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{{Adams | |||
| number = ML093160122 | |||
| issue date = 11/12/2009 | |||
| title = IR 05000244-09-008; 06/15/2009 - 06/19/2009 and 08/24/2009 - 08/27/2009; R. E. Ginna Nuclear Plant; Special Inspection Team Report | |||
| author name = Lew D C | |||
| author affiliation = NRC/RGN-I/DRP | |||
| addressee name = Carlin J T | |||
| addressee affiliation = R. E. Ginna Nuclear Power Plant, LLC | |||
| docket = 05000244 | |||
| license number = DPR-018 | |||
| contact person = Clifford J W | |||
| case reference number = EA-09-249 | |||
| document report number = IR-09-008 | |||
| document type = Inspection Report, Letter | |||
| page count = 29 | |||
}} | |||
See also: [[followed by::IR 05000244/2009008]] | |||
=Text= | |||
{{#Wiki_filter:UNITED STATES NUCLEAR REGULATORY | |||
COMMISSION | |||
REGION I 475 ALLENDALE | |||
ROAD KING OF PRUSSIA, PA 19406-1415 | |||
November 12, 2009 EA-09-249 | |||
Mr. John T. Carlin Vice President, RE. Ginna Nuclear Power Plant RE. Ginna Nuclear Power Plant, LLC 1503 Lake Road Ontario, New York 14519 | |||
RE. GINNA NUCLEAR POWER PLANT -NRC SPECIAL INSPECTION | |||
TEAM REPORT 05000244/2009008; | |||
PRELIMINARY | |||
WHITE FINDING Dear Mr. Carlin: On June 16-20, 2009, and August 24-27,2009, the U.S. Nuclear Regulatory | |||
Commission (NRC) conducted | |||
the onsite portions of a special inspection | |||
at RE. Ginna Nuclear Power Plant. office inspection | |||
reviews were conducted | |||
in the intervening | |||
weeks. The enclosed report documents | |||
the inspection | |||
team's findings and observations | |||
which were discussed | |||
with you and others members of your staff on August 27, 2009, during a preliminary | |||
exit briefing, and on October 7, 2009, during the final exit meeting. The special inspection | |||
was conducted | |||
in response to a turbine driven auxiliary | |||
feedwater (TDAFW) pump overspeed | |||
trip on May 26, 2009. The team included a subsequent | |||
overspeed | |||
trip on July 2,2009 into its inspection | |||
scope. The NRC's initial evaluation | |||
of this condition | |||
satisfied | |||
the criteria in NRC Inspection | |||
Manual Chapter 0309, "Reactive | |||
Inspection | |||
Decision Basis for Reactors," for conducting | |||
a special inspection. | |||
The basis for initiating | |||
this special inspection | |||
is further discussed | |||
in the inspection | |||
team's charter that is included in this report as Attachment | |||
B. The inspection | |||
examined activities | |||
conducted | |||
under your license as they relate to safety and compliance | |||
with the Commission's | |||
rules and regulations | |||
and with the conditions | |||
of your license. The inspectors | |||
reviewed selected procedures | |||
and records, observed activities, and interviewed | |||
personnel. | |||
This letter transmits | |||
one self-revealing | |||
finding that, using the reactor safety Significance | |||
Determination | |||
Process (SOP), has preliminarily | |||
been determined | |||
to be White, a finding with low to moderate safety significance. | |||
The finding is associated | |||
with the failure to preclude recurrence | |||
of a significant | |||
condition | |||
adverse to quality associated | |||
with the corrosion | |||
of the governor control valve of the turbine driven auxiliary | |||
feedwater (TDAFW) pump, that led to a failure of the TDAFW pump during surveillance | |||
testing on July 2, 2009 and was the likely cause of the overspeed | |||
trip on May 26, 2009. Following | |||
the July test failure, Ginna replaced the | |||
J. Carlin 2 governor control valve stem and conducted | |||
weekly monitoring | |||
of the governor control valve during surveillance | |||
testing to identify any potential | |||
for stem binding. In addition, corrective | |||
actions included a follow-up | |||
inspection | |||
of the governor control valve during the fall 2009 refueling | |||
outage. There is no immediate | |||
safety concern present due to this finding | |||
because the system is now operable and the long term corrective | |||
actions are being implemented | |||
in Ginna's corrective | |||
action program. The final resolution | |||
of this finding | |||
will be conveyed in a separate correspondence. | |||
As discussed | |||
in the attached Inspection | |||
report. the tinding is also an apparent violation | |||
of NRC requirements. | |||
specifically, 10 CFR Appendix B, Criterion | |||
XVI. "Corrective | |||
Actions." and is therefore | |||
being considered | |||
for escalated | |||
enforcement | |||
action in accordance | |||
with the Enforcement | |||
Policy, which can be found on the NRC's Web site at http://www.nrc.gov/readingrm/doc-collections/enforcementl. | |||
Following | |||
a discussion | |||
of the preliminary | |||
safety Significance | |||
of this finding during the initial exit briefing on August 27,2009. a phone call was held between Glenn Dentel, Branch Chief, Division of Reactor Projects. | |||
