ML20237E186
| ML20237E186 | |
| Person / Time | |
|---|---|
| Site: | Mcguire, Catawba, McGuire  |
| Issue date: | 08/20/1998 |
| From: | Tuckman M DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEIN-97-080, IEIN-97-80, NUDOCS 9808310021 | |
| Download: ML20237E186 (6) | |
Text
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d)) M Duke Energy Corpor ti:n 526 South Church Street P.O. Box 1006 (EC07H)
Charlotte, NC 28201-1006 M. S.sTuckman.
(7W) 382-2200 om Executive We l$sident (7M)3824360 m Nkkar Gmnation August 20, 1998 U.S. Nuclear Regulatory Commission I
j Attention:
Document Control' Desk Washington, D.C.
20555
Subject:
Duke Energy Corporation Catawba Nuclear Station, Units 1 and 2 Docket Numbers 50-413, 50-414 McGuire Nuclear Station, Units 1 and 2 Docket Numbers 50-369, 50-370 Request for NRC Position Regarding Instrument Calibration Setting Tolerances for Trip Setpoints in the Technical Specifications (TS) for the Catawba and McGuire Nuclear Stations.
During a review of the Catawba and McGuire Nuclear Station Technical Specifications (TS), questions arose with respect to l
the acceptability of station procedures that verify the trip setpoints for the Reactor Trip System Instrumentation and the Engineered Safety Features Actuation System Instrumentation, An analysis of this issue has been completed and Duke Energy As submitting its position for NRC concurrence in accordance with the guidance provided in Information Notice 97-80.
Backaround Catawba TS Tables 2.2-1 and 3.3-4 and McGuire TS Tables 2.2-1 and l
l 3.3-4 specify the Trip Setpoints for the respective station's Reactor Trip System Instrumentation and the Engineered Safety Features Actuation System Instrumentation. When calibrating these instruments, current station practice is to leave the as-left f
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U.S.dNucl' ear Regulatory Commission Page 2 August 20, 1998 Trip Setpoint at the value specified in the TS Tables +/- an instrument calibration setting tolerance. Since this methodology allows the TS Trip Setpoints to be exceeded by the instrument calibration setting tolerance, Problem Investigation Process (PIP) items 0-C98-1186_and 0-M98-0966 were generated to evaluate whether this practice is in literal compliance with the Catawba and McGuire TS requirements.
Original Regulatory Position and Licensing Basis Section 7.1.2.1.7 of the Catawba UFSAR and 7.1.2.4 of the McGuire UFSAR provide instrument range and setpoint design criteria for safety-related instrumentation at the respective station. These sections describe three setpoints - Safety Limit Setpoint, Limiting Value, and Nominal Setpoint. The Limiting Value is described as the Technical Specification value. Duke Energy interprets this Limiting Value to be the Limiting Safety System Setting (LSSS). The Nominal Setpoint is the value set into the instrument. This as-left setpoint value allows for normal instrument drift such that the Technical Specification limit (limiting or LSSS value) is not exceeded. These UFSAR sections provide no further clarification as to the acceptability of allowing the Reactor Trip System Instrumentation and the i
Engineered Safety Features Actuation System Instrumentation as-left Trip Setpoints to be exceeded by the instrument calibration setting tolerance. In addition, a review of the Catawba and I
McGuire Safety Evaluation Reports (SER) identified no specific information relevant to this issue.
Consequently, a review was performed of NUREG-0800, Revision 1 July 1981. This is the NRC Standard Review Plan which was used to l
provide the methodology and acceptance criteria for the NRC's acceptance of the Catawba and McGuire UFSAR's as documented in the respective station's SER. Section 7.1 of that NUREG lists f
Regulatory Guide
(. G) 1.105, Revision 1, as an acceptable R
I reference for use when determining safety-related instrumentation setpoints. Section C of the RG, " Regulatory Position", Step 1 makes the following statement:
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U.S."Nucl~ ear Regulatory Commission Page 3 August 20, 1998 "The setpoints should be estabt!.shed with sufficient margin between the technical specification limits for the process variable ~and the nominal trip setpoints to allow for (a) the inaccuracy of the' instrument, (b) uncertainties in the calibration, and (c) the instrument drift that could occur during the interval between calibrations."
This RG position statement is consistent with the setpoint design criteria provided in.Section 7.1.2.1.7 of the Catawba UFSAR and 7.1.2.4 of the McGuire UFSAR. However, similar to these UFSAR sections, it also provides no further clarification as to the acceptability of allowing safety-related instrumentation as-left Trip Setpoints to be exceeded by the instrument calibration setting tolerance.
The setpoint methodologies used for Reactor Protection System and Engineered Safety Features Actuation System instrumentation at the Catawba and McGuire Nuclear Stations was reviewed to determine if they provided any clarification regarding this issue. Some of this instrumentation is calibrated using a setpoint methodology outlined in a document titled " Westinghouse Reactor Protection System / Engineered Safety Features Actuation System Setpoint Methodology". A statement in the Westinghouse document indicates that no action is required by plant staff as long as the as-left Trip Setpoint error is less than or equal to that required to ensure the Allowable Value (LSSS value for Catawba and McGuire) is not exceeded. The above Westinghouse j
setpoint methodology information indicates that, as long as the LSSS value is not exceeded, it is acceptable for safety-related instrumentation as-left Trip Setpoints to be exceeded by the instrument calibration setting tolerances. The balance of the Reactor Protection System and Engineered Safety Features Actuation System instrumentation is calibrated using a setpoint methodology described in an Engineering Directives Manual (EDM).
