ML20002E386

Startup Physics Test Rept Unit 1 Cycle 6.

ML20002E386
Person / Time
Site:	Prairie Island
Issue date:	01/22/1981
From:	NORTHERN STATES POWER CO.
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ML20002E384	List: ML20002E383 ML20002E386
References
NUDOCS 8101270697
Download: ML20002E386 (4)

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.Prairis Island V Stercup Physics Tact Raport Unit 1 Cycle 6 1.0 Introduction The Prairie Island Unit I reactor had 40 reload fuel assemblies maaufactured by Exxon Nuclear Company installed in 1980 during the fif th refueling for <. hat facility.

2.0 Startup Physics Test - Introduction Reference 1 identified the startup related tests conducted for the Unit 1 Cycle 5 startup. Tests described in detail with analytical results in that report included the following:

(a) Zero Power Isothermal Temperature Coefficient (b) Control Banks' Rod Worth (c) Critical Boron Concentration (d) Boron Worth (e) Power Distribution Measurements This report provides test results for the above tests conducted during the startup of Prairie Island Nuclear Generating Plant, Unit 1. The procedures used in the startup test program were the most recent revision reviewed by the Plant Operations Committee.

3.0 Startup Physics Tests - Results Table 1 summarizes the following data for each test performed.

(a) Test (b) Procedure / Effective Revision (c) Parameter (d) Measured Value (e) Acceptance Criteria 4.0 Summary The data presented in Table 1 shows acceptable agreement with the acceptance criteria.

The Quadrant Power Tilt Ratio (QPTR) was larger than expected. Power waa limited to 50% while extensive analysis was performed to identify the cause of the tilt. No single definitive cause was ident ified .

Safety concerns of the larger than expected QPTR were reviewed in depth. The intent of limiting the QPTR to 1.02 is to continuously, radially, monitor the flux shape to limit the core peaking factors. Since core peaking factors were recently directly measured using incore measurement and all peaking f actors were well within their limits, no safety concerns exist.

Following discussions between Exxon and the NRC Staff, Core Performance Branch, power was increased to 90% and then 100%. Incore flux maps were taken at both power levels.

Additional incore maps continued to show peaking factors well within their limits. The excore nuclear instruments were calibrated. The tilt is being monitored by additional flux maps to ensure a stable predictable flux shape.

5.0 Reference (1) Letter, L 0 Mayer (NSP) to J G Keppler (NRC) dated August 1, 1979.

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v Table 1 Unit 1 Cycle 6 Startup Test Results 1.0 HZP Isothermal Temperature Coefficient Procedure: D32 Revision: 1 (9/6/79)

Test Condition Measurede Acceptance Criteria 1so ARO -2.67 pcm/F <0 pcm/F 2.0 Control Banks' Worth Measurements Prodecure: D30 Revision: 2 (7/24/80)

Test Condition Measured Worth Acceptance Criteria Control Bank D 768 pcm 778 pcm + 15%

Control Bank C 1377 pcm 1371pcm][15%

Control Bank B 772 pcm 878 pcm + 15%

Control Bank A

~

1639 pcm 1636pcm}[15%

All Control Banks 4556 pcm 4663 pcm j; 10%

3.0 Critical Boron Concentration ,

Procedure: D34 Revision: 1 (9/6/79)

Test Condition Measured Value Acceptance Criteria All Rods Out 1411 ppm 1403 j; 50 ppm D+C+B+A In 886 ppm 840 j; 50 ppm 4.0 Differential Boron Worth Procedure: D30 Revision: 2 (7/24/80)

Test Condition Acceptance Criteria Measuredd{

<All Control Banks > -8.7 pcm/ ppm -8.2 pcm 10%

p pm --

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5.0 Power Distribution Marnuriments Procedure

Spill 6 Revision: 5 (9/12/80)

Plant Condition Parameter Value Acceptance Criteria HZP, ARO MAX (RRIm -RRIp )/RRI p Pi > 0.9 -7.3% + 10%

Pi T 0.9 8.7% 7 15%

N v,

9 Maximum 2.33 at z = 8.3f t <4.16 at z =8.3ft Limiting 2.32 at z = 9.0ft <4.12 at z =9.0ft F ** 1.56 <1.86 kn QPTR*** 1.044 <1.02 48% Power MAX (RRIm -RRIp )/RRI p Pi > 0.9 -4.6% + 10%

Pi I'0.9 3.8% 7

__ 15%

F **** 1.88 at z = 7.3ft <4.20 at z =7.3ft Q

F g 1.50 <l.71 QPTR 1.026 <1.02 99% Power MAX (RRIm -RRIp )/RRI p Pi > 0.9 -4.5% + 10%

Pi T 0.9 4.4% 115%

F 9 Maximum 1.75 at z = 5.9f t <2.17 at z = 5.9ft Limiting 1.74 at z = 7.3ft <2.12 at z = 7.3ft F

bH 1.47 <1.55 QPTR 1.019***** <1.02

• Values include uncertainties of 1.05.

Criteria is 2.145 x K(z)/P.

• • Values include uncertainties of 1.04.

Criteria is 1.55 [1 + 0.2(1-P) } (1-REP (BU)] .

• • • The excore nuclear instruments had not been calibrated at th is t ime . The value shown is from incore instruments which are not limited by the Technical Specifications.

• • • • The limiting and maximum occurred at the same axial location.

• • • • • Additional Maps taken in the same period indicated QPTR's from 1.017 to 1.0208.

O

-Legend HZP Hot Zero Power i ARO All Rods Out RRI m

Reaction Rate Integral - measured RRI Reaction Rate Integral - predicted P

Pi Relative assembly power QPTR Quadrant Power Tilt Ratio M iso isothermal temperature coefficient pcm/ F '

db boron worth pcm/ ppm

<All Control Banks > average value overall control banks i

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