and yourself on October 1. 2009. During this call, you indicated | |||
that R.E. Ginna Nuclear Power Plant does not contest the characterization | |||
of the rIsk significance | |||
of this finding, and therefore | |||
you have declined to further discuss this issue at a Regulatory | |||
Conference | |||
or provide a written response. | |||
Please note that by declining | |||
to request a Regulatory | |||
Conference | |||
or submit a written response, you relinquished | |||
your right to appeal the final SOP determination. | |||
in that by not doing either, you would not meet the appeal requirements | |||
stated in the Prerequisite | |||
and Limitation | |||
sections of Attachment | |||
2 of IMC 0609. You will be advised by a separate correspondence | |||
of the results of our deliberations | |||
on this matter. In addition. | |||
the report documents | |||
two findings of very low safety significance (Green). The findings involved violations | |||
of NRC requirements. | |||
However, because of the very low safety significance | |||
and because they are entered into your corrective | |||
action program (CAP). the NRC is treating these findings as non-cited | |||
violations (NeVs) consistent | |||
with Section VI.A.1 of the NRC Enforcement | |||
Policy. If you contest any NCV in this report, you should provide a response within 30 days of the date of this inspection | |||
report, with the basis for your denial, to the Nuclear Regulatory | |||
Commission, A TIN.: Document Control Desk, Washington, DC 20555-0001; | |||
with copies to the Regional Administrator, Region I; the Director, Office of Enforcement; | |||
and the NRC Resident Inspector | |||
at R.E. Ginna. In addition. | |||
if you disagree with the characterization | |||
of any finding in this report, you should provide a response within 30 days of the date of this inspection | |||
report. with the basis for your disagreement, to the Regional Administrator, Region I, and the NRC Resident Inspector | |||
at R.E. Ginna Nuclear Power Plant. The information | |||
you provide will be considered | |||
in accordance | |||
with Inspection | |||
Manual Chapter 030? In accordance | |||
with 1 0 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and its enclosure, and your response (if any) will be available | |||
electronically | |||
for public inspection | |||
in the | |||
J. 3 NRC Public Document Room or from the Publicly Available | |||
Records (PARS) component | |||
of the NRC's document system (ADAMS). ADAMS is accessible | |||
from the NRC Web Site at http://www.nrc.gov/reading-rm/adams.html(the | |||
Public Electronic | |||
Reading Room). Sincerely, ,/;I,/;tJ--fbr-Division of Reactor Projects Docket No.: 50-244 License No.: DPR-18 | |||
Inspection | |||
Report 05000244/2009008 | |||
w/Attachment | |||
A: Supplemental | |||
Information | |||
w/Attachment | |||
B: Special Inspection | |||
Charter cc w/encl: Distribution | |||
via ListServ | |||
J. 2 NRC Public Document Room or from the Publicly Available | |||
Records (PARS) component | |||
of the NRC's document system (ADAMS). ADAMS is accessible | |||
from the NRC Web Site at httg:llwww.nrc.gov/reading*rm/adams.html(the | |||
Public Electronic | |||
Reading Room). Sincerely, IRAJ James W. Clifford for: David C. lew, Director Division of Reactor Projects Docket No.: 50-244 License No.: DPR-18 | |||
Inspection | |||
Report 05000244/2009008 | |||
w/Attachment | |||
A: Supplemental | |||
Information | |||
w/Attachment | |||
B: Special Inspection | |||
Charter cc w/encl: Distribution | |||
via | |||
SUNSI Review Complete: | |||
gtd (Reviewer's | |||
DOCUMENT NAME: G:\DRP\BRANCH1\Ginna\TDAFW | |||
SIT\AED Track Changes Ginna Report Rev 4 After declaring | |||
this document "An Official Agency Record" it will be released to the To receive I!I copy of this document, indicate in the box: "C' =Copy without attachmenVenclosure "e" =Copy with attaclhmentlenclosure "N";:; No co ML093160122 | |||
RI/ENF OFFICE RI/DRS RI/DRP NAME CCahill/cc* | |||
JClifford/jwc | |||
DATE 10/21109 11/05/09 *see prior concurrence | |||
OFFICIAL RECORD COpy Distribution | |||
w/encl: S. Collins, RA (R10RAMaii | |||
Resource) | |||
ROPreports@nrc.gov | |||
M. Dapas, ORA (R10RAMaii | |||
Resource) | |||
D. Lew, DRP (R1DRPMaii | |||
Resource) | |||
J. Clifford, DRP (R1DRPMail | |||
Resource) | |||
l. Trocine, RI OEDO RidsNrrPMREGinnaResource | |||
RidsNrrDorlLpl1-1 | |||
Resource G. Dentel, DRP N. Perry, DRP J. Hawkins, DRP K. Kolaczyk, DRP, SRI S. Kennedy, DRP, SRI L. Casey, DRP, RI M. Rose, DRP, OA D. Bearde, DRP | |||
Docket License Report Team | |||
Approved U.S. NUCLEAR REGULATORY | |||
REGION 50-244 DPR-18 05000244/2009008 | |||
Constellation | |||
Energy, R. E. Ginna Nuclear Power Plant, LLC R. E. Ginna Nuclear Power Plant Ontario. New York June 15-19, 2009 and August 24-27.2009 | |||
C. cahill, Senior Reactor Analyst, Division of Reactor Safety S. Kennedy, Senior Resident Inspector, Division of Reactor Projects K. Kolaczyk, Senior Resident Inspector, Division of Reactor Projects J. Bream, Project Engineer. | |||
