ML20073A734

Cycle 4 Startup Test Rept

ML20073A734
Person / Time
Site:	Seabrook
Issue date:	09/12/1994
From:	NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO)
To:
Shared Package
ML20073A731	List: ML20073A728 ML20073A734
References
NUDOCS 9409200385
Download: ML20073A734 (10)

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l Docket No. 50-443 1

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SEABROOK STATION UNIT NO.1 STARTUP TEST REPORT i CYCLE 4 1

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9409200385 940912 PDR ADOCK 05000443 P PDR

INDEX j l.0 CilRONOLOGICAL

SUMMARY

l 2.0 CORE DESIGN

SUMMARY

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l 3.0 LOW POWER PliYSICS TESTING

SUMMARY

(LPPT) l 4.0 POWER ASCENSION TESTING

SUMMARY

(PAT)

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J 5.0 TEST RESULTS i l

TABLEI LPPT RESULTS  :

l l TABLE 2 PAT FLUX MAP RESULTS' .l TABLE 3 FULL POWER TilERMAL/ HYDRAULIC DATA

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1.0 CHRONOL OGICAL

SUMMARY

Cycle 4 Fuel Load was completed July 9,1994. Subsequent operation / testing milestones were completed as follows:

INITIAL CRITICALITY 07/29/94 LPPT COMPLETED 07/31/94 ON LINE 07/31/94 30% PAT COMPLETED 08/02/94 50% PAT COMPLETED 08/03/94 1 l

75% PAT COMPLETED 08/04/94 90% PAT COMPLETED 08/04/94 I

FULL POWER 08/05/94 100% PAT COMPLETED 08/10/94  ;

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2.0 CORE DESIGN

SUMMARY

Cycle 4 will be Seabrook Station's second 18-month fuel cycle. The Cycle 4 core is designed to operate for 16820 MWD /MTU (441 Effective Full Power Days). 72 fresh fuel assemblies were

' loaded into the Cycle 4 core with 36 having an enrichment of 3.6 w/o and 36 having an enrichment of 4.0 w/o. By comparison, Cycle 3 utilized 76 fresh fuel assemblies with enrichments of 4.0 and 4.4 w/o.

' The reload fuel mechanical design is identical to that used in Cycle 3. The operating features of these fuel assemblies are a removable top nozzle, debris filter bottom nozzle, integral fuel burnable absorber, extended burnup capability and anti-snag grids.

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3.0 1,0W POWER PIIYSICS TESTING

SUMMARY

Testing was performed in accordance with the following general sequence:

1. Initial Criticality: Criticality was achieved using a controlled dilution once shutdown and ,

control banks had been withdrawn

2. Zero Power Test Range Determination: This was determined after the point of adding heat had been demonstrated. Additional emphasis was placed on this measurement to prevent testing too low in the test range, thus miniraizing gamma contribution to the -

excore signal.

3. On-line Verification of the Reactivity Computer: This was determined using stable startup rates during flux doubling measurements.

4. Boron endpoint measurements: Data was obtained with all rods out and control banks .

inserted.

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5. Isothermal Temperature Coefficient Measurement (ITC): ITC was based on the reactivity change resulting from an RCS temperature change. The Moderator Temperature Coefficient (MTC) was calculated from the ITC Data.

6. Rod Worth Measurements: Individual Control Bank wonhs were measured during rod l insertion. Total Control Bank worth was measured during withdrawal in overlap.

4.0 POWER ASCENSION TESTING

SUMMARY

l Testing was performed at specified power plateaus of 30%,50%, .75%,90% and 100% Rated Thermal Power (RTP). Power changes were governed by operating procedures and Fuel Preconditioning Guidelines specified by the fuel vendor, Westinghouse.

In order to determine the core power distribution, Hux mapping was performed at 30%, 50% and 100% using the Fixed incore Detector System'. The resultant peaking factors were compared to Technical Specification limits, to verify that the core was operating within its design limits.

Thermal-hydraulic parameters, nuclear parameters and related instrumentation were monitored throughout the Power Ascension. Data was compared to previous cycles' power ascension data -

to identify any calibration or system problems. The major areas analyzed were:

1. Nuclear Instrumentation Indication: Overlap data was obtained between Intermediate i

Range and Power Range channels. Secondary plant heat balance calculations were performed to verify the Nuclear Instrumentation indications.

