ML081410060

Technical Specification Bases (Tsb) Change

ML081410060
Person / Time
Site:	Oconee
Issue date:	05/14/2008
From:	Baxter D Duke Energy Corp
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML081410060 (24)

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DAVE BAXTER Vice President 4Energy Oconee Nuclear Station Duke Energy Corporation ON01 VP17800 Rochester Highway Seneca, SC 29672 864-885-4460 May 14, 2008 864-885-4208 fax dabaxter@dukeenergy.com U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Attention: Document Control Desk

Subject:

Duke Power Company LLC Oconee Nuclear Station Docket Numbers 50-269, 270, and 287 Technical Specification Bases (TSB) Change On April 22, 2008 Station Management approved revisions to Technical Specification Bases' (TSB) for TS 3.3.8, Post Accident Monitoring (PAM) Instrumentation, Function 17, Subcooling Monitor to refer to Inadequate Core Cooling Monitoring (ICCM) trains instead of channels.

If any additional information is needed, please contact Reene Gambrell at 864-885-3364.

Very truly yours, Dave B xter, Vice President Oconee Nuclear Site www. duke-energy.com

U. S. Nuclear Regulatory Commission May 14, 2008 Page 2 cc: Mr. L. N. Olshan Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Mr. L. A. Reyes, Regional Administrator U.S. Nuclear Regulatory Commission - Region II Atlanta Federal Center 61 Forsyth St., SW, Suite 23T85 Atlanta, Georgia 30303

'Andy Hutto Senior Resident Inspector Oconee Nuclear Station S. E. Jenkins, Section Manager Division of Waste Management Environmental Control 2600 Bull Street Columbia, SC 29201 bcc: w/o attachments L. F. Vaughn Ken Ashe - MNS R. D. Hart - CNS R. L. Gill - NRI&IA w/attachments Document Management ELL NSRB MR Coordinator (Ron Harris)

Licensing Working Group

Attachment #1 Proposed TSB revision Remove Page Insert Page B 3.3.8-1 B 3.3.8-1 3.3.8-2 B 3.3.8-2ý 3 .3 .8-3 B 3.3.8-3 3.3.8-4 B 3.3.8-4 3.3 .8-5 B 3.3.8-5 3.3.8-6 B 3.3.8-6 3.3.8-7 B 3.3.8-7 3.3.8-8 B 3.3.8-8 3 .3.8-9 B 3.3.8-9 3.3.8-10 B 3.3.8-10 3.3.8-11 B 3.3.8-11 3.3.8-12 B 3.3.8-12 3.3.8-13 B 3.3.8-13 3.3.8-14 B 3.3.8-14 3.3.8-15 B 3.3.8-15 3.3.8-16 B 3.3.8-16 3 .3.8-17 B 3.3.8-17 3.3.8-18 B 3.3.8-18 3.3.8-19 B 3.3.8-19

PAM Instrumentation B 3.3.8 B 3.3 INSTRUMENTATION B 3.3.8 Post Accident Monitoring (PAM) Instrumentation BASES BACKGROUND The primary purpose of the PAM instrumentation is to display unit variables that provide information required by the control room operators during accident situations. This information provides the necessary support for the operator to take the manual actions for which no automatic control is provided and that are required for safety systems to accomplish their safety functions for Design Basis Events.

The OPERABILITY of the accident monitoring instrumentation ensures that there is sufficient information available on selected unit parameters to monitor and to assess unit status and behavior following an accident.

The availability of accident monitoring instrumentation is important so that responses to corrective actions can be observed, and so that the need for and magnitude of further actions can be determined. These essential instruments are identified by the ONS specific Regulatory Guide 1.97 analysis (Ref. 1), UFSAR, Section 7.5 (Ref. 2), and the NRC's Safety Evaluation Report for the ONS Regulatory Guide 1.97 analysis (Ref. 3) which address the recommendations of Regulatory Guide 1.97 (Ref. 4),

as required by Supplement 1 to NUREG-0737 (Ref. 5).

The instrument channels required to be OPERABLE by this LCO equate to two classes of parameters identified during unit specific implementation of Regulatory Guide 1.97 as Type A and Category 1 variables.

Type A variables are specified because they provide the primary information that permits the control room operator to take specific manually controlled actions that are required when no automatic control is provided and that are required for safety systems to accomplish their safety functions for accidents.

