ML20005A518
| ML20005A518 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 06/25/1981 |
| From: | Withers B PORTLAND GENERAL ELECTRIC CO. |
| To: | Clark R Office of Nuclear Reactor Regulation |
| References | |
| TAC-42281, TAC-43444, NUDOCS 8106300417 | |
| Download: ML20005A518 (8) | |
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===! Pcrtfard General Eectric Cent _any Fi C
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June 25, 1981 Trojan Nuclear Plant Docket 50-344 License NPF-1 f-a,, /.
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Director of Nuclear Reactor Regulation V\\
ATTN:
Mr. Robert A. Clark, Chief
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Operating Reactors Branch No. 3
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'd 'g Division of Licensing
'. J.M h w H U. S. Nuclear Regulatory Commission Washington, DC 20555
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Dear Sir:
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In accordance with Paragraph 2.C. (11) of Facility Operating Licdn
'i'N No. NPF-1, all fuel assemblies subject to cross-flow baffle jetting were visually inspected at the end of core cycle 3 at the Trojan Nuclear Plant.
In addition, the final FSAR-required visual examination was performed for the initially loaded (cycle 1) fuel assemblies that were also in the cycle 3 core. No significant degradation was detected in either of the inspections. A more detailed description of the examination methods and the corresponding results are in the attached " Preliminary Report on Trojan EOC-3 Fuel Examination", which is based on information supplied by Westinghouse who performed the inspection and prepared a preliminary report under contract to EPRI.
Sincerely, o
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Bart D. Withers Vice President Nuclear Attachment c:
Mr. Lynn Frank, Director State of Oregon Department of Energy J M 0
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Trojtn Nuclsar Plant Licensa NPF-1 Docket 50-344 ATTACUMENT to PCE to NRC LETTER DATED JUNE 25, 1981 Preliminary Report on Trojan ELC-3 Fuel Examination j
1.
Examinations Performed 1.1 Binocular Visual Examination Nineteen (19) of the 67 total fuel assemblies from core I that were also in core III were examined during core unloading to assess their condition. Examinations were performed on 15 of the 62 region 3 assemblies, both region 1 assemblies and one of the three region 2 assemblies (see attached Table 1 for specific assemblies).
1.2 TV Visual Examinations 1.2.1 Baffle Joint Fuel Assemblies Twelve (12) fuel assemblies occupying exterior or exterior /
interior baffle joint locations in cycle 3 were examined for evidenas of baffle jetting flow damage (see attached Table 1 fu. specific assemblies).
1.2.2 EPRI Program Fuel Assemblies Fourteen (14) fuel assemblies were examined (one region 1 and one region 2 not in core III; five region 3, five region 4 and two region 5 that were in core III) at high and/or low magnification and pre-and post-crud sampling to assess their condition and crud distribution (see attached Table 1 for specific assemblies).
1.2.3 Other Fuel Assemblies Two (2) other assemblies (one region 3 and one region 5) were examined on all four faces he_ause of a report of high load indications during their removal from the core (see attached Table 1 for specific assemblies). In addition, all of the feel assemblies from core I that were also in core III were visetlly examined routinely with the underwater TV stations l
set up in the Containment and Fuel Building upender areas.
1.3 Crud Sampling Selected rods from twelve (12) fuel assemblies (one region 1 and one region 2 not in core ';II; cne region 2, four region 3, three region 4 and two region 5 that were in core III) were I
sampled to determine crud thickness and chemical and radio-l chemical composition (see attached Table 1 for specific I
assemblies).
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Trojan Nuclocr Plcnt License NPF-1 Docket 50-344 1.4 Zire Oxide Thickness Measurements Selected rods from eight (8) fuel assemblies (one region 1 and one region 2 not in core III; three region 3, two region 4
'and one region 5) were measured to assess the degree of zire clad waterside corrosion (see attached Table 1 for specific assemblies).
1.5 Assembly Length Measurements Cursory length measurements were made in four region 3 assemblies from core III (see attached Table 1 for specific assemblies).
1.6 Assembly Grid Width Measurements The bottom (No. 1) grid of one region 1 assembly (A41) not in core III was measured to assess the accuracy capability of the Television Visual Measuring System when used to measure grid width.
1.7 Removable Rod Examinations from C-44 Eight (8) selected removable rods from removable rod assembly C-44 were removed, examined and returned to the same locations after examination. Specific examinations included; a) Breakaway and withdrawal force meaaurements to assess grid spring force relaxation.
b) Grid ce 1 friction force measurements in four selected cells to further quantify grid spring force relaxation.
c) High magnification TV visual examinations before and after cleaning to assess rod integrity, appearance and crud distribution.
d) Profilimetry, after cleaning to assess clad creepdown.
2.0 Examination Results Preliminary results of the examinations based upon onsite observations are as follows:
2.1 Of the 12 baffle assemblies examined only one rod, rod No. 3 on face 2, between grids 1 and 2 from the bottom of assembly E43, which occupied core baffle position B-4 in cycle 3, showed evidence of being affected by baffle joint jet flow.
This rod was bowed to the left toward rod No. 2 with a channel closure between rods 2 and 3 which might be > 50%.
The rod was not bowed anywhere else along its length nor had it grown longer than adjacent rods. The rod did not appear damaged or fretted, and continued use of the assembly should l
Trojen Nuclect ?lsnt Liesnto NPF-1 Docket 50-344 pose no problems. The three solid stainless stoel rods in assemblies EIS (face 2, rods 14, 15, 16) and EOS (face 1, rods 2, 3, 4),.which occupied baffle positions B-12 and M-2 respectively in cycle 3, where baffle joint flow induced damage was found in cycle 2, were examined in detail and found to be in excellent condition, almost indistinguishable i
from adjacent zire rods except for their greater length and modified end plugs. Assembly EOS was also examined thoroughly on all four faces because of reportedly higher than normal i
loads during removal from the core. However, no anomalies or atypical appearan:e was observed during the examination.
