss of CC pump suction strainers could result in failure and seal injection) and blocked). of the pump. Loss of the degradation of many safety LPSW system would affect functions, the operability of almost all plant safety systems and the CC system (see above).
l 30 SYSTEM DESCRIPTION 3.1 MAKEUP AND PURIFICATION SYSTEM OVERVIEW The Makeup and Purification (MU&P) System consists of the piping and process squipment required to remove, process and replace reactor coolant at the flowrates required to maintain constant Reactor Coolant System (RCS) coolant volume. The major functions performed by the MU&P System are:
- 1. Letdown Control: Controlled removal of reactor coolant from the RCS and reduction of coolant temperature and pressure at a preset flowrate.
- 2. Purification: Removal of impurities from the reactor coolant using boric acid saturated ion exchange resins.
3 Coolant Processing and Chemical Addition: Recovery of concen-
- . trated boric acid and demineralized water from letdown reactor coolant; supply of demineralized (boric acid free) water and concentrated boric acid to adjust reactor coolant boric acid concentrations; and supply of lithium hydroxide to control reactor coolent pH.
- 4. Reactor Coolant Pump (RC Pump) Seal Return: Collection, filtering and cooling of coolant flowing past the RC Pump shaft face seals.
- 5. RC Pump Seal Injection: Injection and filtering of processed letdown coolant to the RC pumps' shaft seals at a constant flowrate.
- 6. RC Hakeup: Injection of process letdown coolant to the RCS at a flowrate controlled to maintain constant reactor coolant volume.
In addition to the normal functions performed by the MU&P System, portions of the system are used to provide emergency injection of coolant following design basis plant accidents.
The major equipment and process flows within the MU&P system are illustrated in Figures 1 and 2. For the purposes to this study, the overall system has l
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f been divided into six subsystems, which are indicated in Figures 1 and 2 and described in the following sections.
i 32 SUBSYSTEM DESCRIPTIONS The MU&P System was divided into six subsystems as shown in Figures 1 and 2.
This section presents a brief functional description of each subsystem
, including any assumptions which were required to define the various operating nodes of the system. Descriptions are based on material in the Oconee FSAR (Reference 1); specific FSAR reference drawings for the subsystems are as follows:
j Subsystem 1.0 Letdown Subsystem: Letdown Coolers to Three-Way Valve
- Figure 9-2A*, Figure 9 3-2 (Sheet 4);
Subsystem 2.0 RC Pump Seal Return Subsystem Figure 9 3-2 (Sheets 1 and 4);
I Subsystem 3 0 HPI Pump Subsystem: Letdown Storage Tank, Inlet Filters, l and HPI Pumps Figure 9 3-2 (Sheet 4);
- Subsystem 4.0 RC Pump Seal Injection Subsystem Figure 9 3-2 (Sheets 1 and 4);
Subsystem 5 0 RC Makeup Subsystem
! Figure 9 3-2 (Sheets 1 and 4);
Subsystem 6.0 Chemical Processing Subsystem: RC Bleed, Boron Recovery, and Chemical Addition l Figure 9.3-1 (Sheet 1), Figures 9 3-2 (Sheet 1),
Figure 9 3-5 (Sheets 1, 3 and 4) i j Subsystems 1 through 5 of the MU&P System are shown in Figure 1. The Chemical Processing Subsystem is shown in Figure 2.
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3 2.1 Letdown Subsystem The main functions of this subsystem are to cool ' nd a depressurize the letdown
! flow from the RCS and to remove impurities. This subsystem interfaces with
- Reference 2 15 i
the HPI Pump and Chemical Processing Subsystems at the 3-Way valve. Letdown cooler HP-C1 A or HP-C1B reduces the temperature of the letdown flow to a i temperature suitable for purification in the letdown desineralizers and l subsequent injection into the RCS. Heat in the letdown cooler is rejected to the Component Cooling System. The letdown flow rate is limited by a fixed j block orifice which reduces the letdown pressure from RCS operating pressure
! to a pressure slightly above atmospheric. HP-7, a normally closed, remotely operated control valve in parallel with the block orifice can be opened to i increase the flow rate if required. In addition, normally closed HP-42, in j parallel with HP-7, may be manually positioned for flow control. Upon leaving 4
j the letdown coolers, a one-to-two gallon per minute sample flow is continuously bypassed around the block orifice through a radiation monitor
! loop and a boron meter loop. Reactor coolant is monitored for gamma activity and boron content before being returned to the letdown strema upstream of the purification desineralizer. The letdown flow normally passes through l purification domineralizer HP-11 to remove reactor coolant impurities other than boron and then to the 3-way valve HP-14.
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i 3 2.2 RC Puen Seal Return Subsystem The RC pump seal return subsystem consists of the return piping and instrumentation from the RC pump seals, seal return coolers, and a single I filter installed upstreas of the coolers. The system provides for the return l and seal water cooling in the circulation loop of seal water through the I reactor coolant pumps. This subsystem also is used to remove heat added by 1
j the operating HPI pump or pumps.
(
I A set of four return lines, one from the face seals on each RC pump, normally f collects the seal return flow into a common return header. Another set of l four return lines, normally closed, collects the flow bypassing the face seals f when required on each RC pump. These lines are utilized when the leakage rate past the face seals on any operating pump is less than one spa (normal flow is f
approximately three spa per pump).
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The reactor coolant pump seal return header is an outflow line which pene- l j trates the Reactor Building. The header has an electric motor-operated l isolation valve inside the Reactor Building and a pneumatic valve outside which are automatically closed by an engineered safeguards (ES) signal. The seal return filter and coolers are outside the Reactor Building.
f The seal return filter is installed in the seal return line upstream of the seal return coolers to remove particulate matter. A bypass is installed to l permit servicing during operation.
] T'le seal return coolers are sized to remove the heat added by the operating HPI pumps and the heat picked up in passage through the reactor coolant pump
, seals. Heat from these coolers is rejected to the Recirculated Cooling Water i
j (RCW) System. Two coolers are provided in parallel and one is normally in
! operation. The flow from the seal return coolers discharges directly to the inlet header of the Letdown Storage Tank (LST).
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.l 323 HPI Pn=n Subsvgj;,gg This subsystem consists of two makeup filters, the LST, three HPI pumps, pump discharge manifold, and other associated piping. The system collects the seal return and letdown flows from the RCS for the normal operation of the HPI j pumps and discharges it to the RC pump seal and makeup subsystems.
I The LST serves as a receiver for letdown, seal return, chemical addition, and 1
j system makeup. The tank also accommodates temporary changes in system coolant l volume. All flows except seal return pass through one of the makeup filters before entering the LST. One filter is normally in operation and one is apare. The LST is continuously charged with hydrogen for RCS oxygen control.
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During normal operation of the RCS, one high pressure injection (HPI) pump continuously supplies high pressure water from the LST to the seals of each of the reactor coolant pumps and to a askeup line connection to the Loop A RCS
! cold legs. Three HPI pumps are provided, each capable of supplying the
- required reactor coolant pump seal'and makeup flow. One is normally in i
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operation while another-is in standby status to be used as needed. The third pump is used only for emergency injection. ;
} 3 2.4 RC Pman Seal Iniection Subsystem This subsystem distributes seal injection water to the four RC pumps. It f
- consists of the seal injection header from the HPI pump discharge manifold, two RC pump seal filters, four individual injection lines (one to each RC pump), and associated piping and instrumentation.
Seal injection flow is filtered prior to entering the individual seal j injection lines. One filter is normally in operation and one is spare. In addition, a bypass around both filters is available to permit maintenance during operation.
l' A flow control valve in the seal injection header to the pump seals auto-natically maintains the desired total injection flow to the seals. Manually pre-set throttle valves in each pump seal injection line provide a capability ,
i !
to balance the seal injection flow rates. A portion of the water supplied to the seals enters the RCS (~5 gpa per RC pump). The remainder returns to the
]
letdown storage tank after passing through the seal return subsystem (~3 spa l
per RC pump).
.i l The four individual injection lines penetrate the Reactor Building. These l l lines each contain a stop-check valve inside and outside the Reactor Building f for Reactor Building isolation.
j 3 2.5 ac Makeun Subsystea
! The RC makeup subsystem is designed to control makeup requirements during i
j normal operation, design raector coolant system transients, and Reactor Coolant System cooldown. The subsystem consists of a makeup header off the i 1 j HPI pump discharge manifold, a flow control loop, two main reactor inlets to
! the Loop A cold legs, and additional paths, bypassing the makeup flow control
. valve, feeding a small amount of flow to the reactor cold leg inlet nossles l and the pressuriser spray line. j
! l t
4 18
Normal makeup flow is delivered to the two reactor cold legs of Loop A.
During normal operation, makeup flow is diverted around the emergency HPI flow path through a flow control valve. The pneumatically operated control valve throttles the makeup flow to the two reactor cold legs to maintain constant pressurizer level. The flow bypassing the makeup control valve is assumed to provide a minimum flow to minimize temperature changes in the reactor cold leg inlet nozzles and the pressurizer spray line.
3 2.6 Chemical Processing Subsystem This subsystem serves three functions:
- 1. Intermittent letdown of reactor coolant to a holdup tank and replacement with domineralized water or continuous operation of a deborating domineralizer;
- 2. Recovery of boric acid and domineralized water from letdown reactor coolant for reuse in the plant; 3 Chemical addition including the addition of boric acid to reactor coolant for reactivity control, lithium hydroxide for pH control, hydrazine for oxygen control during shutdown. The subsystem also provides caustic for resin regeneration in the domineralizers and chemistry control in the boron recovery operation.
Major components in this subsysytem have been shown in Figure 2.
RC Bleed HolduD DC Bleed Holdup is used for the collection and storage of reactor coolant.
The coolant is received from the letdown line both as a result of reactor coolant expansion during startup and for boric acid concentration reduction during startup and normal operation. It is either conveyed to the coolant bleed holdup tank for storage or passed through a deborating domineralizer for boric acid removal and returned as unborated makeup to the makeup line. It van assumed that one deborating domineralizer is in operation, one is regenerated and available in stand-by, and a third is being regenerated at any 19
time. A spray nozzle in the coolant bleed tanks on the inlet line allows some of the gases to be released. Recirculating the tank allows further stripping l action to occur. Domineralized water can also be returned to the makeup line from the desineralized water holdup tank. Coolant from the bleed holdup tank is pumped to boron recovery for processing.
The coolant bleed holdup tank and the concentrated borio acid storage tank are vented to the gaseous waste vent header to provide for filling and emptying without overpressurization or causing a vacuum to exist. In addition, each tank is equipped with a relief valve and a vacuum breaker. Pressurized nitrogen can be supplied to each tank to allow purging.
Instruments and. controls for operation of this system are located in the control roca. Instruments and controls for the coolant bleed holdup tanks and I pumps, desineralized water holdup tank and pump, and the concentrated borio acid storage tank and pump are duplicated on local auxiliary control boards.
Boron Recovery Boron recovery is operated on a batch basis and is sized to process all of the reactor coolant bled from the RCS operating on an 8-hour per day basis. The system receives coolant from the bleed holdup tank through the coolant bleed evaporator domineralizers (one in operation; one available in stand-by) into the feed tank which is sized to hold sufficient feed for about five hours of evaporator operation. The coolant is then pumped into the evaporator by the evaporator feed pump which maintains a level in the evaporator while the recirculating pump recirculates the coolant until the temperature is stabi-lized. The distillate is returned to the feed tank until the distillate is of the desired quality for pumping to the condensate test tanks. The evaporator concentrate is sampled and normally pumped to the concentrated borio acid storage tanks at approximately 8700 ppa boron. The evaporator concentrate can
! be allowed to increase to 26000 ppa boron and pumped to the drumming station for ultimate disposal as solid waste.
20
I Chemical Addition The chemical doition portion of this sy.9 tem delivers the necessary chemicals to other/ systems as required. Dorio acid is provided to the spent fuel pool, borated water sl.orage tank, letdown storage tank, and core flooding tanks as i takeup for leakage or to enange the concentration of borio acid in the ossociated systens. Sodium hydroxide (caustic) is added to the waste Cvaporator feed tank during evaporator operation and to the deborating domineralizer during desineralizer resin regeneration.
A borio acid mix tank and a concentrated borio acid storage tank are provided as *;urces of concentrated borio acid solution. These tanks provide redundant supplies of borio acid solution to increase the reactor coolant system boron concentration to that required for cold shutdown. Tank heaters and electrically heat traced transfer lines maintain the fluid temperature above that required to assure solubility of the borio acid. Three borio acid pumps
, cre provided to transfer the concentrated borio acid solution from the borio
. acid tank te the corated water storage tank (DWST), makeup filters, spent fuel storage pool, or the core flooding tanks. One high pressure pump supplies borio acid to thi core flooding tanks. The two low pressure pumps supply borio acid to other tanks.,sy. items, and locations.
The caustic six tank is used to prepare solution which neutralizes the feed to the waste evaporator. It also supplies sodium hydroxide to the deborating domineralizer' for regeneration. The caustic pump transfers sodium hydroxide from the caustic mix tank to the intended destination. g Lithium hydroxide is mixed and added to the RCS from the lithium hydroxide tank. Tne lithius hydroxion pump transfers lithium hydroxide from the Lioli tank to the letdown line upstream of the askeup filters.
A 55-gallon drum supplies hydrazine to the Reactor Coolant System; the hydrat.ine is used to scavenge dissolved oxygen, primarily following a reactor shutd.wn. The hydrazine pump transfers to the letdown line upstream of the makeup filters, f
21
/
33 MU&P SUPPORTING SYSTEMS The operation of the MU&P equipment requires that plant systems providing support functions operate properly. The major support functions required by the MU&P system are Control Instrumentation, Cooling Water, Instrument Air and l
Electric Power. '
Although the detailed analysis of support system failures are beyond the scope of the present analysis, degraded operating states of the support systems must be understood to adequately specify MU&P system interface failure modes. A brief description of the systems providing support functions is given below.
331 control Instrumentation The control instrumentation function is provided by a number of separately identified instrumentation " systems." These include the Non-Nuclear Instrumentation (NNI), Engineered Safeguards Protective System (ESPS), and a variety of miscellaneous control circuits and local control panels.
The principal instrumentation system controlling the Makeup and Purification system is the NNI. This system, described in References 1, 4 and 5, provides parameter measurement and control room display and manual and automatic control signals. The major automatic control circuits are the makeup control which regulates the makeup valve position t;o maintaAn constant pressurizer level, the seal injection control which regulates the seal injectica valve position to maintain constant flowrate and the 3-way valve control which transfers the letdown flow to the LST upon low LST level, control rod insertion limit or demineralized water / boric acid makeup " batch complete" limit.
The Engineered Safeguards Protection System (ESPS) is designed to initiate emergency functions upon detection of plant accident conditions. Among these actions are the isolation of letdown and seal return flow, opening the j flowpath from the BWST to the HPI pumps, initiating operation of the three HPI pumps and initiating unthrottled injection to the RCS through four flowpaths.
22
I Although the operation of the emergency HPI mode in response to an accident is I not considered, the impact on normal MU&P system operation following a spurious ES signal is considered as an interface failure.
In addition to the major instrumentation systems affecting the MU&P system, a large number of individual control circuits are provided to control individual components. In general, these circuits are considered as individual interfaces to MU&P system components.
332 cooline water Cooling water is provided to the MU&P system by the Component Cooling (CC) system, the Low Pressure Service Water (LPSW) system and the Recirculating Cooling Water (RCW) system. The CC system provides cooling water to the letdown (LD) coolers, the LPSW provides cooling water to the HPI pumps' motor bearings and the RCW provides cooling water to the seal return coolers. The CC, LPSW and RCW systems are described in Reference 1.
333 Instrument Air Plant instrument air is required to position MU&P system pnaumatic valves.
Instrument air is provided by three compressors and associated distribution piping and equipment. Very little information describing the instrument air system was available. The assumed . system configuration was based on RCW and electric power interface information obtained from References 1 and 3 334 Electric Power MU&P system pump and valve moters' are provided electric power by the F. ant 3
electric power distribution system. Electric power is distributed from Standby Buses #1 and #2 through transformers to 4160 VAC switengear groups TC, TD and T E. The power source of each of the switch gear groups is automatically transferred between Bus #1 or Bus #2 based on power availability. The 4160 VAC switchgear groups supply power to the three HPI pumps' motors and 600 VAC buses through transformers. The power sources of many of the 600 VAC buses also are automatically transferred. 600 VAC buses supply 208 VAC buses through transformers. MU&P system motor operated valves 23
l 1
and small pump motors are powered by the 208 VAC buses. The power distribution system is defined by the plant one-line electric power distribution drawings, Reference 3 4
1
.i 24 6 - . , , - , , , .. - . - - - - _ _ _ _ - - - - - - _ _ - - - - - - - - - - _ . - - - - - . - _ _ .
- _ = - __ - __ __
4.0 FAILURE MODES AND EFFECTS ANALYSIS i
! 4 .1 TECHNICAL APPROACH The analysis results documented in this report have been developed using failure modes and effects analysis (FMEA) techniques. A FMEA identifies failure modes for components of concern and traces their effects on other components, subsystems, and systems. Emphasis is placed on identifying significant effects associated with specific component failures. The advantage of the analysis technique is that while it is simple to apply, it 4
provides for an orderly examination of potentially important failure modes throughout a system.
In a FMEA, the impact or effect of a potential fault is documented in tables which identify the failed component being considered. Support systems associated with the component (for example, electric power for a motor-operated valve) also must be considered. Potential component fault modes due to internal failures or unavailability of support systems, the impact of the fault on system operation, and potential remedial action if the fault occurs are listed in the FMEA tables. Analysis of the completed tables permits identification of failures which have significant impact on system operation.
Because of the multiplicity of functions provided by the Mu&P systes, an initial FMEA was performed on c. aubsystem level. MU&P subsystems are ,
described in Section 3 0. Interfaces between each subsystem, including inlet and outlet links to other subsystems, eupport systems, and other reactor plant systecs, were carefully defined during the analysis to pernit integration of tne aubsystem analyses into a single analysis package for the entire syrtem.
Faults due to component failures were tracad through the linxed subsystems to '
identify the impact or such failuras on the entire system. The impact of a
support system unavailabilities was traced in a similar way, except faults in all subsystems due to the unm ailability were concurrently traced for impact.
Certain faults were grouped 6 facilitate analysis. As an example of this, a failed closed state was defined for normally open manual valves. This failure state included faults due to _ internal damage, due to plugging and due to 25
l l
inadvertant closure. Similarly, filter plugging was considered in the same category as plugged lines.
The FMEAs for each subsystem are detailed in Appendices A through F. These appendices describe each component considered in the subsystem analyses, along with appropriate fault documentation, as described above. The subsystem FMEAs were formatted to permit computerized data basing at some future date, if desired, for the inventory of components, the failure modes, the int 9tfaces involved, the effects, and the remedial actions available. The impact of the subsystem faults at the subsystem boundaries is summarized in Section 4 3 The integration of the subsystem analysis results into a system-level failure analysis is documented in the following section.
4.2 SYSTEM LEVEL FMEA RESULTS As discussed in Section 4.1, Technical Approach, the high complexity of the MU&P functions required that postulated failure modes and their effects be considered in two levels of detail. In the first step,.the effect of individual MU&P subsystem component failures on subsystem functions and subsystem interfaces was analyzed. The MU&P subsystems defined for this analysis have been described in Section 3 2. The results of the subsystem level results are described in Section 4 3 The second step of the analysis involved the integration of the subsystem failure effects to datermine system and plant level failure modes and effects.
In addition to considering failure effects resulting from component failure occurring within MU&P subsystems, the systems level analysis considered interfacing support syctems failures. The support systems, described in Section 3 3, typically interface with multiple MU&P subsystems. As such the effects of functional support systems' failures are considered at the system level.
The system and plant level effects were analyzed based on a set of eight functional failures that represent both component failures within the MU&P subsystems and interfacing support system failures. The set of functional 26
l l
l failures considered is discussed in Section 4.2.1. The system and plant level effects of each of the functional failures are described in Section 4.2.2.
System and plant level effects considered to be of potential significance to reactor colant overcooling or undercooling or degradation of safety functions have been summarized in Section 2, Summary of Results.
4.2.1 Functional Failures The systems level FMEA considered two categories of failure: functional failures originating within the MU&P system and functional failures of interfacing support systems.
The use of " functional failures" in a FMEA is not typical of the general methodology. However, in performing the analysis it was recognized the effect of many individual component failurec would produce identical system level effects, and the analysis could be made more tractible by grouping these.
Thus, the particular failure modes of sets of components were grouped into functional failure mode (e.g., any of several series valves failing closed could result in the functional failure, blocked flow). This procedure will produce acceptable results provided that any component failure mode of significance is covered by one of the functional failure modes. Furthermore, the traceability of the constituent component failures must be maintained.
The functional failures cf interfacing eupport systems were treated in a more general fashion. The functional failures were selected based on their potential direct effects on the MU&P system. Other failure modes of support systems, not effecting the MU&P system would be normally considered in FMEA's of the specific support systems, but was nct identified in this study.
4.2.1.1 Functional Failures Occurring Within the MU&P Four functional failure modes were selected for the MU&P system level analysis: Pressure Boundary Failure, Flow Blockage, Flow Increase and Loss of Chemical Addition or Purification Capability. Although several component failures would produce one of these functional failures, the system level Effects differ depending on the location of the particular failure. Thus, the l
27
4 l
four general functional failures were considered for each MU&P subsystem and, j in some cases, more than one location within a subsystem.
The development of the functional failure modes was based on the identified component failures from the detailed component level system analyses. Table 2 lists the functional failure modes and significant precipitating component failures for each subsystem. The major function failures and their precipitating compcnent failures are discussed below.
Pressure boundary failures include any release of the letdown reactor coolant froc the MU&P system. Primary attention has been given to pressure boundary failures which can occur due to system operation or misoperation. These include valve stem seal failures in high pressure portions of the system, opened and subsequently failed open relief valves, unisolated vent or drain paths, and cracks in potentially high vibration or high thermal stress areas.
Although some postulated pressure boundary failures would be unlikely as an isolated event, consideration was given to undetected mispositioned valves.
For instance, the possibility of a technician entering the containment and opening redundant drain isolation valves is very small. However, during cooler maintenance. both drain valves could be opened and the drain path isolated from the rest of the system as part of a normal maintenance procedure. If the valves were not restored to their original positions and plant operation subsequently resumed, placing the affected cooler in operation would result in significant leakage of reactor coolant.
Flow blockage functional failures involve a significant reduction or complete termination of the process flowrate. As with other functional failures, the location of the failure was found to affect the system response and, for this reason, flow blockages were considered for each subsystem.
The principal flow blockage found was spurious closure of the MU&P in-line valves. These closures could occur due to failures within the valve operator, a failed control signal (interface failure), a maintenance failure or, in some l
1 l
l 28
cases, loss of instrument air pressure (interface failure). Other flow
- blockage or loss of flow failures included plugged filters and tripped pumps.
Flow increase functional failures typically were found to result from a control valvs or its bypass valve failing open. Other failures resulting in a greater potential for increased flow, such as starting a second pump, would be
- limited in their effect by the control system.
i
! Failure of chemical addition or coolant purification capability typically was found to result from a flow blockage or the opening of a flowpath bypassing operating demineralizers or filters. These particular failure modes, however, were considered in the assessment of impact on makeup flow chemistry or purity rather than flowrate.
) 4.2.1.2 Suocort System Functional Failures The MU&P system interfaces directly with seven major support systems: two
- control instrumentation systems, three cooling water systems, the instrument air system, and the A.C. electric power distribution system. The impacts of failures of these support functions has been assessed to identify specific effects on the MU&P system and, to the extent known, the impact on other plant systems.
Although detailed FMEA's of the support systems have not been attempted as i
part of this study, the support system configurations were reviewed and some
! potential support systems failure modes identified. In general, the failure i modes which were identified were only those that specifically effected MU&P functions.
The two control instrumentation systems considered were the Engineered Safeguards Protection System (ESPS) and the Non-Nuclear Instrumentation (NNI).
The MU&P system does not require the ESPS for any of its normal operating modes. However, spurious actuation of the ESPS has a significant impact on the MU&P system and was included as a failure mode for this reason. The normal control instrumentation for the MU&P is the NNI system. Other control 29
circuits which may or may not be formally part of the NNI have been included to the extent they were known. The failure modes considered include "high" and " low" failures of each MU&P control circuit and combinations of these failures based on specific failures of the NNI power supplies.
Failures of the three major cooling water systv.as, Component Cooling (CC), Low Pressure Service Water (LPSW) and Recirculating Cooling Water (RCW) were considered based on their potential impacts on the MU&P. In general, loss of cooling water to the specific serviced MU&P component and loss of the complete cooling water system were assumed. Component isolation typically could occur due to valve closures. System failures were considered as a bounding failure.
In addition to direct MU&P impacts, cooling water failures were traced through other MU&P support systems requiring cooling water (e.g., Instrument Air).
Complete loss of instrument air to all MU&P components was the only failure mode of this support system considered. Although loss of instrument air to a specific subset of these components may be possible, insufficient information was available to specify those failure modes.
Failures of single buses supplying AC power to MU&P components were considered. In general, buses were assumed to be deenergized due to a bus fault or loss of single supply bus. Failures of multiple supplies with provisions for automatic transfer was not considered. Multiple bus failures were considered based on the possibility of a single common supply bus failure
( i. e. , if two buses could be manually transferred to a single bus, the failure mode was considered). The buces considered under AC power failures ranged from the 4160 VAC switchgear groups TC, TD and TE to the 208 VAC buses.
Failure of 120 VAC instrument buses are considered as part of instrumentation failures. MU&P components directly requiring DC power could not be found.
4.2.2 System and Plant Level Effects The functional failures describec above have been evaluated to assess their l
impact on overall MU&P system function and consequential effects on the plant.
The results of the systems level FMEA are discussed below and described in 30
Tables 3 through 10. One table for each of the following MU&P and support system functional failure types (as described in Section 4.2.1) is included:
- 1. Pressure Boundary Failures
- 2. Flow Blockages 3 Flow Increases
- 4. Loss of Chemical Addition, Coolant Purification Capability
- 5. Control Instrumentation Malfunctions
- 6. Cooling Water Failures 7 Instrument Air Failures
- 8. AC Electric Power Failures The significant failure modes and effects have been summarized in Section 2, Summary of Results.
4.2.2.1 Pressure Boundary Failures The effects and required remedial actions for each of the MU&P Pressure Boundary (P.B.) failures discussed in Section 4.2.1 are listed in Table 3 The significant effects are discussed below for the potential locations of MU&P P.B. failures. The effect of hydrogen gas release is discussed separately.
P.B. Failures in the Hiah Pressure Letdown Pinina (Letdown Subsystem)
( P.B. failures in the high pressure letdown piping, as discussed in Section 4.2.1, can result from LD cooler tube failures, unisolated vent or drain paths or valve stem seal failures. The effect of small leaks (>10 gpm) are expected to be limited to plant shutdown and repair. Larger leaks such as a tube failure or an unisolated drain path would result in decreasing RCS pressure and pressurizer, level and significant decrease in the LST level. If the RCS pressure decrease did not result in automatic initiation of the HPI mode, the operator must provide an alternate supply of borated water to the operating HPI pump prior to draining the LST to prevent pump damage. These P.B.
failures can be isolated by operator action.
31
The principal significance of these P.B. failures is considered to be the loss of reactor coolant from the RCS and simultaneously creating the potential for consequential failure of the operating HPI pump due to the single cause.
Isolatable small LOCA's have been considered to be of significance to pressurized thermal shock (PTS) sequences.
P.B. Failures in the Low Pressure Letdown or Pumo Seal Return Pinina (Letdown.
HPI Pumn and RC Pumn Seal Return Subsystems)
The principal effect of a P.B. failure in the low pressure letdown piping is the reduction of the LST level and potential for consequential failure of the operating HPI pump. As above, this condition requires that an alternate supply of borated water be supplied to the HPI pump prior to draining the LST.
In the low pressure letdown piping, however, the maximum rate of LST inventory decrease would be limited to the letdown or seal return flowrate.
Furthermore, once the leak is isolated (resulting in a probable isolation of letdown), the rate of LST inventory decrease would be limited further to the seal injection and makeup valve bypass flowrates.
P.B. Failures in the Makeuo and Seal Iniection Pioina (Makeuo and Seal Iniection Subsystems}
Potential P. B. failure locations in the high pressure makeup and seal injection piping were found to be fewer than in the letdown piping. An unisolated drain line following seal injection filter maintenance could result in: diversion of makeup and seal injection flow to the high activity waste tank; decreasing LST and possibly pressurizer levels; and possible HPI pump runout. In addition, an attempt to terminate the leak by improperly closing a low pressure drain valve (e.g., HP-375) could result in piping rupture.
A P.B. failure of this type can be isolated. However, the LST inventory will continue to be transferred to the RCS until the setpoint pressurizer level is restored. The continued LST inventory loss would require that an alternate supply of borated water be supplied to the HPI pump to prevent consequential pump failure. Until the leak is isolated, the emergency HPI function is degraded.
l 32
I Valve stem seal failures, in general, are expected to be small. This leakage will result in a very slow decrease in the LST level.
Also of potential concern is the possibility of a vibration induced piping crack in the high pressure HPI pump discharge piping. The effects of this failure would be similar to th'e unisolated drain path P.B. failure discussed above. However, depending on the locations of the crack and accessible isolation valves, one or two HPI pumps may be unavailable for emergency cervice until the crack is repaired. Additional effects of the high pressure water jet through the crack are possible but unevaluated.