2. RCS Delta-T Indication: The initial scaling of RCS AT was left the same as Cycle 3. At the 75% power plateau, actual full power AT was extrapolated out using data from 30%,

50% and 75% power and AT rescaled accordingly. Final adjustments were performed at 100% power and the values provided in Table 3.

j 3. Upper Plenum Anomaly: In early 1992, Westinghouse notified North Atlantic that

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Seabrook Station may be susceptible to a phenomenon known as the Upper Plenum Anomaly (UPA). The UPA is primarily characterized by aperiodic step changes of 1 F to 2*F in hot leg temperature. A Design Document was written to implement a number of operating contingencies should the UPA be present. No Upper Plenum Anomaly was identified.

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4. RCS Temperatures: Data was obtained for all Narrow Range Loop temperatures.

Evaluations of Delta-T ( F) and Tavgffref Indication were performed.

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5. Steam and Feedwater Flows: Data was obtained to evaluate flows for individual loop agreement between transmitters and loop steam flow / feed flow deviations.

6. Steam Pressures: Data was obtained to evaluate steam generator pressures for individual loop agreement between transmitters as well as individual turbine impulse pressures.

7. Incore/Excore Calibration: The core was operated at its natural axial power shape during flux mapping at 50% and 100% RTP. Scaling factors were calculated using the single point methodology and then used to recalibrate the Nuclear Instrumentation System.

8. RCS Flow: A primary heat balance was performed at 90% and 100% RTP to detennine total RCS flow.

Other than procedure changes to accommodate the new fixed incore detector system and single point incore/excore calibration, the power ascension test program required no changes from Cycle 3.

• 1 5.0 RESUI.TS ,

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1. . Low Power Physics Testing: Both acceptance and review criteria were revised per Westinghouse letter 94 NA#-G-0030, recommended Westinghouse physics test results.

All acceptance criteria were met. All review criteria were met. See Table 1 for results.  ;

i 2.- Flux Mapping: No problems were identified during the flux maps at 30%,50% and 100% RTP. See Table 2 for results.

3. Full Power Thermal /llydraulic Evaluation: No problems were encountered with any instrumentation. No Upper Plenum Anomaly was identified. Total RCS flow was ,

determined to be 100.9% of the allowable Technical Specification limit. See Table 3 for ,

results.

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l TABLE 1 1.OW POWER PilYSICS RESilLTS: CYCLE 4 ITEM MEASURED PREDICTED ERROR CRITERIA I

i RCS BORON AT CRITIC ALITY (ppm) 1686 1707 21 70 CBD @ 163 STEPS)

BORON END POINTS: (ppm)  !

ALL RODS OUT 1730 1707 23 139 l CONTROL BANKS INSERTED 1230 1241 11 i 68*

I ARO ITC (pcmFF) -3.07 -3.16 0.09 2* l ARO MTC (pcmFF) -1.50 -1.39 N/A <0 CONTROL BANK  !

ROD WORTilS: (pem)

D 553 541 12 100* I C 899 966 67 134*

B 926 921 5 138* i A 1080 1119 39 162*

OVERLAP 3458 3547 11 23192 354' NOTE:

• Review criteria, all others are acceptance criteria.

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. TABLE 2 POWER ASCENSION FI,UX MAP RESUI TS: CYCLE 4 ITEM MAP 1 MAP 2 MAP 3 DATE OF MAP 08/01/94. 08/02/94 08/05/94 POWER LEVEL (%) 29.4 48.2 99.8 I

CBD POSITION (STEPS) 178 194 226 I 1

i RCS BORON (ppm) 1634 1455 1182 )

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Fx,,. (UNRODDED/ RODDED) 1.6978/1.7084 1.6389 1.5943 F 3n 1.5452 1.4808 1.4165 INCORE TILT 1.0034 1.0042 1.0064 i

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. I TABLE 3 FUl_L POWER THERMAL-ilYDRAULIC DATA: CYCI.E 4 1

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ITEM VALUE )

RCS T4va 586.5 F RCS DELTA-T l Loop 1 57.02 F ,

2 58.19 F 3 57.08 F 4 57.55 F RCS FLOWS Loop 1 99126 GPM 2 98022 GPM l 3 101537 GPM l 4 98703 GPM TOTAL 397388 GPM AUCTIONEERED HIGH T 3va 587.56 F T ate 586.90 F IMPULSE PRESSURE 665.8 PSIG SG PRESSURES i

A 976.4 PSIG B 975.6 PSIG C 975.7 PSIG D 973.5 PSIG l

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