ML20134F357

Provides Info in Response to NRC RAI Re Core Reload Methodology

ML20134F357
Person / Time
Site:	Crane
Issue date:	10/28/1996
From:	James Knubel GENERAL PUBLIC UTILITIES CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
6710-96-2318, NUDOCS 9611050180
Download: ML20134F357 (7)

Text

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GPU Nuclear. inc.

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Route 441 South i

NUCLEAR Post Office Box 480 1

Middletown, PA 17057-0480 Tel 717-944 7621 6710-96-2318 October 28, 1996 i

l U. S. Nuclear Regulatory Commission Att: Document Control Desk.

Washington, DC 20555 Gentlemen:

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Subject:

Three Mile Island Nuclear Station, Unit 1 (TMI-1)

Operating License No. DPR-50 l

Docket No. 50-289 Response to Request for Additional Information -

1 Core Reload Methodology In response to NRC questions raised during discussions on July 19,1996 and August 19, 1996, GPU Nuclear is providing the attached information.

This additional information is related to GPU Nuclear Topical Report TR-092P, Revision 0,"TMI-l Reload Design and Setpoint Methodology," submitted on February 27,1996 for NRC review and approval for in-house GPU Nuclear core reload design.

If any additional information is required, please contact Mr. David J. Distel, GPU Nuclear Regulatory Affairs at (201) 316-7955.

Sincerely, J. Koubel Vice President and Director, TMI DJD/ pip Attachment c:

Administrator, Region I

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I NRC TMI Senior Resident Inspector f

NRC Senior Project Manager, TMI l

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9611050100 961028 PDR ADOCK 05000289 P

PDR

9' 6710-96-2313 Page 1 of 2 j

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l NRC Ouestion:

Figure A.9 page 149 indicates the maximum allowable peaking limits. The licensee 's Maximum Allowable Peaking (MAP) limitsfor the axialpeak vahtes of1.3 and less do not agree as well as j

thosefc>r axialpeak values of1.5 andgreater. The licensee indicated that they did not base this analysis on Cycle 10 specific data but on composite bounding datafrom previous cycles.

It appears as though the licensee has not demonstrated their ability to repeat the vendor analysis.

GPU Nuclear Response:

As discussed with the NRC on August 19,1996, GPU Nuclear has performed a confirmatory re-analysis of the entire RPS MAP limit analysis (axial peaks from 1.1 to 1.9) using recently available vendor-provided bounding thermal-hydraulic input data to provide a more direct comparison. The MAP limit analysis, as described in Section 3.6 of the subject topical report TR-092P, consists of l

two parts: (1) determination of the analysis target DNBR limits at two limiting pressure-i temperature statepoints (low pressure and high temperature points as shown in Table 1), and (2) a I

parametric analysis for various axial power shapes by iterating the hot assembly power until the l

target DNBR limit is reached. The new comparative results are given in the attached Table 1 (for target DNBRs), and Figure 1 and Table 2 (for the MAP limits).

Analysis Target DNBR Limits:

In Table 1, the analysis target DNBR results at the pressure-temperature limit statepoints as well as the bounding T-H data are shown. The GPU Nuclear target DNBR results are 1.1834 at the low pressure statepoint and 1.1824 at the high temperature statepoint. The corresponding values of the vendor analysis are 1.1802 and 1.1855, respectively, which agree with the GPU Nuclear results to within 0.3%.

RPS MAP Limits:

As shown in Figure 1 and Table 2, the new GPU Nuclear MAP results agree well with the vendor results. For the axial peaks from 1.1 to 1.2, the agreement of MAP limits is excellent (within 1%)

and GPU Nuclear predictions for the axial peaks from 1.5 to 1.9 are 0.7% to 2.8% more conservative than those of the vendor analysis.