Division of Reactor Projects Glenn T. Dentel, Chief Projects Branch 1 Division of Reactor Projects | |||
2 SUMMARY OF FINDINGS IR 05000244/2009008; | |||
06/15-19/2009 | |||
and 08/24-2'712009; | |||
R. E. Ginna Nuclear Plant; Special Inspection | |||
Team Report. The report covered two on-site inspection | |||
visits and related in-office | |||
inspection | |||
activities | |||
by a special inspection | |||
team consisting | |||
of a Senior Reactor Analyst. two Senior Resident Inspectors. | |||
and one Project Engineer. | |||
One apparent violation (A V) with potential | |||
for greater than Green safety significance | |||
and two Green findings were identified. | |||
The significance | |||
of most findings is indicated | |||
by its color (Green. White, Yellow, or Red) using Inspection | |||
Manual Chapter (lMC) 0609, "Significance | |||
Determination | |||
Process." Findings for which the significance | |||
determination (SDP) process does not apply may be Green or be assigned a severity level after NRC management | |||
review. The NRC program for overseeing | |||
the safe operation | |||
of commercial | |||
nuclear power reactors is described | |||
in NUREG-1649, "Reactor Oversight | |||
Process," Revision 4, dated December 2006. NRC Identified | |||
and Self-Revealing | |||
Findings Cornerstones: | |||
Mitigating | |||
Systems Preliminary | |||
White: A self-revealing | |||
apparent violation (A V) of 10 CFR 50, Appendix B, Criterion | |||
XVI, uCorrective | |||
Actions," was identified | |||
for the failure to preclude recurrence | |||
of a signIficant | |||
condition | |||
adverse to quality (SCAQ) associated | |||
with the Turbine Driven Auxiliary | |||
Feedwater (TDAFW) pump governor control valve. Specifically, after identifying | |||
corrosion | |||
of the govemor control valve stem in April 2005, Ginna did not take adequate corrective | |||
actions to preclude the recurrence | |||
of corrosion | |||
which led to the binding of the gave mar control valve and failure of the TDAFW pump on July 2,2009. In addition, the inspectors | |||
concluded | |||
that governor control valve stem binding was the likely cause of the failure of the TDAFW pump on May 26,2009. The overspeed | |||
trip of the TDAFW pump on May 26. 2009. was originally | |||
determined | |||
by Ginna to be failure of the governor control system relay valve. Governor control valve stem corrosion | |||
is a SCAQ because corrosion | |||
of the stem can IHad to governor control valve stem binding and failure of the TDAFW pump as discussed | |||
in NRC Information | |||
Notice (IN) 94-66: "Overspeed | |||
of Turbine-Driven | |||
Pumps Caused by Governor Valve Stem Binding" and other related industry operating | |||
experience | |||
documents. | |||
Immediate | |||
corrective | |||
actions inCluded entering this condition | |||
in the corrective | |||
action program (CAP). conducting | |||
a root cause analysis (RCA). replacing | |||
the governor control valve stem, and conducting | |||
weekly monitoring | |||
of the governor control valve during surveillance | |||
testing to identify any potential | |||
for stem binding. In addition, corrective | |||
actions included a follow-up | |||
inspection | |||
of the governor control valve during the fall 2009 refueling | |||
outage. Ginna will continue to monitor the govemor control valve under an enhanced TDAFW surveillance | |||
program to ensure TDAFW pump operability. | |||
The finding is more than minor because it is associated | |||
with the equipment | |||
performance | |||
attribute | |||
of the Mitigating | |||
System cornerstone | |||
and affects the cornerstone | |||
objective | |||
to ensure the availability, reliability, and capability | |||
of systems that respond to initiating | |||
events to prevent undesirable | |||
consequences. | |||
Specifically. | |||
stem corrosion | |||
caused binding of the governor control valve and led to the failure of the TDAFW pump. This finding was assessed using IMC 0609 and preliminarily | |||
determined | |||
to be White (lOW to moderate safety significance) | |||
based on a Phase 3 analysis with a total (internal | |||
and Enclosure | |||
external contributions) | |||
calculated | |||
conditional | |||
core damage frequency (CCDF) of B.6E-6. This finding has a cross-cutting | |||
aspect in the area of Problem Identification | |||
and Resolution, Corrective | |||
Action Program, because Ginna did not implement | |||
a corrective | |||
action program with a low threshold | |||
for identifying | |||
issues completely, accurately, and in a timely manner commensurate | |||
with their safety significance | |||
[P.1(a} per IMC 0305]. Specifically, Ginna did not identify issues | |||
with corrosion | |||
of the governor control valve within the corrective | |||
action program. (Section 2.1.1) Green: A self-revealing | |||
non-cited | |||
violation (NCV) of 10 CFR 50, Appendix B, Criterion | |||
XVI, "Corrective | |||