Category 1 variables are the key variables deemed risk significant because they are needed to:

• Determine whether systems important to safety are performing their intended functions; OCONEE UNITS 1, 2, & 3 B 3.3.8-1 BASES REVISION DATED 05/05/08 I

PAM Instrumentation B 3.3.8 BASES BACKGROUND (continued)

Provide information to the operators that will enable them to determine the potential for causing a gross breach of the barriers to radioactivity release; and Provide information regarding the release of radioactive materials to allow for early indication of the need to initiate action necessary to protect the public and to estimate the magnitude of any impending threat.

These key variables are identified by the ONS specific Regulatory Guide 1.97 analysis (Ref. 1). This analysis identifies the unit specific Type A and Category 1 variables and provides justification for deviating from the NRC proposed list of Category 1 variables.

The specific instrument Functions listed in Table 3.3.8-1 are discussed in the LCO Bases Section.

APPLICABLE The PAM instrumentation ensures the availability of information so SAFETY ANALYSES that the control room operating staff can:

• Perform the diagnosis specified in the emergency operating procedures. These variables are restricted to preplanned actions for the primary success path of accidents (e.g., loss of coolant accident (LOCA));

Take the specified, preplanned, manually controlled actions, for which no automatic control is provided, which are required for safety systems to accomplish their safety functions; Determine whether systems important to safety are performing their intended functions; Determine the potential for causing a gross breach of the barriers to radioactivity release; Determine if a gross breach of a barrier has occurred; and Initiate action necessary to protect the public and estimate the magnitude of any impending threat.

OCONEE UNITS 1, 2, & 3 B 3.3.8-2 BASES REVISION DATED 05/05/08 1

PAM Instrumentation B 3.3.8 BASES APPLICABLE The ONS specific Regulatory Guide 1.97 analysis (Ref. 1) documents SAFETY ANALYSES the process that identifies Type A and Category 1 non-Type A (continued) variables.

PAM instrumentation that meets the definition of Type A in Regulatory Guide 1.97 satisfies Criterion 3 of 10 CFR 50.36 (Ref. 6). Category 1, non-type A, instrumentation must be retained in Technical Specifications because it is intended to assist operators in minimizing the consequences of accidents. Category 1, non-Type A variables are important for reducing public risk, and therefore, satisfy Criterion 4 of 10 CFR 50.36 (Ref. 6).

LCO LCO 3.3.8 requires two OPERABLE channels for all but one Function to ensure no single failure prevents the operators from being presented with the information necessary to determine the status of the unit and to bring the unit to, and maintain it in, a safe condition following that accident.

Furthermore, provision of two channels allows a CHANNEL CHECK during the post accident phase to confirm the validity of displayed information.

Where a channel includes more than one control room indication, such as both an indicator and a PAM designated recorder, the channel is OPERABLE when at least one indication is OPERABLE (applicable to Unit 2 only).

The exception to the two channel requirement is containment isolation valve position. In this case, the important information is the status of the containment penetrations. The LCO requires one position indicator for each electrically controlled containment isolation valve. This is sufficient to redundantly verify the isolation status of each isolable penetration.

either via indicated status of the electrically controlled valve and prior knowledge of the passive valve or via system boundary status. If a normally active containment isolation valve is known to be closed and deactivated, position indication is not needed to determine status.

Therefore, the position indication for valves in this state is not required to be OPERABLE.

Each of the specified instrument Functions listed in Table 3.3.8-1 are discussed below:

OCONEE UNITS 1, 2, & 3 B 3.3.8-3 BASES REVISION DATED 05/05/08 I

PAM Instrumentation B 3.3.8 BASES LCO 1. Wide Ranqe Neutron Flux (continued)

Wide Range Neutron Flux indication is a Type B, Category 1 variable provided to verify reactor shutdown. The Wide Range Neutron Flux channels consist of two channels of fission chamber based instrumentation with readout on one recorder. (Note: four channels are available only two are required). The channels provide indication over a range of 1 E-8% to 200% RTP.

2. Reactor Coolant System (RCS) Hot Lecq Temperature RCS Hot Leg Temperature instrumentation is a Type B, Category 1 variable provided for verification of core cooling and long term' surveillance. The two channels provide readout on two indicators. Control room display is through the inadequate core cooling monitoring system. The channels provide indication over a.range of 50EF to 700EF.

3, 5. Reactor Vessel Head Level and RCS Hot Leg Level Reactor Vessel Water Level instrumentation is a Type B, Category 1 variable provided for verification and long term surveillance of core cooling. The reactor vessel level monitoring system provides an indication of the liquid level from the top of the Hot Leg on each steam generator to the bottom of the Hot Leg as it exits the vessel and from the top of the reactor vessel head to the bottom of the Hot Leg as it exits the vessel.

Compensation is provided for impulse line temperature variations.

