ML20247G868

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App 4B, Hot Loop Flow Testing of Sys 80 Fuel & Control Element Assembly Components, to CESSAR 80+ Std Design
ML20247G868
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Site: 05200002, 05000470
Issue date: 03/30/1989
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ABB COMBUSTION ENGINEERING NUCLEAR FUEL (FORMERLY
To:
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ML20247G537 List:
References
NUDOCS 8904040335
Download: ML20247G868 (12)
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Text

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CESSAR naincy,,,

O APPENDIX 4B HOT LOOP FLOW TESTING OF SYSTEM 80 FUEL AND CEA COMPONENTS O

O 8904040335 890330 PDR ADOCK 05000470 PDC K

CESSAR EininCATION i

( . EFFECTIVE PAGS LISTING CHAPTER _4_

APPENDIX 4B Table of Contents Pace Amendment i

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Text i

Pace

.4B-1 4B-2 4B-3 Ficures i l

4B-1 4B-2 4B-3 4B-4 1

Amendment B March 31,_1988

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1 TABLE OF CONTENTS l

CEAPTER 4 APPENDIX 4B Section Subiect Pace No.

l 1.0

SUMMARY

4B-1 1 2.0 TEST FACILITY DESCRIPTION 4B-1 1 3.0 TEST COMPONEHIS 4B-1

'3.1 STACKUP 4B-1 i 1

3.2 FUEL ASSEMBLIES 4B-1 3.2.1 DETAILS OF DESIGN 4B-1 3.2.2 SPACER GRID SPRING SETTINGS 4B-1 1

() 3.2.3 FUEL ARRAY IN TEST 4B-2

! 3.3 CONTROL ELEMENT ASSEMBLY 4B-2 3.4 SUPPORT STRUCTURES 4B-2 l 4.0 TEST RESULTS 4B-2 4.1 SCRAM TIME vs ACCEPTANCE CURVE 4B-2 4.2 PRESSURE DROPS IN FUEL 4B-2 4.3 FUEL ROD FRETTING 4B-3 4.4 GUIDE TUBE WEAR 4B-3 i

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CESSAR EnHricari:n  !

9 LIST OF FIGURES l l

Fiqura subiect )

4B-1 C-E TF-2 Hot Loop Piping Isometric j l

4D-2 System 80 Fuel Hot Loop Tests, Component Stackup j in TF-2 4B-3 Cross Section Through Fuel Shroud and Fuel Array TF-2 Tests 4B-4 Test Scram vs Acceptance Curve, 525*F Four Pump Flow Sett ing in TF-2 0

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11

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CESSAR Mncarien I l

i O i1 1.0

SUMMARY

l Hot loop flow testing for System 80 was completed during 1980 and 1981. Test components included an array of five fuel assemblies, a- twelve rod control element assembly (CEA) and supporting 1 structures. Pressure drops and CEA scram times were measured for j a range of temperature and flow rate settings. Results were nearly as predicted based on analyses and the results of hot. loop ,

tests preceding those for System 80. A 1300 hour0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br /> wear test was j run, finding no fretting wear on fuel rods and no other wear on i fuel exterior surfaces. Some wear occurred inside rodded CEA )

guide tubes, but at acceptable rates.

2.0 TEST FACILITY DESCRIPTION Tests were performed in the 36" ID main section of the C-E TF-2 hot loop. The piping arrangement in this loop is shown in Figure 4B-1. The loop is rated at 15000 gpm, 650*F, 2500 psia. System j 80 wear tests were near loop limits, at 14000 gpm, 620*F, 2250 l psia. The loop includes systems which maintain steady ]

temperature and pressure and nominal reactor water chemistry. '

3.0 TEST CO)(_PONENTS O~ 3.1 STACKUP The test component stackup is shown in Figure 4B-2. The support .

structures were bolted to lugs and a support ring at the bottom )

of the test vessel . The fuel assemblies and CEA were enclosed within lower and upper support structures which were joined by bolts at the fuel alignment plate.

3.2 FUEL ASSEMBLIES 3.2.1 DETAILS OF DESIGN Fuel assemblies closely matched the production reactor fuel design, as described in Section 4.2.2. Differences include:

a. Fuel rod loading -

46% of the fuel rods (544) were of prototype construction, with depleted UO pellets. 54%

(636) were dummy rods of solid stainless 8 teel. Prototype ,

rods were used in all positions of concern with respect to fretting wear.

b. Lower end fitting leg braces -

Braces are deleted between legs of the lower end fitting. The test design, with braces, is considered less favorable with respect to O

d fretting wear.