Actions," was identified | |||
for the failure to establish | |||
adequate measures to correct a longstanding | |||
issue associated | |||
with steam admission | |||
valves leakage. As a result, the leakage most likely contributed | |||
to the build-up of corrosion | |||
on the TDAFW pump governor control valve stem and contributed | |||
to the failure of the TDAFW pump on May 26, 2009, and on July 2, 2009. The steam admission | |||
valves had been leaking since at least 2005. However, G.inna did not take adequate measures to correct the leakage or minimize the impact of the leakage on governor control valve performance. | |||
Immediate | |||
corrective | |||
actions included entering this condition | |||
in the corrective | |||
action program, conducting | |||
a root cause analysis, replacing | |||
the governor control valve stem, and conducting | |||
weekly monitoring | |||
of the governor control valve during surveillance | |||
testing to identify any potential | |||
for stem binding. Additionally, the steam admission | |||
valves were inspected | |||
and re-worked | |||
and the governor control valve was inspected | |||
during the fall 2009 outage. Ginna will continue to monitor the governor control valve under an enhanced TDAFW surveillance | |||
program to ensure TDAFW pump operability. | |||
Planned corrective | |||
actions include | |||
the steam admission | |||
valves in May 2011. The finding is more than minor because it is associated | |||
with the equipment | |||
performance | |||
attribute | |||
of the Mitigating | |||
Systems cornerstone | |||
and affects the cornerstone | |||
objective | |||
to ensure the availability | |||
and reliability | |||
of systems that respond to initiating | |||
events to prevent undesirable | |||
consequences. | |||
Specifically, leakage through the steam admission | |||
valves can result in continuous | |||
wetting of the governor control valve stem and lead to or accelerate | |||
corrosion | |||
of the governor control valve. This could result in a stem binding of the governor control valve and failure of the TDAFW pump. The inspectors | |||
evaluated | |||
the signifiCance | |||
of this finding using IMC 0609, Attachment | |||
4, "'Phase 1 -Initial Screening | |||
and Characterization | |||
of Findings." The finding is of very low safety significance | |||
because it is not a design or qualification | |||
deficiency, did not represent | |||
a loss of a safety function of a system or a single train greater than its technical | |||
speCification (TS) allowed outage time, and did not screen as potentially | |||
risk Significant | |||
due to external events. This finding has a cross-cutting | |||
aspect in the area of Problem Identification | |||
and Resolution, Corrective | |||
Action Program, because Ginna did not thoroughly | |||
evaluate problems such that the resolutions | |||
address causes and extent of conditions, as necessary, In a timely manner, commensurate | |||
with their significance | |||
[P.1 (c) per IMC 0305]. Specifically, Ginna did not thoroughly | |||
evaluate the potential | |||
effect of the steam admission | |||
valve leakage on the governor control valve performance. (Section 2.1.2) Green: The inspectors | |||
identified | |||
an NCVof 10 CFR 50, Appendix B. Criterion | |||
III, "Design Control," for the failure to establish | |||
measures to ensure that a modification | |||
performed | |||
on the governor control valve bushing was a suitable application | |||
of materials | |||
for the TDAFW pump. During a review of the RCA associated | |||
with the TDAFW pump failures, the inspectors | |||
noted that Ginna did not consider the potential | |||
impact of Enclosure | |||
removing some of the hardened layer of the bushing on the corrosion | |||
rate of the governor control valve. Following | |||
concerns raised by the inspectors, Ginna inspected | |||
the governor control valve bushing during the fall 2009 refueling | |||
outage and observed corrosion | |||
of the bushings. | |||
Ginna noted that the corrosion | |||
of the bushings appeared to have been caused by the lapping of the bushing to achieve the increased | |||
clearance | |||
between the stem and the bushings. | |||
Immediate | |||
corrective | |||
actions following | |||
the inspection | |||
of the governor control valve during the fall 2009 refueling | |||
outage included entering this condition | |||
in the CAP and refurbishing | |||
the governor control valve with a new stem and bushing. The finding is more than minor because it is associated | |||
with the equipment | |||
performance | |||
attribute | |||
of the Mitigating | |||
System cornerstone | |||
and affects the cornerstone | |||
objective | |||
to ensure the availability, reliability, and capability | |||
of systems that respond to initiating | |||
events to prevent undesirable | |||
consequences. | |||
Specifically, lapping of the valve bushing resulted in an unanticipated | |||
corrosion | |||
mechanism | |||
of the govemor control valve that impacted the reliability | |||
