ML102510137
| ML102510137 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 08/30/2010 |
| From: | Bronson K Entergy Nuclear Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 2.10.039, TAC ME3543 | |
| Download: ML102510137 (14) | |
Text
SEntergy Entergy Nuclear Operations, Inc.
Pilgrim Nuclear Power Station 600 Rocky Hill Road Plymouth, MA 02360 Kevin H. Bronson Site Vice President August 30, 2010 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555-0001
SUBJECT:
Entergy Nuclear Operations, Inc.
Pilgrim Nuclear Power Station Docket No. 50-293 License No. DPR-35
REFERENCE:
LETTER NUMBER:
Dear Sir or Madam,
Entergy Response to NRC Request for Additional Information dated June 3, 2010, in support of Proposed License Amendment for Pilgrim Setpoint and Setpoint Tolerance Increases for Safety Relief Valves (SRV) and Spring Safety valves (SSV), and Related Changes (TAC NO. ME3543)
- 1.
Entergy Letter NO. 2.10.016, Proposed License Amendment to Technical Specifications: Revised Technical Specification for Setpoint and Setpoint Tolerances Increases for Safety Valves (SRV) and Spring Safety Valves (SSV), and Related Changes, dated March 15, 2010.
2.10.039 This letter dockets Entergy's response to NRC Request for Additional Information (RAI) forwarded to Pilgrim Licensing staff by an e-mail, dated June 3, 2010. The RAI included two (2) requests (RAI-1 and RAI-2) related to the Setpoint Methodology for the proposed Anticipated Transient Without Scram (ATWS)/High Pressure Recirculation Pump Trip (RPT) trip setpoint.
Attachment A provides Entergy's response to NRC RAI-1 and 2. to Attachment A provides a detailed response to RAI-1, related to the Setpoint Calculation Methodology, which was developed by General Electric Hitachi (GEH), following an NRC, Entergy, and GEH Staff conference call on July 9, 2010. contains proprietary information as defined in 10 CFR 2.390. GEH as the owner of the proprietary information, has executed an Affidavit provided within this Enclosure (Affidavit Pages 1, 2 and 3), which identifies that the information has been handled and classified as proprietary, is customarily held in confidence, and has been withheld from public disclosure.
The proprietary information was provided to Entergy in a GEH transmittal that is referenced by the Affidavit. The proprietary information has been faithfully reproduced in the Enclosure such that the Affidavit remains applicable. GEH hereby requests that the enclosed proprietary information (Enclosure 1) be withheld from public disclosure in accordance with the provisions of 10 CFR 2.390 and 10 CFR 9.17. Information that is not considered proprietary is provided in to Attachment A.
4ce
Entergy Nuclear Operations, Inc.
Pilgrim Nuclear Power Station Letter Number: 2.10.039 Page 2 to Attachment A provides ATWS/RPT summary results of setpoint calculations.
This information is not proprietary.
The Entergy response to NRC RAI-1 and RAI-2 supports the proposed License Amendment for Setpoint and Setpoint Tolerances Increases for Safety Relief Valves (SRV) and Spring Safety Valves (SSV), and Related Changes and the No Significant Hazards Consideration determination submitted by Reference 1.
There are no commitments made in this submittal.
If you have any questions, please call Mr. Joseph Lynch, Pilgrim Licensing Manager at 508-830-8403.
I declare under p nalty of perjury that the foregoing is true and correct. Executed on the 36'0" day of ".l at
,2010 Sincerely Kevin Bronson Site Vice President SJB/wgl Attachment A: Entergy Response to NRC Request for Additional Information Related to Proposed License Amendment for SRV and SSV Setpoint and Setpoint Tolerances Increases (34 pages, including Enclosures 1, 2 and 3))
Encl. 1 to Attachment A: "SRV-TP-2030, Response to Request for Additional Information-l", GEH Proprietary Information, (10 Pages).