The Reactor Vessel Water Level channels consist of two Reactor Vessel Head Level channels that provide readout on two indicators (RC-LT0125 and RC-LT01 26) with one channel recorded in the control room and two RCS Hot Leg Level channels that provide readout on two indicators (RC-LT0123 and RC-LT0124) with one channel recorded in the control room.

4. RCS Pressure (Wide Range)

RCS Pressure (Wide Range) instrumentation is a Type A, Category 1 variable provided for verification of core cooling and RCS integrity long term surveillance.

OCONEE UNITS 1, 2, & 3 B 3.3.8-4 BASES REVISION DATED 05/05/08 1

PAM Instrumentation B 3.3.8 BASES LCO 4. RCS Pressure (Wide Range) (continued)

Wide range RCS loop pressure is measured by pressure transmitters with a span of 0 psig to 3000 psig. The pressure transmitters are located outside the RB. Redundant monitoring capability is provided by two trains of instrumentation. Control room indications are provided through the inadequate core cooling plasma display. The inadequate core cooling plasma display is the primary indication used by the operator during an accident. Therefore, the accident monitoring specification deals specifically with this portion of the instrument string.

RCS Pressure is a Type A, Category 1 variable because the operator uses this indication to monitor the cooldown of the RCS following a steam generator (SG) tube rupture or small break LOCA. Operator actions to maintain a controlled cooldown, such as adjusting SG pressure or level, would use this indication. In addition, high pressure injection (HPI) flow is throttled based on RCS Pressure and subcooled margin. For some small break LOCAs, low pressure injection (LPI) may actuate with RCS pressure stabilizing above the shutoff head of the LPI pumps. If this condition exists, the operator is instructed to verify HPI flow and then terminate LPI flow prior to exceeding 30 minutes of LPI pump operation against a deadhead pressure. RCS Pressure, in conjunction with LPI flow, is also used to determine if a core flood line break has occurred.

6. Containment Sump Water Level (Wide Range)

Containment Sump Water Level (Wide Range) instrumentation is a Type B, Category 1 variable provided for verification and long term surveillance of RCS integrity. The Containment Sump Water Level instrumentation consists of two channels with readout on two indicators (LT-90 and LT-91) and one recorder. The indicated range is 0 to 15 feet.

OCONEE UNITS 1, 2, & 3 B 3.3.8-5 BASES REVISION DATED 05/05/08 1

PAM Instrumentation B 3.3.8 BASES LCO 7. Containment Pressure (Wide Range)

(continued)

Containment Pressure (Wide Range) instrumentation is a Type B, Category 1 variable provided for verification of RCS and containment OPERABILITY. Containment Pressure instrumentation consists of two channels with readout on two indicators (PT-230 and PT-231) and one channel recorded. The indicated range is -5.0 psig to 175 psig.

8. Containment Isolation Valve Position Containment isolation valve (CIV) position is a Type B, Category 1 variable provided for verification of electrically controlled containment isolation valve position. In the case of CIV position, the important information is the isolation status of the containment penetration. The LCO requires one channel of valve position indication in the control room to be OPERABLE for each electrically controlled CIV in a containment penetration flow path, i.e., two total channels of CIV position indication for a penetration flow path with two electrically controlled valves. For containment penetrations with only one electrically controlled CIV having control room indication, Note (b) requires a single channel of valve position indication to be OPERABLE. This is sufficient to redundantly verify the isolation status of each isolable penetration via indicated status of the electrically controlled valve, as applicable, and prior knowledge of passive valve or system boundary status. As indicated by Note (a) to the Required Channels, if a penetration flow path is isolated by at least one closed and deactivated automatic valve, closed manual valve, blind flange, or check valve with flow through the valve secured, position indication for the CIV(s) in the associated penetration flow path is not needed to determine status. Therefore, the position indication for valves in an isolated penetration flow path is not required to be OPERABLE. Note (c) to the Required Channels indicates that position indication requirements apply only to CIVs that are electrically controlled. The CIV position PAM instrumentation consists of limit switches that operate both Closed-Not Closed and Open-Not Open control switch indication via indicating lights in the control room.

OCONEE UNITS 1, 2, & 3 B 3.3.8-6 BASES REVISION DATED 05/05/08

PAM Instrumentation B 3.3.8 BASES LCO 9. Containment Area Radiation (Hi-gh Range)

(continued)

Containment Area Radiation (High Range) instrumentation is a Type C, Category 1 variable provided to monitor the potential for significant radiation releases and to provide release assessment for use by operators in determining the need to invoke site emergency plans. The Containment Area Radiation instrumentation consists of two channels (RIA 57 and 58) with readout on two indicators and one channel recorded. The indicated range is 1 to 107 R/hr.