Although a piping crack of this type could be induced by the normal operation of the MU&P system, the postulated failure is considered beyond the scope of
- control system failures."
Release of Hydronen Gas In addition fo the direct effects of releasing or diverting the process fluid, the hydrogen gas dissolved in the fluid can be released creating the potential l
for fires or explosions. For most of the P.B. failures discussed, including unisolated drain lines or safety valve lif ts, the process fluid and dissolved gas would be diverted to waste tanks where the released gas could be contained. Postulated piping cracks, however, release the fluid directly to the equipment rooms. Depending on the room ventilation in the areas involved, the release of hydrogen gas may represent an additional, though unevaluated, hazard.
i 4.2.2.2 Flow Blocknae Failures Table 4 lists the effects of system level flow blockage failures and possible remedial actions. The principal initiating cause of flow blockage failures identified was the closure of in-line valves in the major MU&P subsystems.
The significance of flow blockage failures varied with the potential for draining the LST or blocking the flow to the operating HPI pump.
l I 33 l
Flow blockage failures in the Makeup, Seal Injection, Seal Return and the high pressure piping in the letdown subsystem were found to have relatively minor effects. Makeup blockages result in the gradual increase in LST level and decrease in pressurizer level due to the 62 gpm letdown and seal return flowrate and 32 gpm seal injection flowrate. Blockage of seal injection, seal return or letdown in the high pressure piping results in gradual increase in pressurizer level and decrease in LST level due to the net flowrate into the RCS of 20 gpm or less. The effects of flow blockage failures in other MU&P subsystems are discussed below.
Flow Blockare in the Low Pressure Letdown Pioing (Letdown. HPI Pumo.
Subsystem)
Flow blockage failures in the low pressure letdown piping results in pressurization of the piping and diversion of the letdown flow to waste tanks through the letdown relief valve. A similar effect also occurs if the 3-way valve transfers the letdown flow to the Bleed Holdup tank.
Following these flow blockage failures, the LST level will decrease at a rate limited by the existing letdown flowrate. Manual closure of the containment isolation valves (in the high pressure letdown piping) results in throttling of the makeup flow to the RCS and limiting the rate of LST level decrease to the seal injection and makeup valve bypass flowrates.
As discussed above, the operator must remove the flow blockage or provide an alternate source of borated water to the HPI pump prior to draining the LST to prevent HPI pump failure.
Flow Blocknee in the HPI Pumn Suction Pining ( HPI Pumn Subsystem)
A flow blockage in the pump suction piping such as closure of valve HP-23 will result in immediate HPI pump cavitation. Unless the operator removes the flow blockage, trips the operating HPI pump (s) or opens a flow path from the BWST rapidly, failure of the operating pump (s) is expected to occur.
l l
i l
34
Information available to the operator to diagnose this flow blockage is limited and may be confusing. Decreasing pressurizer level, low seal injection flow alarms and an increasing LST level also would be produced by an HPI pump trip. If the operator attempted to restore flow by starting the backup HPI pump, the backup pump may fail also.
4.2.2 3 Flow Increase Failures The effects and required remedial actions of identified MU&P flow increase failures are listed in Table 5. One flow increase failure was found to have significant results. Other flow increase failures were controlled by
! automatic control instrumentation or resulted in a gradual increase in LST level.
An increase in the makeup flowrate, potentially resulting from the makeup control valve or the HPI discharge valve opening, would result in a decreasing LST level. The rate of LST level decrease could be comparable to the rates resulting from P.B. or flow blockage failures. As with other failures i
resulting in decreasing LST level, the operator must throttle makeup flow, j increase letdown flow or provide an alternate source of water to the HPI pump
! prior to draining the LST to prevent failure of the operating HPI pump.
4.2.2.4 Loss of Chemical Addition or Coolant Purification Canability The analysis of the effects of P.B. failures, flow blockages and flow increases addressed the physical transport of the process fluid through the MU&P system and the effects of flow perturbations. However, one of the major functions of the MU&P is the r'moval of impurities from the letdown coolant and modification of the fluid chemistry. Effects and required remedial actions for failures of coolant purification and chemical addition capability cre listed in Table 6 and discussed below.
The analysis of loss of chemical addition or purification capability did not identify any failures of significance which would occur in near term plant operation. The major effect of failures of this type is expected to be exceeding resctor coolant chemistry specifications. While this may result in l
35 i
a required plant shutdown, no consequential failures of safety significance could be identified even if the reactor were operated over periods of days or weeks.
Failure of boric acid addition or failure to terminate demineralized water addition are unlikely due to system redundancy. In addition, even if these failures were to occur, additional control rod insertion failures and/or improper plant cooldown would have to be postulated to result in effects of significance.
Bypassing the makeup or seal injection filters may result in increased HPI pump or RC pump seal wear - if significant quantities of particulates built up or were injected into the MU&P. However, flowpaths from potential sources of particulates which bypass the makeup filters could not be identified.
4.2.2.5 Succort Systems Failures In addition to considering the effects of MU&P system failures, the analysis considered the consequential MU&P failure modes and effects resulting from required support system failures. As discussed in Section 4.2.1, the support systems considered were the ESPS and NNI control instrumentation systems, the CC, LPSW and RCW cooling water systems, the instrument air system and the electric power distribution system.
The support systems were reviewed to identify potential failure modes which effect, specifically, MU&P functions. As such the postulated support system failure modes were considered adequate to address consequential MU&P failure modes. However, detailed specification of support system f ailure modes or their plant level effects would require detailed FMEA's of the specific support systems which was not attempted in this study.
The MU&P and selected plant level effects of support system interface failure are discussed below.
l l
36
l Control Instrumantation Malfunctions The effects and required remedial actions of automatic control instrumentation malfunctions are listed in Table 7 The failure modes considered include spurious one or two channel ESPS actuation, failure of each NNI control circuit affecting the MU&P and combinations of control circuit failures resulting from specified NNI instrument power supply failures. Failures of nanual control circuits of individual MU&P isolation valves have not been l listed separately in Table 7 Typically, failures of these circuits can result in the opening of normally closed valves or closing of normally open valves. These failure modes have been considered under flow blockage and flow increase failures listed in Tables 4 and 5 No effects of significance affecting the MU&P were identified beyond those previously discussed in Tables 4 and 5 Cooline Water Failures Three cooling water systems provide cooling water to MU&P components. The CC system provides cooling water to the LD coolers, the LPSW system provides cooling water to the HPI pumps' motor bearing coolers and the RCW provides cooling water to the seal return coolers.
The effects and required remedial actions for cooling water systems failures are listed in Table 8. Two failure modes were postulated for each cooling water system: loss of cooling water to the cerviced MU&P component and complete cooling water system failure.
The MU&P response to loss of CC to the operating LD cooler would be automatic closure of the containment isolation valve on high letdown temperature. As previously discussed, this results in throttled makeup flow and a slow decrease in the LST level. The operator would be required to provide an alternate source of borated water for the HPI pumps prior to draining the LST to prevent pump damage. . Complete failure of the CC system would result in loss of cooling to the RC labyrinth seals in addition to the LD cooler. If an alternate supply of cooling wrter was not provided to the operating HPI pump 37
and pump failure occurred, the RC pump seals could be damaged due to the concurrent failure of seal injection and cooling water. Although this !
sequence is improbable, RC pump seal failures could occur with a degraded HPI capability.
The effect of loss of LPSW to the operating HPI pump motor bearings would result in bearing overheating and eventual damage. Although the details of j the cooling water distribution piping to the HPI pumps were not available, it was assumed that cooling water to an individual pump could be isolated following HPI pump motor maintenance and improperly remain in an isolated state. Indication of cooling water isolation is unknown.
j Complete failure of the LPSW is considered to be an extremely unlikely event.
However, if the LPSW system failed (due to common mode plugging of the LPSW ,
l 4
pumps' suction strainers, for instance), cooling water would be lost to several operating and standby systems including the HPI pump motors and the CC systems of Oconee Units 1 and 2. The overall effects of this event have not been evaluated in detail.
The loss of RCW to the operating seal return cooler would result in the gradual increase in the LST fluid temperature. Whether this temperature could rise to the point where the HPI pump !PCH became inadequats has not been evaluated. The rate of increase in temperature is expected to be slow.
As with the LPSW system, complete failure of the RCW is expected to be extremely unlikely. If this event occurred, however, loss of cooling water to the instrument air system and main feedwater and steam system components would occur. Loss of instrument air, causing closure of the letdown, makeup and seal return isolation valves would result in a more rapid rise in the j temperature of the water pumped through the HPI pump recirculation path.
Other plant level effects include loss of main feedwater.
, 38
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Tnstrumant Air Failure i The effect of a loss of instrument air and required remedial actions are listed in Table 9 As described above, loss of instrument air would result in closure of the letdown and seal return isolation valves and the makeup control valve and the seal injection control valve will open. The seal injection flowrate is not expected to increase significantly. Assuming the total seal injection flowrate doubles, the net injection rate would be approximately 40 gpm. The LST level would be decreasing gradually governed by this rate.
Although the operator must monitor the LST level, and restore letdown or provide an alternate source of borated water to the LST, this effect is not considered to be of major significance. Other plant level effects include probable reactor trip resulting initially in high SG levels and subsequently trip of the main feedwater pumps.
AC Electric Power Failures Table 10 lists the effects and required remedial actions for AC electric power failures. As discussed in Section 4.2.1, failure of each bus supplying MU&P components was assumed resulting in the components and other buses supplied from the failed bus being deenergized. Automatic transfer devices were assumed to operate properly thus limitir4 the number of deenergized buses to those which are ascumed failed, supplied from a single deenergized bus with or uithout the possibility of manual transfer. In cases where a bus could be supplied from either of two buses with manual transfer capability, the bus was assumed potentially deenergized if either of the supply buses was assumed failed.
I Most effects of bus failures were not considered significant. The effects on the MU&P system fell into two basic categories: operating pumps, including the operating HPI pump, stopping and electric motor cperated valves deenergized and incapable of changing position on demand. Deenergizing the operating HPI pump or other pump motors was not found to be significant due to the availability of energized backup pumps and lack of consequential pump damage.
i I
39
i
, Since motor operated valves do not change position following electric power j failure, there were no imuediate effects following assumed bus failures.
However, a possible configuration was identified with significant possible i effects. Although beyond the scope of control system failures, this failure mode is identified for completeness.
1 The BWST isolation valve HP-24 and HPI discharge valve HP-26 are powered from
- 208 VAC Bus XS1; 208 VAC Bus IS2 powers the corresponding valves in the other train, HP-25 and HP-27 It was found that 208 VAC buses XS1 and XS2 can be j manually transferred to the same 600 VAC supply bus, i
In this configuration, a single failure of 4160 VAC buses TC or TD or 600 VAC buses IS1, IS2, X8 or 19 could prevent the four identified HPI valves from moving to their emergency positions on demand. Since the HPI function is l defeated, this configuration may be a violation of the single failure i criterion. 1 In addition, should an ES signal occur (for any reason), HPI pump C would fail
]
j due to the blocked suction path and the LST level would be decreasirs due to continued RC pump seal injection and makeup coni.rol valve bypass flow. The l operator must provide an alternate supply of borated water to the HPI pumps 1
i prior to draining the LST (or trip the pumps) to prevent failing the remaining 4
two HPI pumps.
f
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j 43 SUBSYSTEM LEVEL RESULTS
! Detailed FMEAs of the subsystems described in Section 3 2 were completed and are presented in Appendices A-F. The results of these analyses are summarized q in this section. Included are tables for each subsystem which provide a list of the failure effects at the subsystem boundaries along with the failures e
{ which can lead to those effects.
1
. Brief discussions of the major effects for each subsystem also are included in this section. Effects such as incorrect process signals and P.B. failures 3 have been discussed previously in Section 4.2. Even though process signals i
l 1
40
that do not directly control could still potentially induce operator response leading to additional effects, given an incorrect signal, such responses were considered secondary and were generally not discussed further. Effects on isolation capability were also not discussed further since isolation was not considered normal operation and could generally be effected with available backup when required. Reactor coolant leaks are discussed with system level results and are likewise not discussed further here.
4.3 1 Letdown Subsystem The major effects at the subsystem interface resulting from the various subsystem failures include: reduced, increased, and terminated letdown flow to three-way valve HP-14; reactor coolant leaks; bypassing of letdown flow around the purification demineralizers; and failure to reduce the temperature of letdown flow from the subsystem. These effects can be precipitated by such failures as internal component failures, spurious control signals, or a loss of cooling water to the operating cooler. The detailed Letdown system FMEA ,
results are presented in Appendix A.
Reduced letdown flow can result from valves developing stem seal leaks.
Reduction in letdown flow can also result from the spurious opening of relief valves downstream of the block orifice. A radiation monitor loop and a boron geter loop bypass the block orifice. If a drain valve in either loop is left t
l open af ter maintenance, a significant leak could occur whec the use of the loops is initiated. A leak in one of these loops wouLd reduce the letdown flow from the subsystem. Another possible failure is the opening of the normally closed control valve HP-9 due to operator error or a spurious control signal which would result in letdown ficw diverted to the Unit 2 LST.
Increased letdown flow can result from normally closed manual or control valves such as HP-42 or HP-7 being opened or failing open. Increased letdown flow can also occur if a spurious control signal opens HP-7, HP-9, or HP-11.
If such a signal is received by HP-9 or HP-11, the increased letdown flow may result from the addition of Unit 2 letdown flow.
41
Termination of letdown flow can result from internal component failures and spurious control signals. Normally open manual or control valves can fail closed obstructing letdown flow, resin beads in purification demineralizer HP-X1 can agglomerate and plug resulting in flow blockage, or a main pipe or orifice can plug obstructing flow. Spurious control signal ordering closure to HP-1, HP-3, HP-5, HP-6, or HP-8, can also terminate letdown flow.
Reactor coolant leaks can occur due to pipe cracks, a tube rupture in letdown cooler HP-C1 A or HP-C1B or an unisolated vent or drain path.
Subsystem failures resulting in bypassing of the purification demineralizers may result in failure to remove RC impurities. If the normally closed valve !
HP-13 is opened due to operator error or spurious control signal, the letdown l flow would bypass the purification demineralizer.
A loss of cooling water to the operating cooler would result in an increase in temperature of the letdown flow out of the subsystem. High cooler discharge temperature initiates isolation of the letdown flow upstream of the deminera-lizer. If the temperature interlock failed to close the letdown isolation valve HP-5 upon loss of cooling water to the operating cooler, the purifi-cation demineralizer HP-X1 could experience excessive heating causing resin beads to decompose or melt and subsequently block letdown flow.
432 RCP Seal Return Subavstem Single failures within the seal return subsystem can result in the following effects at the subsystem interfaces: blockage of flow from the RC pump seals; loss of, or reduced flow to the letdown storage tank (LST); and, temperature effects on discharge flow to the LST (high and low). Other effects of sub-system failures include reactor coolant leaks to the RCW or the auxiliary building; incorrect process indicators (flow, pressure, temperature signals);
and, lack of system isolation when demanded. The results of the RCP Seal Return Subsystem FMEA are presented in Appendix B..
l 42
I l Different degrees of flow blockage from the RC pump seals can result from subsystem failures. Blockage from a single pump can result from valve failures or blockages on one of the return lines from the individual pumps.
Seal blockage from all four RC pump can result from any blockage in the common seal return header upstream of the LST. Potential failures in this category include: filter plugging; cooler tube blockage; and failed closed reactor building (RB) isolation valves and inline valves such as filter isolation valves, cooler isolation valves, and check valves. In addition to internal faults or inadvertent closure of a valve, loss of instrument air can result in the closure of the pneumatic RB isolation valve; a spurious signal from the I&C system can close the other RB isolation valve; and a spurious ES signal can close them both. If detected, blockages associated with the filter or coolers can be bypassed with local action.
Failures which result in reduced flow to the LST include loss of HPI pump l recirculation flow (input from the HPI Pump subsystem); and component faults j-l within the subsystem, such as cooler tube rupture, leaks, or the inline flow 1 blockages. Failures which result in complete loss of seal return and HPI pump recirculation flow to the LST are limited to closure failures (blockages, inadvertent closure, etc.) of inline isolation and checir valves downstream of ,.
- the HPI pump recirculation line inlet (just upstream of the seal return coolers).
Temperature variations in the seal return flow to the Lir can result from faults internal and external to the setsystem. High discharge temperature can l result from internal cooler damage, vapor lock in the cooler, or loss of RCW.
Loss of flow from the hPI pump recirculation lino (Subsystem 3 0) to the system and through the cooler retults in reduced flow and somewhat lower seal
! return discharge temperature to the LST.
l 4.3 3 HPI Pumns Subsystem Failures in this subsystem primarily affect output flow to RC makeup system i and RC pump seal injection. Inlet flow can also be blocked from the seal return subsystem if the check valve to the LST plugs or fails closed.
43
Component faults within the subsystem can also result in reduced H2 concen-tration in the reactor coolant makeup. The results of the HPI Pump Subsystem FHEA are presented in Appendix C.
Effects on discharge flow from the subsystem to RC makeup and seal injection include immediate loss of flow, reduced flow, and eventual loss of available makeup. Failures that result in loss of available makeup in the LST can lead to cavitation of the HPI pumps (if the LST empties while feeding the HPI pumps) and consequential pump damage or failure. These failures include blockages upstream of the LST (inline valves failed or inadvertently closed, makeup filter plugged as well as loss of instrument air or a spurious I&C signal closing the makeup filter inlet valve), and loss of inlet flow to the subsystem from letdown, seal return, or RC Bleed. If detected, most of the blockages can be bypassed from the control room. However, many blockages that restrict flow into the LST cannot be bypassed during steady state operation. ,
j l
Failures which result in immediate loss of RC makeup and seal injection include: valve failures on the suction or discharge of the operating HPI pump; and pump failures (both due to internal damage, loss of low pressure service water, and loss of power supply). The precipitating valve failures can occur due to internal faults or due to a spurious I&C signal to certain cotcr-operated valves on the pump manifold. Flow can be lost to only the RC makeup header or only to seal injection as a result of similar valve failures on the HPI pump discharge manifold (internal faults, inadvertent closure, spuricus I&C signals). In most cases the system can be realigned with alter-nate valving and/or an alternate HPI pump to restore flow. However, there is potential for loss of NPSH and damage in bringing the alternace pump onstream '
if sequencing and alignment are not correct.
Some reduction in subsystem discharge flow can result from a failed check valve (loss of backflow prevention) on the discharge of a nonoperating HPI pump. This failure mode would allow recirculation back through the non-operating pump and the operating pump suction, resulting in reduction of actual discharge flow. ,
1 44 l
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Deviations in RCS chemistry quality can occur as a result of two internal subsystem faults as well as loss of inlet flows from the Chemical Addition System. Internally the H2 supply valve to the LST tank can fail closed, cutting off the H2 supply; and the vent valve on the LST can fail closed, allowing potential accumulation of non-H2 noncondensible gases in the LST and reduction of H2 mass transfer to the reactor coolant.
Incorrect level indication in the LST due to transmitter failure, connection leaks, or loss of power to the transmitter, could lead an operctor to take faulty remedial action. This could result in overfilling the LST, which could reduce or stop H2 addition, or allowing the LST level to drop, which could result in loss of NPSH to the HPI pumps and ultimate loss of subsystem dis-charge flow to makeup and seal injection as discussed above.
4.3.4 RC Pumn Seal Iniection The major effect of single failures within the seal injection subsystem is loss of or reduced seal flow to the RC pumps. Other effects include increased seal injection flow to a single pump and incorrect process signals (pressure and flow) transmitted to the I&C system and the control room. The results of the RC Pump Seal Injection Subsystem FMEA are presented in Appendix D.
Subsystem failures can result in loss of seal injection flow to all four RC pumps, loss of flow to only a single pump, increased flow to a single pump, and reduced flow to all four pumps. Loss of seal flow to all four pumps can result from blockages in the inlet header (inline valves failed or inadver- ,
tantly closed, filters plugged, or orifice plugged) or loss of inlet flow to the system from the HPI pumps. Inline blockage from failure of the header flow control valve failing closed can result from an I&C signal failure, in addition to an internal fault. If detected, blockages associated with the filter path or the control valve can be bypassed, but no bypass exists in the cvent of failure of the inlet block valve. Reduced flow to all four pumps can result from partial failures of inline components, system leaks, and I&C-fault-induced failures of the header flow control valve.
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45
Component faults in one of the four individual injection lines can result in loss of seal injection to a single RC pump. Each line has a throttle valve, and a flow measuring nozzle, and check valves that could potentially fail closed or plug. If one of the throttle valves fails open, increased flow to a single RC pump can result.
435 Reactor Coolant Makeun Subsystem
- Single failures in the RC makeup subsystem can impact normal makeup flow to the cold legs, cooling flow to the cold leg inlet nozzles and pressurizer spray lines, and inlet flow rate from the letdown storage tank in Subsystem 3 0. The results of the RC Makeup Subsystem FMEA are presented in Appendix E.
2 .
Failure effects on the normal makeup 1. w to the cold leg include: loss of flow, reduction in flow, increased flow, and flow imbalance between the two cold leg inlets. Loss of input flow from the HPI pumps (Subsystem 3 0) and
- failure of the block valve on the inlet header (plugging, damage, inadvertant closure, etc.) will result in total loss of makeup flow. In addition, single downstream blockages in the main flow path can stop normal makeup flow, but i some flow will continue to the RCS via the minimum flow bypass loop to the cold leg inlet nozzles and the pressurizer spray line. These blockages could potentially result from failures associated with the flow control valve, block valves, and inline check valve. Failures in the instrument air system or I&C system, in addition to internal damage, could fault the flow control valve.
4 However, both a remote operated and local bypass around the flow control valve ,
are available to resume flow.
4 Increazad flow thraugh the normal makeup path can result from either the flow control valve or the normally closed motor operated ES valve failing open. In
', addition to internal faults, the control valve can fail open due to an instru-ment air system fault and a control signal fault, and the ES valve can open on a spurious ES or I&C signal.
46 l
Failures which result in flow imbalance between the two reactor cold legs are limited to component faults within the subsystem. These include blockages associated with the check valve or flow orifice on one of the cold leg inlets.
Failure effects on the bypass flow paths to the cold leg inlet nozzles and the pressurizer spray line include loss of flow and excess flow to one of the inlet nozzles. Loss of flow to both nozzles and the spray line can result from failure of the inlet block valve to the minimum flow bypass loop and the inlet block valve to the subsystem. Loss of flow to one nozzle can result from failure of either the throttle valve or the block valve on either cooling flow line. Loss of flow to the pressurizer spray line which branches off one of the cooling flow lines can likewise result from line blockages upstream of the spray line inlet. Excess flow to one nozzle and possibly the spray line can result from the throttle valve on one of the lines failing open. Like-wise, a temporary reduction in flow in these lines can result from open-valve-failures in the normal makeup flow path, diverting flow away from the minimum flow bypass loop. Instrument air system and I&C system faults, in addition to internal faults, could produce this eff ect through inadvertant opening of the flow control valve or the ES valve.
Excess flow rate through the subsystem via failed open valves could also potentially result in drep in the letdown storage tank level and possible les; of NP3H to the HPI pumps (Subsystem 3 0) and increased level in the pressurizer.
i 4.3.6 Chgaical PIER
- Eing Subsystem l
l The major effects of failurcs in this subsystem is loss of demineralized watcr return to the LST, loss of RC bleed holdup and transfer capability, loss of chemical addition capabilities including boric acid addition, loss of boron recovery capability, and loss of deboration capability. These effects are summarized in Table 11 and discussed below. The results of the Chemical Processing Subsystem FMEA are presented in Appendix F.
l 47
Failures which result in loss of domineralized water return to the reactor coolant system include electric power supply failure to the transfer pump, transfer pump failure, and failures in any one of several manual isolation or control valves. Failures in control valves HP-15 and HP-16, either from control signal failures or internal valve failures, can also result in loss of return flow. Since this system is operated on demand only, failure to supply the holdup tank with demineralized water or allowing the tank to remain empty can result in no demineralized water available when required. However, the valve configuration would allow makeup from the bleed holdup tank (although it would not have been through the boron recovery cycle) or makeup from the Unit 2 demineralized water or bleed holdup tanks.
Loss of bleed holdup and transfer capability can result from valve failures, plugs in lines due to loss of trace heating, and unavailability of the holdup tank. However, valve configuration would allow bleed flow to ths demineral-ized water holdup tank or the Unit 2 bleed or demineralized water holdup tanks. Electric power supply failure or transfer pump failure can result in loss of flow to boron recovery which also leads unavailability of the holdup tank for subsequent bleed and makeup cycles.
Addition of hydrazine and lithium hydroxide to the reactor coolant is also a per-demand-operation. Failure to supply either chemical can result from i manual isolation, control, or check valve failures; or allowing either tank to remain empty. Valve configuration would allow pumping either chemical to its destination through the other chemical pump; however, if both chemicals are required simultaneously, failure of either pump results in unavailability of that chemical.
Failure to provide caustic to the LPI pumps, RC bleed evaporator, and deborating domineralizers can result from isolation valve failures, electric power supply and pump failures, or allowing the mix tank to remain empty. No remedial action within the subsystem is available to compensate for loss of caustic either within the subsystem or at the interfaces.
48
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1 j t I
2 Loss of concentrated bcric acid to the makeup filters and the BWST can result
- from allowing the concentrated boric acid storage tank to empty, various i canual isolation or control valve failures, electric power supply or transfer
! pump failures', or plugs in lines due to trace heating failures. Two sources
! cf concentrated boric acid are available: a boric acid mix tank and the concentrate from boron recovery. In the event of failure of one source, the
! other would be available to supply boric acid requirements. The valve configuration would also allow boric acid addition from the Unit 2 concen-l l trated boric acid storage tank.
I
't l Failures in the boron recovery operation result in no concentrate flow to the 4 .
j concentrated boric acid storage tank. Component failures include various i pumps and annual valves, either of two control valves, the evaporator, feed storage tank, and trace heating. Support system failures such as steam supply l
cnd electric power can also result in boron recovery failure. Recirculation j paths can be established so that concentrated boric acid is returned either to l the evaporator' or the evaporator feed tank rather than the storage tank.
i 1
i Failure of the deboration capability in the on-line deborating desineralizer l results from various manual isolation and control valve failures, failure of caustic filw for regenerating the resin, and plugs in lines due to trace heating f ailures. These failures result in the requirement that a second j domineralizer is available. F1cw can also be diverted to the bleed holdup tank with makeup'piovided from the domineralized water holdup tank.
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TABLE 2. FUNCTIONAL FAILURES AND POTENTIAL PRECIPITATING COMPONENT FAILURES Precipitating Functional Failure Component Failure Comments
-1. Pressure Boundary Failures 1.1 Letdown Subsystem 1.1.1 In Containment Through wall piping crack, Through wall piping cracks are Pressure valve stem seal failure, included for completeness but Boundary unisolated vent or drain are not considered a " control (P.B.) path, LD cooler tube system failure." Valve stem Failure failure, seal failures and unisolated vent or drain path are possible though unlikely.
M 1.1.2 Out-of- Through wall piping crack, Through wall piping cracks are Containment valve stem seal failure, included for completeness but High Pressure unisolated vent or drain are not considered a " control P.B. Failure path, system failure." Valve stem Upstream of seal failures and unisolated Block Orifice vent or drain path are possible though unlikely.
1.1.3 Out-of- Opened and/or failed open Relief valves will open Containment relief valve, unisolated following a letdown flow Low Pressure vent or drain path, blockage. Diversion of Unit 1 P.B. Failure diversion of Unit 1 flow to Unit 2 possible due to Upstream of letdown to Unit 2. a mispositioned demineralizer 3-Way Valve isolation valve. Valve stem seal leakage and cracks in low pressure piping not considered.
TABLE 2. FUNCTIONAL FAILURES AND POTENTIAL PRECIPITATING COMPONENT FAILURES (Continued) 1 Precipitating Functional Failure Component Failure Comments 1.2 P.B. Failure in the Opened and/or failed open Relief valves will open HPI Pump Subsystem relief valve, unisolated following a letdown flow vent or drain path, blockage. Vibration induced vibration induced piping piping cracks included since cracks. they could result from normal operation. In the pump suction piping such cracks are not expected to result in significant leakage.
1.3 P.B. Failure in the Opened and/or failed open Relief valves may or may not u Seal Return. Subsystem relief valve, Seal Return open following a seal return Cooler tube failure, flow blockage. In addition, unisolated vent or drain reactor coolant expected to be path, diverted to containment through R.C. pumps' vapor vents.
1.4 P.B. Failure in the vibration induced piping Significant through-wall piping Makeup Subsystem cracks, unisolated vent cracks are unlikely but are or drain path, valve stem included due to expected pump seal failure. induced vibration.
l 1.5 P.B. Failure in the Vibration induced piping Significant through-wall piping i
Seal Injection cracks, unisolated vent cracks are unlikely but are Subsystem or drain path, valve stem included due to expected' pump seal failure. induced vibration.
l 1.6 P.B. Failure in the Unisolated vent or drain Chemical Processing paths.
Subsystem l
(
l l
TABLE 2. FUNCTIONAL FAILURES AND POTENTIAL PRECIPITATING COMPONENT FAILURES (Continued)
Precipitating Functional Failure Component Failure Comments
- 2. Flov Blockages 2.1 Letdown Subsystem Spurious isolation valve Plugged demineralizer Blockage closure due to valve considered unlikely unless operator, signal or condition existed prior to maintenance failure, loss placing the demineralizer in of instrument air, plugged use.
purification demineralizer.