Encl. 2 to Attachment A: "SRV-TP-2030, Response to Request for Additional Information-l", GEH Non-proprietary Information, (6 Pages).
Encl. 3 to Attachment A: GEH Report, 0000-0105-0835-R2 Pilgrim Nuclear Power Station, ATWS High Pressure Recirculation Pump Trip (RPT)", Rev. 2, March 2010 (15 pages) cc:
Regional Administrator, Region 1 U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 John Giarrusso Mass Emergency Management Agency 400 Worcester Road Framingham, MA 01702 Robert Gallagher, Acting Director Massachusetts Department of Public Health Radiation Control Program Commonwealth of Massachusetts 529 Main Street, Suite 1 M2A Charlestown, MA 02129-1121 Mr. James S. Kim, Project Manager Plant Licensing Branch I-1 Division of Operator Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission One White Flint North 0-8C2 11555 Rockville Pike Rockville, MD 20852 Senior Resident Inspector Pilgrim Nuclear Power Station
ATTACHMENT A (Includes Enclosures 1, 2, and 3) to Entergy Letter Number 2.10.039 ENTERGY RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION p
RELATED TO PROPOSED LICENSE AMENDMENT FOR SRV AND SSV SETPOINT AND SETPOINT TOLERANCE INCREASES (Total 34 pages)
Attachment A to Enterqy Letter No. 2.10.039 ENTERGY RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION PROPOSED LICENSE AMENDMENT FOR SRV AND SSV SETPOINT ( TAC NO. ME3543)
References:
- 1. NEDC-31336P-A, "General Electric Instrument Setpoint Methodology', Class 3, September 1996 [NRC Accession Number ML072950103].
- 2. GEH Report 0000-0105-0835-R2, Pilgrim Nuclear Power Station, ATWS High Pressure Recirculation Pump Trip (RPT)", Rev. 2, March 2010 NRC REQUEST FOR ADDITIONAL INFORMATION (RAI-1):
"Setpoint Calculation Methodology: Provide documentation, including calculations, of the methodology used for establishing the limiting TRIP setpoint or nominal trip setpoint and limiting acceptable values for the As-Found and As-left setpoints as measured during the periodic surveillance testing. Indicate related Analytical Limits and/or other limiting design values and the source of these values".
This request relates directly to the ATWS/RPT setpoint calculation.
ENTERGY RESPONSE TO RAI-1 General Electric Hitachi (GEH) has calculated the ATWS/RPT Trip Level Setting value using the NRC approved setpoint methodology contained in NEDC-31336P-A (Reference 1). to this Attachment A, SRV-TP-2030, provides the Response to Request for Additional Information-I, which includes GEH ATWS/RPT Setpoint Calculation Methodology, and is considered proprietary information under 10 CFR 2.390. to this Attachment A provides the non-proprietary version of Enclosure 1, to this Attachment A "Instrument Limits Calculation for ATWS High Pressure Recirculation Pump Trip RPT)", GEH document No. 0000-0105-0829, dated March 2010 (Reference 2), provides the summary results for ATWS/RPT setpoint calculations.
NRC provided clarifications regarding the applicability of TSTF-493 and the scope of RAIs during the conference call on July 9, 2010 and through additional e-mail communications.
The proposed License Amendment for SRV and SSV setpoint and setpoint tolerance increases includes a revised value in Technical Specification Table 3.2-G, "Instrumentation that Initiates Recirculation Pump Trip and Alternate Rod Insertion", Trip Function for High Reactor Dome Pressure of 1215 +/- 5 psig, to address the requirements of an Anticipated Transient Without Scram (ATWS). This increased value for ATWS RPT/ARI trip setting level is based on the increased reactor pressure due to increased SRV setpoint, as explained in GEH Report attached to Entergy Letter No. 2.10.016, dated March 15, 2010. This trip level setting is for the ATWS/RPT/ARI initiation to comply with the ATWS Final Rule, 10 CFR 50.62, requirements.
