LR-N05-0021, Revised Backup Stability Protection Evaluation Report
| ML050260267 | |
| Person / Time | |
|---|---|
| Site: | Hope Creek  |
| Issue date: | 01/12/2005 |
| From: | Perino C Public Service Enterprise Group |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LR-N05-0021 | |
| Download: ML050260267 (15) | |
Text
PSEG Nuclear LLC P.O. Box 236, Hancocks Bridge, New Jersey 08038-0236 O PSEG NuclearLLC JAN 1 2 2005 LR-N05-0021 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 REVISED BACKUP STABILITY PROTECTION EVALUATION REPORT HOPE CREEK GENERATING STATION FACILITY OPERATING LICENSE NPF-57 DOCKET NO. 50-354
Reference:
LR-N04-0432, "Backup Stability Protection Evaluation Report," dated October 19, 2004.
This letter provides updated information regarding the evaluation performed to establish Backup Stability Protection (BSP) regions for Hope Creek Cycle 13.
By the referenced letter, PSEG Nuclear LLC (PSEG) provided a report for the NRC staffs information describing the evaluation performed to establish BSP regions to be used for stability monitoring in the event the Oscillation Power Range Monitor (OPRM) system becomes inoperable. Recent changes to the reference loading pattern for Hope Creek Cycle 13 made it necessary to re-perform the BSP evaluation. The revised BSP evaluation report is provided for the NRC staffs information in Attachment 1.
Attachment I contains information which the General Electric Company (GE) considers proprietary. GE requests that the proprietary information in Attachment 1 be withheld from public disclosure in accordance with 10 CFR 2.390. An affidavit in support of this request is included with Attachment 1. A non-proprietary version suitable for public disclosure is provided in Attachment 2.
Should you have any questions regarding this transmittal, please contact Mr. Paul Duke at 856-339-1466.
Sin ristina L. Perino Director - Licensing and Nuclear Safety.
Attachments (2)
This letter forwards proprietary information in accordance with 10CFR 2.390. The balance of this letter may be considered non-proprietary upon removal of Attachment 1.
95-2168 REV. 7199
Document Control Desk LR-N05-0021 JAN 1 2 2005 C
Mr. S. Collins, Administrator - Region I U. S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Mr. D. Collins, Project Manager - Hope Creek U. S. Nuclear Regulatory Commission Mail Stop 08C2 Washington, DC 20555 USNRC Senior Resident Inspector - Hope Creek (X24)
Mr. K. Tosch, Manager IV (without Attachment 1)
Bureau of Nuclear Engineering PO Box 415 Trenton, NJ 08625 This letter forwards proprietary information in accordance with 10CFR 2.390. The balance of this letter may be considered non-proprietary upon removal of Attachment 1.
Document Control Desk LR-N05-0021 GENE-0000-0029-61 93-02-RI (Non-proprietary)
GE Nuclear Energy GerW EL-cnc Capany 175 Catrer Averne, San Jose CA 95125 GENE-0000-0029-6193-02-Ri eDRE 0000-0026-5528 Class I November 2004 BSP Evaluation Report ELLLA Backup Stability Protection Evaluation for Hope Creek Cycle 13
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GENE-0000-0029-61 93-02-RI Disclaimer The only undertakings of the GE respecting information in this document are contained in the contract between the company receiving this document and GE. Nothing contained in this document shall be construed as changing the applicable contract. The use of this information by anyone other than a customer authorized by GE to have this document, or for any purpose other than that for which it is intended, is not authorized. With respect to any unauthorized use, GE makes no representation or warranty, and assumes no liability as to the completeness, accuracy or usefulness of the information contained in this document, or that its use may not infringe privately owned rights.