10. Not Used

11. Pressurizer Level Pressurizer Level instrumentation is a Type A, Category 1 variable used in combination with other system parameters to determine whether to terminate safety injection (SI), if still in progress, or to reinitiate SI if it has been stopped. Knowledge of pressurizer water level is also used to verify-the unit conditions necessary to establish natural circulation in the RCS and to verify that the unit is maintained in a safe shutdown condition. The Pressurizer Level instrumentation consists of two channels (Train A channel consisting of two indications and Train B channel consisting of one indication) with two channels indicated and one channel recorded.

(Note: two indications are available in Train A, but only one is required). The indicated range is 0 to 400 inches (11% to 84%

level as a percentage of volume).

OCONEE UNITS 1, 2, & 3 B 3.3.8-7 BASES REVISION DATED 05/05/08 1

PAM Instrumentation B 3.3.8 BASES LCO 12. Steam Generator Water Level (continued)

Steam Generator Water Level instrumentation is a Type A, Category 1 variable provided to monitor operation of decay heat removal via the SG. The indication of SG level is the extended startup range level instrumentation, covering a span of 0 inches to 388 inches above the lower tubesheet.

The operator relies upon SG level information following an accident (e.g., main steam line break, steam generator tube rupture) to isolate the affected SG to confirm adequate heat sinks for transients and accidents.

The extended startup range Steam Generator Level instrumentation consists of four transmitters (two per SG) that feed four gauges.

13. Steam Generator Pressure Steam Generator Pressure instrumentation is a Type A, Category 1 variable provided to support operator diagnosis of a main steam line break or SG tube rupture accident to identify and isolate the affected SG.; In addition, SG pressure is a key parameter used by the operator to evaluate primary-to-secondary heat transfer.

Steam generatorpressure measurement is provided by two pressure transmitters per SG. Each instrument channel inputs to the ICCM cabinet that provide safety inputs to two indicators located on the main control board in the control room. One channel per SG also provides input to a recorder located in the control room.

14. Borated Water Storage Tank (BWST) Level BWST Level instrumentation is a Type A, Category 1 variable provided to support action for long term cooling requirements, i.e.,

to determine when to initiate the switch over of the core cooling pump suction from the BWST to sump recirculation. BWST level measurement is provided by three channels with readout on two indicators and one recorder. (Note: three channels are available only two are required). Two of the three channels provide inputs OCONEE UNITS 1, 2, & 3 B 3.3.8-8 BASES REVISION DATED 05/05/08 I

PAM Instrumentation B 3.3.8 BASES LCO 14. Borated Water Storage Tank (BWST) Level (continued) to the ICCM cabinet which provides inputs to qualified indicators on the Control Board. The third channel provides an input to a recorder. The channels provide level indication over a range of 0 to 50 feet (13% to 100% of volume).

15. Upper Surge Tank (UST) Level Upper Surge Tank Level instrumentation, is a Type A, Category 1 variable provided to ensure a water supply for EFW. EFW draws condensate grade suction from the USTs and the Condenser Hotwell.

Two Category 1 instrumentation channels are provided for monitoring UST level. These instrument channels are inputs to corresponding train A and B Inadequate Core Cooling Monitoring (ICCM) system cabinets. The ICCM Train A cabinet provides UST level input to a recorder and to a qualified indicator, both located in the Control Room. The ICCM Train B cabinet also provides an input to a qualified indicator located in the Control Room. The range of UST level indication is 0 to 12 feet.

UST Level is the primary indication used by the operator to identify loss of UST volume. The operator can then decide to replenish the UST or align suction to the EFW pumps from the hotwell.

16. Core Exit Temperature Core Exit Temperature is a Type A, Category 1 variable provided for verification and long term surveillance of core cooling.

The operator relies on this information following a LOCA to secure HPI and throttle LPI, following a SBLOCA to throttle HPI and begin forced HPI cooling if needed, and following a MSLB and SG Tube Rupture to throttle HPI and isolate the affected SG.

OCONEE UNITS 1, 2, & 3 .B 3.3.8-9 BASES REVISION DATED 05/05/08 I

PAM Instrumentation B 3.3.8 BASES LCO 16. Core Exit Temperature (continued) /

There are a total of 52 Core Exit Thermocouples (CETs) per Oconee Unit. Twenty-four (12 per train) meet seismic and environmental qualification requirements (Category 1). The unit computer is the primary display for 47 CETs. Five CETs are displayed on the corresponding SSF Unit console. The CETs are distributed to provide monitoring of four or more in each quadrant for each train. The ICCM plasma displays (1 per train) located in the Control Room serve as safety related backup displays for the twenty-four Category 1 CETs. The range of the readouts is 50'F to 2300 0 F.