Entergy Staff's review of the Standard Technical Specification Generic Change, TSTF-493, "Clarify Application of Setpoint Methodology for Limiting Safety System Settings" provisions confirms that TSTF-493, Regulatory Guide 1.105, Rev. 3 and 4, and Regulatory Issue Summary Letter No. 2007-17 guidance are not applicable to the ATWS RPT/ARI trip setting level value because ATWS RPT/ARI is not a Limiting Safety System Settings (LSSS) function based on the following.
Page 1 of 3
ATWS-RPT initiates an RPT to aid in preserving the integrity of the fuel cladding following events in which a scram does not, but should, occur. ATWS RPT instrumentation satisfies Criterion 4 of 10 CFR 50.36(c) (2) (ii). Thus, ATWS RPT does not fall within the scope of LSSS.
- 2. NRC Letter on "Industry Plan to Resolve TSTF-493, Clarify Application of Setpoint Methodology for LSSS Functions", dated February 23, 2009, does not include the ATWS RPT function in the Table of Contents for NUREG-1433, Boiling Water Reactor/4 Plants, since it does not fall within the scope of LSSS.
Based upon the above, Entergy concludes that the setpoint calculation for the new TS value of 1215 + 5 psig is related to the ATWS-RPT and it is not applicable to the TSTF-493.
Accordingly, Entergy has applied the NRC approved setpoint methodology as described in the NRC approved General Electric Hitachi (GEH) Report, NEDC-31336P-A, "General Electric Instrument Setpoint Methodology,"
Class 3, September 1996 (NRC Accession No.
NRC RAI-2 "Describe the measures to be taken to ensure that the associated instrument channel is capable of performing its specified functions in accordance with applicable design requirements and associated analyses. Include information on the controls employed to ensure that the as left trip setting after completion of periodic surveillance is consistent with the setpoint methodology.
Also discuss the plant corrective action processes, including plant procedures, for restoring channels to operable status when channels are determined to be "inoperable" or "operable but degraded." If the controls are located in a document other than the TS, e.g. plant test procedure, describe how it is ensured that the controls will be implemented".
This request relates directly to the ATWS/RPT trip setting.
ENTERGY RESPONSE TO RAI-2 The ATWS/RPT setpoint calculation was documented in Pilgrim Calculation No. I-NI-1 10, dated June 10, 1993. This calculation is revised by Enclosures 1 and 3. Appropriate surveillance procedures are implemented to control the setpoints, address setpoint drift, as found and left values, and surveillance practices for instruments that are required to protect LSSS safety limits.
The Pilgrim staff follows EN-DC-1 15, "Engineering Change Process" to ensure that calculated setpoints that protect safety limits are translated accurately from design documents and associated analysis into calibration procedures. The station process includes the following elements.
- 1. Instrumentation and Control (I&C) Design personnel prepare the design documents including calculations to determine the setpoint that will ensure that the protective action occurs at the proper value.
- 2. The set point is implemented via an Engineering Change (EC) process, which complies with the applicable requirements of 10 CFR 50, Appendix A and B requirements, and licensing basis information.
- 3.
I&C Maintenance personnel enter the calculated calibration values into the calibration procedure, as part of EC process. With respect to ATWS/RPT Trip Setting Level value, Pilgrim has implemented a surveillance procedure, 8.M.1-29, "ATWS Trip Unit Calibration Test". The procedure makes reference to the Technical Specification Value included in TS Table 3.2.G/4.2.G, and provides for the following requirements:
Acceptance Criteria, based on controlled engineering documents Page 2 of 3
Corrective Action Acceptance Verification I&C Procedure Feedback Form
- 4. Procedure 8.M.1-29 requires that a condition report be written in accordance with Entergy procedure, EN-LI-102, "CorrectiveAction Process", if the technician finds the as-found value is outside the no adjust limits. Condition Reports (CR) are coded for drift evaluation and trending.