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GENE-0000-0029-61 93-02-RI BACKGROUND The stability Interim Corrective Actions (ICA) published by the BWR Openers' Group in Reference 1 can be summarized as guidance for reactor operation in regions of the power/flow domain where the margin to thermal hydraulic instability has been reduced. The ICA regions were based upon empirical evaluations and experience of BWR operation, and were described in terms of relative core flow and flow control lines (rod lines). The regions were not based upon specific analyses and hence do not provide constant margin to potential thermal hydraulic instability events. In Reference 2, the BWR Owners' Group recommended that plants review the applicability of the generic ICA regions on their respective core designs based on the fact that
"...aggressive core designs may have reduced stability margin". Reference 3 describes the method that GE proposed for licensees to review the applicability of their ICA regions.
INTRODUCTION The objective of this evaluation is to establish Backup Stability Protection (BSP, Reference 3) regions for Hope Creek Cycle 13 plant operation at bounding feedwater temperatures. The Cycle 13 core will contain 600 SVEA96+ fuel assemblies and 164 GE14 fuel assemblies. The results contained in this report are applicable for Cycle 13 operation in the Extended Load Line Limit Analysis (ELLLA)1 domain. The BSP Region I (Scram Region) and Region II (Controlled Entry Region) are established using ODYSY stability acceptance criterion: core decay ratio (DR) less than or equal to 0.8 and channel decay ratio less than or equal to 0.56 (Figure 1). The base BSP regions are the same as the ICA regions. If the ODYSY calculations determine that the intersections of the BSP regions with the natural circulation line (NCL) and highest flow control line (HFCL) are larger than the ICAs, then the larger BSP regions are used for stability monitoring in the event that the Oscillation Power Range Monitor (OPRM) system becomes inoperable.
The Upper Boundary Rodline in the ELLLA region reflects an approximate maximum rodline that can be achieved (Reference 4).
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GENE-0000-0029-61 93-02-RI ANALYSIS The following application procedure is designed to produce a reasonably conservative calculation of the BSP stability regions on the power/flow map (Figure 2), which have the potential for reactor instability, considering all manual BSP requirements (Reference 3). The procedure for DR calculations is summarized as follows:
- 1. Obtain accurate cycle and exposure dependent inputs from the core simulator. Rodded depletions are used in these calculations. The core and channel DR calculations are performed for a number of exposure points (approximately every 1000 MWD/ST apart) during the cycle to determine the limiting exposure.
- 2. Perform DR calculations at the limiting exposure along the HFCL and the NCL to search for the bounding state points. Table 1 outlines the key assumptions used in this analysis.
- 3. Plot the decay ratio results on the stability criterion map (see Figure 1). Using a linear interpolation scheme along the HFCL and along the NCL to determine the power/flow state points which produce core decay ratio that satisfies the acceptance criterion shown in Figure 1. The power/flow state points, that meet this acceptance criterion, define the region boundary endpoints on the HFCL and the NCL.
- 4. Use the following Generic Shape Function (GSF) to construct the region boundary:
tI W-W, W-W, _)
P = PB[-]
L J
W PB where:
P=percent rated power PA~percent rated power at point A (HFCL) 4 of 12
GENE-0000-0029-61 93-02-RI PB=percent rated power at point B (NCL)
W=percent rated core flow WA=percent rated core flow at point A W=percent rated core flow at point B 5 of 12
GENE-0000-0029-6193-02-R1 II Table 1 Key Assumptions for BSP Regions Calculation Application Assumptions I
Xenon concentration
- For Region I on the NCL, constant Xenon at rated operating condition
- For Region II on the NCL, no Xenon
- For Region I on the HFCL, constant Xenon at rated operating condition
- For Region II, equilibrium feedwater temperature at off-rated operating condition 6 of12
GENE-0000-0029-61 93-02-RI RESULTS AND DISCUSSION
((
)) The results were calculated based on the verified Hope Creek Cycle 13 ODYN base deck. For Hope Creek-Cycle 13 operation, the limiting core decay ratio occurs at BOC for both BSP Scram-Region NCL and HFCL boundary points as shown in Table 2. Therefore, the determination of BSP boundary intercepts on the NCL and HFCL for the Scram Region and the Control Entry Region were performed at the BOC condition.