2.2 HPI Pump Subsystem Spurious isolation valve HPI pump trip not formally a
, Blockage closure due to valve " blockage" but does result in u operator, signal or loss of flow.
maintenance failure, plugged makeup filter (s),
spurious operation of 3-way valve, HPI pump trip.
2.3 Seal Return Spurious isolation valve Filter plugging would be Subsystem Blockage closure due to valve gradual and not expected to operator, signal or significantly reduce flowrate.
maintenance failure, plugged seal return filter.
2.4 Makeup Subsystem Spurious control valve Blockage closure due to valve operator signal or instrument air failure, spurious closure of manual isolation valve due to maintenance failure.
t
TABLE 2. FUNCTIONAL FAILURES AND POTENTIAL PRECIPITATING COMPONENT FAILURES (Continued)
Precipitating Functional Failure Component Failure Comments 2.5 Seal Injection Spurious control valve Subsystem Blockage closure due to valve operator or signal failure, spurious closure of manual isolation valve due to maintenance failure.
2.6 Chemical Processing Spurious isolation valve Transfer pump trip not formally Subsystem Blockage closure due to operator, a blockage but does result in signal or maintenance loss of flow, g failure, transfer pump trip.
- 3. Flow Increases 3.1 Letdown Subsystem Spurious opening of LD Flow Increases control valve due to valve operator or signal failure.
3.2 HPI Pump Subsystem Spurious transfer of 3-way Start of second HPI pump also Flow Increases valve, spurious opening of will result in an increase in BWST isolation valve (s) , pump recirculation flowrate.
spurious addition from I chemical processing subsystem.
3.3 Seal Return Subsystem RC pump seal failure, RC pump failure not formally Flow Increases opening seal bypass within MU&P system.
flowpath.
TABLO 2. FUNCTIONAL FAILURES AND POTENTIAL PRECIPITATING COMPONENT FAILURES (Continued)
Precipitating Functional Failure Component Failure Comrents 3.4 Makeup Subsystem Spurious opening of MU Flow Increases control valve or HPI injection valves due to valve operator or signal failure.
3.5 Seal Injection Spurious opening of seal Subsystem Flow injection control valve Increases due to valve operator or signal failure, loss of instrument air.
U 3.6 Chemical Processing Subsystem Flow Increases 3.6.1 Plow to Spurious transfer of 3-way Internal Chemical Processing Subsystem valve, increased letdown Subsystem flow increases not Increases flowrate during bleed listed in Table 2.
operations.
3.6.2 Flow to HPI Spurious opening of control Pump Subsystem valve due to valve operator Increases or signal failure or spurious start of transfer pump during feed and bleed operations.
TABLE 2. FUNCTIONAL FAILURES AND POTENTIAL PRECIPITATING COMPONENT FAILURES (Continued)
Precipitating Functional Failure Component Failure Comments
- 4. Loss of Chemical Addition, Coolant Purification Capability 4.1 Failure of Chemical Spurious closure of control Addition from Chemical or isolation valve, failure Processing Subsystem of transf er pump (s) ,
depletion of inventory.
4.2 Failure of Hydrogen Spurious closure of Supply pressure regulator, 8: inventory depletion.
4.3 Bypass of Filters Spurious opening of bypass or Demineralizers valve due to valve operator, signal or maintenance failure.
TABLE 3. PRESSURE BOUNDARY FAILURES IN THE MAKEUP AND PURIPICATION SYSTEM Failure / Location Effect Remedial Actions
- 1. Letdown Subsystem 1.1 In-Containment RCS leak or small LOCA - Emergency procedures for RCS Pressure Boundary decreasing LST and leaks or small LOCA's must be (P.B.) Failure pressurizer levels, followed depending on wnether decreasing RCS pressure, the leak rate exceeds the and high contaminent capacity of the MU&P system.
radiation alarms alert The operator must initiate an the situation. If the LST alternate supply of borated is drained prior to ES, water to the LST or directly actuation of the HPI mode, to the HPI pumps. Letdown the operating HPI pump (s) flowpath may be isolated and w may fail. the isolated and the HPI mode of operation may be initiated automatically if the RCS pressure decreases to 1500 psi.
T l
TABLE 3. PRESSURE BOUNDARY FAILURES IN THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure / Location Effect Remedial Actions 1.2 LD Cooler Tube RCS leak or small LOCA - Emergency procedures for RCS Failure decreasing LST and leaks or small LOCA's must be pressurizer levels and high followed depending on whether CC surge tank and radiation the leak rate exceeds the alarms alert operator to capacity of the MU&P System.
the situation. Until iso- Automatic isolation of the LD lated, reactor coolant coolers from the RCS will not will pressurize the CC not occur. The operator must system resulting in the isolate the LD cooler (s) from in-containment CC relief the RCS based on high CC surge valves opening and dis- tank level and pressure. The charging to the containment situation may be confused by E sump. If the LST is drained high containment sump levels prior to ES actuation of and possible radiation alarms the HPI mode, the resulting from the CC relief operating HPI pump (s) may valve discharge. The operator fail, must initiate an alternate supply of borated water to the LST or directly to the HPI 1 pumps.
TABLE 3. PRESSURE BOUNDARY FAILURES IN THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure / Location Effect Remedial Actions 1.3 Out-of-Containment RC leak or small LOCA Leak path must be isolated by High Pressure P.B. outside containment. closing containment isolation Failure Upstream Decreasing LST and possibly valves. Procedures for a of Block Orifice pressurizer level.s, possibly letdown line failure or leakage decreasing RCS pressure, outside containment must be high level radiation alarms followed (if they exist).
and high auxiliary building Procedures covering subsequent sump levels alert operator shutdown of the plant without to the situation. Leakage letdown must be followed, will continue until the unless the leak path can be letdown flow path is isolated from the letdown path, isolated by the operator The operator must initiate an 8 or automatically isolated Liternate supply of borated by the ESPS if RC pressure water to the LST or directly to decreases to 1500 psi. the HPI pumps.
Effect of significant reactor coolant discharge unknown (see High Energy Line Break Analysis). If the LST is drained prior to ES actuation of the HPI mode, the operating HPI pump (s) may fail.
TABLE 3. PRESSURE BOUNDARY FAILURES IN THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure / Location Effect Remedial Actions
- 1.4 Out-of-Containment RC leak outside contain- Procedures for a letdown line Low Pressure P.B. ment. Leak flowrate will failure or leakage outside Failure Downstream be limited to a small containment must be followed of Block Orifice increase above existing (if they exist). Operator must
- and Upstream of flowrate. Local radiation isolate the leak and open an 3-Way Valve alarms, high sump or waste alternate flowpath from the
' holdup tank levels and BWST or bleed holdup / boric acid decreasing LST level alert tanks to the HPI pumps. Proce-operator to the situation. dures covering subsequent Manual isolation of letdown shutdown of the plant without is required. If the LST letdown must be followed.
is allowed to be drained, o the operating HPI pump (s) may fail.
i 1
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TABLE 3. PRESSU3E BOUNDARY FAILURES IN THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure / Location Effect Remedial Actions
- 2. HPI Pump Subsystem 2.1 P.B. Failure Between RC leak outside contain- Procedures for a letdown line 3-Way Valve and LST ment. Leak flowrate will failure or leakage outside be limited to a small containment must be followed increase above existing (if they exist) . Operator must flowrate. Local radiation isolate the break and open an alarms, high sump or waste alternate flowpath from the holdup tank levels and BWST to the HPI pumps if makeup decreasing LST level alert to the LST is terminated.
operator to the situation. Procedures covering subsequent Manual isolation of letdown shutdown of the plant without
$ may be required. If the letdown must be followed.
LST is allowed to be drained, the operating HPI pump (s) may fail. In addition, failures in locations downstream of check valve HP-7 could result in the release of H 2 which create the potential for fires or explosions.
TABLE 3. PRESSURE BOUNDARY FAILURES IN THE NAKEUP AND PURIFICATION SYSTEM (Continued)
Failure / Location Effect Remedial Actions 2.2 P.B. Failure Between RC leak outside contain- Operator should trip the the LST and HPI Pumps ment. Local radiation operating HPI pump if low or alarms, high sump, waste erratic flow persists, isolate i holdup and/or bleed holdup the leak and provide an l tank levels, decreasing operable path for boric acid seal injection and makeup addition and RC pump seal flowrates and possibly injection. The letdown path decreasing LST level to the Bleed Holdup tanks then alert operator to the must be initiated to control situation. Larger leak pressurizer level.
W rates may result in HPI pump cavitation and
$ reduction in pump flowrate.
This will result in the !
makeup control valve, HP-12, and seal injection control valve HP-31, opening to compensate, exacer-bating the cavitation. This condition could lead to HPI pump damage unless the pump is manually tripped. If the HPI pump is tripped, RC pumps can continue to operate with CC water. In addition, leak paths in these locations may result in the release of H2 which create the potential for fires or explosions.
i
TABLE 3. PRESSURE BOUNDARY FAILURES IN THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure / Location Effect Remedial Actions
- 3. RC Pump Seal Return Subsystem 3.1 P.B. Failure Between Small RC leak outside or Isolate and repair the leak.
RC Pumps and HPI inside containment. Local If the leak must be isolated, Pump Subsystem radiation alarms, high sump, the flow past RC pumps' seals waste tank or quench tank will be diverted to tha level and a decreasing LST containment sump or quench level cierts operator to tank.
the situation.
3.2 Seal Return Cooler Small leak to RCW System. Isolate the affected cooler
$ Tube Failure Increasing RCW surge tank and divert seal return flow level, high RCW radiation through spare cooler.
alarms and decreasing LST tank level alert the operator to the situation.
', TABLE 3. PRESSURE BOUIERRY FAILURES IN THE MAEBUP AND PURIFICATION SYSTEM (Continued) l Failure / Location Effect Remedial Actions
- 4. Makeup Subsystem - RC leak or high energy Procedures for an RC leak or a P.B. Failure Between line failure outside or high energy line break must be HPI Pumps and RCS 'inside containment. Local followed. Operator should trip Pressure Boundry Chech radiation alarms, high sump the operating HPI pump, if Valves levels, possible low seal required, isolate the break and injection flowrate alarms provide an operable path for j and decreasing LST and boric acid addition and RC pump Pressurizer levels alert seal injection. Depending on operator to situation. the failure location, RC Pump 4 Significant P.B. failures seal injection may or may not will result in opening the be possible.
makeup control valve and ,
E increacing the rate of ,
t decrease of the LST level, t If the LST is allowed to be drained, failure of the operating HPI pump (s) may occur. Unless tripped i automatically by motor protection devices (if they 1 I
l exist) or by the operator, pump damage could occur.
l Effect of makeup fluid dis-I charge unknown (see High Energy Line Break Analysis) .
In addition, breaks in these I locations may result in the !
- release of H2 creating the potential for fires or explosions.
t
TABLE 3. PRESSURE BOUNDARY FAILURES IN THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure / Location Effect Remedial Actions
- 5. Seal Injection RC leak or high energy Emergency procedures for a high Subsystem - P.B. Failure line failure outside or energy line break must be Between Makeup Subsystem inside containment. Low followed. Operator should trip and RC Pumps seal injection flowrate the operating HPI pump, if alarms, local radiation required, isolate the break and alarms, high sump or waste provide an operable path for tank levels, and decreasing boric acid addition and RC pump LST level alert operator to seal injection. Depending on situation. Significant the failure location, RC Pump piping failures will result seal injection may or may not in opening the makeup be possible.
control valve and
& increasing the rate of decrease of the LST level.
If the LST is allowed to be drained, failure of the operating HPI pump (s) may occur. Unless tripped automatically by motor protection devices (if they exist) er by the operator, pump danage could occur.
Effect of makeup fluid discharge unknown (see High Energy Line Break Analysis).
In addition, breaks in these locations may result in the release of H2 creating the potentiat for fires or explosions.
TABLE 3. PRESSURE BOUNDARY FAILURES IN THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure / Location Effect Remedial Actions
- 6. Coolant Processing and Radiaticn alarms and high Operators must isolate the Storage Subsystem - P.B. sump level alert the failure and take appropriate Failure in the Coolant operator to the situation. measures to control flooding.
Processing and Storage Flooding may be a problem The BWST can supply RCS boric subsystem due to size of Bleed Holdup acid requirements if required.
Tanks (~100,000 gal.).
Normal letdown / makeup will be automatically initiated if a low LD Tank level results.
l l
l l
i l
TABLE 4. FLOW BLOCKAGES ID THE MAKEUP AND PURIFICATION SYSTEM Pallure/ Location Effect Remedial Actions
! 1. Letdown Subsystem 1
l.1 Flow Blockage in Reduced letdown from RCS Operator can establish an 1 High Pressure Letdown results in makeup flow alternate letdown flowpath Path to Isolation throttled due to increasing or clear the flow blockage.
Valve Downstream of pressurizer level. Seal Minimum HPI pump flow recir-i Block Orifice - injection results in a culation must be maintained. ;
Letdown-Makeup continued net injection of Continued operation may Operation or 20 gpm and gradually require makeup to LST Operatior With decreasing LST level. or throttling seal injection Deborating flow.
Demineralizers
!O 1.2 Flow Blockage in Increased line pressure Provide an alternate source of Low Pressure Letdown lifts letdown line relief makeup water to the LST or Path to Connection valve. Leak rate less HPI pumps. Close the letdown q
With 3-Way Valve - than preexisting letdown containment isolation valve (s) i Letdown-Makeup flowrate. Decreasing LST to isolate the relief valve and Operation or level and increasing remove the flow blockage.
4 Operation With waste holdup tank level I Deborating alert operator to the Demineralizers situation. Unless a source of water is provided to the LST or HPI pump is I
provided, LST will be drained possibly resulting in damage to the operating HPI pump. If relief valve falls to close after blockage is cleared, see t
Table 1, Pressure Boundary Failures.
l 1
TABLE 4. FLOW BLOCKAGES IN THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure / Location Effect Remedial Actions 1.3 Plow Blockage in Increasing level in Operator can establish an High Pressure Letdown pressurizer results in alternate letdown flowpath Path to Isolation throttling makeup flow. or clear the flow blockage.
Valve Downstream of Demineralized water or Minimum HPI pump flow recir-Block Orifice - boric acid flow to LD culation must be maintained.
Letdown to Bleed tank will continue Continued operation requires Holdup Tank Operation resulting in an alarmed throttling makeup to LD tank high LD tank level. to avoid filling tank.
1.4 Plow Blockage in Letdown ' low diverted to Remove flow blockage. After Low Pressure Letdown waste hoicup tank. No letdown-makeup operation Path to Connection change in LST level until resumed, see Item 1.2.
. With 3-Way Valve - letdown-makeup operation
- Letdown to Bleed resumed - see Item 1.2.
Holdup Tank Operation
- 2. 3-Way Valve 2.1 3-Way Valve Switches Flow to LST stops while Operator manually can transfer from Letdown to LST makeup to RCS continues at the 3-Way Valve to direct flow to Chemical previous flowrates. Low to the LST, open the bypass Processing Subsystem LST level is alarmed line from the letdown line to and the level signal may the makeup filters or provide automatically transfer makeup to the LST from the valve to original position. Chemical Processing Subsystem.
Unless an alternate source If LST level cannot be of makeup water to LST maintained, the operator must is provided, the LST throttle makeup flow to the RCS will be drained possibly or trip the HPI pumps.
resulting in damage to the operating HPI pumps.
TABLE 4. FLOW BLOCKAGES IN THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure / Location Effect Remedial Actions 2.2 3-Way Valve Switches LST level will increase Return 3-Way Valve to original from Letdown to and be alarmed on high position or isolate makeup Chemical Processing level. flow from Chemical Processing l Subsystem to LST Subsystem to LST.
2.3 3-Way Valve Fails to Following a low LST Operator manually can open the switch Letdown to LST level demand, failure to bypass line f rom the letdown on Demand transfer will result in line to the makeup filters or continued decreasing in provide makeup to the LST LST level. Unless from the Chemical Processing an alternate source of Subsystem. If LST level
, makeup water to the LST cannot be maintained, the e is provided, the LST operator must throttle makeup will be drained flow to the RCS or trip the possibly resulting in HPI pumps.
demage to the operating HPI pumps. Following a
" batch complete" or
" control rod insertion limit" demand, makeup to the LST will be isolated resulting in a low LST level (see above).
4 1
TABLE 4. FLOW BLOCKAGES IN THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure / Location Effect Remedial Actions
- 3. HPI Subsystem 3.1 Flow Blockage in Increased line pressure Provide an alternate source of Piping From 3-Way lifts letdown line relief makeup water to the LST or Valve to LST - valve. Leak rate less HPI pumps. Close the letdown Letdown-Makeup than preexisting letdown containment isolation valve (s)
Operation or flowrate. Decreasing LST to isolate the relief valve and Operation With level and increasing remove the flow blockage.
Deborating waste holdup tank level Demineralizers alert operator to the situation. Unless a source y of water is provided to the o LST or HPI pump is provided, LST will be drained possibly resulting in damage to the operating HPI pump. If relief valve falls to close after blockage is cleared, see Table 3, Pressure Boundary Failures.
3.2 Flow Blockage in Flow to LST stops while Operator can establish an Piping from 3-Way makeup to RCS continues at alternate letdown flowpath to Valve to LST - previous flowrates. Unless the LST or clear the flow Letdown to Bleed an alternate source of blockage. Continued operation Holdup Tank Operation makeup water to LST is may require throttling seal provided, the LST will injection flowrate.
be drained possibly resulting in damage to the operating HPI pumps.
TABLE 4. FLOW BLOCKAGES IN THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure / Location Effect Remedial Actions 3.3 Flow Blockage in Low indicated makeup flow- Operator must open path from Piping From LST rate and low seal injection the BWST or trip the operating to HPI Pump Inlets flowrate alarms alert oper- HPI pump (s) . To terminate flow ator to the situation. leakage through the relief Unless the operator trips valves, the flow blockage must the operating HPI pump (s) be removed or a letdown or establishes a flowpath flowpath to the Bleed Holdup from the BWST rapidly, the tanks established. If the operating HPI pump (s) will operating HPI pump (s) fail, the fail. In addition, the operator must establish a blockage will result in flowpath through the remaining pressurization of the operable HPI pump (s) for RC g letdown piping and lifting pump seal injection and bora-the letdown and LST tion of the RCS.
relief valves. If the relief valves fail to close following removal of the blockage, see Table 3, Pressure Boundary Failures.
3.4 Operating HPI Low indicated makeup Operator may isolate letdown Pump (s) Stop flowrates, and low seal flow and start an alternate injection flowrates alert HPI pump after assessing operator to the situation, the reason for the stoppage.
Continued letdown flow and Letdown flow may then be RC pump seal return flow restored.
result in an increasing LST level and a decreasing pressurizer level.
TABLE 4. FLOW BLOCKAGES IN THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure / Location Effect Remedial Actions
- 4. Flow Blockage in Seal RC pumps' seal return flow Bypass or remove the blockage.
Return Subsystem alarms alert operator to If the blockage isolated the the situation. Leakage HPI recirculation path, past the RC pumps' increase letdown (and makeup) seals will be released to flow, if required. Monitor LST the containment sump or level and initiate makeup quench tank through the of demineralized water / boric pumps' vapor vents. acid if required.
- 5. Flow Blockage in Operator alerted to the Remove or bypass the flow Makeup Subsystem situation by decreasing blockage using one or more of pressurizer level and the four HPI lines to the RCS w increasing LST level. to restore pressurizer level.
Continued operation would If required, reduce letdown slowly drain the pressurizer flow or boric acid /deminera-possibly resulting in a lized water flows to prevent reactor trip. With the filling the LST.
pressurizer at an initially low level, the pressurizer may be drained during the subsequent transient.
TABLE 4. FLOW BLOCKAGES IN THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure / Location Effect Remedial Actions
- 6. Flow Blockage in RC Seal injection flow to one Restore seal injection.
Pumps Seal Injection or more RC pumps will cease. Observe RC pump procedures Subsystem Operator alerted to the for operation without seal situation by seal injection injection.
low flow alarms. Reactor coolant will pass through the labyrinth seal (thermal barrier) where it will be cooled by the CC water supplied to th" pump. The lower tempere-.re reactor coolant flows through the Cf RC Pumps' seals and back to the LST.
- 7. Coolant Processing and Storage Subsystem 7.1 Flow Blockage in Decreasing LST level Clear or bypass flow blockage Letdown Path will result in the auto- and restore deborating Through Deborating matic transfer of the demineralizer operation.
Demineralizers 3-Way Valve to the LST.
However, until letdown flow path is restored, the letdown piping will be pressurized resulting in the letdown relief valve lifting and diverting letdown flow to the waste holdup tank.
TABLE 4. FLOW BLOCKAGES IN THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure / Location Effect Remedial Actions 7.2 Plow Blockage in Letdown line pressure will Operator manually can transfer Letdown Path From increase resulting in the 3-Way Valve to the LST or 3-Way Valve to Bleed letdown relief valve close the letdown containment Holdup Tank opening and diverting isolation valve.
letdown flow to the waste holdup tank.
7.3 Plow Blockage in Decreasina LST l'evel Clear or bypass flow blockage Makeup Path to LST will result in the auto- and restore letdown flowpath matic transfer of the to Bleed Holdup tanks.
3-Way Valve to the LST.
E i
TABLE 5. FLOW INCREASES ID THE MAKEUP AND PURIFICATION SYSTEM Failure / Location Effect Remedial Actions
- 1. Letdown subsystem 1.1 Plow Increase in Makeup valve to RCS opens Attempt to reduce flowrate or Letdown Path to in response to decreasing manually isolate.
3-Way Valve-Normal pressurizer level. LST Letdown-Makeup level may increase.
Operation or Single LD cooler operation Deborating could result in increased Demineralizer letdown fluid temperatures.
Operation If sufficiently high, letdown will be automatically isolated
- l (see Table 4, Item 1.1).
1.2 Flow Increase in Makeup valve to RCS opens Attempt to reduce letdown Letdown Path to in response to decreasing flowrate. If required,
- 3-Way Valve-Letdown pressurizer level. LST transfer 3-way valve position to Bleed Holdup Tank level decreases. to LST.
3-wa-; valve will automatically transfer
. letdown to LST if LST level is sufficiently low. Single LD cooler operation could result in increased letdown fluid temperatures. If sufficiently high, letdown will be automatically isolated.
TABLE 5. FLON INCREASES IN THE NAKEUP AND PURIFICATION SYSTEM (Continued)
Failure / Location Effect Remedial Actions
- 2. 3-Way Valve 2.1 3-Way Valve Switches Flow to LST stops while Operator manually can transfer from Letdown to LST makeup to RCS continues at the 3-Way Valve to direct flow to Chemical Processing previous flowrates. Low to the LST, open the by-Subsystem LST level is alarmed pass line from the letdown and the level signal may line to the makeup filters or automatically transfer provide makeup to the LST valve to original position. from the Chemical Processing Unless an alternate source Subsystem. If LST level of makeup water to LST cannot be maintained, the is provided, the LST operator must throttle makeup 1
% will be drained possibly flow to the RCS or trip the resulting in damage to the HPI pumps.
operating HPI pumps, 2.2 3-Way Valve Switches LST level will Return 3-Way Valve to original from Letdown to increase and be alarmed position or isolate makeup Chemical Processing on high level. flow from Chemical Processing Subsystem to LST Subsystem to LST.
- 3. HPI Pump Subsystem 3.1 Flow Increase in LST level increases. Reduce or isolate flow from Flowpath to LST Excessive addition boric acid or bleed holdup from Chemical of demineralized water tanks. Transfer letdown flow Processing Subsystem will result in control to LST if required.
rod insertion and automatic termination of demineralized water flow to LST.
3.2 Flow Increase in LST level will increase. Isolate BWST from HPI pump Flowpath to HPI subsystem.
Pumps from BWST
i s_
TABLE $) '/I 4N INCREASES ID THE NAKEUP AND PURIFICATION SYSTEN (Continued) ,
s , ,
\ .
l
.~ ,
Failur e/ Location Effect .
L'emedial Actions
~
t w '
- 4. Flow Increase in Seal Makcup flow to RCS auto- Observe operating procedures '
Retur2 Subsystem natically increased in for increased seal return flow
_ response to decreased ' which may be indicative of a i pressurizer level.* damaged RC pump seal. s
. Attempt to throttle makeup 5.- Flow Increase in Makeup Operator alerted to the s Subsystem i situation by increastd flowrate. Ir> cease letdow'n ;
pressurizer level and flowrate if required to prevent i and decreased LST level. filling pressurizer or draining .
Unless the LST level LST.- I decrease can be terminated by throttling 3 makeup flow, increasing letdown flow or providing an alternate source of i borated water to the HPI l pump (s), the LST will be drained possibly resulting in HPI pump failure. ,
l
- 6. Flow Increase in RC Pump Increasing pressurizer Attempt to throttle RC pump Seal Injection Subsystem level will result in seal injection flow.
automatic throttling of makeup flow to RCS to compensate for increased seal injection. l l
t
l i
TABLE 5. FLOW INCREASES IN THE MAKEUP AND PURIFICATION SYSTEM (Continued) l Failure / Location Effect Remedial Actions 7.6 Coolant Processing and Storage Subsystem 7.1 Flow Increase in Makeup valve to RCS opens Attempt to reduce letdown l
Flowpath to Bleed in respGnse to decreasing flowrate. If required, Holdup Tanks from pressurizer level. LST transfer 3-way valve position l Letdown Subsystem level decreases, to LST.
l 3-way valve will automatically transfer
! letdown to LST if LST
! level is sufficiently low. Single LD cooler E$ operation could result in increased letdown fluid temperatures. If sufficiently high, letdown will be automatically isolated.
7.2 ? low Increase in LST level increases. Reduce or isolate flow from Flowpath to HPI Excessive addition of boric acid or bleed holdup Subsystem from demineralized water tanks. Transfer letdown flow Chemical Processing will result in control to LST if required.
Subsystem rod insertion and automatic termination of
! demineralized water flow to LST.
i i
TABLE 6. LOSS OF CHEMICAL ADDITION, COOLANT PURIFICATION CAPABILITY IN THE MAKEUP AND PURIFICATION SYSTEM Failure Effect Remedial Actions
- 1. Boric Acid Makeup From None during normal If required for plant shutdown, Concentrated Boric Acid operation. concentrated boric acid may be Tanks to LST Fails added to the LST from the boric acid mix tank or lower concentration boric acid may be injected from the BWST to the RCS.
- 2. Demineralized Water Failure to reduce the boric Restore demineralized water Makeup to LST Pcils acid concentration of the makeup to LST.
reactor coolant will result 3 in a slow decrease in core power due to decreasing core reactivity.
- 3. Lithium Hydroxide Slow decrease in pH of Monitor pH of reactor coolant.
Addition to LST Fails reactor coolant. If pH Restore lithium hydroxide exceeds specifications, addition to LST or shutdown plant shutdown will be plant if required.
required.
- 4. Hydrazine Addition to None during plant power Restore hydrazine addition LST Fails operation. Hydrazine is capability.
required in the RCS only during plant shutdown for oxygen concentration reduction (Note: hydrazine is used during power operation for feedwater oxygen control. If feedwater oxygen concentration exceeds specifications, plant shutdown is required.).
TABLE 6. LOSS OF CHEMICAL ADDITION, COOLANT PURIFICATION CAPABILITY IN THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure Effect Remedial Actions
- 5. Hydrogen Supply to Slow reduction in hydrogen Monitor oxygen concentration LST Isolated concentration and increase in reactor coolant. Restore in oxygen concentration in hydrogen addition to LST reactor coolant. If oxygen or shutdown plant if required.
concentration exceeds specification, plant shutdown is required.
16 . Purification Slow increase in reactor Monitor reactor coolant Demineralizers coolant impurities. If chemistry. Restore Bypassed or Depleted dissolved impurity purification demineralizer m concentration of reactor operation or shutdown plant if coolant exceeds r equired.
specifications, plant shutdown may be required.
- 7. Seal Injection Filters Filter unavailable for Restore seal injection filters Bypassed removal of particulates to operation.
prior to injection through RC pump seals. Unless bypassed, purification demineralizers and/or letdown filters can remove coolant particulates.
TABLE 7. EFFECTS OF CONTROL INSTRUMENTATION MALFUNCTIONS ON THE MAKEUP AND PURIFICATION SYSTEM Failure Effect Remedial Actions
- 1. Spurious ES Signals Letdown and seal return After confirming no emergency (1 or 2 Output Channels) lines isolated, 2 or 3 HPI condition exists, the operator pump injection mode may bypass the ES system, initiated. RC pumps restore letdown and seal return continue to operate with flow, and return to pressurizer seal leakage flow level controlled, single HPI directed through the pump makeup operation.
pumps' vapor vents.
- 2. Spurious NNI Automatic m Control Signals (Circuit Failures) 2.1 High Letdown Fluid Letdown flow isolated. Operator alerted to the Temperature Circuit Makeup flow will be situation by high letdown Isolates Letdown throttled automatically temperature alarm. The Valve HP-5 based on increasing operator can manually restore pressurizer level. letdown flow and repair Pressurizer level will temperature circuit.
continue to rise slowly and the LST level decrease due to the net 20 gpm seal injection input (See Table 4, Item 1.1, 1.2).
TABLE 7. EFFECTS OF CONTROL INSTRUMENTATION MALFUNCTIONS ON THE MAKEUP AND PURIFICATION SYSTEM (Continued) l Failure Effect Remedial Actions 2 . 2. Low LST Level, MU&P system operation The operator is alerted to the "CRD Dilution transfers from " Bleed and situation by a spurious low Permit" or the Feed" to normal letdown- level alarm if the LST
" Batch Complete" makeup operation.* level transmitter failed low.