2.2 Assembly C03 was also examined in detail because of reportedly higher than normal loads during removal from the core. This assembly also showei no anomalies or atypical appearance.
4 2.3 Rod how on all of the assemblies examined was generally minor.
Most channel closures observed were less than 50% of nominal and no two rods were touching.
2.4 Fuel assembly structural integrity was excellent for all 4
assemblies. There was no evidence of fuel assembly bow or twist, grid, thimble tube, rod or nozzle damage and no depressed nozzle holddown springs.
i 2.5 Rod growth was apparent in some region 3 assemblies where growth had occurred toward the bottom nozzle (non-uniform bottom gaps, fairly uniform top gaps);. however, there was still significant gap space between. rod and bottom plate.
2.6 A qualitive assessment of crud deposition is as follows:
4 Region 5 F/A's: Uniformly lustrous, suggesting little 4
or no crud deposition during cycle 3.
Region 4 F/A's: Uniformly light crud over the assemblies.
Region 3, 2 and 1 F/A's: Moderate above grid 6, light with some moderate areas below grid 6.
2.7 Region 3 fuel assembly growth, based upon the cursory measurement performed, was approximately 100 mils which is not abnormal.
2.8 An assessment of oxide thickness indicates none or very light oxide ranging from 0 to 3 microns on one region 5, j
0 to 5 microns on two region 4, and 0 to 10 microns on three j
region 3 fuel assemblies (more precise values will require l
detailed analysis of the data).
2.9 Examination and measurement of the eight (8) removable fuel rods from C-44 indicates that they are in excellent condition. 4 e
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Trojnn Nucl:ar Pltne i
Licznto NPF-1 Docket 50-344 There were no anomalies observed, and crud was moderate to f
light from top to bottom, breakaway and withdrawal forces were typical for three cycle assemblies averaging approxi-mately 30 lbs and 5 lbs respectively, rod clad creepdown obtained from the profilametry data was also typical averag-ing about 2 mils. Again, these results are based upon cursory review and more precise values will require detailed analysis of the data.
i LSP/4mm10B15 ;
TABLE 1 TROJAN EOC-3 FUEL ASSEMBLY EXAMINATIONS EPRI EXAMS F/A Baffle Einocular Low High Crud Post Oxide F/A F/A Other No.
Side TV Visual MAG TV MAG TV Sample Crud Meas.
Length Grid TV(18)
_ 2)
(3)
(4)
TV(5)
Width
(
(1)
A26 X
A37 X
A61(6)
X(7)
X X
X X(10)
B04 X
X B30(8)
- (9)
X X
X C01 X
X(3)(11)
C03 C06 X
X C09 X
C10 X
C12 X
C20 X
C23 X
C24 X
C26 X
X X
X X
C27 X
C31 X
X X
X X
X C32 X
C44(12)
X X
X X
X X
C46 X
C48 X
C49 X
X X
C57 X
X C61 X
C64 X
D32 X
X X
X D33 X
X D41 X
X X
X D49 X
D50 X
E02 X(14)
E04 X(13)
E05 X(13)(15)
X(3)(11)
E08 X(13)
E12 X(14)
EIS X(13)(16)
E29 X(13)
E35 X
X l
E43 X(13)(17)
E47 X(13) l E51 X(13) 1 ES3 X(14)
E56 X(14)
E60 X
X X
X P00R ORIGINAL
FOOTNOTES TO TABLE 1 (1)
Four rods full screen, sides (s) next to baffle only (2)
All four faces examined in SFP during core unloading (3)
All four faces examined, two passes per face, 9 rods full screen (4)
Lef t to right across each face above and below each grid and at grid mid-points, 3 rods full screen (5)
During oxide thickness measurements, rod being measured only (6)
Assembly discharges at E0C-1 (7)
Exam of rods sampled for crud at EOC-1 only (8)
Assembly discharged at EOC-2 (9)
Exam of rods sampled for crud at EOC-2 only (10)
All four faces of grid 1 only (11)
High load upon removal from core -- no damage found (12)
Removable rod assembly (13)
F/A next to exterior baffle joint in cycle 3 (one face next to baffle)
(14)
F/A next to exterior and interior baffle joint in cycle 3 (two faces next to baffle with one of these faces next to an exterior and interior joint)
(15)
Next to joint where assembly damage was found in cycle 2, rods 2, 3, 4, face 1, solid stainless steel (16)
Next to joint where assembly damage was found in cycle 2, rods 14, 15, 16, face 2 solid stainless steel (17)
Rod No. 3, face 2 (next to baffle joint), between grids 1 and 2 bowed lef t (18)
All of the fuel assemblies from core I that were also in core III were visually examined routinely with the underwater TV stations set up in the Containment and Fuel Building upender areas LSP/4mm10B20 l
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TABLE 2 TROJAN EOC-3 RDiOVABLE FUEL ROD EXAMINATIONS (From Removable Rod Assembly C,44)
Breakaway /
Grid Cell F/R LOC. IN Withdrawal Friction High No.
C-44 (1)
Force Force MAG.TV Profilomeerv(2)(3) 917 J10 X
X X
X-918 H8 X
X X
X 922 15 I-X X
924 E9 X
X X
X 925 J8 K
X X
930 H10 X
X X
937 M9 X
X X
X 940 Il3 I
X X
(1) All rods were returned to r.he same location af ter, examination (2) All rods were brush cleaned prior to profilometry to remove loose crud (3) All rods were also high MAG TV examined during profilometry (after cleaning) l t
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