For the axial peak of 1.3 at the bottom portion of the fuel assembly (X/L = 0.2), the GPU Nuclear result (MAP = 2.3803)is 2.2% higher than the vendor result (MAP = 2.329). However, the impact of this 2.2% higher MAP limit at the bottom portion of the fuel assembly (X/L = 0.2) on the setpoint analysis is insignificant because, as illustrated in Figure 5.5 (page 110) of TR-092P (included in this response as Figure 2), the MAP limits are not limiting in the determination of the negative core offset (or axial imbalance) limit but are limiting for the positive core offset limit (X/L 2 0.5). The GPU Nuclear MAP limits for the 1.3 axial peak would result in a more conservative setpoint than the vendor MAP limits considering that GPU Nuclear MAP limits are

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i 6710-96-2313 Page 2 of 2 Attachment 1

more conservative than those of the vendor in the upper half of fuel ussembly (X/L ;t 0.5) in Figure 1. Additionally, it is noted that the GPU Nuclear M AP limits are determined using the VIPRE-01, Mod 02 code consistent with GPU Nuclear Topical Report TR-087, whereas the l

vendor MAP limits are determined using the LYNXT code Furthermore, as described in Section 3.6.3 (page 60) of TR-092P, the MAP margin verification analyses are to be performed during the reload design process to ensure reasonable peaking margins in determining the setpoints. This veiification analysis is needed to determine the real DNBR margin by incorporating the actual axial power distribution data directly into VIPRE-01 replacing a smooth, mathematically-derived axial power distribution used in the MAP ar.alysis.

This MAP margin verification analysis will identify and correct any problem for cases v here a l

non-conservative MAP margin exists.

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l TABLE 1. ANALYSIS TARGET DNBR LIMIT Boundina T-H Input Data Low Pressure Point Hiah Temperature Point Pressure (psia) 1800 1837.8 RCS Inlet Enthalpy (Btu /lbm) 568.9 572.15 Heat Flux (MBtu/hr-ft2) 0.20175 0.20175 RCS Flow (Mlbm/hr-ft2) 2.537 2.5283 l

RCS Inlet Temperature (F) 566.65 569.2 Tarnet DNBR Limit Results Low Pressure Point Hiah Temperature Point l

Vendor Target DNBR 1.1802 1.1855 GPUN Target DNBR 1.1834 1.1824 DNBR % Difference 0.27 0.26 I

TABLE 2. TMI-1; RPS MAP COMPARISON BETWEEN GPUN & VENDOR (BOUNDING DATA)

AX1AL PEAK PEAK LOCATION MAP DIFF.

l (X/L)

VENDOR MAP GPUN MAP

(%)

1.1 0.2 1.907 1.9069

-0.01 1.1 0.4 1.901 1.8990

-0.10 1.1 0.6 1.888 1.8952 0.38 1.1 0.8 1.866 1.8704 0.23 1.2 0.2 2.117 2.1382 1.00 1.2 0.4 2.104 2.1102 0.30 1.2 0.6 2.078 2.0796 0.08 1.2 0.8 2.032 2.0148

-0.85 1.3 0.2 2.329 2.3803 2.20 1.3 0.4 2.304 2.3108 0.30 1.3 0.6 2.265 2.2360

-1.28 1.3 0.8 2.175 2.1255

-2.27 1.5 0.2 2.758 2.7204

-1.36 1.5 0.4 2.673 2.5975

-2.83 1.5 0.6 2.537 2.4666

-2.78 1.5 0.8 2.391 2.3285

-2.62 1.7 0.2 3.033 2.9807

-1.73 1.7 0.4 2.886 2.8288

-1.98 1.7 0.6 2.718 2.6682

-1.83 1.7 0.8 2.577 2.5096

-2.62 1.9 0.2 3.205 3.1820

-0.72 1.9 0.4 3.042 3.0101

-1.05 1.9 0.6 2.877 2.8344

-1.48 1.9 0.8 2.725 2.6647

-2.21 NOTES: MAP DIFF. = (GPUN-VENDOR)NENDOR*100 i

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