I&C System Engineers are assigned corrective actions to evaluate the drift of critical components to determine if the instrument has been having repeat issues.
Upon implementation of EC 500071987, Pilgrim procedure 8.M.1-29 will be revised to include revised Technical Specification values and applicable attributes for the ATWS/RPT setpoint calculations and control program.
Pilgrim follows Entergy Fleet procedure, EN-LI-102, "Corrective Action Process" to implement the site corrective action program. This process complies with the requirements of 10 CFR 50, Appendix B. Equipment and instrument operability, restoring operability, accepting degraded conditions with compensatory measures, and operability evaluations are developed in accordance with Entergy Fleet procedure, EN-OP-104, "Operability Determination Process."
Corrective Actions taken to restore operability follow the process prescribed in EN-LI-1 02.
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ENCLOSURE 2 TO ATTACHMENT A SRV-TP-2030 Response to Request for Additional Information-1 GE Non-Proprietary Information (6 paaes) j
ENCLOSURE 2 SRV-TP-2030 Response to Request for Supplemental Information-I GEH Non Proprietary Information Information Notice This is a non-proprietary version of SRV-TP-2030, Enclosure 1, from which the proprietary information has been removed. Portions of the enclosure that have been removed are indicated by an open and closed bracket as shown here ((
)).
GEH Non-Proprietary Information SRV-TP-2030 NRC RAI # I To support the NRC assessment of the acceptability of the setpoint change provide the following information for the setpoint change:
- 1. Setpoint Calculation Methodology: Provide documentation, including calculations, of the methodology used for establishing the limiting trip setpoint or nominal trip setpoint and limiting acceptable values for the as-found and as-left setpoints as measured during the.
periodic surveillance testing. Indicate related Analytical Limits and/or other limiting design values and the source of these values.
- 2. Describe the measures to be taken to ensure that the associated instrument channel is capable of performing its specified functions in accordance with applicable design requirements and associated analyses. Include information on the controls employed to ensure that the as left trip setting after completion of periodic surveillance is consistent with the setpoint methodology. Also discuss the plant corrective action processes, including plant procedures, for restoring channels to operable status when channels are determined to be "inoperable" or "operable but degraded." If the controls are located in a document other than the TS, e.g.
plant test procedure, describe how it is ensured that the controls will be implemented.
Response to RAI # 1 GEH Setpoint Calculation Methodology GEH setpoints are calculated using the NRC-approved methodology contained in NEDC-31336P-A (Reference 1-2).
Conceptually, the GEH method is based on Instrument Society of America (ISA) Method 2, but results in more conservative setpoints and is referred to as "Method 2 plus."
According to this NRC-approved methodology, the GEH setpoints are calculated from the Analytic Limit (AL), or if there is no AL, from the Allowable Value (AV) using a top down approach. The margins are calculated as follows:
" between the AL and the Nominal Trip Setpoint (NTSP), and
" between the AV and the NTSP.
The margin between the AL and the final NTSP is at least equal to, and generally greater than, that needed to meet the 95% probability requirement of Regulatory Guide (RG) 1.105.
GEH's setpoint methodology for operating plants uses single-sided distributions in the development of AVs and NTSPs for instrument channels that provide trips when the process variable being measured approaches the setpoint in one direction only, as described in ISA Standard 67.04 part II. Each of the setpoint functions calculated for the Pilgrim Nuclear Power Station (PNPS) Safety Relief Valve-Spring Safety Valve (SRV-SSV) Setpoint Change project Page 1 of 6 GEH Non Proprietary Information SRV-TP-2030 provide trips where the setpoint is approached in only one direction. Per the Safety Evaluation (SE) from the NRC (dated 6 November 1995) for Reference 1-2:
"The GE methodology utilizes single-sided distributions in the development of trip setpoints and allowable values.
The staff has stated that this methodology is acceptable provided that a channel approaches a trip in only one direction."