The ICCM CET function uses inputs from twelve incore thermocouples per train to calculate and display temperatures of the reactor coolant as it exits the core and to provide indication of thermal conditions across the core at the core exit. Each of the twelve qualified thermocouples per train is displayed on a spatially oriented core map on the plasma display. Trending of CET temperature is available continuously on the plasma display. The average of the five hottest CETs is trendable for the past forty minutes. ,

An evaluation was made of the minimum number of valid core exit thermocouples (CETs) necessary for inadequate core cooling detection. The evaluation determined the reduced complement of CETs necessary to detect initial core recovery and to trend the ensuing core heatup. The evaluations account for core nonuniformities and cold leg injection. Based on these evaluations, adequate or inadequate core cooling detection is ensured with two sets of five valid CETs.

Table 3.3.8-1 Note (d) indicates that the subcooling margin monitor takes the average of the five highest CETs for each of the ICCM trains. Two channels ensure that a single failure will not disable the ability to determine the representative core exit temperature.

OCONEE UNITS 1, 2, & 3 B 3.3.8-10 BASES REVISION DATED 05/05/08

PAM Instrumentation B 3.3.8 BASES LCO 17. Subcoolinq Monitor (continued)

The Subcooling Monitor is a Type A, Category 1 variable provided for verification and long term surveillance of core cooling. This variable is a computer calculated value using various inputs from the Primary System.

Two channels of indication are provided. One channel of indication is provided by ICCM Train A, the other is provided by ICCM Train B. An operable Subcooling Monitor shall consist of:

1) One direct indication from one ICCM train for RCS Loop Saturation margin and one direct indication from the other ICCM train for Core Saturation margin, or 2) One direct indication from each of the two ICCM trains for RCS Loop Saturation margin.

The indication readouts are located in the control room. This variable also inputs to the unit computer through isolation buffers and is available for trend recording upon operator demand. The range of the readouts is 200OF subcooled to 50°F superheat. The control room display is through the ICCM plasma display unit.

A backup method for determining subcooling margin ensures the capability to accurately monitor RCS subcooling margin (Refer to Specification 5.5.17).

18. HPI System Flow HPI System Flow instrumentation is a Type A, Category 1 variable provided to support action for short term cooling requirements, to prevent HPI pump runout and inadequate NPSH, and to indicate the need for flow cross connect. HPI flow is throttled based on RCS pressure, subcooled margin, and pressurizer level. Flow measurement is provided by one channel per train with readout on an indicator and recorder. There are two HPI trains. The channels provide flow indication over a range of 0 to 750 gpm.

OCONEE UNITS 1, 2, & 3 B 3.3. 8-11 BASES REVISION DATED 05/05/08 I

PAM Instrumentation B 3.3.8 BASES LCO 19. LPI System Flow (continued)

LPI System Flow instrumentation is a Type A, Category 1 variable provided to support action for long term cooling requirements*

The flow instrumentation is provided to prevent LPI and Reactor Building Spray pump runout as well as providing flow indication for HPI termination. The indication is also used to identify an LPI pump operating at system pressures above its shutoff head. Flow measurement is provided by one channel per train with readout on an indicator and recorder. There are two LPI trains. Prior to completion of the LPI cross connect modification, the LPI channels provide flow indication over a range of 0 to 6000 gpm.

After completion of the LPI cross connect modification, the LPI channels provide flow indication over a range of 0 to 4000 gpm.

20. Not used

21. Emergency Feedwater Flow EFW Flow instrumentation is a Type D, Category 1 variable provided to monitor operation of RCS heat removal via the SGs.

Two channels provide indication of EFW Flow to each SG over a range of approximately 100 gpm to 1200 gpm. Redundant monitoring capability is provided by the two independent channels of instrumentation for each SG. Each flow transmitter provides an input to a control room indicator. One channel also provides input to a recorder on Unit 2. On Units 1 and 3, one channel provides input to separate recorders for EFW flow to each SG.

EFW Flow is the primary indication used by the operator to verify that the EFW System is delivering the correct flow to each SG.

However, the primary indication used by the operator to ensure an adequate inventory is SG level.

22. Low Pressure Service Water (LPSW) flow to LPI Coolers LPSW flow to LPI Coolers is a Type A, Category 1 variable which is provided to prevent LPSW pump runout and inadequate NPSH.

LPSW flow to LPI Coolers is throttled to maintain proper flow balance in the LPSW System.