The methodology described in the EDM is consistent with the I
philosophy in the Westinghouse document as described above. A l
review of current Catawba and McGuire Station practices related l
to Reactor Protection System and Engineered Safety Features
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F9 l
U.S. Nuclear Regulatory Commission Page*4 August 20,-1998 L
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Actuation System instrumentation setpoints indicates that the as-left. instrument calibration setting. tolerances utilized are
" consistent with,the above methodologies,and the Catawba and McGuire Station safety' analyses.
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.The above analysis indicates.that it is acceptable to allow the
-Reactor Trip ~ System' Instrumentation and the-Engineered Safety
-Features Actuation. System Instrumentation as-left Trip Setpoints
- to-be exceeded by.the instrument calibration setting tolerance. A L
. review of the current-licensing basis for the McGuire. Nuclear Station ~ identified no additional information-which would support this conclusion. However, the BASES for the Catawba Nuclear Station TS's 2.2.1, 3.3.1, and.3.3.2 contain information which p
does' provide additional support for this position. The BASES for
-TS 3.3.2; states that:
"The. Engineered Safety' Features Actuation System Instrumentation Trip'Setpoints specified in Table 3.3-4 are the nominal values at
.which the~bistables are set for each functional unit.
A Setpoint l
is considered to be adjusted consistent with the nominal value l-when the "as measured" Setpoint is within the band allowed for-calibration accuracy."
'The BASES for TS's'2.2.1 and 3.3.1 contain similar statements. In this_ situation,.the>" band allowed for calibration accuracy" is the instrument calibration setting tolerance.
Therefore, if the
' instrument setpoint is set at the' nominal value (Trip Setpoint) within the band allowed for-calibration setting tolerances, it is considered to-be set in accordance with the Technical
~ Specifications.
Additional Regulatory Position and Licensing Basis Information Catawba and McGuire-Nuclear Stations have submitted Standardized Technical Specifications (STS) as per NUREG-1431.-The BASES L
. associated with'the STS provide clarifying information;related to-as-left setpoints for the Reactor Trip. System Instrumentation and the Engineered Safety Features Actuation Syotem Instrumentation.
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U.S. Nuclear. Regulatory Commission Page*5
' August 20,~1998-This-information appears.to be consistent with the original
. regulatory position and-licensing basis related to this issue and I
provides further support to Duke Energy's position that it is acceptable to. allow the'as-left Trip Setpoints'for safety-related instrumentation to be exceeded by the instrument calibration setting tolerance.
-STS sections 3'.3.1 and:3.3.2 specify the Trip Setpoints for the Reactor Trip. System Instrumentation and the Engineered Safety Features Actuation System Instrumentation at the McGuire and i
Catawba Nuclear Stations. The BASES for these sections state the following-I "The Trip Setpoints are the nominal values at which the bistables are set. Any bistable is considered to be properly adjusted when the "as-left" value is within the band for CHANNEL CALIBRATION tolerance."
This statement-indicates'that it is acceptable to allow the Reactor Trip System Instrumentation and the Engineered Safety Features Actuation System Instrumentation as-left Trip Setpoints to be exceeded by the instrument calibration setting tolerance.
Conclusion 1
b It is Duke Energy's position that it is acceptable to allow the
. Reactor Trip System Instrumentation and the Engineered Safety j
Features Actuation System Instrumentation as-left Trip Setpoints to'be exceeded by the~ instrument calibration setting tolerance as long as the applicable LSSS value io not exceeded. This is consistent with the setpoint methodologies described in the Westinghouse setpoint methodology document and the EDM. This position is supported by statements in the BASES for the Catawba TS's and'by the BASES for the Catawba and McGuire STS.
-Consequently the' current station practice of leaving the as-left
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Trip Setpoints for these instruments at the value specified in the TS Tables +/- the allowed instrument calibration setting tolerance is appropriate. Duke Energy requests that the NRC review this interpretation and provide a docketed specific position on this-issue.
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.y
-U.S. Nuclear' Regulatory Commission Page'*6-August. 20,:1998 Very truly yours,-
6::_v:
.M.S.
Tuckman XC:
L.A. Reyes U.S. Nuclear Regulatory Commission Regional Administrator, Region II Atlanta Federal Center
'61 Forsyth St.,
SW, Suite 23T85
]
Atlanta, GA 30303 l
D.J. Roberts l
Senior Resident' Inspector (CNS) j U.S.. Nuclear Regulatory Commission Catawba Nuclear Station.
.P.S.
Tam JNRC Senior. Project Manager (CNS)
U.S. Nuclear Regulatory Commission Mail Stop'O-14H25 Washington,.D.C.l20555-0001 i
.S.-Shaeffer y
- Senior Resident Inspector U.S. : Nuclear Regulatory Commission McGuire Nuclear Station i
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