GEH's setpoint methodology for operating plants uses vendor instrument error specifications conservatively to provide setpoints that meet margin requirements to a high degree of confidence.
This was demonstrated by actual data analysis during licensing of the GEH methodology (Reference 1-2). GEH's Instrument Setpoint Methodology was approved by the NRC in November, 1995 while RG 1.105 Revision 2 was in use. RG 1.105 Revision 3 was introduced in December 1999, but the revised content, that quantified the confidence level to be 95%, did not invalidate or affect the approved GEH Setpoint Methodology. Per the SE from the NRC for Reference 1-2:
the BWROG presented data to show that although the GE setpoint methodology does not produce results with a defined confidence level, it was shown that the data analysis can produce results that have a high degree of confidence (95 percent confidence limits).... By establishing that the 95 percent confidence intervals are bounded by the design allowances developed per NEDC-31336, GE has shown that the results produced by the GE setpoint methodology can be established with high confidence."
The AL is a process parameter value used in the safety analysis and represents a limiting value for the automatic initiation of protective actions. From the AL, an AV is first calculated which has margin to the AL based on all measurement errors under trip conditions except Drift. ((
)) All random errors are combined using-Square Root of the Sum of the Squares (SRSS) method, and non-conservative bias errors are added algebraically. The AV represents the limiting value to which a setpoint can drift (as determined from surveillance) and still assure that the AL is protected. ((
)) The AV is the value specified in the Technical Specifications, and is an AL surrogate that assures the AL is protected if the setpoint does not exceed it.
The approved GEH setpoint methodology basically results in two calculated NTSPs as shown in Figure 1-1: NTSP1 and NTSP(Adj).
Page 2 of 6 SRV-TP-2030 GEH Non Proprietary Information
)) NTSP1 is the Limiting Trip Setpoint (LTSP),
as the instrument setting can be no closer to the AL than NTSP 1.
i((
1]i Figure 1-1 However, NTSP1 generally does not have the margin to the AV required by the GEH methodology, and is seldom the. final adjusted NTSP, called "NTSP(Adj)", the second NTSP.
(An intermediate NTSP, NTSP2, is also calculated as part of the NTSP(Adj) calculations.)
((I Relevant equations are shown below. [Notes: IN refers to the random component for each error.
The subscript L refers to the error for the whole instrument loop, and the errors are based on a one-sided approach to the setpoints.]
11]
AV = AL - AVMARGIN (for an increasing setpoint) 1]
NTSP 1-- AL - NTSP I MARGIN (for an increasing setpoint)
= Limiting Trip Setpoint (LTSP)
Page 3 of 6 SRV-TP-2030 Per NEDC-31336P-A (Reference 1-2), ((
GEH Non Proprietary Information 1] As shown in Figure 1-1, ((
All setpoints are reset to the NTSP(Adj), within the ALT, after calibration. ((
)) (also see the equation below). All LATs are equal to their associated ALTs (the tolerance within which the device calibration reading is left after calibration). Relevant equations are shown below.
(calculated for each instrument i in the instrument loop)
LAT ALT
)) If the AV/NTSP1 margin is not sufficient for the LER avoidance test, the NTSP is conservatively adjusted to provide added margin.
The GEH setpoint methodology performs an additional LAT test to determine if the NTSP needs to be adjusted further in the conservative direction. ((
1]
If the NTSP has sufficient margin to meet these requirements for LAT, no adjustment to NTSP is required. However, if margin is not sufficient, the NTSP is adjusted to provide added margin.
Page 4 of 6 SRV-TP-2030 GEH Non Proprietary Information This adjusted NTSP is "NTSP(Adj)", and.it is also checked for LER avoidance. The NTSP(Adj) is the final NTSP that is set into the instrument loop. After each calibration, the instrument is reset to this final NTSP(Adj), within the ALT.