Flow measurement is provided by one channel per train with readout on an indicator and the plant computer via a qualified signal isolator. The channels provide flow indication over a range from 0-8000 gpm.

OCONEE UNITS 1, 2, & 3 B 3.3.8-12 BASES REVISION DATED 05/05/08 1

PAM Instrumentation B 3.3.8 BASES (continued)

APPLICABILITY The PAM instrumentation LCO is applicable in MODES 1, 2, and 3.

These variables are related to the diagnosis and preplanned actions required to mitigate accidents and transients. The applicable accidents and transients are assumed to occur in MODES 1, 2, and 3. In MODES 4, 5, and 6, unit conditions are such that the likelihood of an event occurring that would require PAM instrumentation is low; therefore, the PAM instrumentation is not required to be OPERABLE in these MODES.

ACTIONS The ACTIONS are modified by two Notes. Note 1 is added to the ACTIONS to exclude the MODE change restriction of LCO 3.0.4. This exception allows entry into an applicable MODE while relying on the ACTIONS even though the ACTIONS may eventually require a unit shutdown. This exception is acceptable due to the passive function of the instruments, the operator's ability to respond to an accident utilizing alternate instruments and methods, and the low probability of an event requiring these instruments.

Note 2 is added to the ACTIONS to clarify the application of Completion Time rules. The Conditions of this Specification may be entered independently for each Function listed in Table 3.3.8-1. When the Required Channels for a function in Table 3.3.8-1 are specified on a "per" basis (e.g., per loop, per SG, per penetration flow path), then the Condition may be entered separately for each loop, SG, penetration flow path, etc., as appropriate. The Completion Time(s) of the inoperable channels of a Function are tracked separately for each Function starting from the time the Condition is entered for that Function.

A.1 When one or more Functions have one required channel inoperable, the inoperable channel must be restored to OPERABLE status within 30 days. The 30 day Completion Time is based on operating experience.

This takes into account the remaining OPERABLE channel, the passive nature of the instrument (no critical automatic action is assumed to occur from these instruments), and the low probability of an event requiring PAM instrumentation during this interval.

Condition A is modified by a Note indicating this Condition is not applicable to PAM Functions 14, 18, 19, and 22.

OCONEE UNITS 1, 2, & 3 B 3.3.8-13 BASES REVISION DATED 05/05/08 I

PAM Instrumentation B 3.3.8 BASES ACTIONS B.1 (continued)

Required Action B.1 specifies initiation of action described in Specification 5.6.6 that requires a written report to be submitted to the NRC. This report discusses the results of the root cause evaluation of the inoperability and identifies proposed restorative actions. This action is appropriate in lieu of a shutdown requirement since alternative actions are identified before loss of functional capability and given the likelihood of unit conditions that would require information provided by this instrumentation. The Completion Time of "Immediately" for Required Action B.1 ensures the requirements of Specification 5.6.6 are initiated.

C..1 When one or more Functions have two required channels inoperable (i.e.,

two channels inoperable in the same Function), one channel in the Function should be restored to OPERABLE status within 7 days. This Condition does not apply to the hydrogen monitor channels. The Completion Time of 7 days is based on the relatively low probability of an event requiring PAM instrumentation action operation and the availability of alternative means to obtain the required information. Continuous operation with two required channels inoperable in a Function is not acceptable because the alternate indications may not fully meet all performance of qualification requirements applied to the PAM instrumentation. Therefore, requiring restoration of one inoperable channel of the Function limits the risk that the PAM Function will be in a degraded condition should an accident occur. Condition C is modified by a Note indicating this Condition is not applicable to PAM Functions 14, 18, 19, and 22.

D.1 Not Used.

E.1 When one required BWST water level channel is inoperable, Required Action E.1 requires the channel to be restored to OPERABLE status.

The 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Completion Time is based on the relatively low probability of an event requiring BWST water and the availability of the remaining BWST water level channel. Continuous operation with one of the two required channels inoperable is not acceptable because alternate OCONEE UNITS 1, 2, & 3 B 3.3.8-14 BASES REVISION DATED 05/05/08 1

PAM Instrumentation B 3.3.8 BASES ACTIONS E.1 (continued) indications are not available. This indication is crucial in determining when the water source for ECCS should be swapped from the BWST to the reactor building sump.

Condition E is modified by a Note indicating this Condition is only applicable to PAM Function 14.

F. 1 When a flow instrument channel is inoperable, Required Action F.1 requires the affected HPI or LPI train to be declared inoperable and the requirements of LCO 3.5.2 or LCO 3.5.3 apply. For Function 22, LPSW flow to LPI coolers, the affected train is the associated LPI train. For Function 18, HPI flow, an inoperable flow instrument channel causes the affected HPI train's automatic function to be inoperable. The HPI train continues to be manually OPERABLE provided the HPI discharge crossover valves and associated flow instruments are OPERABLE.