Circuits Transfers 3-Way Valve From the Chemical Processing Subsystem to the LST
, 2.3 Pressurizer Level Flow increase - Makeup See Table 5, Item 5.
" Control Circuit subsystem. See Table 5, Opens Makeup Item 5.
Control Valve (HP-120) 2.4 Pressurizer Level Flow blockage - Makeup See Table 4, Item 5.
Control Closes subsystem. See Table 4, Makeup Control Item 5.
Valve (HP-120) 2.5 RC Seal Injection Seal injection flow ceases Operator slowly restores seal Flow Control and low flow is alarmed. injection flow by manually Circuit Closes RC pump continue to operate- opening HP-31 or its bypass Control Valve with reactor coolant cooled valve HP-140.
HP-31 in the labyrinth sea],
passing through the shaft seals and returning through the seal return subsystem.
- Assumes the signal f rom the 3-Way Valve Operator (HP-14) to the Chemical Processing Isolation Valve (HP-16) closes the isolation valve. If isolation valve remains open, see Table 5, Item 7.2.
TABLE 7. EFFECTS OF CONTROL INSTRUMENTATION MALFUNCTIONS ON THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure Effect Remedial Actions 2.6 RC Seal Injection Small increase in flowrate Operator manually can throttle Flow Control expected. The long term HP-31.
Circuit Opens effects on the RC pumps and Control Valve whether the increased flow HP-31 is sufficient to trip the high seal A P alarms is not known.
- 3. Spurious NNI Automatic -
Control Signals (NNI
, Power Failures) w 3.1 Failure of The makeup control (HP-120) Emergency procedure for loss of Panelboard KI and letdown control valves' KI bus, EP/0/A/1800/3, must be Power to ICS/NNI controls transfer to manual followed. These actions should with their power supply include taking manual control automatically transferring valve (HP-120) and the turbine to Panelboard KU. The bypass valves and verifying valves will remain in other automatic actions.
position. The seal injection control valve (HP-31) automatic control will continue to function with its power supply automatically transferring to Panelboard KU. A spurious low LST signal will result in 3-way valve (HP-14) transferring letdoun flow to the LST.
Numerous other plant controls, alarms and indicators deenergized.
TABLE 7. EFFECTS OF CONTROL INSTRUMENTATION MALFUNCTIONS ON THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure Effect Remedial Actions 3.2 Failure of Hand E/P transducers for the Operator must follow applicable Power to ICS/NNI letdown (HP-7), makeup procedures for loss of Hand (Branch HX) (HP-120) and RC pump seal Power. These actions should (HP-31) flow control valves includue transferring (or freezing in position, verifying the transfer) the Power to these transducers power for the makeup, seal may be transferred to injection and turbine bypass Panelboard KU (whether valves to KU, tripping the main this transfer is automatic, feedwater pump and verifying as with loss of KI, or the automatic initiation and
' , manual is unknown). The control of emergency feedwater.
- 3-Way Valve (HP-14) will be switched to transfer letdown flow to the LST.
Numerous other plant controls, alarms are deenergized.
3.3 Failure of Auto Power Automatic transfer of the Operator must follow to ICS/NNI (Branch H) makeup flow control to applicable procedures for loss manual will occur. The of autopower. These actions valve ( H P-120) will remain should include taking manual in position. Numerous control of makeup flow, other plant controls, tripping the main feedwater alarms and indicators are pumps and verifying the deenergized. automatic initiation and control of emergency feedwater and turbine bypass valves.
TABLE 7. EFFECTS OF CONTROL INSTRUMENTATION NALFUNCTIONS ON THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure Effect Remedial Actions 3.4 Failure of Hand Automatic control of makeup Operator must follow applicable Power Branch HlX valve HP-120 operable. If procedures for loss of HlX to ICS/NNI manual control of valve at power. These actions should s ICS Hand Station selected, include transferring turbine valve will open or close to bypass valve controls to KU midposition. Numerous other and manually controlling them, (non-letdown / makeup) plant tripping the main feedwater controls, alarms and pumps and verifying the ,
indicators are deenergized. automatic initiation and control of emergency feedwater.
'l
$ 3.5 Failure of Hand E/P transducers for the Operator must follow applicable Power Branch H2X letdown (HP-7), Makeup procedures for loss of H2X to ICS/NNI (HP-120) and RC pump seal Power. These actions should (HP-31) flow control valves include transferring (or are deenergized resulting verifying the transfer) the in those valves freezing in power for the makeup and seal position. Power to these injection to KU. Operator transducers to Panelboard should be cautioned to verify KU (whether this transfer operability of indicators he is automatic as with loss uses, of KI, or manual is unknown) . The 3-Way Valve (HP-14) will be switched to transfer letdown flow to the LST. Other makeup / letdown alarms and indicators will also be deenergized. -
TABLE 7. EFFECTS OF CONTROL INSTRUMENTATION MALFUNCTIONS ON THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure Effect Remedial Actions 3.6 Failure of Auto Power Automatic transfer of the Operator must follow applicable Branch H1 to ICS/NNI makeup flow control to procedures for loss of Hl.
manual will occur. The These actions should include valve (HP-120) will remain taking manual control of makeup in position. Numerous flow, tripping the main other plant controls, feedwater pumps and verifying alarms and indicators are the automatic initiation and deenergized. control of emergency feedwater and turbine bypass valves.
3.7 Failure of Auto Power Numerous RC pump and LST Operator should be cautioned to m
Branch H2 to ICS/NNI alarms spuriously verify operability of alarms annunciate and indicators and indicators used for plant deenergized. Although no control / recovery.
automatic controls are affected, if the operator trips the RC pumps, they cannot be restarted due to the spurious low seal injection flow interlock.
TABLE 7. EFFECTS OF CONTROL INSTRUMENTATION MALFUNCTIONS ON THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure Effect Remedial Actions 3.8 Power for Selected Indicated high pressurizer Operator is alerted to the Pressurizer Level level will result in makeup situation by high indicated and Transmitter Fails control valve HP-120 alarmed LST level. The (Branch HEX, HEY closing. Pressurizer level operator should be cautioned to or KU) will decrease and LST verify the operability of level will increase. In pressurizer level indications addition, if HEX or HEY and alarms. Once the power failed power is selected for failure is identified the the SG startup level operator may select one of the transmitter, low indicated two operable pressurizer level SG startup level will result transmitters for indication and m in overfilling the affected control.
SG resulting in an automatic trip of the main feedwater pumps. If KU failed power is selected, the power computer will be lost.
_ _ _ _. _m l
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i 4
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TABLE 8. EFFECTS OF COOLING WATER FAILURES ON THE MAKEUP AND PURIFICATION SYSTEM Failure Effect Remedial Actions
- 1. Component Cooling (CC)
System Failures 1.1 Loss of CC Water Increase in letdown fluid Restore CC flow to operating to Operating LD temperature resulting in or standby LD cooler and place Cooler automatic letdown isolation. in operation. See also Table See Table 4, Letdown 4, Letdown Subsystem.
Subsystem.
1.2 Loss of CC (Unit 1) In addition to letdown flow Restore a flowpath f rom the isolation, cooling water BWST or the Chemical Processing will be lost to RC Pump subsystem to the HPI pumps.
g labyrinth seals and CRDM Restore CC flow to LD cooler cooling jackets. RC Pump and other required components.
can continue to operate without CC, however, only if the seal injection flowrate can be maintained.
Loss of CRDM cooling may result in reactor trip.
- 2. Low Pressure Service Water (LPSW) System Failures 2.1 Loss of LPSW to Motor bearing will overheat Restore LPSW to operating pump Operating HPI Pump eventually requiring HPI or trip operating HPI pump and Motor Bearings pump trip. Long term start backup HPI pump.
operation would damage bearings. .
TABLE 8. EFFECTS OF COOLING WATER FAILURES ON THE MAKEUP AND PURIFICATION SYSTEM (Continued)
A Failurd Effect Remedial Actions 2.2 Loss of LPSW In addition to loss of Depending on the mode of motor bearing cooling for failure, the backup LPSW pump the three HPI pumps, cooling may be started, the HPSW system water to Unit 1 and 2 CC may be used or the cause of coolers (see item 1), the RC failure (e.g., blocked LPSW pump motor bearing coolers, suction strainers, loss of AC emergency feedwater pump power) may be, removed, and turbine coolers, LPI #
coolers, RB cooling units, etc., will be lost.
- 3. Recirculating Cooling 8 Water (RCW) System Failures 3.1 Loss of RCW to Gradual increase in seal Restore RCW to operating cooler Operating Seal return temperature due to or place standby cooler in Return Cooler heat addition from RC pump operation. If seal return seals and HPI pump. It is coolers' cooling water still not known whether or how unavailable, increased letdown quickly the temperature and isolate HPI pump could rise to the point recirculation loop if required.
where the HPI pump NPSH is inadequate.
TABLE 8. EFFECTS OF COOLING WATER FAILURES ON THE MAKEUP AND FURIFICATION SYSTEM (Continued)
Failure Effect Remedial Actions 3.2 Loss of RCW In addition to the above, Follow emergency procedures for cooling water to the main loss of instrument air.
feedwater and condensate Restore cooling water and air pumps (drivers) resulting supply to pneumatic valves and in a loss of main feedwater, restore letdown makeup loss of spent fugl pool operation. If air supply cooling, loss of cooling to cannot be restored, manually air compressors plus loss restore makeup to RCS from BWST of cooling to other or makeup tank, provide makeup miscellaneous functions. to LST from letdown or Reactor and turbine trip Bleed Holdup / Boric Acid tanks, expected. Loss of air if required, restore letdown to
- compressor cooling water LST or Bleed Holdup tank, result in loss of air and restore seal return to the compressors A, B, and C LST.
(existance of backup compressors unknown) , and assumed isolation of letdown, seal return and makeup flows (see Table 6).
Loss of main feedwater will result in automatic start of emergency feedwater with pneumatic control valves automatically supplied from a backup N2 tank.
l l
l l
l l
L_
1 f
e ir 92
.i TABLE 9. EFFECTS OF INSTRUMENT AIR FAILURES ON THE MAKEUP AND PURIFICATION SYSTEM Failure Effect Remedial Actions Loss of Instrument Air Pneumatic valves in the Operator must follow emergency letdown line, seal return procedure for loss of line, RCS makeup line and instrument air. Manually the makeup line from the restore instrument air and/or coolant storage subsystem manually restore letdown, seal close; the seal injection return and makeup flows.
control valve opens and pneumatic valves in other systems move to their failure position. Seal injection flow is passed through the RC pump 8 labyrinth seals to the RCS and through the #1 and #2 shaft seals and the RC pumps' vapor vents to the containment. Main feedwater will trip on high
. SG level (assuming reactor trip following loss of instrument air pressure) and emergency feedwater will be initiated and controlled using backup N2 tanks for pneumatic control valves.
{
{
t t
O a
1 94
TABLE 10. EFFECTS OF AC ELECTRIC POWER FAILURES ON THE MAKEUP AND PURIFICATION SYSTEM Failure Effect Remedial Actions
- 1. 4160 VAC Bus 1TC o Operating HPI pump PlA Start standby HPI pump PlB, Deenergized stops, terminating seal standby LPSW pump B and the
, injection and makeup to standby RCW pump. If required RCS. open the letdown isolation valve which may close on high o LPSW pump A stops, letdown temperature. Restore reducing cooling water bus 1TC to service.
flow to Unit 1 and 2 serviced components by 50% including the component coolers. A gradual increase in g letdown temperature is expected which may result in automatic isolation of letdown.
o RCW pump D, if in operation, stops, reducing the cooling water flow to Unit 1, 2 and 3 serviced components by 33%. Overall effects of the RCW reduction are not known; the specific impact on the seal return temperature is expected to be minor.
k
TABLE 10. EFFECTS OF AC ELECTRIC POWER FAILURES ON THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure Effect Remedial Actions
- 1. 4160 VAC Bus 1TC o One or both HPI discharge Verify that either 208 VAC Bus Deenergized (cont'd) valves (HP-26, 27) and XS1 or XS2 is energized via one or both BWST ITD. Manually transfer one icolation valves to the of these buses if required.
HPI pumps (HP-24, 25) may be deenergized and not able to open if powered via bus TC.
o The discharge valve from both letdown coolers A
$ and B (HP-3, 4) may be deenergized and not able to close if powered via bus TC.
o Air compressor motor B is deenergized and stops if energized via buses XF, X1 and TC. The air supply to serviced components is assumed to be provided by compressors B and C.
- 2. 4160 VAC Bus 1TD o Standby HPI pump PlB Restore bus 1TD to service.
Deenergized and standby LPSW pump B (if connected to bus 1TD) deenergized and unavailable if required.
TABLE 10. EFFECTS OF AC ELECTRIC POWER FAILURES ON THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure Effect Remedial Actions
- 2. 4160 VAC Bus ITD o One or both HPI discharge verify that either 208 VAC Bus Deenergized (cont'd) valves (HP-26, 27) and XS1 or XS2 is energized via one or both BWST ITC. Transfer one of these isolation valves to the buses if required.
HPI pumps (HP-24, 25) may be deenergized and not able to open if powered via bus TD.
o The discharge valve from both letdown coolers A 0 and B (HP-3, 4) may be deenergized and not able to close if powered via bus TD.
o Air compressor motor A is deenergized and stops if energized via buses XD, X2 and TD. The air supply to serviced components is assumed to be provided by compressors A and C.
- 3. 4160 VAC Bus ITE o Standby HPI pump Plc Start standby RCW pump if RCW Deenergized deenergized and pump A was in service. Restore unavailable if required. bus ITE to service.
If RCW pump A is in service, it will stop, reducing cooling water flow to Unit 1, 2 and 3 serviced components by 33%.
TABLE 10. EFFECTS OF AC ELECTRIC POWER FAILURES ON THE MAKEUP AND PURIFICATION SYSTEM (Continued)
Failure Effect Remedial Actions
- 3. 4160 VAC Bus 1TE o Compressor Motors A and/ Transfer compressor motors to Deenergized (cont'd) or B may be deenergized be energized via 4160 VAC buses and stop if powered via lTC and ITD.
backup buses X3 and TE.
The ability of compressor C, assumed to be powered from a Unit 2 or 3 bus, to maintain air pressure is unknown (see Table 9, Failure of Instrument Air).
- 4. 600 VAC, 208 VAC Buses The distillate pump, low Restore power to the XL buses.
XL Deenergized pressure boric acid pump A, Concentrated boric acid boric acid mix tank requirements can be supplied agitator and heater via boric acid pump B.
deenergized. Effect of this failure on plant power operation expected to be small.
- 5. 600 VAC, 208 VAC Buses The low pressure boric acid Restore power to the XN buses.
XN Deenergized pump B and the lithium Concentrated boric acid hydroxide pump and tank requirements can be supplied agitator deenergized. via boric acid pump A.
Effect of this failure Lithium hydroxide can be on plant power operation added using the hydrazine expected to be small. pump.
TABLE 10. EFFECTS OF AC ELECTRIC POWER FAILURES ON THE MAKEUP AND PURIFICATION SYSTEN (Continued)
Failure Effect Remedial Actions
- 6. 600 VAC Buses XS1, o One or both HPI discharge Verify that either 208 VAC bus XS2, X8 or X9 valves (HP-26, 27) and XS1 or XS2 is energized.
Deenergized one or both BWST Manually transfer one of these isolation valves to the buses to an energized 600 VAC
! HPI pumps (HP-24, 25) may bus if required. Restore power be deenergized and not to deenergized bus, able to open if energized via XSl, XS2, X8 or X9. ,
o The discharge valve from both letdown coolers A
$ and B (HP-3, 4) may be deenergized and not able to close if energized via XS1, XS2, X8 or X9.
- 7. 208 VAC Bus XS1 BWST isolation valve to the Restore Bus XS1 to service.
HPI pumps (HP-24) and the HPI pumps A and B HPI
, discharge valve (HP-26) deenergized and not able to open if required.
- 8. 208 VAC Bus XS2 BWST isolation valve to the Restore Bus XS2 to service.
HPI pumps (HP-25) and the i HPI pump C HPI discharge valve (HP-27) deenergized and not able to open if required.
l i
TABLE 10. EFFECTS OF AC ELECTRIC POWER FAILURES ON THE MAKFUP AND PURIFICATION SYSTEM (Continued)
Failure Effect Remedial Actions
- 8. 208 VAC Bus XS2 o The discharge valve from :
(cont'd) both letdown coolers A and B (HP-3, 4) deenergized and not able to close if required.
5 O
TABLE 11. FMEA SUletARY FOR SUBSYSTEM 6.0: CHEMICAL PROCESSING SUBSYSTEM Effects at Subsystem Interface Precipitating Faults / Failure Modes Chemical Addition:
- 1. No N24H Available to a. N2 blanket system fails isolation Makeup Filters
- b. Manual control, isolation valves fail closed
- c. Check valves fail to prevent backflow
- d. Hydrazine drum emptics and not replaced.
Leaks from the tank will eventually lead to the same effect
- 2. Alternate Flow Path a. Electric power supply to hydrazine pump Through Lithium fails Hydroxide Pump Required
- b. Hydrazine pump fails
- c. Manual isolation valves fail closed 3 No LiOH Available a. Demineralized water supply to mix tank to Makeup Filters fails
- b. Lithium hydroxide tank empties and not refilled. Leaks from the tank will eventually lead to same effect i
- c. Manual isolation valves fail closed
- 4. Decreased LiOH Avail- a. Sampling, waste lines downstream of tank able to Makeup Filters fail open
- 5. Incorrect LiOH Concen- a. Manual isolation valve DW-121 fails open tration Available to and dilutes LiOH in tank; fails closed Makeup Filters and results in concentrated LiOH in tank.
- 6. Alternate Flow Path a. Electric power supply to lithium Through Hydrazine Pump hydroxide pump fails Required
- b. Lithium hydroxide pump fails c.
Manual isolation valves fail closed l
l 101 r w a r - , = -
TABLE 11. FMEA SUBSIARY FOR SUBSYSTEM 6.0: CHEMICAL PROCESSING SUBSYSTEM (Continued)
Effects at Subsystem Interface Precipitating Faults / Failure Modes 7 No Caustic Available to a. Demineralized water supply to mix tank LPI Pumps, RC Bleed fails Evaporator Feed Tank, Deborating Demineralizers b. Manual isolation valves fail closed
- c. Causic mix tank empties and not refilled. Leaks from the tank will eventually lead to same effect
- d. Electric power supply to caustic pump fails
- e. Caustic pump fails
- 8. Decreased Caustic Avail- a. Sampling, waste lines downstream of tank able to LPI Pumps, RC fail open Bleed Evaporator Feed Tank, Deborating Demineralizers 9 Incorrect caustic Concen- a. Manual isolation valve DW-120 tails tration Available to LPI open and dilutes caustic in tank; fails Pumps, RC Bleed Evaporator closed and results in concentrated Feed Tank, Deborating caustic in tank Demineralizers Boric Acid Addition:
- 1. No Boric Acid Available a. Flows from boron recovery and boric acid to Makeup Filters, BWST mix tank fail and concentrated boric Filters, BWST acid storage tank empties and not refilled. Leaks from tank will eventually lead to same effect.
- b. Manual isolation valves and manual control valve CS-62 fail closed
- c. Electric power supply to concentrated boric acid transfer pump fails
- d. Concentrated boric acid transfer pump fails 102
TABLE 11. FMEA SUltfARY FOR SUBSYSTEM 6.0: CHEMICAL PROCESSING SUBSYSTEM (Continued)
Effects at Subsystem Interface Precipitating Faults / Failure Modes
- 1. No Boric Acid Available e. Electric power supply to trace heating to Makeup Filters, BWST or trace heating fails leading to Filters, BWST (cont'd) plugged lines
- 2. No Boric Acid Flow Avail- a. Electric power supply to HP boric acid able to Core Flood Tank pump fails
- b. HP boric acid pump fails
- c. Manual isolation valves fail closed 3 Decreased Boric Acid a. Drain, sample lines downstream of Flow Available to storage tank fail open Makeup Filters, BWST
- 4. Boron Recovery or Adequate a. Demineralized water supply to boric acid Concentrated Boric Acid mix tank fails Storage Tank Inventory Required as Boric Acid b. Manual isolation valves fail closed Source (Internal Sub-system Effect Only) c. Manual isolation valve DW-118 fails open and dilutes boric acid in mix tank; fails closed and results in concentrated boric acid in mix tank
- d. Electric power supply to mix tank heater or mix tank heater fails leading to plugged lines
- e. Mix tank empties and not refilled.
Leaks from tank will eventually lead to same effect
- 5. Incorrect Process Para- a. Electric power supplies to transmitters meters to I&C System and fail Control Room
- Boric Acid Mix Tank b. Transmitter signal connection leaks Level, Temperature
- LP Boric Acid Pump c. Transmitters fail Discharge Pressure
- Concentrated Boric Acid Storage Tank i Level l
103 l
TABLE 11. FMEA SUBOIARY FOR SUBSYSTEM 6.0: CHEMICAL PROCESSING SUBSYSTEM (Continued)
Effects at Subsystem Interface Precipitating Faults / Failure Modes RC Bleed Holdun Tantra and Transfer Pnens:
- 1. No Domineralized Water a. Manual isolation and control valves fail to Makeup Filters closed
! b. Domineralized water supply to
, domineralized water holdup tank fails
- c. N2 blanket to domineralized water holdup tank fails resulting in tank unavail-ability
- d. Domineralized water holdup tank empties and not refilled. Leaks from tank
- will eventually lead to same effect i e. Electric power supply to bleed transfer pump fails I f. RC bleed transfer pump fails
- g. Check valves fail to prevent backflow
~
- h. - Control valves HP-15 or HP-16 fail closed (control signal, instrument air supply, electric power supply, valve failure)
- 1. Control valves HP-15 or HP-16 fail open I
allowing backflow from letdown line J. Electric power supply to trace heating or trace heating fails leading to plugged lines 1
k.
Flow orifices plug
- 2. Decreased Domineralized a. Waste, drain, or sample lines downsteam Water to Makeup Filters of holdup tank fail open 3 Increased Domineralized a. Control valves HP-15 and HP-16 fail Water to Makeup Filters open (control signal fails to close valve or spurious signal to open valve) 4
^
104
+
1
TABLE 11. FMEA SUIGIARY FOR SUBSYSTEM 6.0: CHEMICAL PROCESSING SUBSYSTEM (Continued)
/~
Effects at Subsystem Interface Precipitating Faults / Failure Modes
- 4. Alternate Flow Path a. RC bleed flow from letdown fails Through Unit 2 Bleed Holdup Tank Required b. Manual isolation and control valves fail
- closed
. c. N2 blanket to bleed holdup tank fails
+
resulting in tank unavailability
- d. RC bleed holdup tank empties and not f refilled. Leaks from tank will eventually lead to same effect t
- e. Electric power supply to trace heating f; or trace heating fails leading to plugged lines
- f. Waste, drain, sample lines downstream of
} ~, ,
holdup tank fail open
- g. Electric power supply to bleed transfer pump fails n ~
,- h. RC bleed transfer pump fails 1
/
! i. Flow orifice plugs
/
- j. Check valves fail to prevent backflow
~
-5. Incorrect Process a. Electric power supply to transmitters Parameters to IAC Systam fail and. Control Room HC Bleed Holdup Tank b. Transmitter connection leaks Level RC Bleed Flow c. Transmitter fails
- Domineralized Water Holdup Tank Level
- Dominera112ed Water Flow f- 105
TABLE 11. FMEA SUtelARY FOR SUBSYSTEM 6.0: CHEMICAL PROCESSING SUBSYSTEM (Continued)
Effects at Subsystem Interface Precipitating Faults / Failure Modes Boron Recoverv:
- 1. Alternate Flow Path a. Manual isolation valves fail closed Through Second Evaporator Demineralizer Required b. Demineralizer resin fill fails (Internal Subsystem Effect Only) c. Demineralizer tank or tank vents leak
- 2. RC Bleed Evaporator Feed a. Electric power supply to trace heating Tank Required to be Full or trace heating fails leading to at Beginning of Boron plugged lines Recovery Cycle (Internal Subsystem Effect Only) b. RC bleed flow from holdup tank fails
- c. Evaporator distillate, distillate cooler flows fail
- d. Mt:Jal isolation valves fail 3 No Temperature Control a. Cooling water supply to distillate of Distillate Returned cooler fails to Evaporator Feed Tank, Condensate Test Tank b. Loss or degraded heat transfer capability (Demineralized Water) in distillate cooler
- 4. No or Decreased a. Cooler tubes blocked or tube rupture Distillate Flow to leading to decreased flow or coolant Condensate Test Tanks release to distillate (Demineralized Water)
- b. Distillate cooler leaks
- c. Evaporate" wstillate flow fails; see effects i a 1 6
- 5. Boron Recovery Stops; a. Eveyn/stg r,ncentrate flow returned to Concentrated Boric Acid feed tank or evaporator Storage Tanks Required to be Full (Internal b. Evaporator feed tank empties and not Subsystem Effect Only) refilled. Leaks from tank, including vent and relief valves failed open, will eventually lead to same effect
- c. Manual isolation valves fail closed 106
TABLE 11. FMEA SUBSIARY FOR SUBSYSTEM 6.0: CHEMICAL PROCESSING SUBSYSTEM (Continued)
Effects at Subsystem Interface Precipitating Faults / Failure Modes
- 5. Boron Recovery Stops; d. Electric power supply to evaporator feed Concentrated Boric Acid pump or concentrate pump fails Storage Tanks Required to be Full (Internal e. Evaporator feed pump or concentrate Subsystem Effect Only) pump fails (cont'd)
- f. Control valves CT-24 or CT-40 fail to operate (instrument air, control signal, valve failure)
- g. Waste, drain, sample lines downstream of feed tank or evaporator fail open
- h. Steam supply to evaporator fails
- 1. Loss of heat transfer capability in evaporator J. Evaporator empties and not refilled.
Leaks from evaporator will eventually lead to same effect
- k. Electric power supply to trace heating, or evaporator heating fails leading to plugged lines
- 6. Boron Recovery Rate a. Electric power supply to trace heating, Decreases; Concentrated trace heating, or evaporator heating Boric Acid Storage Tank fails leading to plugged lines Required to be Full (Internal Subsystem b. Evaporator tubes blocked or tube rupture Effect Only) leading to decreased flow or steam release to vapor space
- c. Concentrate cooler leaks 7 No Temperature Control a. Cooling water supply to concentrate of Concentrate Returned cooler fails to Boric Acid Storage Tanks (Internal Sub- b. Loss or degraded heat transfer ~
system Effect Only) capability in concentrate cooler
- c. Temperature transmitter control signal to cooling water control valve fails
'\
4 107 l
/
9 TABLE 11. FMEA SUNIARY FOR SUBSYSTEM 6.0: CHEMICAL PROCESSING SUBSYSTEM (Continued)
Effects at Subsystem Interface Precipitating Faults / Failure Modes Deboratina Demineralizer:
- 1. No RC Return to Makeup r. . RC bleed flow from 3-way valve fails Filters
- b. Manual isolation valves fail closed
- c. Control valve HP-16 fails closed (instrument air, control signal, valve failure)
- d. Check valve fails to prevent backflow
- 2. Deboration Stops; Alter- a. Resin in demineralizer naturates or was nate Flow Path Through not regenerated as required due to ~
Second Demineralizer failure to provide caustic.'
Required 3 No RC Return to Makeup a. Manual isolation, control valves fail Filters; Alternate Flow closed Path Through Second Demineralizer Required b. Tank empties. Leaks from tank; including vent and relief valves failed open, will eventually lead to same effect.
- c. Electric power supply to trace heating, trace heating fails leading to plugged lines
- 4. Decreased Return Flow a. Waste, drain, sample lines fail open to Makeup Filters; Alter-nate Flow Path Through b. Demineralizer tank leaks Second Demineralizer Required 108
?
5.0 REFEIntBCES
- 1. Oconee Nuclear Station, Final Safety Analysis Report, 1982.
- 2. Oconee Nuclear Station, Final Safety Analysis Report, Revision 18.
3 Plant Electrical Distribution System Drawings 0701, 0702, 0703, 0704, and 0705.
- 4. Oconee 1 ICS - Instruction Book, Bailey Meter Co., March 1977
'l S. Letter from R. L. 0111 (Duke Power) to R. C. Kryter (ORNL), October 19, 1982.