of the TDAFW pump" The inspectors | |||
evaluated | |||
the significance | |||
of this finding using IMC 0609, Attachment | |||
4. "Phase 1 Initial Screening | |||
and Characterization | |||
of Findings." The finding is of very low safety significance | |||
because it is a design or qualification | |||
deficiency confirmed not | |||
to result in the loss of operability | |||
or functionality. | |||
The inspectors | |||
determined | |||
that this finding has a cross-cutting | |||
aspect in the area of Human Performance, Decision Making. because Ginna did not make a safety-significant | |||
or risk-significant | |||
decision using a systematic | |||
process, especially | |||
when faced with uncertain | |||
or unexpected | |||
plant conditions, to ensure safety was maintained | |||
[H.1(a) per IMC 0305]. Specifically, Ginna did not use a systematic | |||
process such as an engineering | |||
evaluation | |||
to properly evaluate the potential | |||
impact of removing some of the hardened layer of the bushing. [H.1 (a) per IMC 0305] (Section 2.3) Licensee Identified | |||
Violations | |||
None Enclosure | |||
REPORT DETAILS 1. INTRODUCTION | |||
1.1 Background | |||
and Event Description | |||
On May 26, 2009, and July 2, 2009, the TDAFW pump tripped on overspeed | |||
during the performance | |||
of surveillance | |||
testing activities. | |||
These were the second and third times the TDAFW pump had failed a surveillance | |||
test in a six month period. The previous test failure occurred on December 2, 2008, when the TDAFW pump failed to develop acceptable | |||
discharge | |||
pressure during a quarterly | |||
surveillance | |||
test. Details surrounding | |||
the December test failure including | |||
Ginna corrective | |||
actions are discussed | |||
in NRC Integrated | |||
Inspection | |||
Report 50-244/2009002. | |||
Following | |||
each of the three test failures, Ginna declared the TDAFW pump inoperable | |||
and entered the limiting Condition | |||
for Operation | |||
for TS 3.7.5 "Auxiliary | |||
Feedwater." Following | |||
the May 26, 2009, test failure, Ginna troubleshooting | |||
activities | |||
were focused on the TDAFW lubricating | |||
oil system where system pressure oscillations | |||
were noted by test personnel | |||
prior to the pump overspeed | |||
trip. As part of the troubleshooting | |||
efforts, the TDAFW lubricating | |||
oil system was drained and refilled with fresh oil, filters in the lubrication | |||
system were examined and replaced, and several components | |||
in the lubricating | |||
oil system including | |||
the relay and pressure regulating | |||
valves were replaced. | |||
Additionally | |||
the turbine governor linkage was adjusted to original specifications | |||
outlined in the vendor technical | |||
documents. | |||
Although several out of speCification | |||
and missing components | |||
were identified | |||
during this troubleshooting | |||
effort, a definitive | |||
cause for the surveillance | |||
failure was not identified. | |||
Nevertheless, following | |||
the successful | |||
completion | |||
of post maintenance | |||
testing activities, Ginna declared the TDAFW pump operable and commenced | |||
an augmented | |||
surveillance | |||
testing program for the TDAFW pump that tested the pump on a weekly basis. On July 2, 2009, another TDAFW pump overspeed | |||
failure occurred when the pump was undergoing | |||
the augmented | |||
testing program. Troubleshooting | |||
activities | |||
following | |||
this failure were focused on the turbine control system, which did not appear to have functioned | |||
properly during the test. Accordingly, the turbine control and relay valves were disassembled | |||
and inspected, and the governor linkage system was adjusted. | |||
Additionally. | |||
the lubricating | |||
oil system was flushed and examined for particulates. | |||
However, unlike the May 26 failure, these troubleshooting | |||
activities | |||
identified | |||
a definitive | |||
cause, a stuck governor control valve stem, that resulted in the surveillance | |||
test failure. Visual inspection | |||
of the stem, which had become bound to its bushing and had to be forcibly removed, revealed corrosion | |||
buildup where the stem contacted | |||
the upper valve bushing. To restore the control valve to an operable status, Ginna replaced the valve stem and increased | |||
the bushing clearances | |||
to dimensions | |||
specified | |||
by the Ginna TDAFW pump inspection | |||
procedure. | |||
The pump was successfully | |||
tested and declared operable subject to an augmented | |||
testing program. Ginna assigned an RCA team to investigate | |||
the surveillance | |||
test failures. | |||
The Ginna RCA team concluded | |||
that the primary root cause of the failure of the governor contrOl valve to control turbine speed on July 2,2009, was binding caused by a corrosion | |||
mechanism | |||
that occurred between the valve stem and the valve bushings. | |||