4B-1

CESSARE h mu O

c. Inside dimension of guide tubes and upper end fitting posts

- The I.D. in upper ends of guide tubes and in UEF posts for production fuel will be enlarged slightly as a precaution, allowing use of wear sleeves if needed. The tube enlargement should have little effect on guide tube wear tendency, and will speed CEA scrams very slightly.

3.2.2 SPACER GRID SPRING SETTINGS i

All spacer grid springs were set for the minimum restraint of i fuel rods expected during the fuel lifetime. ]

3.2.3 FUEL ARRAY IN TEST i

The array of five fuel assemblies is shown in Figure 4B-3, with  !

relationships to the fuel shroud and CEA.

1 3.3 CONTROL ELEMENT ASSEMBLY System 80 reactors utilize both 4-rod and 12-rod control element assemblies. The twelve-rod CEA was chosen for hot loop tests because it has a lower weight per rod ratio (hence slower scrams) and is a more complex structure. The test CEA was functionally identical to that shown in Figure 4.2-4.

3.4 BUPPORT STRUCTURES The support structures were prototypical sections of a System 80 eactor and provided support and alignment of the fuel assembliea and CEA. The lower ends of the fuel assemblies engage alignment pins on an open grid beam array. The fuel shroud cross section is noted in Figure 4B-3. All possible corner shapes and fuel to l shroud clearances were included. Shroud tubes in the upper guide structure were held by the upper guide structure support plate (UGSSP) and fuel alignment plate (FAP), and engaged the four posts of each fuel upper end fitting. The region between the FAP and the UGSSP is an outlet plenum, where flow passes up around the shroud tubes and exits the outlet nozzle. Effects of a pressure gradient across the reactor outlet plenum were included in tests. The gradient causes flow circulation through small  !

holes in the UGSSP upward near the reactor centerline and downward near the outlet nozzles. In TF-2 the flow circulation was driven through external piping, employing a CEA shroud and seal assembly above the UGSSP.

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1 CESSAR naama J

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4.0 TEST RESULTA 1 4.1 SCRAM TIME vs.' ACCEPTANCE CURVE Hot loop tests previewed the scram performance checks that will be required for. every reactor CEA, during pre-operation functional tests. Measured position vs. time for reactor scrams must fall below an acceptance curve applied in safety analyses.

The reactor scram tests are run at approximately 525'F with all pumps running.. The TF-2 scram for- this condition is plotted in Figure-4B-4, along'with the acceptance. curve.

4.2 PRESSURE DROPS IN FUEL

\

Fuel assembly pressure drops were measured over a range of flow I Reynolds Numbers. Results are in good agreement with I measurements for similar fuel in prior TF-2 tests. The test ,

results support the flow resistances used in design analyses for System 80 and based on the prior measurements. -Those analyses include fuel holddown spring design requirements, support structure ' hydraulic loadings and the prediction of system flow rate.

4.3 FUEL ROD FRETTING )

The test for fuel rod fretting ran 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br />, at 620'F, with  !

flow 2.13,400 gpm through the fuel. The setting was based on ]

worst cace reactor conditions at full power, with 116% design l flow. Test fluid velocities exceeded those expected in any System 80 reactor. No fretting was found on any of the fuel rod surfaces.

4.4 GUIDE TUBE WEAR j In view of observed CEA motion dependence on upper guide structure flow, a saquence of different flow conditions was set during the wear test. With each change of flow conditions the ,

CEA was raised to a new position. Conditions included the l maximum pressure differences expected across the reactor UGSSP, '

both upward and downward, and an intermediate equalized condition. Following the tests all CEA guide tubes were '

inspected with an eddy current probe. Four tubes which gave the largest indications were removed and sectioned longitudinally (clamshelled) for precise inspection. Greatest wear occurred for the UGSSP upflow condition, at points of CEA rod tip contact in guide tubes. Guide tube wear at the highest rate observed in-tests will not contribute to violation of stress limits described in Section 4.2.3.

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LENU , . - FUEL ALIGNMENT PLATE (FAP)

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SUPPORT BARREL AND p FUEL SHROUD ASSEMBLY

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SUPPORT GRID BEAMS BOTTOM PLATE 11 Ml#

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, Figure SYSTEM 80 FUEL HOT LOOP TESTS, jyj / COMPONENT STACKUP IN TF-2 4B-2

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CROSS SECTION THROUGH FUEL SHROUD Jg AND FUEL ARRAY TF 2 TESTS 4B 3

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