))
)) The OL is an operational limit on the opposite side of the setpoint than the AL, and generally represents the parameter value for normal operation.
The following table provides an example of results from a typical setpoint calculation performed using GEH setpoint methodology. The example is for a plant's APRM Neutron Flux Scram setpoint function in units of percent Rated Thermal Power (RTP). Note as stated earlier, the final NTSP(AdJ) is further away from the AL than NTSP 1, the Limiting Trip Setpoint (LTSP).
Table 1-1 Parameter
% RTP AL 122 AV 119.3 NTSP1(LTSP) 118.9 NTSP(Adj) 117.3 GEH Setpoint Calculation Methodology Without an AL In the case where there is no AL, such as for the Anticipated Transient Without Scram (ATWS)
High Pressure Recirculation Pump Trip (RPT) setpoint function, then the input to the setpoint calculation is an AV.
For such a case, NTSP1, the Limiting Trip Setpoint (LTSP) is not pertinent and cannot be calculated. When the input to the setpoint calculation is the AV, then margin is calculated by GEH methodology between the AV and the final NTSP(Adj), as discussed above.
Setpoint Calculation - Pilgrim Nuclear Power Station (PNPS) Specific An ATWS High Pressure RPT setpoint calculation was performed using the GEH setpoint methodology to support the changes for the SRV-SSV Setpoint Change project at PNPS. The ATWS analysis used an AV = 1220 psig, which was used as the starting point for the setpoint calculation.
All calculations were based on the error terms associated with the installed Page 5 of 6 GEH Non Proprietary Information SRV-TP-2030 instruments.
The procedural As Left Tolerances (ALTs) were based on the accuracies of existing instruments (i.e, Pressure Transmitters and Analog Trip Units). The following table summarizes the limit (AV if no AL) associated with the ATWS High Pressure RPT setpoint calculation for PNPS. If a setpoint is not credited in a safety evaluation, there is no applicable AL, in accordance with the GEH setpoint methodology.
Setpoint Function (psig)
(psig)
Source / Basis Initiate Recirculation Pump Trip (RPT) and Alternate Rod Insertion (ARI) when the Reactor pressure exceeds the switch setpoint, to provide ATWS High 1220 1212 a back-up method for, controlling reactivity (i.e.,
Pressure RPT t inserting negative reactivity) in the unlikely event that the Reactor fails to scram when required.
t An AL is not applicable for the ATWS analysis.
With ATWS being such a low probability Special Event, the NRC has traditionally accepted that nominal input and conditions can be used in the analysis (so as not to stack up so many conservatisms on an already low probability event). However, for utilities defining a nominal condition can be difficult, and a standard practice is to use Technical Specifications Limit (i.e., the Allowable Value) in the ATWS analysis. This provides more conservative results. Also, note that this happens to be a setpoint function that is not used for mitigation to protect the safety limit in other analysis bases.
See Reference 1-3 for the representative calculation summaries. Reference 1-3 has already been submitted to the NRC. Reference 1-2 has an Accession Number in the NRC's document system:
ML072950103. The associated spreadsheets for Reference 1-3 may be viewed by the NRC at a GEH, a PNPS, or a NRC office, upon request, and to a schedule agreed to by GEH, PNPS, and the NRC.
REFERENCES 1-2.
eMail message from James Kim (NRC) to Walter Lobo (Pilgrim Nuclear Power Station),
"FW: Pilgrim TAC ME3543, June 3, 2010 3:19 PM EDT.
1-2.
NEDC-31336P-A, "General Electric Instrument Sctpoint Methodology",
September 1996. [NRC Accession Number ML072950103]
1-3.
GEH Report 0000-0105-0835-R2 Pilg-SRVs-T506-ATWS HiPres RPT-Calc-2010, Instruments Limits Calculation, Entergy Operations, Inc., Pilgrim Nuclear Power Station, ATWS High Pressure Recirculation Pump Trip (RPT), Revision 2, March 2010.
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