The RCA team also concluded | |||
that stem binding appeared to be an intermittent | |||
problem and that Enclosure | |||
station members missed opportunities | |||
to identify the failure mode during previous surveillances | |||
and failures. | |||
As such, the RCA team determined | |||
that governor control valve stem binding could not be ruled out as a possible failure mode during the December 2008 and the May 2009 TDAFW pump failures. | |||
At Ginna's request, an independent | |||
vendor reviewed the issues associated | |||
with the governor control valve stem binding to determine | |||
the failure mechanism | |||
that was the cause of the TDAFW pump overspeed | |||
trips. The vendor determined | |||
that the most likely cause of the corrosion | |||
of the governor control valve stem was fresh-water | |||
corrosion (Langelier | |||
corrosion) | |||
that was the result of galvanic interactions | |||
between the nitrided case and the base material of the governor control valve stem. The vendor considered | |||
several variables | |||
that contributed | |||
to the corrosion | |||
mechanism | |||
such as material composition | |||
of the stem and bushing, stem-to-bushing | |||
clearance, steam admission | |||
valve leakage, and TDAFW pump surveillance | |||
frequency | |||
and duration. | |||
1.2 Special Inspection | |||
Scope The NRC conducted | |||
this inspection | |||
to gain a better understanding | |||
of the circumstances | |||
involving | |||
the TDAFW pump overspeed | |||
trips during surveillance | |||
testing on May 26, 2009, and on July 2,2009. The inspection | |||
team used NRC Inspection | |||
Procedure | |||
93812, "Special Inspection," as a guide to complete their review. Additional | |||
inspection | |||
and review activities | |||
were outlined in the special inspection | |||
team charter, provided as Attachment | |||
B. The special inspection | |||
team reviewed procedures, corrective | |||
action documents, work orders, engineering | |||
analyses, and the root cause evaluation | |||
prepared by Ginna. In addition. | |||
the team conducted | |||
equipment | |||
walkdowns | |||
and interviewed | |||
key plant personnel | |||
regarding | |||
the discovery | |||
and resolution | |||
of the condition. | |||
A list of site personnel | |||
interviewed | |||
and documents | |||
reviewed are provided in Attachment | |||
A to this report. 1.3 Preliminary | |||
Conditional | |||
Risk Assessment | |||
Using IMC 0309, "Reactive | |||
Inspection | |||
Decision Basis for Reactors," IMe 0609, "Significance | |||
Determination | |||
Process," and the Ginna Standardized | |||
Plant Analysis Risk (SPAR) model in conjunction | |||
with the Graphical | |||
Evaluation | |||
Module (GEM). the Region I Senior Reactor Analyst (SRA) evaluated | |||
the increase in conditional | |||
core damage probability | |||
for the failure of the TDAFW pump. Based on the nature of the failure and the subsequent | |||
overspeed | |||
trip on an instrumented | |||
diagnostic | |||
run, the condition | |||
was evaluated | |||
as being non-recoverable | |||
in the event of actual demand. Based upon best available | |||
information, an incremental | |||
conditional | |||
core damage probability (ICCDP) in the upper E-6 range (8E-6 per the 82 day exposure period), was calculated. | |||
The exposure period was based on the assumption | |||
that the TDAFW pump would not have started since the last time it passed a surveillance | |||
test on March 5 until May 26 (82 days). The dominant core damage sequence was a station blackout (loss of offsite power (LOOP) with failure of both emergency | |||
diesel generators (EDGs), with no TOAFW and failure to recover offsite power or an EDG in one hour. Based upon this conservative | |||
conditional | |||
core damage probability (CCDP) value, and having satisfied | |||
an IMC 0309 deterministic | |||
criterion, the May 26 degraded TDAFW pump Enclosure | |||
condition | |||
fell within the Special Inspection | |||
to Augmented | |||
Inspection | |||
Team range for reactive inspections. | |||
2. SPECIAL INSPECl"ION | |||
AREAS 2.1 Review of Maintenance | |||
a. Inspection | |||
Scope The team evaluated | |||
the adequacy and completeness | |||
of the maintenance | |||
on the TDAFW system, including | |||
preventive | |||
maintenance, procedural | |||
guidance, post-maintenance | |||
testing, and supervisory | |||
oversight. | |||
The team independently | |||
evaluated | |||
selected procedures, preventive | |||
maintenance | |||
strategies. | |||
condition | |||
reports (CRs). system health reports. and associated | |||
work orders. In addition, the team reviewed the RCA, conducted | |||
equipment | |||
walkdowns | |||
and interviewed | |||
key station personnel. | |||
For the weaknesses | |||
identified, the inspectors | |||
verified that appropriate | |||
corrective | |||
actions have been planned or taken. b. Findings and Observations | |||
1. Failure to Preclude Recurrence | |||
of a Significant | |||
Condition | |||