109
?
l 1
l APPENDII A FAILURE MODES AND EFFECTS ANALYSIS SUBSYSTEM 1.0: LETDOWN SUBSYSTEM t
I
Retsrence Dra.wir32: FGAR Figure 9 3-2 FSAR Figure 9-2A SUBSYSTEM 1.0: LETDOWN COOLERS TO 3-WAY VALVE HP-14 (HP-V10)
Potential Failure Mode lamediate Effects
-e Interface At Subsystem Remedial Action Component Mode lavolved Within Subsystem Interface Within Suosystem 1.3 Letdown Coolers:
1.1.1 Mlaeollaneous 1. Opened or falla Vent or Drain Reduced letdown flow rate; Some letdown flow is Though detection Normally closed, open due to RC leak diverted to sumps; 1s difficult, Manual Talves internal fault hence, reduced letdown close or repair Such as HP-329 flow to 3-way valve when found (lacluding Double HP-14 (HP-TIO) and RC laolation Valves leak Such as HP-32 and IIP-359) 1.1.2 Talve IIP-l (NO) 1. Fatts elooed due to -- Letdown flow to Lton Cooler Letdown flow to 3-way Open llP-V1B and (HP-V14) internal fault IIP-CIA obstructed valve llP-14 (llP-TIO) la use Lton Cooler terminated HP-CIR
- 2. Spuriously closed Control Signal Letdown flow to Ltdn Cooler Letdown flow to 3-way Open HP-TI A HP-CIA obstructed valve HP-14 (HP-TIO) is terminated 3 Fatte to close when - Unobstructed letdown flow If HP-CI A has experienced Csose series required due to to Lton Cooler HP-CIA. a loss of cooling water, isolation valve internal fault Lton Cooler HP-C1A cannot then letdown fluid be isolated if valve HP-1 temperature will (IIP-TIA) is open increase; letdown flow to 3-way valve HP-14 (HP-VIO) will continue untti series toolation valve IIP-3 (HP-V2A) or HP-5 (llP-T3) is closed to protect HP-It. If None HP-CIA has experienced a tube rupture, then an RC leak to CCW system will occur
- 4. Falls to close when Electric Power Unobstructed letdown flcw If HP-CI A has expertenced Close sortes rerguired due to to Lten Cooler HP-CI A. a loss of cooling water, isolation valve unavailability of Lton Cooler HP-CI A cannot then letdown fluid electrie power be isolated if valve HP-1 temperature will (HP-TI A) la open increase; letdown flow to 3-way volve HP-14 (HP-V10) will continue until series isolation valve HP-3 (HP-T2A)
(powered from separate bus or manually closed) or HP-5 (HP-73) la olosed to protect HP-II.
If HP-CI A has experienced Restore electrio a tube rupture, then an power RC leak to CCW system will occur
- ___ . . _ m . _ . _. .- _ _ .___ mm - . . _m _ - . . . _m,_ . . _ _ . -~ .
Referece Drawings: FSaR Figure 9.3-2 SUBSYSTEM 1.0: LETDOWN SUBSYSTEM (Continued)
Potential Patture Mode Immediate Effects laterface At Subsystem Remedial Action Component Mode Involved Within Subsystes laterface Within Suosystee 1.1.) Talve WP-2 (NC) 5. Falle cren d: e to - Unobstructed letdown flow Unless component cooling Close BP-4 (lit-s t B1 internal fault to Lton Cooler HP C18 water provided to Lton ( HP-T28)
Cooler NP-C18, letdown temperature will increase posolbly
. resulting in letdown 4
loolation, f.e.,
termination of letdown flow to 3-way valve HP-14 (NF-V10)
- 2. Spuriously opened Control S!gnal Unobstructed letdown flow Unless component cooling Close HP-2 to Lton Cooler NP-CIS water provided to Ltan (HP-V1B), close Cooler HP-Cit, letdown HP-4 (HP-928) temperature will increase possibly 1 resulting in letdown isolattoa, i.e.,
termination of letdown flow to 3-way valve HP-14 (RP-910)
- 3. Fatts to open when - Use of Lt' Cooler HP-CIB May result in increased None (isolate and regatred due to preventaa letdown temperature or repair) internal fault continued letdown isolation 4 Falls to opes when Electric Power Use of Lton Cooler HP-CIS May result in increased Restore electrio required due to prevented letdown temperature or power unavailability of continued letdown electrio power taolation 1.1.4 Operating Letdeve 1. Loss of cooling water Component Increased letdown Increased letdown fluid Isolate HP-CIA Cooler MP-C14 flow Cooling temperature. High temperatura f4 aably and utilize (or NP-CIS) Water temperature sensed on casulfing in autoontic HP-CIB 1r Systen ~
~
U d N M Liug in letdown flow isolation, cooling water
, , autometto closure of 1.e., termination of available to teolation valve NP-5
.
- letdown flow to 3-way ItP-C15.
a,..o*** (NF-53) and imeteated valve HP-14 (HP-V10) Restore letdown in control room flow if it has been isolated
- 2. Reduction in heat - Increased letdown increased letdown fluid Isolate HP-C1A, transfer capability temperature. High temperature utilize HP-CIB due to fouling temperature sensed on TT-3 and indleated in r control roce
Reference Drawing; PSAR P1gurs 9.3-2 FSAR P1gurs 9-24 SUBSYSTIDI 1.0: LEYD0tM SUBSYSTIDI (Continued)
Potential failure Mode Immediate Effects -
-e Interface at Subsystem Remedial Action r r-at Mode involved Within Subsystem laterface Within Subsystem 1.1.4 Operating Letdown 3 Tube rupture Component Reduced letdown flow rate Reduced letdown flow to Close HP-1 Coolec BP-CIA Cooling due to f!cu diversion 3-vaf valve HP-14 (HP-T14) and (or HP-CIB) Water ( HP-TIO) . Loss of HP-3 (HP-T2 A),
(comt'd) System reactor coolant to CCW and open path system. Decreasing Ltdn through HP-CIB tank level RCS pressure.
Safety injection signal will not isolate letdown cooler. Increased CCW surge tank level, discharge of reactor ecolant through CCW relief valves to RD t.1.5 Standby Letdeum 1. Tube rupture Component Reduced letdown flow rate Reduced letdown flow to Close or verify Cooler HP-C1B Cooling due to flow diversion 3-way valve HP-14 elosure of HP-4 (or HP-CIA) Water ( HP-TIO) . Loss of (HP-t29)3 System rosetor coolant to CCW 1etdown flew system. Decreasing Lton through HP-Cla tank level RCS pressure. is possible Safety injection signal once leak is w!!! isolate letdown isolated cooler. Increased CCW surge tank level, discharge of reactor coolant through CCW relief valves to BB 1.1.6 Talve NP-3 (NO) 1. Falla closed due to -- Letdown flow through HP-CIA Letdown flow to 3-vay Close HP-1
( HP-T2 A) Internal fault is obstructed valve HP-14 (HP-TIO) is (HP-TI A), open terminated HP-2 (HP-T18) to divert letdown flew through HP-CIB
- 2. Spuriously closed Contro! Signal Letdown flow through HP-CIA Letdown flow to 3-way Open HP-3 la otestructed valve HP-14 (HP-TIO) is ( HP-T2 A) terminated 3 Palts to close when - Prevents isolation of If HP-CI A has esperienced None required due to HP-CI A a tube rupture HP-l internal fault (HP-T11) has been closed, and HP-C1B is to be used, then an RC leak to the CCW system will occur.
If HP-CI A has experienced Automatto closure a loss of cooling water of HP-5 and HP-1 (HP-TI A) can ( HP-T))1 not be closed, then HP-CIA cannot letdown fluid temperature t,e isolated will increase and HP-5 until HP-3 (HP-T3s will close (HP-12 A) is terminating letdown flow repaired to itP-14 (HP-TIO)
Res erence Drawings: FSaR Figure 9 3 2 SUBSYST M 1.0: LETDOWN SUBSYSTM (Continued)
Potential Failure Mode Immediate Effecta -e Interface at Subsystem Remedial Action Component Mode involved Within Subsystem Interface Within Suosystem 1.1.6 Valve HP-3 (NO) 4. Falla to close when Electric Power Prevente isolation of If HP-CIA has experienced None (HP-V2A) required due to HP-CIA a tube rupture HP-1 (cont'd) unavailability of (HP-VI A) has been cleaed, power on bue IEIS21 and HP-C1b is to be used, then an RC leak to the CCW system wt!! occur. If Automatic olosure HP-CI A has esperienced a of HP-5 loss of cooling water and (HP-V3); HP-CI A HP-1 (HP-VI A) cannot be cannot be closed, then letdown isolated until fluid toeperature will power is will increase and HP-5 restored on bus (HP-V3) wit! elose IEIS21 terminating letdown flow to HP-14 (HP-TIO)
- 5. Falls to close when Engineered Prevente isolation of If HP-CI A has esperienced None required due to Safeguards HP-CI A a tube rupture, HP-1 fatture of ES Proteettre (HP-VI A) has been closed, algnal System and HP-CIB is to be used.
( ES PS) then an RC leak to the CCW system will occur. If Automatio closure HP-CI A has esperienced a of HP-5 loss of cooling water (HP-V3); HP-CI A and HP-1 (HP-VI A) cannot cannot be be closed, then letdown isolated until fluid temperature will ES signal is increase and HP-5 (HP-V3) restored will close terminating letdown flow to HP-14
( HP-V10) l 1.1.7 Valve HP-4 (NO) 1. Fatta closed due to -- None None Close HP-2 (HP-V28) internal fault (HP-VIB) to divert letdown flow through HP-CIA
- 2. Spuriously closed Control Signal None None Open HP-4
( HP-V28) 3 Falls to clone when --
Prevents isolation of If HP-CIB has esperienced Nonel HP-C1B required due to H P-CI B a tube rupture, then an cannot be internal fault RC leak to the CCW isolated untti systa.s will occur HP-4 (HP-V2B) is repatred
- 4. Fails to close when Electric Power Prevents isolation of If HP-CIB has esperienced Noneg HP-CID required due to HP CID a tube rupture, then an cannot be unavailablltty of RC leak to the CCW isolated until power on bus 1EIS21 system will occur power is restored on bus IEIS21
_ _ . - -~
Reserence Drawiscs: FSIR Figure 9.3 2 SUBSYSTM 1.0: LETDOWN SUBSYSTM (Continued)
Potential Failure Mode Isandlate Effects ,
Interface At Subsystem Remedial Action r=pa==nt Mode Involved Within Subsystem Interface Withtm Subsystem l
1.1.7 Talve HP-4 (90) 5. Faits to elose when Engineered Prevents isolation of If HP-C18 has experienced None; HP-C1B (RF-T28) required due to Safeguards HP-CIB e tube rupture, then an cannot be (cont'd) failure of ES Protective RC leak to the CCW isolated until signal System system will occur ES sigaal is (ESPS) restored 8.2 Stock Orifices 3.2.8 ptiscellaneous 1. Opened or fails open Tent or Drain Reduced letdown flow rate Reduced letdown flow to Though detection Boreally Closed due to internal 3-way valve HP-14 is diffleult, 9teaual Valves fault ( HP-TIO) close or repair Such as RP-36 when found or NP-332 1.2.2 Valve RP-5 (NO) 1. Falls closed due to - letdown flow terminated Letdown riou to 3-way Clos. HP-3
( HP-T)) internal fault valve HP 14 (HP-fl0) (l!P-T2A), HP-4 is terminated (HP-T28), and HP-6 (HP-T4) and repair
- 2. Spuriously closed Control Signal Letdown flow terminated Letdown TIow to 3-way Open HP-5 (HP-T))
valve HP-14 (HP-V10) is terminated 3 Falle to close when - High temperature letdown High temperature letdown Close HP-6 required due to flow to purification flow possibly causing ( HP-V4 ) . If internal fault domineralizar is flow blockage if resin purtrication unobstructed. Increased beads in HP-Il melt resins damaged, letdown fluid temperature use standby may result in melting the demineraliser resin beads in HP-II and thus blocking flow
- 4. Spuriously Instrument Air Letdown flow terminated Letdown flow to 3-way Restore closed due to valve HP-14 (HP-TIO) instrument air, unavailability of is terminated open HP-5 Instrument air ( HP-T3)
(assumed)
- 5. Falls to close when Plant Instru- High temperature letdown High temperature letdown Close llP-6 required due to mentation flow to purification flow possibly causing (HP-T4) and unavailability of desinereltzer is flow blockage if resin restore letdown temperature unobstructed. Increased beads in HP-Il melt temperature interlook letdown fluid temperature interlock. If may result in melting the purification resin beads in HP-Il and resins damaged, thus blocking flow use standby demineraliser
Reference Drawings: FSan Figure 9.3-2 SUBSYSTEM 1.0: LETDOWN SUBSYSTEM (Continued)
Potential Failure Mode Immediate Effects e
Interface At Subsystem Benedial Action Component Mode Involved Within Subsystem Jaterface Within Subsystem I.2.2 valve HP-5 (50) 6. Fatte to close when Engineered Patture of one of two None, if HP-6 (HP-V4) Close HP-6 (HP-V3) required due to Safeguards redundant contatoment successfully closes. (HP-V4) and (cont'd) unava11 ability of Proteettre isolation valves. High Otherwise, high restore g3 ES signal System temperature letdown flow temperature letdown flow signal. If (ESPS) to purification possibly causing flow purification domineraliser is blockage if resin beads resins damaged, unobstructed. Increased in HP-Il melt use standby letdown fluid temperature dominera!!ser may result in melting the resin beads in HP-Il and thus blocking flow 1.2.3 Velve HP-6 (NO) 1. Falta closed due to - Letdown flow to purification Letdown flow to 3-way valve Utilise HP-7
( HP-V4 ) internal fault domineraliser is HP-14 (HP-V10) is (HP-V5) for obstructed unless HP-42 or terminated unless HP-42 letdown HP-7 (HP-V5) is open or IIP-7 (HP-VS) is open throttling
- 2. Spuriously closed Control Signal Letdown flow to purification Letdown flow to 3-way valve Open HP-6 (HP-V4) domineraliser is HP-14 (HP-V10) is or HP-7 (HP-V5) obstructed unless HP-42 or terminated unless HP-42 HP-7 (HP-V5) is open or HP-7 (HP-V5) is open 3 Falls to close when -- Letdown flow to block If HP-5 (HP-V3) has failed Close HP-8 required due to orifice is unobstructed to close and the letdown (HP-VT) to internal fault flow has not been cooled, protect then temperature of purification letdown flow to HP-14 domineraliser (HP-VIO) will continue HP Il to increase and resin beads in HP II may melt causing flow blockage
- 4. Falls to close when Instrument Air Letdown flow to block If HP-5 (HP-V3) has failed Close HP-8 required due to orifice is unobstructed to close and the letdown (HP-V7) to unavailab!Itty of flow has %t been cooled, protect instrument air then temperature of purification (assumed) letdown flow to HP-14 demineraliser (HP-V10) will continue HP-I13 restore to increase and resin instrument air beads in HP-Il may melt causing flow blockage 1.2.4 Block Ortrice 1. Fa!Is plugged -- Letdown flow to purification Letdown flow to 3-way valve Utilize HP-7 domineraliser is IIP-14 (HP-V10) is (HP-VS) for obstructed if HP-42 and terminated $f HP-42 and letdown flow HP-7 (HP-V5) are closed HP-7 (HP-VS) are closed throttling 1.2.5 Flow Transmitter 1. Internal fai.It Plant Instru. None Incorrect information Isolate and FT-29 results in mentation sent to plant operatora repair incorrect signal
- 2. Fatta due to Electric Power Rone Incorrect information Restore electria loss of power sent to plant operators power
altersnee Drsuingu FS2R Figure 9 3-2 FSAR Figure 9-2A SUBSYSTEM 1.0: LETDOWN SUBSYSTEM (Continued)
Potential Failure Mode Immediate Effecta .
Interface At Subayaten Remedial Action Component Mode Involved Within Subsystem Interface Within Suosystem 1.2.6 Valve HP-39 (NO) 1. Falls closed due to -
Letdown flow to purifloation 1.etdown flow to 3-way valve Open HP-7 (HP-V5) internal fault domineralizer is HP-14 (HP-V10) is obstructed if HP-42 and terminated if HP-42 and itP-7 (RP-VS) are closed itP-7 (HP-V5) are closed 1.2.7 Valva NP-42 (NC) 1. Falle opea due to -
Unobstructed letdown flow Increased letdown flow to Isolate block internal fault through orifice bypass to 3-way valve HP-14 orifice to purification dominera11ser ( H P-V10) reduce letdown flow 1.2.8 Valve HP-40 (NO) 1. Falls closed due to - 1.etdown flow to HP-7 (HP-V5) None, if HP-7 (HP-V5) (NC) tr.ternal fault la obstructed la closed. Otherwise, Open HP-42, if reduced letdown flow to required 3-way valve HP-14
( HP-V10) 1.2.9 Valve HP-7 (NC) 1. Fel's open due to - Block orifice bypassed, increased letdown flow to Close HP-40 and/
( HP-V5) m ornal fault increased letdown flow 3-way valve HP-14 or itP-41 and (HP-V10), and potentia!!y repair increased letdown temperatures
- 2. Spuriously opened Control Signal Block orifice bypassed, Increased letdown flow to Close HP-7 increased letdown flow 3-way valve HP-14 ( HP-V5)
( HP-V10)
- 3. Falls to open when -- Additional letdown flow Additional letdown flow Open HP-42 if required due to not provided not provided required, close internal fault HP-40 and HP-41 and repair
- 4. Falls to open when Instrument Air Additional letdown flow Additional letdown flow Utilise HP-42, required due te not provided not provided if required unavailability of restore instrument air instrument air (assumed) 1.* 'O Talve HP-41 (NO) 1. Falls closed due to --
Obstructs letdown flow to Reduced letdown flow to Utilise HP-421r internal fault purification dominera!!ser 3-way valve HP-14 required if HP-7 (HP-V5) la open (HP-110) If HP-7 (HP-V5) la open 1.2.11 Radiation 1. Normally closed High Activity Diversion of letown flow Reduced letdown flow Isolate Loop 3 Monitor Loop manual drain valve Weste Tank, when radiation monitoring to 3-way valve HP-14 elose valve or opened, falls open, Miscellaneous loop used (HP-VIO); flow diverted repair when or not closed Weste Tank to Hiscellaneous Waste found; samplang after maintenance, Tank or High Activity available at or re!!er valve Waste Tank other points in spuriously opens subayates
- 2. Loop becomes plugged - Reduced letdown flow; Reduced letdown flow Unplug when radiation monitoring to 3-vay valve IIP-14 found; samp!!ng prevented ( HP-V10) available at other points in subsystem
_ - . . , _ . . - - . . . _ ~ . - . __, -
Reference Drawings: F3aB Figure 9 3-2 SUBSYSTEN 1.0: LETDONE CUBSYSTBt (Continued)
Poteattet ranur. Mode le.ediat. afr.ets Interface at Subsystem Remedial Action Component Mode involved Within Subsystem Interface Within Suosystem 1.2.12 Borce Meter Loop 1. Normally elosed Righ Activity Diversion of letdove flow Beduced letdown flow to Isolate Leopg manual drata valve DR Tank, when boron meter loop 3-way valve NP-14 elose valve or opened, fails open, Miscellaneous used (RP-110); *seu diverted repair when er mot closed after Waste Tank to High Aosivity DR found; sampling maletenance, or Tank or Miscellaneous available at relief valve Waste Tank ather points in spuriously opens subsystem
- 2. Loop beecess plugged - Reduced letdown flowg baron Reduced letdown flow to Unplug when content measurement 3-way valve HP-14 found; samptsng prevented ( HP-fl0) available at other points in subsystee 1.3 Purifteetion Deelneraliser:
1.3.1 Flow Bonste 1. Fall plugged - Letdown flow to purtrication Letdove flow to 3-way valve deelneralizer is RP-14 (HP-VIO) is reduced obstructed or terminated 9.3.2 Flow Treammitters 1. Intera&1 fault Plant Instru- none None Utilise FT-29 to FT4, IT-6P, and results la mentation determine FT-6 4 taeorrect alsnal letdown flow (requires HP-7 (HP-75) and HP-42 be shut),
repair transmittereg restore electrio power
- 2. Control power failure Electrio Power mone None results la facorrect signal 1 3.3 Pressure Gauge 1. Internal fault Plant Instru- None None Repair when PC-73 results la mentation detected incorrect measurement
Beforence Drawingu PSAR figurs 9.3-2 SUBSYSTBt 1.0: LETDOIN SUBSYSTDI (Continued)
Peteatta! Fatture stade Immediate Effects ,
Interface At Subsystem Remedial Action Component lende Involved Nithin Subsystes laterface N1 thia Subsystem
- 3. Plant lastro- If a spuriously high Letdown flow to 3-way valve Ol en HP-5 134 Temperature Internal fault (NF-V3) after Transmitter TT-3 results la oestation temperature signal is NP-14 (NF-TIO) is secorrect algaal trammoitted, RF-5 (NP-T3) terstaated essessing is setematteally elesed, failureg repair obstructing letdown flow transmitter to perification deelserallser If a spuriously low Bigh temperature letdova Close RP-6 temperatore signal is flow posa!bly causing (HP-94)3 tramanitted, RP-5 (NF-T3) flow blockade if resta repair would not be auteentleally beads la NP-Il melt transettter elooed if required.
sacesolve letdown temperatures would result la purtrication d r* ~ alizar heettag, or resta bead mes . e 4 flow btackage
- 2. Control power Electrie Power If a spr.rtously high Letdown flow to 3-way valve Open HP-5 failure results tempeenture signal la NP-14 (HP-TIO) is (NF-T)) after la facerrect sageal traarattted NP-5 (RP-13) terminated assessing is setometteally elooed, fatture; obstractlag letdown flow restore to purification electrie power desteeraliser If a spurtously low Nigh temperature letdown Close HP-6 temperature signal is flow possibly causlag (NF-94);
a transaatted, NP-5 (WP-T3) flow blockage if resta restore would not be autcoatteally beads in NP-Il melt electrie power elosed if required.
Escessive letdown temperatures would result la purifteetion desameraliser heettag, or resta bead settlag and flow blockage 1.35 lesseellaneous I, selter valve Liquid Naste DC leak Reduced letdown flow to Isolate Beller Salves spuriously opens Drata 3-way valve NP-14 Like 89-52 (ar-43) (uP-910); 3C leak sad permally 2. NC mammal valve Samp!!ag Systee RC leak toduced letdown flow to None (tsolate Closed, sensual falls open due 3-way valve RP-14 and repatr) talves Lake RP-44 to internal fault ( NF-980) if sample flow estate; RC leak 3.3.6 Wolve WP-395 (BO) 3. Fette closed due to - Letdown flow to purtftention Letdown flow to 3-way valve Nome (Isolate laternal fault dealmeralizer is NP-14 (HP-910) is and repatr) obstructed terminated 3
Hererence Drawings: .Tsaa rigure 9.3-2 rsaN rigur. 9-za 35BSYSTBI 1.0: LETDolE SUBSYSTEN (Continued) roteettet Failure Isode lacediate Effects ,
i i Interface at Subsystem Nesodial Aettoo re-* Isode Involved Ntthan Suberstee Interface 111this Subsystem 1.3.7 valve Np-196 (NC) 1. Falls spea due te Outlet of Nedeeed letdeue flow to Neduced letdown flow to Close Nr-57
!aternet fault Letdous purifteetten deelnere!!ser 3-may velve Np-14 ritter NP-FIA (IIF-TIO) . (Letdown flow bypasses NP-It and NP-14 (Nr-vie))
! 1 3.8 Wolve WP-397 (NC) 1. Fette opeo due to Inlet of Neduced letdous flow to Neduced letdeue flew to Close HP-57 1sterest fault Letdeve purifteettoe dentnere!!ser 3-may velve N-34 Filter ur-rta (Br-910). (Leadeue flew bypasses NP-It and
, Mr-se (NF-ste))
1.3.9 palve NP-33 (NC) 1. Fette open due to - Letdeve flew bypasses Letdevan flou eheetstry None
- (IW-g6) internal fault the purtrienties altered deedneraliserg letdous flee ehestetry altered
- 2. Spuriously opened Control Signal Letdows flem hypeases Letdown flow cheetstry Close NP-33 the purifleetles eltered ( Nr.W )
, esmineralisorg letdous 4
flou chestetry altered 3 Falle te open whee -- rurifteetles desteeraliser Letdoun flow to 3-mer volve Opee Isr-9 required due to Wr-It bypese unevettable NP-14 (Nr-vie) is (INP VS) and 1sternet fault if required tereinsted if NP-Il to NP-ti (INr-99) j plugged med use HP-I2 if evetlable
- 4. Peteettet failure to Instruesat Air rurifteettee doeteeraliser Letdous flow to 3-may velve Nestore
, spee due to IIF-Il bypese unevellette NP-14 (Nr-910) se smetrument strg unevellability of if required tereinsted if gir-Il is open NP-9 i $mstruenot air plugged (INP-90) and r
(assumed) NP-II (Illr-79) f and use IIF-E2 1r evettable 1.3.10 valve NP-4 (110) 1. Falle clease due to - Letdeva flow through Letdous flow to 3-may velve Opea pr-9 (Nr-VT) internet fault purifteettoe deelnerallser NP-14 (Nr-tic) se (INP-US) and Mr It to obetracted terminated NP-11 (IIsr-V9) and utilise purifteetion deelnereltzer NP-32 ff not I.eing used by
, Ovit 2
- 2. Sportously closed Control Signal Letdous flow through Letdous flow to 3-usy volve Opee Pr-9 purification desiperaliser Nr-14 (IIr-910) le (tHr-98) and NP-Il is obetructed tereinsted NP-It (INP-99)
, and ut!!tse puritiestion deelneraliser NP-I2 Af not being used by Unit 2 4
Beforence Drawings: F3a8 Figure 9.3-2 SUBSYSTEM 1.0: LETDOWN SUBSYSTEM (Continued)
Poteattel Failure sk>de Immediate Effects e
laterface At Subsystem Somedial Action PW= ant stode Involved Within Subsystem Interface Within Subsystee 1.3.10 Velve DP-8 (50) 3 Falls to close when -
Purtrication deelneraliser Continued letdown flow to close HP-47 (BP-V7) re4mared due to NP-Il isolation is 3-way valve HP-14 (coat'd) internal fault unavailable (NP-V10)
- 4. Falle to close when Instrument Air Puriftention deelneraliser continued letdown flow to Close HP-47; regaired due to RP-Il isolation is 3-way valve HP-14 restore unavettability of unavailable ( HP-V10) instrument air instrument air (assumed) 1.3.11 Purification 1. Fait plugged - Letdown flow is blocked in Letdown flow to 3-way valve Isolate HP-Il Dominere11aer purification domineraliser HP-14 (HP-V10) is using pr-8 NP.Il pr-Il terminated (HP-VT) and use HP-I2 if eve 11able or bypass by opening HP-13 (HP-V6)
(reduced chemistry control) 1.3.12 Stop Check Valve 1. Falle plugged - Letdown flow through Letdown flow to valve Isolate HP-Il NP-47 purification deelneraliser HP-14 (HP-V10) is using HP-8 HP-Il is obstructed terminated (HP-V7) and use HP-I2 af available or bypass by opening HP-13
( HP-96)
(reduced cheatstry control) 1 3.13 Valve RP-9 (DC) 1. Falls open due to - If purification Increased or reduced Remedial action (INP-V8) interant fault domineraliser HP-I2 is letdown flow to 3-way dependent on being used by Unit 2, then valve HP-14 (RP-V10) Unit 2 the letdown flows of the operating two units may t=e staed requirements depending on the pressure difference between the two letdown flove
- 2. Spuriously opened Control Signal If purification increased or reduced Close HP-9 desineraliser BP-I2 is letdown flow to 3-way ( 1 HP-98 )
being used by unit 2, then valve HP-14 (HP-V10) the letdown flows of the two unite may be mined
, depending on the pressure difference between the two letdown flows
_ -. __ -- - m - . _ _ _ _ _ _ . . . _ . _ m . . _ . . . . _ . _ . _ _ . _ . _ _
Reference Dreutngs: F3at Pigure 9.3-2 FSAR Figure 9-2A
. SUBSYSTEM 1.0: LETDOWN SUBSYSTEM (Continued)
Potential Failure Mode Immediate Effects .
