ML052100399
| ML052100399 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 08/31/2004 |
| From: | - No Known Affiliation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| FOIA/PA-2005-0209 57-TR-FS04-58-00 | |
| Download: ML052100399 (9) | |
Text
MILLSTONE 2 POOLSIDE EXAMINATIONS OF FAILED FUEL JULY-AUGUST 2004 Final Report
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I Podb Examinations Of Faed Fuel MilsNe 2 Julyt2004 Fial Report Pmxpamdbr.
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makes any warranty or representation, express or implied, with respect to the accuracy, completeness, or usefulness of the Information contained in this document, or that the use of any Information, apparatus, method, or process disclosed in this document will not Infringe privately owned rights; or
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Poolside Examinations of Failed Fuel at Millstone 2 - Final Report Nature of Changes Section(s)
Item or Page (s)
Description and Justification Note:
This is a final document.
This doe=
Vnt co infomtaon and k suLjecto to he flrst cove page.
Poolside Examinations of Failed Fuel at Millstone 2-Final Report I
TABLE OF CONTENTS Paae 1.0
2.0 INTRODUCTION
AND
SUMMARY
1 BACKGROUND...........
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I This docuent conary information and Is aubject to or tte page.
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Poolside Examinations of Failed Fuel at Millstone 2 - Final Report TABLE OF CONTENTS (Contd)
List of Appendices Appendix A Appendix B Appendix C Appendix D Appendix E This docume coan tary Information and Is subjectto th sthefirst or ttle page.
Poolside Examinations of Failed Fuel at Millstone 2 - Final Report
£ I01E Page iv4 Acronym EOC FA GWd/Mtu IRIS OD PWR SCFM UT Nomenclature Definition End of Cycle Fuel Assembly Gigawatt Days/Metric Ton Uranium Individual Rod Inspection System Outside Diameter Pressurizer Water Reactor Standard Cubic Feet/Minute Ultrasonic Fuel Inspection This document contal pre orma n and Is subject to r
e t or title page.
Poolside Examinations of Failed Fuel r
at Millstone 2-Final Report Page 1
1.0 INTRODUCTION
AND
SUMMARY
During Cycle 15 at Millstone Unit 2, coolant activity increased, indicating the presence of failed fuel. The reactor shut down at EOC-15 for a planned refueling outage in October 2003, and in-mast sipping was performed which identified 11 failed assemblies. Ten 3-cycle assemblies and one 2-cycle assembly were listed as being failed. After the outage, a limited ultrasonic testing campaign was performed bi On 8 of the 11 FAs identified in cycle 15 and I fuel assembly identified in cycle 14 which identified 10 failed rods in 9 of the failed assemblies.
Nine of the failed assemblies were located on the[
Iduring Cycle 15 and exhibited failed rod locations that were similar to failed rod locations previously observed in failed assemblies from These rod locations werer
, Because the failed assemblies were on the Wand the failed rods were located In specific assembly locations, the failure modes were likely to bf Two failed assemblies, however, were not located on thee Each assembly exhibited a single failed rod which was located on thea of the assembly. This did not fit the same failed rod location pattern exhibited by the other fuel assemblies. From the limited amount of Information acquired from the examinations performed by the utility during the refueling outage, this failure mode appeared to be L
Table 1.1 lists the assemblies and rods that were identified as being failed during the EOC-15 refueling outage and subsequent UT examinations. Reference I presented a preliminary assessment of the fuel failures based upon Information collected by the utility during the outage. In that assessment, the failure mode of the assemblies that failed on Divas judged to be due tf 1 Unfailed rods in locations adjacent to the failed rods were suspected of having damage due to the same failure This document co royar Informatlon and Is subect to the res on the first or title page.
Poolside Examinations of Failed Fuel at Millstone 2 - Final Report Page 2 mechanism. Two assemblies that were not located on them had an To gather more information about the failed rods and potentially damaged rods that are believed to be present in these assemblies, a limited fuel examination was performed at Millstone Unit 2 in July-August 2004. Two of the nine assemblies that failed on the!
ivere examined along with the two assemblies that failed in arl location. Additionally, one assembly that failed in Cycle 14 on the Was examined at this time. This report presents the results of the examinations on these five failed assemblies. These examinations confirmed that the assemblies that failed on the Jfailed as a result ofEL Also, adjacent unfailed rods exhibited damage from the same mechanism that caused failure in these assemblies.
Assemblies that failed in thej jnost likely experienced) as the cause of failure. Actual locations were not found, butff adjacent to the failed rod in one assembly was documented in the examination. Since the secondary damage in the other rod was similar in location and appearances is also believed to be a likely failure mode for this assembly.
This docurent corls formation and Is C
subject to the resl the first or tile page.