Adverse to Quality Introduction: | |||
A self-revealing | |||
AV of 10 CFR 50, Appendix S, Criterion | |||
XVI, "Corrective | |||
Actions," was identified | |||
for the failure to preclude recurrence | |||
of a SCAQ associated | |||
with the TDAFW pump governor control valve. Specifically, after identifying | |||
corrosion | |||
of the governor control valve stem in April 2005, Ginna did not take adequate corrective | |||
actions to preclude the recurrence | |||
of corrosion | |||
which led to the binding of the governor control valve and failure of the TDAFW pump on July 2, 2009. In addition, governor control valve stem binding was a fikely failure of the May 26, 2009, TDAFW pump overspeed | |||
trip. This finding was preliminarily | |||
determined | |||
to be White. Description: | |||
On April 11, 2005, Glnna conducted | |||
a periodic major inspection | |||
of the TDAFW pump governor control valve under work order #20401907. | |||
During the disassembly | |||
of the valve, mechanics | |||
noted corrosion | |||
in the bushing area of the stem plug. The vendor recommended | |||
replacing | |||
the valve stem and plug due to the corrosion. | |||
However, Ginna did not recognize | |||
stem corrosion | |||
as a condition | |||
adverse to quality and did not initiate a CR in accordance | |||
with station guidance in IP-CAP-1 r "Condition | |||
Reporting." As a result, Ginna did not conduct any further analysis or evaluation | |||
to determine | |||
the cause of the corrosion. | |||
On July 2, 2009, during surveillance | |||
testing, the TDAFW pump tripped due to overspeed. Ginna | |||
formed an Issue Response Team and developed | |||
a comprehensive | |||
troubleshooting | |||
plan to determine | |||
the cause(s) of the failure. The troubleshooting | |||
plan consisted | |||
of all possible failure modes, possible causes of each failure mode, and actions to validate or refute each "failure mode. Upon disassembly | |||
of the governor control valve, the stem was found seized within its bushings and had to be forcibly removed. Visual inspection | |||
showed pitting on the surface of the stem Where it contacted | |||
the upper valve bushing. Following | |||
completion | |||
of the troubleshooting | |||
activities, Ginnaconcluded | |||
that TDAFW pump failure was due to binding of the governor control valve and that the binding was caused by the build up of corrosion | |||
on the valve stem. Enclosure | |||
Governor control valve stem corrosion | |||
is an SCAQ because corrosion | |||
of the stem can lead to govemor control valve stem binding and failure of the TDAFW pump as discussed | |||
in NRC IN 94-66: "Overspeed | |||
of Turbine-Driven | |||
Pumps caused by Governor Valve Stem Binding," and other related industry operating | |||
experience | |||
documents. | |||
Immediate | |||
corrective | |||
actions included entering this condition | |||
in the CAP, conducting | |||
an RCA, replacing | |||
the governor control valve stem, and conducting | |||
weekly monitoring | |||
of the governor control valve during surveillance | |||
testing to identify any potential | |||
for stem binding. In addition, corrective | |||
actions included a follow-up | |||
inspection | |||
of the governor control valve during the fall 2009 refueling | |||
outage. Because additional | |||
corrosion | |||
was found during this inspection | |||
on September | |||
18, 2009, the control valve was sent to the vendor to be refurbished. | |||
Ginna will continue to monitor the governor control valve under an enhanced TDAFW surveillance | |||
program to ensure TDAFW pump operability. | |||
Ginna also was evaluating | |||
longer term corrective | |||
actions to address the corrosion | |||
including | |||
more frequent governor control valve stem replacement, change of the stem material, and other modifications | |||
to the system design. Planned corrective | |||
actions include replacing | |||
the stem admission | |||
valves in May 2011. The inspectors | |||
noted that governor control valve stem binding also could have been a contributor | |||
to the December 2, 2008, TDAFW pump failure to develop the minimum acceptable | |||
discharge | |||
flow and pressure, and the likely cause of the May 26, 2009, TDAFW pump overspeed | |||
trip. Following | |||
these events, Ginna missed opportunities | |||
to identify potential | |||
stem binding problems after identifying | |||
possible indicators | |||
of this failure mode such as leaking steam admission | |||
valves and rust/corrosion | |||
on the visible portion of the governor valve stem. In addition, during troubleshooting | |||
efforts in May 2009, . Ginna missed an opportunity | |||
to exercise the governor control valve stem with the linkage disconnected | |||
and lube oil pressure not applied. Operating | |||
experience | |||
suggested | |||
that cycling the valve by hand without hydraulics | |||
applied is a prudent action to validate or refute governor control valve stem binding. Analysis: | |||
The performance | |||
deficiency | |||