Interface at Subsysteg Semedial Action Component Stade Involved Withis Subsystem Interface Within Suosystee 1 3 13 Walve WP-9 (NC) 3.- Fatts to open when - Prevents use of spare Potential reduction in Continue to mae t
( S NP-DS) required due to purification deelneralizer ehemistry control HP-It if (coet'd) internal fault NP-32 by unit 1 available or open NP-13 (HP-M) and bypass HP-It
- 4. Potential fatture lastrument Air Prevents use of spare Potential reduction in Continue to use to opea due to purification deelneralizer chemistry control HP-It if uneve11 ability of NP-I2 by unit 1 available or instrument air open HP-13 (anaused) (SP- M) and bypass HP-Ilg
. restore instrument air 1 3 14 Talve HP-It (NC) 1. Falls open due to - If purification Increased letdown flou to Close HP-10 (INP-79) internal fae.it deelnere!!ser NP-12 is 3-vay volve NP-14 (2HP-96) and being used by unit 2, then ( HP-TIO) HP-12 (2HP-99) the letdown flou of unit 2 depending on att! leak into the letdown Unit 2 flou of unit I if unit 2 operating letdcun pressure is requirements greater than unit I letdeve pressure
- 2. Spuriously opened Control Signal If purification Increased letdove flou to Close HP-11 deelneraliser NP-I2 is 3-way valve HP-14 ( t HP-V9) being used by unit 2, them ( HP-V10) the letdown flou of unit 2 ell! leak into the letdown flou of unit 1 if unit 2 letdous pressure is greater then unit t letdous pressure 3 Falta to open when - Prevents use of spare Potential reduction in Continue to use required due to purificattom deelneraliser cheatstry control HP-It if internal fault NP.I2 by unit I available or open HP-13 (HP-96) and bypass NP-It
- 4. Poteattal failure Instrument Air Prevents use of spare Fotential reduction in Centinue to use to open due to purification deelneraliser chemistry control HP-It if unevetlability of NP-32 by unit I available or instrument air open HP-13 (assumed) (HP-M) and bypass HP-Ilg ,
restore instrument air
i APPENDII B FAILURE MODES AND EFFECTS ANALYSIS SUBSYSTEM 2.0: RC PUMP SEAL RETURN SUBSYSTEM
Reference Draulags: FSaB Figure 9 3-2
'****** ' *** 'I SUBSYSTEM 2.0: SCP SEAL WATER RETURN Pet.attal fattur. m de 2.m.diat. aff.ets ,
Interface at Subsystem Benedial Action rv -st bde involved Within Subsystem Interface Within Subsystem 2.3 Seal Leak-off Line(s) (4 Totel, t/DCP):
2.1.1 Pressure 1. Imatrument commeetion -
Small loss of reactor Incorrect pressure sisaal If accessible, Transmitter (s) leak ecolant to 14C system and repair IPT-19, IFT-20, control room component IPT-21, IPT-22 2. Tr===E tter fa11ere - to effeet Incorrect pressure signal If accessible, due te laternal to ISC systee and repair faults eentrol room component 3 Incorrect output R&C System. No effect lacorrect pressure signal Restore power due to loss Electrie to 1&C systee and supply of power Power Supply control room 2.1.2 sooter Operated 1. Closes as spurious ISC Systes Flow stopped la single Seal leak-off flow from a attempt to open Isolation Talve(s) signal leak-off line single RC pump blocked, failed valve BP-220 (19P-9434), control room alare or open seal DP-232 (INP-94)R), bypass salve NP-226 (1BP-743C), (NP-275)
NP-230 (IRP-943D) 2. Inadvertantly -- Flow stopped in eingle Seal leak-off flow free a Roopen valve elooed leak-off Itae single RC pump blocked, control room alara 3 Fatts elesed due to - Flou stopped la single Seal leak-off flow from e Open seal bypass internal fault lenk-off itse single RC pump blocked, valve (HP-275) control rorm alare
- 4. Talve falls to ISC System Flou act isolated Subsystem not isolated Close local elese when required from BCS valves om due to contre! affected !!ne signal failure
- 5. Talve falls te slectrie Power Flow not isolated Subsystem not isolated Restore power, elose en demand Supply from RCS elose local valves on effected line
- 6. Talve falls to - Flou act isolated Subsystem act isolated Close local elose on demand from RCS valves om due to laternal affected llae fault 2.1 3 Hamuel Isolation 1. Talve fatted closed - Flow stopped la alngle Seal leak-off flow from a Open bypass valve Talves (2/11ae) (plasstag, damaged, leak-off line stagle RC pump blocked, around fatted NP-205, NP-207, etc.) control race alare valve (local NP-232, BP-214, metton)
NP-219, NP-221, NP-259, 8P-261 2.1.4 - Flow Traammitter(s) 1. Instrument ecanectica - Small loss of reactor Incorrect flow signal If accessible, 1FT-89, IFT-20, leak ecolant to I4C systas and isolate leaking IFT-21, IPT-22, control room transmitter (s),
IFT-113, IFT-114, flow bypese 1F7-195, IFT-It6 available (local actica just outside of secondary shielding)
Reference Drawings: FSAR Figure 9.3-2 SUBSYSTEM 2.0: RC PUMP MRAI. RETURN SUBSYSTEM (Continued)
Potential Failure Mode Immediate affects ,
Interface at Subsystes Remedial Action Component Mode Involved Withia Subsystem Intectace Within Subsystem 2.1.4 Flow Treassitter(s) 2. Incorrect output due slectrio Power go effect Incorrect flow alsnal Restore power IFT-19, IFT-20, to loss of power Supply, I&C to I&C systee and supply IFT-21, IFT-22, Systes control race IFT-113, IFT-114, 3 Transmitter failure - No effect Incorrect flow signal If accessible, IFT-115, IFT-116 due to internal to I&C system and utillae bypass, (coat'd) fault control room isolate component and repair (local setton just outside of secondary shielding) 2.2 Seal typase Line(s) (Normally Closed Open When #1 Seal-Leakoff Rate is Too Low) (4 Total,1/RCP):
2.2.1 Pressure 1.. Instrument connection - Small loss of reactor Incorrect pressure signal If accessible, Transmitter (s) leak ecolant transmitted to I4C and repair IPT-19, IPT-20, control room component IPT-21, 1PT-22 2. Incorrect output due slectrio Power no effect Incorrect pressure signal Restore power to loss of power Supply, 14C transmitted to 14C and supply Systes control room
- 3. Transeitter failure - No effect Incorrect pressure signal If accessible, due to internal transe11ted to ISC ar.d repair Tault control roce component 2.2.2 Check Talve(s) 1. Talve failed closed - Flow in e' single bypass Seal bypass flow path If accessible, RP-26), HP-266, (plugged, damaged, line stopped blocked from a single repair HP-269. NP-272 etc.) RC pump component
- 2. Talve fails to -- No effect during steady No effect during steady Repair component prevent backflow state state at shutdown 2.2.3 Manual Isolation 1. Talve fatto closed - Flow in a single bypass Seal bypass flow path If accessible.
Talves (2/line) (plugged, damaged, line stopped blocked from a single repair MP-264, HP-265, etc.) RC pump component HP-267, NP-268
, HP-270, NP-271, NP-273 HP-274
, 2.2.4 Flow Transmitter (s) 1. Instrument connection -
Small loss of reactor Incorrect flow signal If accessible,
! IFT-109, IFT-110, leak coolant transmitted to IAC repair
! IFT-111, IFT-112 and control room ecaponent l 2. Transmitter failure - so effect Incorrect flow signal If accessible.
due to internal transmitted to 1&C repair
! fault and control room component 3 Incorrect output slectric Power No effect Incorrect flow signal Restore power due to loss of Supply, IAC transmitted to IAC supply power System and control room 1
.____ . . . _ _ _ _ _ . .. __m _ _ . . _ . _
Beforence Drawingas F3As Figure 9.3-2 (Sneets i rad 4)
SUBSYSTEN 2.0: RC PUNP SEAL RETURN SUBSYSTEM (Continued)
Potential Failure flode lamediate Effseta e
Interface at Subsystee Resedial Actica Component 8eode Involved Within Subsystem Interface Within Subsystee 23 Seal typass totura Reeders 2.3.1 80stor Operate 4 1. Valve fails to open I4C Systee Seal return bypass flow Seat return bypass flou None Isolation Valve when required due blocked path unavailable to all NP-275 (NF-V44) to centrol signal RC pumps failure or closes on spurious signal
- 2. Talve falls to opea Electric Power Seal return bypass flow Seal return bypeso flou testore power on demand or closes Supply blocked path unavailable to all on spurious alsnel RC pumps 3 Valve fatts to open - Seal return bypass flow Seal retura bypass flow popair component on demand due to blocked path unavailable to all if accessible internal fault RC pumps
- 4. Valve fatts opes or I4C System, No effect No effect Repair ocoponent falls to close Electrio if accese1ble when required Power Supply, Internal 232 testor Operated 1. Valve falls opes - Stand pipe fill lines open Potential loss of vent on None Isolattoe Valve due to internal to seat return flow BCP vent seal to Stand Pipe Fill fault and lenheep 57-276 2. Valve opens on I&C Systee Stand pipe fill lines open Potential loss of vent on None (RP-V49) spurious signal to seal return flou SCP vent seal 2.4 Seal Water Cooler Inlet Amaders 2.4.1 80otor Operated 1. Talve falls closed - Seat return flow stopped Seal return flow from all Repair ecaponent Isolation valve due to internet RC pumps stopped RF-20 (NF-V12) fault
- 2. Talve closes on 14C System. E5 Seal return flow stopped Seal return flow from a!! None spurious signal RC pumps stopped 3 Talve landvertantly - Seat return flow stopped Seat return flow form a!! Reopen valve elosed RC pumpe stopped
- 4. Talve falls to close Eteetric Power Reactor building isolation Seal return flow continues Restore power on demand Supply degraded to letdown storage tank 5 Velve fatts to close Es hoactor bu11 ding isolation No effect provided, None when required degraded redundant valve closes
- 6. Valys faits to close I&C Systee Rosetor butidtag toolation Seal return flou continues Ott11se valve when required degraded, seat return flow to letdown storage tank HP-21 mot toolated from coolers
- 7. Valve fails to elose - Reactor building isolation Seal return flow continues Utilize valve on demand due to degraded, seat return flow to letdown storage tank HP-21 internal fault not isolated from ecclers 2.4.2 Pneumatte Operated 1. Valve fatto closed Instrument Air Seal return (tou stopped Seal return flow from all Attempt to open Isolation Valve (assuslag valve is BC pumps stopped valve locally NP-21 (NF-V13) air-to-open)
- 2. Valve closes on 14C Systes Seal return flow stopped Seal retura flow free all attempt to open spurious signal BC pumps stopped valve locally
- 3. Talve closes en ES Seal return flow stopped Seal return flow free all attempt to open apurieue signal BC pumps stopped valve locally
.. - _ _ _ _ .__m __ _. __ _ _ _. _ _ _ . . - _
Reference Drawings: FSAR Figure 3.3-2 (Sheets I and 4)
SOBSYSTEM 2.0: BC PWIP SEAL RETURN SUBSYSTEM (Continued)
Foteattel Failure Nde Ismedsete Effects Interface at subsystem Benedial Aettom re nt Mode lavelved Withtm Subsystem Interface Within Subsystem 2.4.2 Fasematte Operated 4. Talve falls elosed - Seal return flow stopped Seat return flow free all Repair oceponent Isolataea Talve due to internal RC pumps stopped BF-21 (RF-T13) fault (coet'd) 3. Talve fails to elose - Beactor butiding isolation Seal return flow continues Uttitre valve on demand due to degraded, seat rtturn flow to letdown storage tank HP-2C interant fault act isolet. free seat return eoolers
- 6. Talve fasts to elose ES neeetor buttalag isolation no effect provided mone when required degraded redundant valve closes
- 7. Talve falls to elose I&C system Rosetor bu11 ding isolation Seal retura flow continues utilise valve when required degraded, seat return flow te letdown storage tank RP-20 mot isolated free cooters 2.4.3 Seal Detura 1. Talve fatted closed - Seel retura flow reduced or seat return flow from all Depair component Filter Throttle (plugged, damaged, stopped DC pumpe reduced or Talve NP-277 ete.) stopped (RP-T50) 2.4.4 Seal betera 1. Talve fatted elesed - Seat retura flow reduced or Seat return flow from all Open bypass Filter Isolation (plugged, daanged, stopped BC pumps reduced or valve (pr-280)
Talve(s) WP-270, etc.) stopped around faiter WP-279 (local action) 2.4.5 seal seture t. Filter plugsed - seat return flew reduced or seat retura flow from all Open bypass F11ter stopped DC pumps reduced or valve (HP-280) stopped high r around filter transettted on 1FT-114 (local metica) 2.5 seat betern Cooler (s):
2.5.3 sensuel Isolation 1. Talve falls elemed -- Seet roterm flow redueed or Seal water flow free all RC Talve in spare Valve (s) NF-72, (plugging, damaged, stopped pumps reduced or stopped cooler (local WP-74, RP-75, stuek closed, setten)
WP-77 ete.)
2.5.2 operettag BC Seal 1. peat enchanser -
- eat reture flow reduced or Seal water flow from all BC Talve in spare Beture Cooler tubes tierked stopped pumps reduced or stopped cooler (local RF-C1B (or actica) and Spare NP-C14) repair blocked eccler
- 2. Tube fallare BCW Systee Loss of remeter coolant to peactor coolant teakase to Talve is spare RCW system BCW system, reduced seat ecolor (local water return to letdous settoo) or storage tank isolete seal return header from control room if required and take appropriate precautions for stopping seal reture
-- . - . - . - . _ - - _ _ _ - . - - - - - - - - - _ - . . . ~ _ - - - - - - _ - - - _ - --
3.f.r c. ora. stag s esas rigurg ,.3-2 (She.te i ama en 35BSYSTEN 2.0: SC POIE SEAL RETUM SBBSYSTEM (Continued) rot.atta! rallure stede samediat. afreets .
Interface at Sesheystem somedial Settes Compeeemt leede Involved Withtm Seheystem laterface Withia Subsystee 2.5.2 sporettas BC Seal 3 Lees er acu BCu System Laos of moel retare emeling Righ temperature discharge Salve la e,ere Betare Cooler (htak emeler discharge to letdoese storage tank, eeeler if DCW BF-C19 (or temperature) high temperature reading is available to
-l Spero RF-Cla) en TT-M or TT-4 it (local (eastad) action)
- 4. I.oss of heet tremafer - Lose of seat retura eeeltag alp temperature discharge Isolate affected espettttty due te (hi p emeter discharge to letdesse storage tank, cooler and 1 sternal damage temperature) high temperature reedias salve se opere se TT-M or TT-4 (leest actice)
- 5. Taper leek to emeter -- Reduetten la seat retura Nigh temperature discharge Isolate affected 4 eeeling espeelty (high to letdouse storage taak, cooler and emeler discharge high temperature reading valve la opere i temperature) en TT-M or TT-4 (locas setton) f 2.5 3 Caeler sleeharge 1. Talve fatte elened - Seal reture flow redueed or Seal retura flow to letdossa Repair component i W Cheek valve (pluggles, damaged, stepped storage taak reduced er r BF-109 ete.) stepped, seat reture TIcis t i'
from all BC pumpe redeced or stepped
- 2. Walve falls to Seal Water De effect durtag steady Be effect diertag steedF Bo immediate provoet backflees Coolers, state almee pressures at state since pressures at settes i Letdesse outlet laterfaces are outlet interfaces are accessary, Storage Tank, lesser than emeter leiser than ecolor repair lenheisp discharge llas pressure discharge line pressure - at
- Filter (s)
Discharge 2.6 System Inlet Fleese:
i 2.6.3 Seel lajectase 1. Laos of flees Seel Iajeetten Seel reture flow from BCS Slightly hotter discharge None i Flees (Subsystem hetter than moguel seal flow to letdessa storage 4.0), 3C reture tank Pumpe !
I 2.6.2 MPI Pump 1. less of flow NFl Feeps Bedeced flees through seal Seduced flots and somewhat None Seetremlattom (Subsystem retura eeelers eeoler discharge than
- 33) moraal to letdoise storage l
taak I
2.7 System F1ptes:
2.7.1 goats, Bretas, t. System leaks -- Loss of reactor ecolant Loss of resetor costaat, Isolate leaks and j Ptplag Isotrument altshtly reduced flow repair as Commeettoms, etc. to letdoese storage tank moeded :
i
l APPENDIX C FAILURE MODES AND EFFECTS ANALYSIS SUBSYSTEM 3 0: HPI PUMP SUBSYSTEM
n:rtrene ,oravingu rsas rigure 9.3-2 (Sheet in SUBSYSTEM 3.0: LETDOWN STORAGE TANK (LST), IELET FILTERS, AND BPI PUMPS Potential Failure Mode Ismediate Effects Interface At Subayetee Remedial Action Component Hode Involved Within Subsystes Interface Withia Suosystem 31 Letdows (Makeup) Filters (2):
3.1.1 Pneumatie Operated 1. Talve falls closed Instrument Air Loss of flow to LST free Reduction and eventual Utiltre spare Inlet Talve(s) (assumed valve la letdown, cheetcal loss of swallable filter, open HP-1T (BP-T29 A), alr-to-opea) addition, and system sakeup in LST valve locally, RP-18 (RP-T298) makeup bypass to LST, or switch to BW37 if LST level as unacceptably low
- 2. Talve fatta closed - Loss of flow to LST free Beduction and eventual Utilize spare due to internal letdown 'chesteal loss of available filter, bypass fault addition, and systes makeup la LST to LST, or makeup switch to BWST if LST level is unacceptably low 3 Talve closes on IAC System Loss of flow to LST from Reduction and eventual Utilise spare spurious alsnal letdown, cheetcal loss of available filter, open addition, and system sakeup in LST valve locally, makeup bypass to LST or switch to BWST if LST level le unacceptably low
- 4. Talve snadvertently - Loss of flow to LST from Reduction and eventual aeopen valve closed letdown, cheetcal loss of available addition, and system makeup in LST sakeup
- 5. Talve fails to elose IAC, Electric Cannot isolate filter for no effect Repair component when required Power Supply, maintenance Internal 3 1.2 Makeup Filter P 1. Transs1Lter feiture - Potential for undetected Incorrect pressure drop Honttor pressure Transmitter IrT-15 due to internal filter plugging signal to 1&C and drop with local fault control room gage
- 2. Incorrect output Electric Power Potential for untetected Incorrect pressure drop Honitor pressure due to loss of Supply, !&C filter plugging signal to I&C and drop with local power control room gage
- 3. Instrument connection -. Small loss of reactor Incorrect pressure drop Repair leak leak coolant and small signal to I&C and reduction la flow to LST control room 3.3 3 Filter (s) 1. Filter plugged - Letdown, cheatoal addition, Beduced inventory in LST Utillae spare HP-Fla. NP-FtB and system makeup flow and high pressure drop filter or reduced or stopped signal to 1&C from IPT-15 t,ypass filters via HP-19
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Foteattel Failure Mode Immediate Effects laterface at Subsystes Remedial *stion Component Mode Involved Withia Subsystem laterface Wlthin Subayaten 3 2.4 Level framanttters 2. Incorrect outget due Electria Power If selected treaseitter Loss of or tacorrect LST Restore power ILT-33PI, ILT-31F2 to loss of power Supply, IAC indientes low flow free level ladteation, supply or (coat'd) to treasettter System 3-way valve automatteally tacorrect signal to monitor with transfers letdove flow to 3-way valve laterlock redundant LST and operator may etreult and poteattel for transmitter if Sacrease LST level with reduced N concentrattom on a different bleed heldup. Poteattal ta RC3. retor power source for LST tank overfalling, response may also result my addition blockage, la decreased letdova flow and lower N2 *****"EF"II*"
la RC3. If transetStar indientes high, operator may decrease letdown flow and poteattelly reduce NPSH on Nf1 pumps 3 Instrument commeetion - Small loss of LST inventory. Loss of or tacorrect LST Repair component leak Both transmitters level ladleatloa, affected. If selected tacorrect algaat to transettter sadleates low 3-way valve laterlock flow from 3-way valve etremit and potential automatteally transfers for reduced My letdown flow to LST and concentration la RC3.
operator may tacrease LST Operator response may level with bleed holdup, also result la decreased roteettal for LST tank letdown flow overftlling, addition blockage, and over R 2 concentration la RC3. If transeitter ladleates high, operator may decrease letdown flow and poteattally reduce EPSR on BPI pumps 3.2.5 Pressure 1. Incorrect output Electrie Power No effect Loss of or tacorrect LST Restore power Transmitter 177-10 due to loss of Supply, 1&C pressure ladiention supply power System
- 2. Transmitter fatture - No effect Loss of or Snoorrect LST Repair component pressure ladiention 3 Instrument cosaeetten -- Small loss of LST inventory Loss of or incorrect 1.37 Repair component leak pressure indleation 3.3 NFI Pump 3mettaa Naaders.
3.3.3 Isoter Operated 3. Talve fatta closed - Flow to Wr! pumps stopped, Immediate loss of flow to allga supply free Isolation valve loss of BPSM to RFI pump RC makeup and RC pump 94f37 via motor NP-23 (RP-t28) resulttag possible la seals operated volves pump damage and allga alternate HPI pump if required
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a0 R.f.rese. Drawings: rsah Fig.re s.3-2 (sheet il SUBSYSTEM 3 0: HPI PUMP SUBSYSTEM (Continued) .
Potential Failure Mode Immediate Effects Interface At Subsystem Benedial Action Componeet Mode Involved Within Subsystee Interface Within Subsystem 3 4.2 Spare RFI Pumps 2. Fump falls to start -
No disenarse flow from If pump is demanded Utilise alternate RF-F18. BF-FIC due to internal pump demanded because of failure with MPI pump.
(cont'd) fault operating pump, ao flow repair pump to RC askeup or RC pump seals. If pumps are just being switched, no effect 343 Discharge Check 1. Talve la operating - No discharge flow thrcAgh Ro flow free operating RFI Utiltre alternate Talve(s) HP-105, pump discharge fally failed valvo pump te RC makeup or RC RFI pump RF-108 closed (plugging, pump seats damaged, etc.)
- 2. Talve ir standby pump - Backflow through a Reduced flow to seal Isolate failed discharge fatte nonoperating opere pump to injection and/or makeup check valve to prevent backflow suction of operating pump (locat action).
(potential NFI pump Monitor damage) critical flows 3 4.4 seetreutetton 1. Line blockage due seat Return Potentist damage to HFI pump Potential loss of RC makeup Utilize alternate Line(s) Associated to plugged block Cooler Inlet via pump deadheading if and seal lajectica HFI pump (other With rumpet valve or orifice (Subsystem pump discharge to makeup actica HF-FI A, RF-F18, 2.0) and seat injection is not available free HP-FIC enough for pump operation outside the subsystem) 3 4.5 Discharge Block 1. Talve in operating RCP Seals, No discharge flow through No discharge flow from Ut111 e alternate Talve(s) HP-106 pump discherse Reactor Inlet failed valve operating HFI pump to HP1 pump (HP-V344), Rf-ISO fails closed Line Loops RC pumps seats or RC (HP-T3%B), hP-114 (plugged, damaged. A, B and makeup (HP-V34C) etc.) Crossovers A and B 3 4.6 Motor Operated 1. Valve otoses on IAC System If rump RF-FI A operating. If pump sfF-FI A operating, If operating pump Isolation Talve . spurious signal flow to sent injection is flow to seal injection is is RF-FI A, HP-115 (HP-T35A) stopped. If pump HF-FIB stopped. If pump HF-F18 start pump is operating, flow to is operating, flow to HP-F18. If normal RC makeup is normal RC makeup is operating pump stopped stopped to HF F18, start RF-FI A or (for unthrottled makeup) open valve HP-118 to reactor inlet 1,00F B
Raference Draulags: F3tB Figure 9.3 2 (sbe.t i)
SUBSYSTEM 3.0: HPI PUMP SUBSYSTEM (Continued)
Potential fallere Mode Immediate Effects laterface At Subsystem Semedial action Composest Mode Involved Within Subsystem laterface Withia Subsystem
).4.6 leotor Operated 2. Talve faite closed -
If pump RP-Pla operettag, If pump BP-Pla operettag. If operettag pump Isolation valve due to laternal flow to seal injectica as flow to seal tajection is is RP-P11, BP-It5 (NF-T158) fault stopped. If pump RP-Pts stopped. If pump RF-Pas start pump (coat'd) is operettag, flow to is operettag, flow to BP-F18. If moraal BC meteep is normal 3C matroup la operettag pump storped stopped is PP-F19, start Bf-PIA or (for metkrcttled makeup) open valve 2P-118 to reactor inlet LOOP 3 3 Talve laadvertantly - If pump HP-PIA operating, if pump BP-PI A eperettag, Seogen valve closed flow to seal injection is flow to seal tajeetion is stopped. If pump RP-Pts stopped. If pump BP F13 la operettag, flow to is operating, flow to normal BC makeup la normal BC makeup is stopped stopped
- 4. Talve fails to close IAC System, Intended isolation act so effect om steady state Otilize local when required Electrie effected operation isolatloa Power Supply, valves or Internal Fault 3.4.7 1solattom falvo 1. Talve falls open - Loss of separation between No effect durtag normal NP-118 (5P-9358) (damaged, etc.) Utilise RF-117 BPI injectica paths & operation stace Sajectica for isolettoa and 8 path 8 1s normally closed 3 4.8 Isolettoa valve 1, talve falla closed -- Loss of ability to use Loss of att11ty to use Depair ecaponent BP-117 (ar-735C) (plugging, damaged, NP-Pts as spare for safety kP-P1B as spare for safety etc.) lajectice to cold les 8 lajectJoe to cold les B 35 tystem Intet flows:
3.5.1 Deactor Coolant 1. Loss of flow Subsystem 1.0 Reduettom and eventual loss Loss of letdove flow to Letdown Inlet flow Meetter L37 level of evallable makeup la subsystem and utillao LST, loss of letdown flow sufply from to subsystem BWST, bleed holdup task, or borte acid taak 3.5.2 BC Bleed Makeup I. Loss of flow sut,sy stem 6.0 If in letdeva/ bleed and Peed Inlet Plow Loss of batch taputs to Bostore letdous feed operattas mode, LST from BC bleed flow to LST reduction in LST level makeup 3.5.3 BCP Seal Beterm 1. Loss of flow Subsystem 2.0 Partist loss of flow to Poteatta! Iong-term loss Monitor LST Inlet Flow LST, loss of RFI pump of LST level and level, ut1Ilse rectroulatfoe requirement to switch AC bleed makeup to BW37 section or BWST If required
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APPENDII D FAILURE MODES AND EFFECTS ANALYSIS SUBSYSTEM 4.0: RC PUMP SEAL INJECTION SUBSYSTEM
Rifsrtace Drenings: F3AR Figure 9,3-2 (Sheet.1 cod 4)
SUBSYSTEM 4.0: RC PUMPS SEAL INJECTION Potential Fa11ere hde Immediate Effects Interface At Subsysten Benedial Action Component Mode Involved Witata Subsystem Interface Usthin Subsysten 4.1 BC Pumps Seal Injection Reader:
4.1.1 Seal Injection 1. Valve falls closed - Seal injection flow stopped Seal injection flow to RC Regatr component 8eeder Manual (plugged, damaged, pumps stopped Isolation valve oto.)
RP-126 (EP-f279)
- 4.1.2 Seal Injection 1. Incorrect output due 14C System, No effect Incorrect pressure signal Depair component Beeder Pressure to loss of power Electric Transmitter SPT-38 Power Supply
- 2. Instrument connection -- Small loss of reactor Incorrect pressure signal Repair eceponent leek ocolant 3 Transmitter fatture - No effect Incorrect pressure signal Depair component due to internal fault 4.2 BC Pump Seal Filters:
4.2.1 Operating Filter 1. talte falls closed -
Flow through filter stopped Seal injectton flow to Valve in spare Manual Isolation (plugged, d m ged, BC pumps stopped filter path, or Velves NP-29, etc.) bypass both HP-132, NP-133, mata and NP-134 standby filters (local action) 4.2.2 Operettag Seal 1. Filter plugged -- Flow through filter stopped Seal injection flow to Valve in spare Filter HP-F-18 BC pumps stopped filter path, or (HP-F-14 Standby) bypass both main and standby filters (local action) 4.2 3 Manual Isolation I. Valve falls to - No effect during normal No effect during normal If one of these Valves for Standby open on demand operation. Loss of spare operation when spare or backups has Filter or Bypees or bypass capaatty bypass is not demanded fatted, utillae HP-28. NP-135 the remainics one if required 4.2.4 Standby Filter ~ 1. Talve falle closed - Flow through standby filter No effect Valve in filter Manuel Isolation (plugged, damaged, prevented bypass if felves RP-129, etc.) required (local MP-330, NP-131 action) 4.3 Seal Injection Flow Control 4.3.1 Flow Oriftee 1. Orifice plugged - Seal injection flow reduced Seal injection flow to RC Repair component or stopped and control pumps stopped signal to throttle valve incorrect
Reference Drawlege: FSta Figure 9 3-2 SUBSYSTEM 4.0: RC PUMP SEAL INJECTIOll SUBSYSTEM (Continued)
Poteattal Failure Mode lamediate Effects Interface At $4bsystem Remedial Action Component Mode lavolved Within Subsystem Interface Within Subsystem Flow Controller / 1. Electrio Power Incorrect signal to flow Neglisable effect for high Monitor and 4.3.2 Transettler failure control flow Transeitter IPT-75 Supply, control valve, potentially flow since flow is I4C System, resulting in too much or throttled downstreme. On free individual Internal too little flow. low flow, reduced seat seal injection Fault injection flow to RC lines if pumps. Incorrect signal required to 14C systee Instrument Air Full HPI pump discharge Negligable effect on seal Manually control 433 Flow control valve 1. Talve fails open flow to individual seal injection supply seat flow with HP-31 (HP-942) (valve assumed air-to-elose) injeetton lines HP-140 or with individual seat injection line throttle valves (local setton)
- 2. Talve falls open Control Signal Full HPI pump discharge Negligable effect on seal Manually control from IFT-75. flow to individual seal injection supply seat flow with Electric injection lines HP-140 or with Power Supply individual seat injection line
( throttle valves (local action) 3 Talve fails open - Full HPI pump discharge Neglfgable effect on seal Manually control due to 1 sternal flow to individual seal injection supply seal flow with damage injection lines HP-140 or with individual seal injection line throttle valves (local action)
- 4. Valve falls closed Control Signal Seal injection flow reduced Seal injection flow to RC Talvs in bypass from IFT-75, or stopped pumps stofred and annually Electric control seal Power Supply flow from header (HP-140) or from individual seal injection 114a-(local action)
- 5. Talve fatto closed - Seal injection flow reduced Seal injection flow to Sc valve in bypass due to internal er stopped pumps stopped and manually damage or plugging, control seal etc. flow from header (HP-140) or from individual seal injection I!nes (local action)
R2fersnes Draulngis FSAR Figure 9 3-2 (Sh.ets i and 4)
SUBSYSTEM 4.0: BC PUMP SEAL INJECTION SUBSYSTEM (Continued )
Potential Failure Mode Immediate Effects Interface at Subsystee Remedial Action Coerement Mude Involved litthan Subsystem Interface Within Subsystee 4 3.4 Manual Isolation 1. Talve falls closed - Seal lajection flow stopped Seal injectico flow to RC falvo in bypass Talve(s) HP-138, (plugged, daanged, pumps stopped and annually "
pr-139 ete.) control seal flow free header (HP-140) or from individual seal injection lines (locas action) 4.4 Individual RC Pump Seal Injection t. Anes (4 Total,1/RC Pump):
4.4.1 Flow Transeitter(s) 1. Incorrect output due 14C Syntes, No effect Incorrect flow alsnal Restore power IFT-101, IFT-102, to loss of power Electrie to control room 1FT-103, 1FT-104 Power Supply
- 2. Instrument connectica -
Small loss of reactor Incorrect flow signal Repair oceponent leak coolant to control roce if accessible 3 Transmitter failure - No effect Incorrect flow signal Depair component due to laternal to control room af accessible fault 4.4.2 Manual Throttle 1. Talve falls closed - Seal injection flow in Seal injection flow to one Repair component valve (s) HP-64, (plugged, damaged, affected line stopped RC pump stopped if accessible RP-65 HP-66, etc.)