Therefore, HPI is in a condition where one HPI train is incapable of being automatically actuated but capable of being manually actuated. The required Completion Time for declaring the train(s) inoperable is immediately. Therefore, LCO 3.5.2 or LCO 3.5.3 is entered immediately, and the Required Actions in the LCOs apply without delay. This action is necessary since there is no alternate flow indication available and these flow indications are key in ensuring each train is capable of performing its function following an accident. HPI and LPI train OPERABILITY assumes that the associated PAM flow instrument is OPERABLE because this indication is used to throttle flow during an accident and assure runout limits are not exceeded or to ensure the associated pumps do not exceed NPSH requirements.

Condition F is modified by a Note indicating this Condition is only applicable to PAM Functions 18, 19, and 22.

G.1 Required Action G.1 directs entry into the appropriate Condition referenced in Table 3.3.8-1. The applicable Condition referenced in the Table is Function dependent. Each time an inoperable channel has not met the Required Action and associated Completion Time of Condition C OCONEE UNITS 1, 2, & 3 B 3.3.8-15 BASES REVISION DATED 05/05/08 1

PAM Instrumentation B 3.3.8 BASES ACTIONS G.1 (continued) or E, as applicable, Condition G is entered for that channel and provides for transfer to the appropriate subsequent Condition.

H.1 and H.2 If the Required Action and associated Completion Time of Conditions C, D or E are not met and Table 3.3.8-1 directs entry into Condition H, the unit must be brought to a MODE in which the requirements of this LCO do not apply. To achieve this status, the unit must be brought to at least MODE 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and MODE 4 within 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br />. The allowed Completion Times are reasonable, based on operating experience, to reach the required unit conditions from full power conditions in an orderly manner and without challenging unit systems.

1.1 If the.Required Action and associated Completion Time of Condition C, D or E are not met and Table 3.3.8-1 directs entry into Condition I, alternate meansof monitoring the parameter should be applied and the Required Action is not to shut down the unit, but rather to follow the directions of Specification 5.6.6 in the Administrative Controls section of the Technical Specifications. These alternative means may be temporarily installed if the normal PAM channel cannot be restored to OPERABLE status within the allowed time. The report provided to the NRC should discuss the alternative means used, describe the degree to which the alternative means are equivalent to the installed PAM channels, justify the areas in which they are not equivalent, and provide a schedule for restoring the normal PAM channels.

Both the RCS Hot Leg Level and the Reactor Vessel Level are methods of monitoring for inadequate core cooling capability. The subcooled margin monitors (SMM), and core-exit thermocouples (CET) provide an alternate means of monitoring for this purpose. The function of the ICC instrumentation is to increase the ability of the unit operators to diagnose the approach to and recovery from ICC. Additionally, they aid in tracking reactor coolantinventory.

The alternate means of monitoring the Reactor Building Area Radiation (High Range) consist of a combination of installed area radiation monitors and portable instrumentation.

OCONEE UNITS 1, 2, & 3 B 3.3.8-16 BASES REVISION DATED 05/05/08 I

PAM Instrumentation B 3.3.8 BASES (continued)

SURVEILLANCE As noted at the beginning of the SRs, the SRs apply to each PAM REQUIREMENTS instrumentation Function in Table 3.3.8-1 except where indicated.

SR 3.3.8.1 Performance of the CHANNEL CHECK once every 31 days for each required instrumentation channel that is normally energized ensures that a gross failure of instrumentation has not occurred. A CHANNEL CHECK is normally a comparison of the parameter indicated on one channel with a similar parameter on other channels. It is based on the assumption that instrument channels monitoring the same parameter should read approximately the same value. Significant deviations between the two instrument channels could be an indication of excessive instrument drift in one of the channels or of something even more serious. CHANNEL CHECK will detect gross channel failure; therefore, it is key to verifying that the instrumentation continues to operate properly between each CHANNEL CALIBRATION. The high radiation instrumentation should be compared with similar unit instruments located throughout the unit. If the radiation monitor uses keep alive sources or check sources OPERABLE from the control room, the CHANNEL CHECK should also note the detector's response to these sources.

Agreement criteria are based on a combination of the channel instrument uncertainties, including indication and readability. If a channel is outside the criteria, it may be an indication that the sensor or the signal processing equipment has drifted outside its limit. If the channels are within the criteria, it is an indication that the channels are OPERABLE. If the channels are normally off scale during times when surveillance is required, the CHANNEL CHECK will only verify that they are off scale in the same direction. Offscale low current loop channels are, where practical, verified to be reading at the bottom of the range and not failed downscale.