Table 2 Decay Ratios of BSP Scram-Region NCL and HFCL Boundary Points as a Function of Cycle Exposure at Bounding Feedwater Temperature of 400.00F Power/Flow Point 1/
Exposure Core DR Highest Feedwater (Case # / Name)
Rated Rated (MWD/ST)
Channel DR Temperature Power Flow I
Scram Region, Region I, NCL Points l
__[
__0.581 0.066 400.0 0.569 0.146 400.0 l ______0.561 0.161 400.0 0.467 0.317 400.0 0.380 0.477 400.0 0.447 0.514 400.0 0.593 0.524 400.0 0.701 0.516 400.0 0.726 0.576 400.0 0.747 0.531 400.0 0.800 0.590 400.0 0.914 0.708 400.0 Scram Region, Region 1, HFCL Points 0.442 0.060 400.0 0.422 0.135 400.0 0.433 0.134 400.0 0.373 0.312 400.0 0.367 0.421 400.0 0.411 0.440 400.0 0.481 0.450 400.0 7 of 12
GENE-0000-0029-61 93-02-RI 0.563 0.444 400.0 0.574 0.506 400.0 0.618 0.469 400.0 I
I I
0.673 0.524 400.0
.11 0.822 0.632 400.0
- EOC = 10347 MWD/ST.
BSP Regions for Cycle 13 ELLLA Operation and Comparison with Current Cycle 12 ICA Regions The computed DR results at the bounding state points B, Bi, A and Al on the NCL and the HFCL for the ELLLA operation are shown in Table 3. The Controlled Entry Region NCL bounding point Bl is replaced by a lower NCL bounding point BI-ICA, shown in Table 3, in order to enclose the standard ICA Controlled Entry Region. The BSP Regions boundaries are established using the GSF as shown in Figure 2 at the bounding feedwater temperature (400.00F). The BSP Regions for the ELLLA operation are compared with Current Cycle 12 ICA Regions in Figure 2, and indicate that the BSP Regions are close to the corresponding Cycle 12 ICA Regions.
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GENE-0000-0029-61 93-02-RI Table 3 ODYSY Decay Ratio Results at Bounding Feedwater Temperature (400.0°F) for ELLLA Operation*
Power/Flow Exposure Core DR Highest Feedwater Point Rated Rated Channel Temperature Power Flow DR CD Scram Region, Region I, NCL Point I
I 0.80 0.56 400.0 Controlled Entry Region, Region 1I, NCL Points l
I 0.80 0.46 315.3 l
< 0.80
< 0.46 Scram Region, Region I, HFCL Point I
I 1 0.73 1
0.57 400.0 Controlled Entry Region, Region II, HFCL Point 0.69 0.57 3750
- The Power/Flow state points shown above (A, B, Al and BI-ICA) are the BSP regions boundary endpoints on the HFCL and the NCL.
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GENE-0000-0029-61 93-02-RI REFERENCES
- 1. BWROG-94079, "BWR Owners' Group Guidelines for Stability Interim Corrective Action,"
June 1994.
- 2. BWROG-02072, "Review of BWR Owners' Group Guidelines for Stability Interim Corrective Action," November20, 2002.
- 3. OG 02-0119-260, GE to BWR Owners' Group Detect and Suppress II Committee, "Backup Stability Protection (BSP) for Inoperable Option III Solution," July 17, 2002.
- 4. NFS04-193, PSG-04-0043, "Responses to Design Input Request for Hope Creek Cycle 13 Redesign DIVOM, OPRM Setpoint, and BSP Evaluations to Support Operation in the ELLLA Domain," November 18, 2004.
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GENE-0000-0029-61 93-02-Ri Fig. 1 Decay Ratios of Hope Creek Cycle 13 BSP Region Boundary State Points ((
))
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GENE-0000-0029-6193-02-Ri Fig. 2 BSP Regions for Cycle 13 ELLLA Operation and Comparison with Current Cycle 12 ICA Regions Core Flow (Mb/hr) 0 10 20 30 40 500 70 so 90 10o 110 120 120
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