NP-67 2. Valve falls open - Flow in effected line Seal injection flow to a Repair component, unthrottled single DC pump highar utilize stop than setpoint check valves in line on short tore basis for flow thrott11 rig if required (local action) 4.4.3 Check talves 1. Valve falls closed --
Flow in affected seal Seal injection flow to a Repair ocoponent (2/line) injection line stcpped single RC pump stopped if accessible RF-144 HP-145, 2. valve rette to -
no effect since there are 2 no effect stace there are Repair componeut HP-146, NP-147, prevent backflow , check valves per line 2 check valves per line at shutdown HP-283, HP-284, (one inside and ore HP-286, HP-393 outside RR) 4.4.4 Manual Isolation 1. Talve falta closed -
Flow in affected Seal Seal injection flow to a Repair component valves On Line to Injection line atcpped single RC pump stopped if accessible RC Pump HP-394 HP-285 4.5 System Inlet Flows:
4.5.1 Seal Injection 1. Loss of flow Subsystem 3.0 No flow Loss of Seal Injection Home Flow Free to DC pumps HPI Pumpe
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APPENDII E FAILURE MODES AND EFFECTS ANALYSIS SUBSYSTEM 5.0: REACTOR COOLANT MAKEUP SUBSYSTEM
Refsmsos Drawings: FSAB Figurs 9.3-2 SUBSYSTEM 5.0: REACTOR COOLANT (RC) MAKEUP Potentiat rallure Mode immediate effect.
Interface At Subsystem Benedial Action Component Mode involved Within Subeystem Interface Within Subsystem 5.1 Beactor talet Line Loop & Header:
5.t.1 Manual isolation 1. Talve falla closed - Makeup flow stopped Loss of normal makeup flow Sepair component, f alse NP-110 (plugging, damaged, if required (RP-T27A) ete.) provide oakeup flow via Loop B injection path (open local HP-18 and throttle with remote HP-27) 5.1.2 Flow Transmitter 1. Transeitter failure -- No effect Incorrect flow signal on Sepair component IFT-7, 78 and 78 due to internal one transmitter fault
- 2. lautorrect output due I1C System, No effect Incorrect flow signal from postore power to signal failure Electrio all 3 transeitters supply Power Supply 3 Instrument connection - Small loss of reactor Incorrect flow signals Depair component leak ecolant from all 3 transmitters 5.1 3 Motor Operated I. Talve opens on IEC System Makeup flow is not lacreased makeup flow, Manually close valve RP-26 spurious signal throttled increased pressuriser valve (local (HP-724A) level, drop in LST level, action) potential loss of HPI pump NPSN
- 2. Talve opens on ES Makeup flow is not Increased makeup flow, Manually close spurious signal throttled increased pressuriser salve (local level, drop in LST level, action) potential loss of HP1 pump NPSB 3 Valve inadvertantly - Habeup flow is not Increased makeup flow, Close valve opened throttled increased pressuriser level, drop in LST level, potential loss of HPI pump NPSH 4 Talve falls open -- Makeup flow is not increased makeup flow. Isolate with due to internal throttled increased pressuriser HP-118 (local fault level, drop in LST level, action) (u111 potential loss of HP1 stop makeup pump NPSH flow)
(Modes involving failure to open are part of emergency HPI and not included here) 52 Minimus Flow Rypass Loops:
5.2.1 Manual isolation 1. Talve fails closed - No flow through minlaus No rooling flow to Repair component Talve HP-234 (plugging, damaged, flow loop pressuriser spray line k etc.) or cold leg inlet nossles, no effect en makeup espeetty
Beforence Drawings: F918 Figuro 9 3-2 (Sheeta 1 and 4)
SUBSYSTEN'S.0: REACTOR COOLANT MAKEUP SUBSYSTEM (Coritirtued)
Pot.attel Fati.re Mode lamediate effects it Subsystes Benedial Actica laterface hithia Subsysten Withia Subsystes laterface C&st Mude lavolved incorrect f!cu signal sepair componeet
- 1. Imatrument connection - Small loss of coolant 5.2.2 Flow Treaseitters to control roce IFT-IIT, IFT-118 leek Incorrect flow signal Bestore power
- 2. Incorrect output due Electrio Power No effect to control roce supply to loss of power Supply, I&C System Incorrect flow signal Depair eosponent Bo effect 3 Transmitter faltare -
to control roce due to laternal fault M1alous flow path blocked No cooling flow to one Repair component 5.2.3 Manual Throttle 1. Talve fails closed -
to one of two reactor cold leg talet aossle talte HP-241 (plugging, damaged, cold leg inlet nozzles etc.)
-- Mieluum flow path Eueens flow (full HPI pump If required valve
- 2. talve falls open discharge to stateue HP-234 unthrottled to one of two flow loop) to one reactor ave 11able to reactor cold leg intet nossles, automatie cold les intet nossle, block flow into reduction la flow through potential drop la LST toop (local actica), repair moraal makeup valve level component Manteue flow path blocked No effect on reactor Repair component 5.2.4 Manual Throttle 1. Talve falta closed -
to pressuriser spray line makeup, but no cooling Talve HP-235 (plugging, damaged, flow to pressuriser spray etc.)
and one of two reactor lina or to one cold leg cold leg talet nozzles inlet nossle Minisue flow path Excess flow to Close valve
- 2. Talve falls open -
unthrottled to pressuriser pressuriser spray line HP-234, or spray 11oe and one of two and to one reactor cold valves RP-340 reactor cold legs, leg intet nozzle, and HP-356 in automatie reduction la potential drop in LST reactor level building flow through normal makeup valve (local action)
Manteus flow path blocked No bypass flow to sepair ecaponent 5.2.5 Menval Isolation 1. talve fails closed --
to pressuriser spray line pressuriser spray 11ae
. Talve HP-340 (plugging, damage, etc.)
Manteus flow path blocked No bypass cooling flow to Repair component 5.2.6 Manual Isolation 1. Talve falls encaed -
to one of two reactor one of two reactor cold Talve RP-386 (plugging, damage, leg inlet nozzles (no cold legs etc.) effect on normal makeup) 53 Norest Makeup Flow control Loop:
Incorrect flew signal Monitor flow with Instrument connection - Sea 11 loss of coolant FT-7, repair 5.3.1 Flow Transmitter 1. from all transmitters 1FT-10, 108, 108 teak component incorrect flow signal Monitor flow with
- 2. lacorrect output due Electric Power No effect from all transmitters FT-7, restore due to loss of Supply, I&C powere supply power System Incorrect flow algna! Monitor flow with None 3 Transellter failure -
from failed transmitter FT-7, repair component
Betscence Oraecings: FSin Figure 9 3-2 SUBSYSTEM 5.0: REACTOR COOLANT MarRUP SUBSYSTEM (Continu;d)
Potential Pa11ere Mode immediate Effects Interface at Subsystes Benedial Action Componest Mode Involved Withis Sutsystes Interface Within Subsysten 532 Flow control valve 1. talve fatte elosed Imatrument Air normal flow to reactor eypass flow continues. If required.
NP-120 (BP-T23) (assustag valve inlets stogg+1, flow Overall sigasficant manually la ear-to-opes) through minisme flow loop reductica la makeup flow control with continues bypass valve BP-26
- 2. Talve faite elemed - Normal flow to reactor Bypass flow coattaues. If required, due to internal inlets stopped, flow Overall sigaffleant manually fault through alminum f!cw loop reductica la makeup flow c^mtrol with continues bypass valve HP-26 3 Talve closes doma 14C System Boreal flou to reactor Pypass flow continues. If required, due to incorrect talets reduced, flow Overall sigelticant manually control algaal through staisua flow loop reductica la sakeup flow control with continues typese valve HP-26
- 4. Talve falls opes -- BPI flow not throttled. Escess makeup flow to EC3, Isolate valve due to internal Ezeess makeup flow to temporary decreased HP-120 and fault RCS bypass flow to manually pressuriser spray line, control flow potential drop la LST with bypass holdup, poteattal loss valve RP-26 of MPsa to RPI pump
- 5. valve opens up due IAC System uP1 flow not throttled. Emeess makeup flow to RCS, Isolate valve to incorrect Excess makeup flow to temporary decreased HP-120 and control signal RCS bypass flow to manually pressuriser spray line, control flow potential drop la LST with bypass holdup, poteattal loss valve HP-26 of NPSN to RPI pump 533 Manual Isolation 1. Talve falle closed - Normal makeup flow to RCS Bypass flow coattaues. Isolate valve Valves HP-119, (plugging, desage, stopped, bypass flow Overall sisatricant NP-120 and HP-128 etc.) through statsue flow loop reductica la sakeup flow manually coattaues control flow with bypass valve fiP-26 5.3.4 Check valve 1. Talve fa11s closed - normal makeup flow to ac3 eypass flow eentinues If required, HP-194 (p!wgglag, damage, stopped, bypass flow Overall sigatricant provide makeup etc.) through statous flow loop reduction la makeup flow flow via Loop B continues injection gath (open local HP-118 and throttle with remote HP-27)
- 2. Talve fails to - No effect during steady No effect durlag steady Repair component prevent backflow state og'eration state operatica at shutdown 5.3.5 Inlet t.ine 1. Orifice plaryed - Normal flow to one of two Flow 1mbalance between Repair component Oriftees cold legs stopped or the two reactor cold reduced, tacreased flow legs to the other ccid leg
- . _ - - . _ - _ - -~
Reference Drawings: FSAR Figure 9.3-2 (sb..ts i and =>
SUBSYSTEM S.0: REACTOR C00LAET MAKEUP SUBSYSTEM (Continued)
Foteatta! Failure Mode Immediate Effects Interface At Subsystem Semediel Action Component Mode Involved Withia subsystes laterface Within Subsysten 5.3.6 Inlet Line 1. Talve failed elooed - Normal flow to one of two . Flow imbalance between Repair component Check Valves (plugging, damage, reactor cold legs stopped the two reactor cold NF-126, NP-127 etc.) or reduced, increased flow legs to the other cold leg
$.4 Subsystem input Flow Free 1. Subsystem 3 0 Loss of enkeup flow and Loss of makeup flow and mone 5.4.1 Loss of flow ,
NPI Pumps flow to pressuriser aprey bypass flow to Itae pressuriser sprey line
- 2. Reduced flow Subsystem 3.0 Reduced makeup flow and Reduced makeup flow and None reduced flow to bypass reduced flow to pressuriser spray line pressuriser spray line 5.5 System Piping:
5.$.s Vests, Draine, 1. Systes leaks - Loss of reactor coolant Loss of reactor coolant, Isolate lenke and Piping, Instrument potential for reduction repair as Connections, ete. In reactor coolant makeup needed rate
APPENDII F FAILURE MODES AND EFFECTS ANALYSIS SUBSYSTEM 6.0: CHEMICAL PROCESSING SUBSYSTEM
Sefarence Drawiry;s: PSAA Figure 9,3-1 (Sheet 1) rsae Figure 9 3-2 (Sheet 3)
SUBSYSTEM 6.0: CHEMICAL PROCESSING SUBSYSTEM Potential Failure Mode lamediate Effects v
Interface At Sebeystem acmedial Action Craponent fode involved Withia Su Mystem laterface Within Subsystem 6.8 Cheeleal Addittom:
6.1.1 Manual Control 1. 52 blanket system N2 Possjble NyHg backflow; no Blanket No Ny H g ava!!able to Close contre!
Valve (N-83) falls Ny blanket in N H24 drum enkeuP filters valve N-81
- 2. Valve fails closed - No N 2 blanket in N H24 drums Probat,1y none possible arriosive mixture 6.l.2 Check Valve 1. Fails to prevent --
Ny Hg backflowg possible No NyHg evallable to Close control (N-84) backflow emploalve misture makeup (11ters valve N-83 6.1 3 pydrazine Drum 1. Drum leaka - Possible esplosive mistureg Eventual loss of N 2Hg Isolate drum and eventual loss of suction available to makeup replace pressure to pump filters
- 2. Drum emptied -
No N2g H No NyNg available to Isolate drum and maEeup filters replace 6.1.4 leanual Isolation 1. Valves fait closed -
No Nype No Ny Hg available to None Valves (CA48, makeup filters CA-45) 6.t.5 Manual Isolation 1. Valves fait closed -
No NyNg None if alternate flow Open CA-463 Valves (CA-$2 path available crossover to CA $4) pump CA-P3 6.1.6 Hydrasine Pump 1. Electric p<mer Elects te Power Pump stopsg no N H24 None if alternate flow (CA-P4) Cren CA-463 nupply falls path available crossover to pump CA-P3
- 2. Pump fails --
No NyHg Mone if alternate flow Open CA-463 path available creasover to pump CA-P3 6.1 7 Check Valve 1. Fails to prevent -
Possible backflow to drum No N3Hg swallable to Close CA-$4 (CA-$6) backflow if pump is not runnarig maleup filters 6.1.5 Manual Isolation 1. De.mineraltsed water Demineralized No demineralfred water No LSOH available to None Valve (14-121) supply fails Water to tank makeup filters
- 2. Valve fails elooed ==
No desineralized water No LiOH or incorrect L10H Concentration to tarik concentratica available checked via to makeup filters sampling
- 3. Valve falls open --
D11utes L10H in tank Incorrect L10H Concentration concentration available checked via to enkeup filters sampling 6.t.9 L10H Mia Tank f. Tank leaks -
Eventual lass of suction Eventual loss of L10H None (CA-T)) pressure to pump available to makeup filters
- 2. Tank emptles -- No L10H No L10H available to None makeup filters 6.5.10 Sampling Waste f. I tnes fall open -- Decreased Lt0H Decreased L10tl evallat,le None Lines to makeup filters
Reference Drawings: FSAR Figtre 9.3 1 (Sheet 1)
FS AR Figure 9.3-2 (Sheet 3)
FS A A rigure 9.3-$ (Sheets 1,3,44)
SUBSYSTEM 6.0: CHEMICAL PROCESSING SUBSYSTEM (Continued)
Potential Fa11ure Mode Immediate Effects Interface At Subsystem semedial Action involved Within Subsystem Interface Within Subsystem Component Mmie 6.1.11 Itanual Isolation 1. Valve fails closed - No L10H No LtC48 available to None makeup filters Valve (CA-44) 6.1.12 Manual Isolation 1. Valves fall closed - No L10H None if alternate flou Open CA-463 path available crossover to Valve (CA-47, pump CA-P4 CA-49)
Llectrie Power Pump stops; no L10l! None if alternate flow Open CA-46; 6.1.13 L10H Pump (CA-P3) 1. Electric power supply falls path available crossover to pump CA-P4 No L10H None if alternate flou Open CA-46;
- 2. Pump falls -
crossover to path available pump CA-P4 6.1.14 Check Valve 1. Falls to prevent - Possible backflow to tank No L10H available to Close CA-49 backftcu if pump is not running makeup filters (CA-$1) 6.1.15 Manual Isolation 1. Demineralized unter 1+eineralized No danineralised water to No caustic or incorrect Concentration Valve (DW-120) supply fails Water tanki no caustle or caustic concentration checked via incorrect caustle available to LP) pumps sampling concentration available to borne recovery
- 2. Valve falla closed - No desineralized water No caustio or incorrect Concentration to tank; no caustic caustic concentration checked via or incorrect caustle available to LPI pumps sampling concentration available to horon recovery Valve falls open -- Dilutes caustic la tank; 1peerrect caustic Concentration 3
incorrect caustic concentration avallat,le checked via concentration available to LPI pumps sampling to boron retovery Tank leaks Eventual loss of suction Eventual loss of caustic None 6.1.16 Caustic Mis Tank 1. -
available to LPI pumps (CA-71) pressure to pump No caustle available to No caustic available to pone
- 2. Tank empties -
boren recovery LPI pumps No caustic available to No caustic avallatile to None 6.1.17 Manual Isolation 1. Valves fait closed -
LPI pumpa Valves (CA-34, teron recovery CA-35, CA-37)
Pump stops no caustle No cauntie available None 6.1.18 Caustic Pump 1. Electrie power Electrie Power supply falls available to boron to 4.P! pumps (CA-P1)
- recovery
- 2. Pump falls - No caustle available to No caustle available None boron recovery to I.Pl ruars 6.1.19 Sampling. 1. Linen fall open -- Decreased caustic available Decreased caustic available None to boron recovery to LP) pumps Waste Lines
Befsrence Creutngs FSAR Figure 9 3-1 (Sheet 1)
FSAR Figure 9 3-2 (Stett 3)
FSAR Figure 9.F5 (Sheets 1,3,44) ssBSYSTal 6.0: CBEMICAL PROCESSIEG SUBSYSTEN (Continued)
Fotential Failure pode lamediate Effects Interface At Subsystee Remedial Aetton Component Mode favolved Within subayates laterface Within Subsystem 6.2 Borto acid Addition:
6.2.1 Manual !aolation 1. beatneralized water Dweireralised No deelneraltsed water to None if concentrated Concentration valve (DN-118) supply falls Water tank; no borto acid or borto acid available checked via incorrect borte acid from boron recovery or sampling concentration available adequate concentrated to concentrated boric borte acid storage tank acid storage tanks inventory la available
- 2. Valve falla closed - No deelneralised water to None if concentrated Concentration tanks no borte acid or borte aetd available checked via incorrect borto acid free boron recovery or saapitr4 concentration available to adequate concentrated concentrated boric acid boric acid storage tank storage tanks inventory is available 3 Valve fails open -- Dilutes borto acid; None if concentrated Concentration incorrect borte acid borte acid available checked via concentration to concen- from boron recovery or campting trated borto acid storage adequate concentrated tanks boric acid storage tank inventory la available 6.2.2 Borto Aeld 1. Electric pwer Electric Power Heater fallag borto acid None if concentrated Replace heaterg may crystalliseg small borto acid avallat.le unplug Itnes Mis Tank supply fatta potential for plugging fra boron recovery or (CA-T2) adequate concentrated and lose of flow to storage tanks borto acid storage tank inventory is available
- 2. Heater fails -- Borte acid may crystalliseg None if concentrated geplace heateri small potential for boric acid available unplug !!nes plugging and loss cf flow free ten recovery or to storage tanks adequate concentrated borte meld storage tank inventory la available 3 Tank seeks - Eventual loss of suction None if concentrated None pressure to pumps borie acid avallatile fra boron recovery or adequate concentrated ,
borto acid storage tank inventory la available i
- 4. Tank esplies - No borto acid flow to None if concentrated Pope concentrated boric borto acid available acid storage tanks fr m boron recovery or adequate concentrated borte acid storace tank inventory is available Electric Power No local level indication No level indloation to None 6.2.3 t.evel Transmitter 1. Electrio power supply fails 14C systre Process Signal Incorrect algnal to No sevel indication to None
- 2. Connection leaks transmitter 18C systre 3 Transmitter falls - No local level Indication No level indication to None IAC system
Reference Draulngs: FSAR Figure 9 3 1 (Sheet 1)
FSAR F1ture 9 3-2 (Sheet 3)
FSAR Figure 9 3-5 (Sheeta 1,3,84)
SUBSYSTEM 6.0: CHsDf1 CAL PROCESSIBG SUBSidTEM (Continued)
Potectial Failure Mode Immediate Effects Remedial Action l At .%bsystem Interface Within Subsystem Pbde involved Withia Subsystem Interface Congenent Electrie Power No local temperature None None 6.2.4 Temperature 1. Electrie power supply falls indication Transmitter None
- 2. Connection leaks Process Signal Incorrect etsnal to None transmitter No local temperature None None
- 3. Transmitter f alls -
indication No borte acid to None if concentrated None 6.2.5 Manual Isolation 1. VmIvo fails closed -
tierto acid available storage tanks faive (CA-4) frun boron recovery or adequate concentrated borte acid storage tank inventory is available Electric Power Borte acid may crystallizes None if concentrated Restore trace 6.2.6 Miscellaneous 1. Electrio pouer supply to trace small potential for borto acid available heatingg unplug tiping heating falls plugging and loss of flow fram boron recovery or lines to concentrated boric acid adequate concentrated storage tanks
- borto acid storage tank inventory is available
- 2. Trace heatirg fails - Borie acid may crystallize 3 None af concentrated Restore trace i email potential for borte acid evallable heating; unplug l plugging and loss of flow from boron recovery or lines to concentrated borto acid adequate concentrated l storage tanks borto acid storage tank I. inventory is available No borte acid to concen- None Alternate flow 6.2.7 Manual Isolation ~ 1. Talve fails closed --
path through trated borto atorage valve (CA-5) tanks; alternate flow CA-P2B path available available Electric Power Pump stops; no boric seid Mone Alternate flow 6.2.8 LP Borte Acid 1. Electrio power to concentrated storage path through I%sp (CA-P2 A) aupply falls tanks; alternate flow CA-F2B path available available No borto acid to concen- Mone Alternate flow
- 2. Pump fails --
trated borto acid storage path through tanks; alternate flow CA-F2B path available available
- 4 boric acid to concen- None Alternate flow 6.2.9 Manual isolation 1. Valve fa!!n closed --
trated boric acid storage path through Valve (CA-7) tanka; alternate flow C A-F2B
- path available available .
-- Possible backflow to sin None Close isolation 6.2.10 Check Valve (CA-15) 1. Falls to prevent t,ackflow tank if pump is not valve CA-73 running; alternate flow alternate flow path available path through CA-P2B available
. . _ _ . _m .___ .
Reference Drawings: FSAR Figure 9.3 1 (Sheet 1)
FSan Fscure 9 3-2 (Sheet 3)
F57R Figure 9.3-$ (Sheets 1.3.5%)
SUBSYSTEM 6.0: CMBEICAL PROCESSING SUBSYSTIBE (Continued)
Potential Failure mde lamediate Effects Interface At Subsystem Remedial Action Ccagement his levolved Within Subsystee laterface Withip Subsysten 6.2.11 Manual Isolation 1. Talves fall closed - No borte acid to concen- None if concentrated None Valves (ICA-16 treted boric acid borte acid available ICA-13. ICA-18 storage tanks from boron recovery or ete.) adequate concentrated borte seid storage tank inventory is available 6.2.12 Pressure 1. f.lectrio imwor Electric Fouer No local pressure indication No pressure indication to None Tranzettter supply falls 1&C systen
- 2. Connection leaks Process Signal lacorrect alsnal to No pressure indleation to None trinseltter 14C system 3 Transeitter falls - No local pressure indleation No pressure indleation to None 14C system 6.2.13 Check Talve 1. Falls to prevent - Possible backflew if pump None if concentrated borte Close ICA-16 (CA-85) backflow is not running acid available free ICA-16 concentrated boric acid transfer pumps 6.2.14 mnual isolation 1. valve fasta elesed - No boric acid No boric acid available None Talve (CA-25) to core flood tanks 6.2.15 IIF Borte Acid I. Electric pouer Electric Power Pump stops; no boric acid No boric acid available None Pump (CA-P5) supply falls to core flood tarA
- 2. rump fa11s - No borte acid No boric acid evallat.le None to core flood tank 6.2.16 mnual isolatt'n 1. valves fall to opan. - No borte oc1J No borto acid available None Talves (ICA-26 fall closed to core flood tank 1CA-28) 6.2.17 Manual Control 1. Talve falls closed -- No horie acid to concen. No borte acid available Alternate flow valve (CS-62) trated borte acid storace to makeup filters. BWST path available tanks 6.2.18 Concentrated Borto 1. N2 blanket N2 Planket Fossible borto acid None Close control Acid Storage Tank system falls backflow valve CS-62 (1WD-722) 2. Electrie power Electric Power Borte acid crystallites; No borte acid evallable Alternate flow seepply to trace potential plugging and to makeup filters. BdST path available heating falla loss of flow 3 Trace heating falls - Borte acid crystallizes; No borte meld available Alternate ficw potential plugging and to makeup filters. PWST path available loss of flow
- 4. Inlet terte acid Borte Acid No borte acid None onless concentrated Alternate flow flow fatic Fr<e Min borte acid storage tanks path available Tank /ftC BAced are empty Evaporator Concentrate Cooler
Reference Drausrast FSAR Figure 9.3 1 (Sheet 1)
FS AR Figure 9.3-2 (Sheet 3)
FSAR Figure 9.3-$ (Sheets 1,3,M)
SUBSYSTEM 6.0: CHEMICAL PROCESSING SUBSYSTEM (Continued)
Fotentist fatture stode Jamediate Effects Interface At Subayates Remedial Action Mode involved Within Subsystee Interface Within Subsystem Contement 6.2.18 Concentrated Sorte 5. Tank leaks -- rossible floodinal Eventual loss of borte Alternate fim acid Storage Tank eventual loss of acid available to makeup path ava!!able (1WD-T22) suctica pressure to filters, BWST (cont'd) pump
- 6. Tank empties -- No borte acid No torie acid available Alternate flow to makeup filters, BWST path available
- 7. Tank went, re!!ef -- Cover gas release to vent None Nonc valves fall open header
- 8. t rata, sample lines - Decreased borto acid Decreased borte acid Alternate fim fall open available to makeup path available filters, BWST Electrso rever No local level indication No level indleation to pone 6.2.19 Level Transmitter 1. Electrie pmer supply IAC system
- 2. Connection leaks Process Signal Incorrect alsnal to No level indleation to None transmitter IAC system 3 Transmitter falls - No local level indication No level indleation to Bone 1&C system 6.2.20 Manual isolation, 1. Valves fall closed - No boric acid No borte acid available Alternate flow Control valves to makeup filters, t%iST path available (CS-63, CS-64, CS-67) 6.2.21 Concentrated Borte t. Electric power Electric rover rump stopal no borte acid No boric acid available Alternate fim acid Transfer rump supply falls to makeup filters, BWST path available (1WD-F22) 2. Pump falla -- No borto acid No torto acid available Alternate ficw to makeup filters, PWST path available r 6.2.22 Manual toelattos. 1. Valve fatim closed -- No borte seid No borte acid available Alternate flow to makeup filters, I!WST path available Valve (CS-68) 6.2.23 Manual Isolation 1. Valves fait closed - No borio acid No borio acid evallatil,s Alternate flow Valves (CS-72, to available to makeup path available CS-19) filters, DWST 6.2.24 Check Valve 1. Falls to prevent -- rosett,le backflow if pump Nor.e if concentrated close CS-72 (CS-73) t,ack flow la not running borte seid available fr<a LP terie acid pump 6.3 NC Bleed Bioldup Tanks and Transfer rumps RC Bleed flow falls RC Bleed Flow RC bleed holdup tank could Mosua if alternate fim Alternate bleed i 631 leanual Contsol 1.
path available flow available
' Valve (CS-43) emptyl no impact since rest of subsystem operates only on demand
- 2. Valve falla cloned - RC bleed hoidup tank could None if alternate fl m Bleed flow can be emptyl no impact since path avallat'le diverted to rest of subsystem 2WD-T21A operates only on demand
Reference traussigs: FS89 Figure 9.3-1 (Sheet 1)
FSAS Figure 9 3-2 (Sheet 3)
F5at Figere 9.3-5 (Saests 1.3, A4)
SUBSYSTEM 6.0: CBIBEICAL PROCESSING SUBSYSTIDI (Continued)
Peteattal Fatture tbde lamediate Effecta laterface at Subsystee temedial Aetica Componest Mode Involved Within Subsystes laterface Within Subsystee BC Bleed Noldup Tank can mt be purged; no Bone if alternate ficw Nces 632 1. My blartet 52 Blanket path avallatte erstem falls sepact since rest of Task (IWD-7214) subsystee operates only om deeand
- 2. Tank leaks -- Fossible flooding; eventual mone af alternate ricw Alternate bleed loss of suction pressure path available flou availat,le to pump; no tapact ainee rest of subsystem operates caly ce demand 3 Tank empties - No flow; no sepact since None if alternate flow Alternate t!eed rest of subsystem operates path avallat.le ficas avallatte only om demand Cover gas release to vent mone mone
- 4. Tank went, re!!st -
valves fall open header pone 633 Level Transmitter 1. Uectrie power U ectric rever Bo accal level indleattoa no level indicattom to supply falls 1&C system Frocess Signal Incorrect signal to no level indtestion to Mone
- 2. Conneettoa leak transettter I&C system Bo local level andleation to level indicatica to None 3 Transmitter failure -
IAC system Doctrio Power Borte acid may crystalltre; None if alternate flow Restore trace 6.3.4 9ttecellaneous 1. U ectrie power heating; unplug supply to trace small poteattal for path available Piping beatts.g falle plugging and loss of flows lines; al ter-no lepact since rest et nate tieed f3ce autmystes operates only on available demand .