The Frequency is based on operating experience that demonstrates channel failure is rare. The CHANNEL CHECK supplements less formal but more frequent checks of channels during normal operational use of the displays associated with this LCO's required channels.

SR 3.3.8.2 and SR 3.3.8.3 A CHANNEL CALIBRATION is a complete check of the instrument channel, including the sensor. This test verifies the channel responds to measured parameters within the necessary range and accuracy.

OCONEE UNITS 1, 2, & 3 B 3.3.8-17 BASES REVISION DATED 05/05/08 I

PAM Instrumentation B 3.3.8 BASES SURVEILLANCE SR 3.3.8.2 and SR 3.3.8.3 (continued)

REQUIREMENTS Note 1 to SR 3.3.8.3 clarifies that the neutron detectors are not required to be tested as part of the CHANNEL CALIBRATION. There is no adjustment that can be made to the detectors. Furthermore, adjustment of the detectors is unnecessary because they are-passive devices, with minimal drift. Slow changes in detector sensitivity are compensated for by performing the daily calorimetric calibration and the monthly axial channel calibration.

For the Containment Area Radiation instrumentation, a CHANNEL CALIBRATION may consist of an electronic calibration of the channel, not including the detector, for range decades above 10 R/hr, and a one point calibration check of the detector below 10 R/hr with a gamma source.

Whenever a sensing element is replaced, the next required CHANNEL CALIBRATION of the resistance temperature detectors (RTD)sensors or Core Exit thermocouple sensors is accomplished by an inplace cross calibration that compares the other sensing elements with the recently installed sensing element.

SR 3.3.8.2 is modified by a Note indicating that it is applicable only to Functions 7 and 22. SR 3.3.8.3 is modified by Note 2 indicating that it is not applicable to Functions 7 and 22. The Frequency of each SR is based on operating experience and is justified by the assumption of the specified calibration interval in the determination of the magnitude of equipment drift.

REFERENCES 1. Duke Power Company letter from Hal B. Tucker to Harold M.

Denton (NRC) dated September 28, 1984.

2. UFSAR, Section 7.5.

3. NRC Letter from Helen N. Pastis to H. B. Tucker, "Emergency Response Capability - Conformance to Regulatory Guide 1.97,"

dated March 15, 1988.

4. Regulatory Guide 1.97, "Instrumentation for Light Water Cooled Nuclear Power Plants to Assess Plant and Environs Conditions During and Following an Accident," Revision 3, May 1983.

OCONEE UNITS 1, 2, & 3 B 3.3.8-18 BASES REVISION DATED 05/05/08 1

PAM Instrumentation B 3.3.8 BASES REFERENCES 5. NUREG-0737, "Clarification of TMI Action Plan Requirements,"

(continued) 1980.

6. 10 CFR 50.36.

OCONEE UNITS 1, 2, & 3 B 3.3.8-19 BASES REVISION DATED 05/05/08

Attachment #2 Markup of current TSB

PAM Instrumentation B 3.3.8 BASES LCO 17. Subcoolinq Monitor (continued)

The Subcooling Monitor is a Type A, Category 1 variable provided for verification and long term surveillance of core cooling. This variable is a computer calculated val " , nputs Ir;. .;

the Primary System. 0/a Two channels of indication are p ovided'An operable Subcooli-' g 4 Most of: 1) One di *on from one e t-.

f- RCSLo* Satul ion mar n e c T5indca . mthe o 1e1 fr Cor SatJratio mari,.or 2) ne direct indication from each f th U W RC Loop Saturation Th ication r adouts are located in t control room.

This variable also inputs t com rough isolation buffers and is available for trend recording upon operator demand. The range of the readouts is 200°F subcooled to 501F superheat. Thecontrol room display is through the ICCM plasma display unit.

A backup method for determining subcooling margin ensures the capability to accurately monitor RCS subcooling margin (Refer to Specification 5.5.17).

18. HPI System Flow HPI System Flow instrumentation is a Type A, Category 1 variable provided to support action for short term cooling requirements, to prevent HPI pump runout and inadequate NPSH, and to indicate the need for flow cross connect. HPI flow is throttled based on RCS pressure, subcooled margin, and pressurizer level. Flow measurement is provided by one channel per train with readout on an indicator and recorder. There are two HPI trains. The channels provide flow indication over a range of 0 to 750 gpm.

OCONEE UNITS 1, 2, & 3 B 3.3.8-11 BASES REVISION DATED" '