Borte acid may cryatallize; None if alternate ficw Bestcre trace l
- 2. Trace beating falls -
beating; unflug small poteattal fce path available plugging and loss of flou; lines; alter- j no sepact since rest of nate t.leed flow I subsystem operates only available l i
om demand 1
Weste, train, 1. Lines fall open - Decreased flow; no sepact mone if alternate riou Alternate t,leed 6.35 since rest of subsystem path available (Icw available 3.asple Lines operates only ce demand
- No flow to pump; so impact mone af alternate flow Alternate t.leed ,
6.3.6 ttanual isolation t. valves fait closed einee rest of autsystes path available ficw avallatile !
valves (CS-42 CS-148, CS-44) sperates only on demand pone af alternate ficw Alternate t,leed BC Bleed Transfer 1. Hectrie preer Flectric romer. Pump stops; no flew to 6.3.7 teron recovery path avallatlo flou avallat,le Pump (1WD-F281) supply falls 50 flcw to teron recovery None if alternate ficu Alternate tieed
- 2. Fump falla -
path available flow avalletle Cheek Valve 1. Falls to prevent - Possible backflow if pump None if alternate flcw Close contrcl 6.3.0 is not running path available valve CS-46 (CS-45) t.ack flse
__ _ _ . . . . . _ _ _ . _ _ _ . _ m . _ __
peterence Drawings: iSAR Figure 9.3-4 (Stieet 1)
Tsaa Figure 9 3 2 (Sheet 3)
F? As Figure 9.3-5 (Sheets 1,3,&4)
SUBSYSTEM 6.0: CIMDtICAL PROCESSING SUBSYSTEM (Continued)
Foteettal failure Nde lamediate Effects Interface at Subsystem Remedial Action Compoment Ibde favolved Within Subsystee Ir.terface Within Subsysten 6.3.9 Flw Ortrice 1. Oriftee p!was - No flow to boren recovery mone If alternate flow Alternate bleed path available flow available e 6.3 10 Flow Traammitter 1. Electrie power Electric Power No local flow indiention I6o flow indication to None supply falls 14C systee
- 2. Conneetton leak Frocess Signal lacorrect signal to No flow indleattom to None transmitter lac system 3 Transmitter f atture - No local f!cu indleation No flow indleation to None 1&C systen 6.3.11 Manual Control 1. Valve rette closed - No flow to boron recovery None if alternate flow Alternate tleed valve (CS-46) path available flow available 6.3.12 Manual Iscletton 1. Valven fall closed - No flow to baron recovery None if alternate (Iow Alternate bleed Velves (CS-80, path available flow avallat,le CS-472, CT-1) 6.3.13 Manual Isolatton 1. Destneralized water !*stneralized Deelneralized water holdup No deelneralized water Alterna te Valve (CT-88) supply falls Water tank could empty to makeup filters demineralized water flow path available
- 2. Talve falls closed -- Deatnereltzed water holdup No desineralized water Alternate tank could empty to makeup ft!ters deelneralized water flow path swallable 6.3.14 at Domineralized 1. Ny blanket syntes W2 Planket Tank cannot be purged No deelneralized water Al ternate Water Holdup falls and is unavailable to makeup filters deelneralized Tank (IWD-7218) water flow path available
- 2. Tank leaks -- Poestble flooding; Eventual loss of Al ternate eventual loss of deelneralized water deelneralized suction pressure to mak>.up filters water flow path to pump available
- 3. Tank empties - No deelnerallred water No desireralized water Al ternat e to makeup filters desineralized water flow leth available 4 Tank went, retter - Cover gas release to vent None None valves fall open header 6.3.15 Level Transmitter 1. Electric power Electrie Power Ne local level indication No level indleation to None supply falls ISC systen
- 2. Conneetton leak Process Signal Incorrect signal to No level Indiention to None transettter 14C system
- 3. Transmitter failure - Na local level indication No level indication to None 14C systaa t
6.3.16 Waste Drata, 1. Lines fall open - Decreased deetperalized Decreased deelneralized Alt ernate Sample Lines water water to makeup filters deelneralized water flow path available
Aefersnce Drautross: FSAR Figure 9.3-1 (Sheet 1)
FSAR Figure 9.3-2 (Sheet 3)
FS AR Figure 9.3-5 (Sheeta 1,3,64)
SUBSYSTIDI 6.0: CHEMICAL PROCESSING SUBSYSTEM (Contintled)
Potential Failure mde lamediate Effects Interface At Subayates semedial Action Mode involved utthin Subsystem Interface Nithin Subsystem Component 6.3.17 Miscellanecua 1. Electrie power Electric Power Borie acid may crystallise; No desineratived water Restore trace supply to trace small potential for to makeup filters heating; Piping plugging and loss of flow upplug lines; heating falls alternate demineralized a water flow path available
- 2. Trace heating falls - Borte acid may crystallizeg No deminerallred water pestore trace small potential for to makeup filters heating; plugging and lose of riou unplug !! ness alternate deminereltzed water flow path available 6.3.18 Manual Isolation 1. Talves fall closed - No demineralized water No demineralized water Alternate Valves (CS-52, to pump to makeup filters demineratised water flow path CS-149 CS-54) available 6.3.19 RC Bleed Transfer 1. Electrio power Electrio Power Pump steps: no No deminerall ed water Alternate Pump (IND-P218) sus ply falls demineralized water to makeup filters demineralized water flow path available
- 2. Pump falls - No demineraitsed water No demineralized water Al terna te to makeup filters demineralized water flow path available 6.3.20 Flow Oriftee 1. Orifice plugs -- Decreased dcmineralized Decreased deminerallred Alternate water water to makeup (11ters demineralized j water flow path evallable 6.3.29 Hanual Control 1. Valve falls closed - No deelneralized water No deminerall2ed water Alternate Talve (CS-56) to makeup filters demineralized water flow path available l
- 1. Flectric Power No local flow indication No flow indleation to None 6.3 22 Flow Transmitter Electric swer
!&C system supply falle Connection leak Process Signal Incorrect signal to No flow indication to None 2.
transmitter IRC system 3 Transmitter failure -- No local flow indication ho flow indication to None ISC system l
6.3.23 Check Talve 1. Falle to prevent - Possible backflow if pump No demineralized water Close control teack fl ow is not running to makeup filters valve CS-56 (CS-55) l l
r
m _ _ _ __ < - . _ _ m s- _
Screrence Dcawings: FSAS Figure 9.3 1 (Sheet 1)
FSSR Figure 9.3-2 (Sheet 3) rr u rigore 9.3-5 (Sh.et. i.3.ai)
SUBSYSTat 6.0: CBF3GCAL PROCESSING SUBSYSTEN (Contintled)
Potential failure Mode lamediate Effects Interface At Subsystem Aceedial Action Comsonent Mude involved Within Subsystem Interface Within Subsystem 6.3.24 Manual Isolation 1. Valves fall closed -- No demineralized water No demineralized water Al ternate Valves (CS-83, to makeup filtere demineralized CS-85. CS-100) water ficw available 6 3.25 Check valve 1. Falle to prevent - Possible backflow if pump No d* mineralized water Close CS-85 (CS-86) tackflow ta not running to make ap filters 6.3.26 Control Valve 1. Control signal falls Control Sigaal 1.osa of flow to No d mineralized water None
( HP-15) to open valve Frce Flow makeup filters to makeup filters Orifice
- 2. Control signal falls Control Signal Loss of flow control to increace in domineralized Close manual to close valve Frce Flcw makeup filters water to makeap filters isolation Ortftco valves; close HP-136
- 3. Instrument air Instrument Air Loss of flow to No demineralized water None supply falls makeup filters to makeup filters
- 4. Electrio power Electric Power loss of flow to No demineralized water None supply fails makeup filters to makeup filters
- 5. Sportous signal to Control Signal Loss of flow control to increase in demanerallred Close manual open valve Frce Flw makeup filters water to makeup filters isola tion Ortrice valves; close HP-136
- 6. Spurious signal to Control Signal Loss of flow to No deelneralized water None close valve Frce Flow makeup filters to makeup (11ters Oriftee
- 7. Internal valve - 1.oss of fire to makeup No dcmineral4:ed water None failure filters to makeup filters 6.3.27 Manual Isolation 1. Valves fait closed
- No flow to flow orifice No domineralized water hone Valves (HP-191, to makeup filters HP-192) 6.3.28 Hanual Isolation 1. Valves fall closed - No flow to flow crlftee; No deelneralized water Open HP-54 Valves (HP-52, potentint control signal to makeup filters; HP-53) fatture alternate fire path available 6.3 29 Manual isolation 1. valve falls open - No firm to f1w orifice; t.oss of control of close HP-136 if Valve (HP-54) potential control, signal d* mineralized water flP-15 should be fetture to makeup filters closed 6.3.30 Flow Orifice 1. Orifice plugs - No flow; potential control No demineralized water Open HP-54 signal failure to makeup filters; alternate flow path available 6.3.31 Flow Transats ter t. Electrio prwer Flectric Power Incorrect signal to fire No flow indication in None supply falls control valve (see 6.3.26) 1&C system
- 2. Connection leaks Process Signal Incorrect signal to No flew indication in None transmitter !&C system
pefersnee Drawings: r$as Figure 9.3-1 (Sheet 1) r3as rigure 9.3-2 (Sheet 3) rsaa Figure 9.3-5 (Shests 1,3,44)
SUBSYSTEM 6.0: CHEMICAL PROCESSING SUBSYSTEM (Continued)
Potential Failure Mode lamediate Effecta Interface At Sut, system gemedial Action Within Subsystem Interface Within Subsystem Component fede Involved Incorrect signal to flow No flow indleation in None 6.3.31 Flow Transmitter 3 Transmitter falls --
(cont'd) control valve (see 6.3.26) ISC systee 6.3.32 Control Valve 1. Control alrnal falla control Signal 1.oss of flow to No demineralised water None to open valve From 3-Way makeup filters to makeup filters (HP-16)
Val we
- 2. Control signal falla Control Signal Loss of flow control to Increase in domineralized Close manual to close valve f rom 3-Way makeup filters water to makeup (11ters toolation Valve val ves close HP-192 3 Instrument air Instrument Air 1.oss of flow to No desineralized water None supply fails makeup filters to makeup filters No demineralized water pone
- 4. Electrio power f.loctric Power Loss of flow to supply falls makeup filters to makeup filters
- 5. Spurious nianal to Control Sisnal Loss of flow control to Increase in deelneralised Close manual open valve From 3-Way makeup filters water to makeup filters teclation Valve valves; close HP-192
- 6. Spurious signal to Control Signal Loss of flow to No demineralized water None close valve From 3-Way sakeup filters to makeup filters Valve 7 Internal valve -- 1.oss of flow to No demineralized water None failure makeup filters to makeup filters 6.4 . Boron Recovery 6.4.1 Manual isolation I. RC bleed flow RC Bleed Flow No flow to feed tank. Tank None if feed tank is full Alternate flow i Valves (CT-3. falls From Holdup has 6-hour capacity 1 t< con path avallat,le )
CT-51 Tank recovery will continue untti tank is empty Valves fall closed - No flow to deelneraliserg None if alternate flow Alternate flow 2.
no effect since second path available path avallatale demineraliser available Resin Fill No desineralialma capacity; None if alternate flow Alternate flow 6.4.2 RC Bleed I. Seein fill falls path available path available Evaporator no effect since second Desireraliser desineraliser swallable Tank leaks Dectcased flow; no effect None if alternate flow Alternate flow
- 2. -
since second demineralizer path available path available available 3, Tank went falla -- Decreased finw; no effect None if alternate flow Alternate flow open since second demineralizer path available path avallatile available 6.4.3' Manual Isolation 1. valves fall closed -- No flows no effect since None if alternate flow Alternate flow second demineralizer path avellable path available Valves (CT-4. CT-6) avallatie 6.4.4 Manual Isolation 1. valve falls closed -- No flow to feed tank. Tank None if feed tank is full Establish has 8-hour capacity g boron recirculation Votre (CT-14) flow fram recovery will continue until tank is empty evaporator
Reference Drawings: ISAR Figure 9.31 (Sheet 1)
FS AR Figure 9.3-2 (Sheet 3)
F? AR figure 9.3-5 (Sheets 1,3,84)
SUBSYSTEM 6.0: CHEMICAL PROCESSING SUBSYSTEM (Continued) fotential failure Mode lamediate Effects At Sut, system Remedial Action Interface Within Subsystem Mode Involved Within Sut,ayates laterface Ceeponent Boric acid may crystallise; None unless concentrated Restore trace 6.4.5 Miscellanecas 1. Electric power Fleftric Power borto acid storage tanks beating; unplus supply falls small potential for Piping lines pluggles and loss of flow are empty Borte acid may crystallize 3 None unless concentrated Restore trace
- 2. Trace heating falls -
beatings unplus small potential for boric acid storage tanks plugging and loss of flow are empty lines Evaporator No fice to feed tank. Tank None if feed tank la full Estabitsh 6.4.6 Manual Isolation 1. Evaporator has 8-hour capaesty; boron recirculation Talvea (CT-16, demineraliser Deelneraliser flow from finu falls; CT-16 Flow recovery will continue CT-19, C A-88, until tank is empty evaporator CT-49. CT-36) falla closed None 2, Caustic flew falls; Caustic Flow Cheeleal imbalance in boron Cheetcal lobalance in recovery system. borte acid to makeup CA 88 falls claned filters, BW37 Diattilate flew falls; Distillate No f!cu to feed tank. Tank None if feed tank la full Estabitsh 3
has 8-hour capacityg boron s eeirculation CT-49 fails closed Cooler recovery will continue flow from Flow evaporator until tank to empty Concentrate Concentrated borto acid None unless concentrated Close CT-38 to 4 Concentrate flow - terio acid storage tanks force back to feed tank; Flow returned to feed tank: no baron recovery are empty concentrate CT-36 falls open flow to concentrate cooler Valve CT-t9 falls No flow to feed tank. Tank None if feed tank ta full Establish
- 5. -
has 8-hour capacity; boron recirculation closed (!m from recovery will continue until tank is empty evaporator Fall to prevent -- Possible backflow to None unless concentrated Close isolation 6.4.7 Check Talves t.
concentrate pump, borte acid storage tanks valves CT-16 (CT-18, CT-37, backflow and CT-19 evaporator deelneraliser are empty CT-17)
Tank leaks -- Decreased flow; eventual None if feed tank ta full None 6.4.8 BC Bleed 1. loss of suction pressure Evaporator feed to pump. Tank has 8-hour Tank (WD-Tt2) capacity; teron recovery will continue unt!! tank is empty No flow. Baron recovery None unless concentrated None
- 2. Tank empties -
stops until tank refilled borin acid storage tanks are empty Tank went, reller - Decreased flow. Tank has None if feed tank is full None
- 3. 8-hour capacity; boron valves f att open recovery util continue untti tank to empty ho local level indication None None 6.4.9 1.evel Tranreitter 1. Electric s=wer Electric Power supply falls None Process Signal Incorrect signal to None
- 2. Conneetton leak transmitter None 3 Transmitter fatture - No local level indtration None
T s _
Reference Drawings 2 FSaa Figwre 9.3-1 (':heet 1) s FSan F1 ure 9 3-2 (:heet 3)
F3an f?gure 9.3-5 (Sheets 3.3.44)
SUBSYSTBt 6.0: CBBGCAL PROCESSING SUBSYSTEM (Continued) ,
Fotestial Fataure Itude immediate Effects N- w .
x _d.
lat erface at Subsystem tenedial Setton Component Mode lavol ved Within Subsystem Interface Within Subsystem 6.4.10 fannual toolattom 1. Talves fall closed - No flow to evaporator feed Nose unless concentrated Establish Valves (Cl-22, pump. hectroulation flow borte acid storage tanks recirculation CT-23) path can be established are empty flow from through evaporator but evaporator baron recovery stops 6.4.11 BC Bleed f. Deetrie smeer^ Electrie Power Pump stops; ao flow to None unless concentrated Establish Eesperator Feed supply falls evaporator. Reeiroulation borto a.Ad storag,e tarks recirculation Pump (WD-F46) flow path can be are empty flow from established through evaporator evaporator but boron recovery stops
- 2. Pump falls -- Nu flow to evaporator. None unless concentrated Estabilah poetreulation flow path borte acid storage tanks recirculation can be estabit4 ed through are empty flow from evaporator but tmron evaporontor recovery stops 6.4.12 Fressure 1. Electric power Electrio Power No local pressure anoication None None Transmitter Fatja supply fails
- 2. Connection leak Frocess Signal Incorrect signal to None None transmitter 3 Traansitter falls -- No local pressure indicatica None None 6.4.13 peanual isolattoa 1. Talve fasts closed - No flow to evaporator. None unless concentrated Estab!!sh Valve (CT-24) Seeltculattom flow path boric acid storage tanks recirculation can te estatiltshed through are empty flow from evaporator but boron evaporator recovery stops 6.4.14 Control Talve f. Control strnal Control Signal I.oss of flow control to None unless concentrated Establinh (CT-24) falls to open/ - From evaporator. Could flood borte acid storage tanks rectreulation valve clone fraporator evapesator or allow are empty flow to feed trvel dryout. Nectreulation tank or flow paths to feed tank evaporater or evaporater can be established. Boron recovery atopa.
- 2. lastrument air Instrument Air t.oss of flow control to None unless concentrated Establish ausply Ibils evaparatw. Could ficod borto acid storage tanks recirculation evaporator or allow are empty flow to feed dry out. Recirculation tank or flow paths to feed tank evaporator or evaporator can te established. Boron recovery stopa
Beference Drawingu Fsaa Figure 9.3-1 (Sheet 1)
FSAR Figure 9.3 2 (Sheet 3)
FS AR Figure 9.3 5 (Sheets 1,3,44)
SUBSYSTEM 6.0: CHEMICAL PROCESSING SUBSYSTEM (Continued)
Potential Failure Mode lamediate Effects Interface at Subaystee Remedial action Component Mode Invc,1 ved Within Subsystem Interface Withia Subsysten 6.4.14 control valve 3 Spurious signal control Signal taas of flow control to None unless concentrated Establish (CT-24) to open/ valve Frce evaporator. Could flood borto acid storage tanks rectroulatfee (cont'd) olose Evaporator evaporator or allw are empty flow to feed I.evel dryout. Recirculation tank or (1sm paths to feed tank evaporator or evaporator can be established. Boron recovery stopa
- 4. Internal valve - Loss of flow control to hone unless concentrated Establish s' allure evaporator. Could flood borte seld storage tanks rectreulation evaporator or allow are empty flow to feed dryout. Rectroulation tank or flow paths to feed tank evaporator or evaporator can be established. Boron recovery stopa 6.4.15 Check valve 1. Fatts to prevent -- rossible t,ackflow if pump None unless concentrated Close ccatrol (CT-29) backflow is not running borto acid storage tanks valve CT-28 are empty 6 .4.16 Waste, Drain, l. Lines fall open - Decreased flow to None unless concentration Establish Sample Lines evaporator. Recirculation borte acid storage tanks rectreulation flow path can be are empty flow to establi:hed through evaporator if evaporator but boron required recovery stops N 2 Disnket Possible captosive alsture pone Bk>ne 6.4.17 BC Bleed 1. Ny t,lanket oystem Evaporator fetis forma (WD-EVI) 2. Sican supply falls Steam Evaporator floods. No Mone unless concentrated Establjah boron rerovery boric acid storage tanks rectreulation are empty path to feed tank
- 3. Blocked tut,es -- Decreased heat transfer; None unless concentrated Establish decrease in boren boric acid storage tanks rectroulation recovery are empty path to feed tank 4 Tube rupture -- Steam released to Ik no untens concentrated Es tat.11 sh evaporator vapor space; boric acid storage tanka rectroulation decrease in boron aru capty path to feed recovery tank
- 5. Lors of heat transfer -- Evaporator floods. No None unless concentrated Establish capability boron recovery boric acid storage tanks rectreulation are empty path to feed tank
- 6. Electric pme-r Electric Fouer Concentrate heater falla; None untens concentrated Restore heater; nupply falla potrntint plugging and boric acid storage tanks unplus lines loss of flow are empty
y .
~^ '
- seference creus e s rsaa Fires 9.3-1 (Sheet 1)
' FSAS Figtere 9.)-2 (3heet rsar risme ti-s (she.t.3)i,3, - m SUBSYSTEM 6.0: CHBGCAL PROCESSING SUBSYSTEN (Continued)- -"
e rotennel raour. tea. 1 ediate Effects L,
Interface ,
At Sutayatee Remedia! Action Ca ponent loude Invclved W1tAin Subsystem laterf ace ' Withia Subsystem 6.4.17. RC Bleed 7. Inlet ficas frces - No borco recovery None unless concentrated Establish
. Evaporator feed pump fatte borte aetd storage tanks rectroulation (WD-EVI) ase empty flesa path untit (coat'd) feed ricw restored
- 8. Evaporator leaks - Eventual loss of suction None unless concentrated Nome pressure to pump borto acid storage tanks
- are empty
- 9. Evaporator empttas -- Possible damage to Noce unless concentrated Shut off steam evaporator; no bores 4, borto acid storage tanks fice recovery are empty
- 10. Evaporator vent. -- Cover gas release to .ent Won. None reller valves header fall open 6.4.18 Evaporator Level 1. Electric power Electrie Feuer Incorrect signal to Nona unless concentrated Nono
- Trenamitter supply fails evaporator feed pump 'urto acid storage tenta w
diacharge flow control are empty volve (see 6.4.14)
- 2. Connection leaks Process Signal Incorrect signal to pone unless concentrated None evaporator feed pump borte seld storage tanka discharge flow control are empty valve (see 6.4.14) 3 Transmitter falls - Incorrect signal to None unless concentrated None evaporator feed pump borte acid storage tanks discharge flow control are empty valve (see 6.4.14) 6.4.19 Temperature 1. Electric power Electria Power Incorrect afsnel to see 6.4.26 None Transmitter supply fails transmitter and concentrate cooler discharge flea control (see 6.4.P6)
- 2. Connection leaks Process Signal Incorrect signal to See 6.4.26 None transmitter and concentrate cooler discharge fice control (see 6.4.26) 3 Trannoitter failure - Incorrect signal to See 6.4.26 None transmitter and concentrate cooler discharge ficas control (see 6.4.26); no local temperature indicatice 6.4.70 Distillate Cooler 1. CoolinE uater Cooling Water Hifh temperature distillate Mone Establjah recir-
.(WD-C9) supply fails returned to feed tank culation path to feed tank P. Blocked tube -- Decreased heat transfer; None Estabitsh reelr-high temperature eulation path distillate returned to to feed tank feed tank
e l
l teference Drawings: F3&a Fifure 9.3-1 (Sheet 1) rsas rigere 1,3-2 (sheet 3) rs n rig.r. s.3-5 (saeets i.3 t4) l l SUBSYSTEM 6.0: CHEMICAL PROCESSING SUBSYSTEN (Continued) rotential Failure Mode Immediate Effects laterface at Subsystee Benedial setton laterface Withis Subeystee Ceeponent Mode lavolved Withtm Subsystem l
Cooling unter released to e,one Estabitsh rectr-6.4.20 Distillate Cooler 3 Tube rurture -
eutation path l (WD-C9) distillates 4tletes feed tank concentrattoa to feed tank (cont'd) Decreased heat transferg uvae Estab!!ah rectr-4 Loss of heat transfer --
celattom path capabili t y high teoperature distillate returned to to feed tank feed tank
- 5. Cooler leaks -- Deeressed distillate flow Decreased distillate Estabitsh rectr-available to conden- eulattom path sate test tanks to feed tant (deelmaralized water) no distillate flow No distillate avallat>1e pone
- 6. Inlet flow fatta Evaporator Distt!!ste to ecadensate test temas (deelneralized water)
Electrio Feuer rump stops no concestrate pone unless concentrated mone 6.4.29 Concentrate 1. Electrio power borte acid storage tanks (Sectro.) Fusp supply fails fice are empty No concentrate f!cw Nome unless concentrated gone (WD-F4) 2. rump falls --
borte acid storage tanks are empty Possible backflow if pump some unless concentrated Close CT-38, 6,4.22 Check Valve 1. Falla to prevent -
backflow to not running borte acid storage tanks CT-40
('.f-35) are empty Electric pmer Electric Fever No local pressure ladication None bone 6.4.23 Pressure 1.
Tranreitter supply fails Connection leaks Fracess Signal Incorreet signal to Ikme uime 2.
transettler
-- Na local pressure indicatten None hone 3 Transettter falls Concentrate flow Wone unless concentrated Open CT-40 to 6.4.24 Manual Isolation 1. Talve fatis open -
borte meld storage tanks divert flow racirculated to
. Valve (CT-38) evaporator. No boron are empty through recovery; possit'le concentrate etaporator flcoding cooler Talve falls closed - Fossible flooding of hone Flow can be 2.
concentrate coolerg toen diverted of temperature control in through CT-36 evaporator teck to feed tank Cooling water supply coolsng Water liigh temperature borte acid None Close control 6.4.25 Concentrate Cooler t.
valve CT-40 (WD-?) faite
- returned to concentrated borte acid storage tanks Blocked tube tecreased heat transferg None Close control
- 2. -
valve CT-40 high temperature borte acid returned to concen-trated boric seld storage tanks
aerscence Dra.tness tsas figure 9.3-1 (Sheet t)
FSAs algere 9.3-2 (Sheet 3) fyas t s:vre 9.3-5 (sheets s.3,st)
SUBSYSTEM 6.0: CHBtICAL PROCESSING SUBSYSTEM (Continued)
Potenttal Failure Ptode lunedtate Effects Interface At Subsystem Nemedial Setion Component Itode Irvolved Within Subsystem laterface Withia Subsystem 6.4.2'a Concentrate Cooler 3. Tut,e rupture -- Cooling water released to Nome Concentration can (WD-1) concentrateg dilutes te adjusted (cont'd) boric acid concentration fr<a borte acid six tank 4 Less of heat transfer - Ifigh temperature boric seid None Close control capabt!!ty returned to concentrated valve CT-40 borio acid storage tanks
- 5. Cooler leaks - Overcased concentrate flow None unless concentrated None borte acid storage tanks are empty
- 6. Inlet flow rests Evanwater No concentrate flow None unless concentrated Close contrel Conecntrate beric acid storage tanks valve CT-40 are empty
- 7. Cooling water control Control Signal No concentrate flow None ualeas concentrated Close control valve falla f ree Concen- borte acid storage taats salve CT-40 trate Cooler are empty Discharge Temperature 6.4.?6 Temperature 1. Electric Feser Electric P,wer No signal to cooling water No alsnal to cooling See 6.4.24 Transmitter - supply falls control valve water control valves see 6.4.24
- 2. Connection leaka Frocess Signal No signal to tranraitter No signal to cooling See 6.4.2%
water control valve; see 6.4.24 3 Trancoltter fails - No signal to cooling water No signal to cooling See 6.4.24 control valve water control valve; see 6.4.24 6.4.27 Control Valve 1. Instrument air lastrument Air 1.oss of concentrate flow None unless concentrated Close cooling (CT-40) aupply fails control borio meld storage tanks water control are repty valve; divert eencefitrate flow back to eve 6erator throigh CT-38 or to feed tank through CT-36
- 2. Control signal falla Control Signal I.ose of concentrate flow None ernless concentrated Close cooling to open/close fron control borte acid storage tanks water control valve Evaporator are empty valvel divert 1emperature concentrate Transmitter flow tack to '
evaporator through CT-38 or to feed tank tierough CT-36 1
J i
_ _ _ _ _ _ _ _ _ _ _ - -. - - . . . -- . _ . . . . . . . .. . . . _ . - .. . _ . .)
Reference Drawingst FSAS figure 9 3-1 (Sheet 1)
F348 Figwre 9.3-2 (Sheet 3)
FSAR fifure 9.3-5 (Sheets 1.3.&4)
SUBSYSTEM 6.0: CHEMICAL PROCESSING SUBSYSTEM (Continued)
Potential Failure Mode lamediate Effects laterface At Sutoystem Remedial Action Comienent Mode lavolved tilthin Subsystem Interface Within Subsystem 6.4.27 Control Tal-e 3 Spurious alsnal to Control Signal Loss of concentrate flow None unless concentrated Close cooling (CT-40) open/close valve from control borte acid storage tanks water control (cont'd) Evaporator are empty valves divert Temperature concentrate Transmitter ficw back to evaporator through CT-36 or to feed tank through CT-36
- 4. Internal valve - Imas of concentrate flow None unless boric acid Close cooling fatture control storage tanks are empty water control valvel divert concentrate flow been to evaporator through CT-38 or to feed tank through CT-36 6.5 Deborating Demineralizer:
6.5.3 Manual control 1. RC Bleed flew falla RC Bleed Flow No flew to deborating No firw to makeup filters None valve demineraliser
- 2. Valve falls closed - No flow to deborating None if alternate flow Alternate flow demineraliser path available path avallatte 6.5.2 Manual laolation 1. valve falla closed -- No flow to deborating None if alternate f!cw Alternate flow Valve demineraliser path available path available 6.5.3 Deborating 1. Tank leaka - Decreased bleed flow None if alternate flow Alternate ficw Demineralizer path available path available
- 2. Tank emptten -- No blee4 flow None if alternate flow Alternate flow path available path available 3 Tank went, reiser -
Decreased bleed flow None if alternate flow a! ternate flaa valves fall open path available path available 4 Resin naturates -- No boron removal from None if alternate flow Alternate flow bleed flow path available path available
- 5. Caustle fli= falls Cauntio No demineralizer mone af alternate flow Alternate flow regeneration path available path available 6.5.4 Mtseellaneous 1. F.lectric sawer Electric Power Borio aesd may crystallizeg None if alternate flew Restore trace Pipt e's nupply to trace email potential for path available heatingg unglug heating falls plurging and loss of flow lines
- 2. Trace heating fails - Dorte acid may crystallisel None if alternate ficv Restore trace small potential for path available heatingg unplug pluffing and loss of ficw linen 6.5.5 waste, Drain. 1. I snes fall ope n -- Decreased tleed fire Nene if alternate flow Alternate flow Sample Linea
- path available path available 6.5.6 Manual laolation 1. valves fall closed - No bleed flow None if alternate flcw Alternate flciw Valves path available path avallatle
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