is that Ginna did not take adequate measures to correct a condition | |||
that had the potential | |||
to impact the operability | |||
of the TDAFW pump. Specifically, after identifying | |||
corrosion | |||
on the governor control valve stem in 2005, Ginna did not take adequate corrective | |||
actions to preclude the recurrence | |||
of corrosion | |||
which led to the binding of the governor control valve and failure of the TDAFW pump. The finding is more than minor because it is associated | |||
with the equipment | |||
performance | |||
attribute | |||
of the Mitigating | |||
System cornerstone | |||
and affects the cornerstone | |||
objective | |||
to ensure the availability, reliability, and capability | |||
of systems that respond to initiating | |||
events to prevent undesirable | |||
consequences. | |||
Specifically, stem corrosion | |||
caused binding of the governor control valve and led to the failure of the TDAFW pump. In accordance | |||
with IMe 0609, Attachment | |||
4, "Phase 1 -Initial Screening | |||
and Characterization | |||
of Findings," a Phase 2 risk analysis was required because the finding represents | |||
an actual loss of safety function of a single train for greater than the TS allowed outage time of 7 days. The Phase 2 risk evaluation | |||
was performed | |||
in accordance | |||
with IMC 0609, Appendix A, Attachment | |||
1, "User Guidance for Phase 2 and Phase 3 Reactor Inspection | |||
Findings for At*,power | |||
Situations." Because the precise time is unknown for the inception | |||
of TDAFW pump inoperability, an exposure time of one-half of the time period (t/2) between discovery (May 26, 2009) to the last successfully | |||
completed | |||
quarterly | |||
surveHlance | |||
test (March 5, 2009) was used. This t/2 exposure time Enclosure | |||
9 equals 51 days. Using Ginna's Phase 2 SDP notebook, pre-solved | |||
worksheets, and an initiating | |||
event likelihood | |||
of 1 year (>30-days | |||
exposure time), the inspector | |||
identified | |||
that this finding is of potentially | |||
substantial | |||
safety significance (Yellow). | |||
The dominant sequence identified | |||
in the Phase 2 notebook involves a loss of offsite power (LOOP), failure of both EDGs, and the subsequent | |||
loss of the TDAFW pump, with the failure of operators | |||
to restore offsite power within 1 hour: LOOP (2) + EAC (3) + TDAFW (0) + REC1 (0) = 5 (Yellow). | |||
In recognition | |||
that the Phase 2 notebook typically | |||
yields a conservative result, a | |||
NRC Region I Senior Reactor Analyst (SRA) performed | |||
a Phase 3 risk assessment | |||
of this finding. The SRA used Ginna's Standardized | |||
Plant Analysis Risk (SPAR) model, Revision 3.45, dated June 2008. and graphical | |||
evaluation | |||
module, in conjunction | |||
with the System Analysis Programs for Hands-On Integrated | |||
Reliability | |||
Evaluations (SAPHIRE). | |||
Version 7, to estimate the internal risk contribution | |||
of the Phase 3 risk assessment. | |||
The following | |||
assumptions | |||
were used for this assessment: Based on the guidance provided in the Risk Assessment | |||
of Operational | |||
Events Handbook, Revision 1.01, the calculated | |||
exposure was determined | |||
to be 1198 hrs. The summation | |||
of this exposeure | |||
time was determined | |||
as follows: One half the exposure time, (tI2), was applied for the period between March 5 -May 26, 2009 The full exposure time, (t). was applied for the unavailability | |||
and troubleshooting | |||
from May 26 -May 29, 2009. One half the exposure time. (tI2), was applied for the period between June 25 -July 2, 2009 The full exposure time, (t), was applied for the unavailability | |||
and troubleshooting | |||
from July 2 -July 5, 2009 To closely approximate | |||
the type of f*lilure exhibited | |||
by the TDAFW pump, the fail to start basic event <AFW-TDP-FS-TDP> | |||
was changed from its baseline failure probability | |||
to 1.0, representing | |||
a 100 percent failure to start condition. Based on the nature of the failure. and no recovery procedures | |||
in place, there was no recovery credit assigned to the May failure. The loss of service water initiating | |||
event frequency (IE-LOSWS) | |||
was increased | |||
from its nominal value of 4.0E-4 to 2.0E*3 to more closely model the risk of a LOSWS at the Ginna station. This is consistent | |||
with Ginna's understanding | |||
of the risk of this event. All remaining | |||
events were left at their nominal failure probabilities. The model was modified by Idaho National Laboratory (INL) to include convolution | |||
correction | |||
factors. Convolving | |||
the failure distribution | |||
eliminates | |||
the simplifying | |||
assumption | |||
that all failure to run events happen at time=O. Inclusion | |||
of this correction | |||
can reduce station blackout (SBO) core damage frequency (CDF) significantly | |||
for plants like Ginna that have low EDG redundancy. Since all observed failures happened upon the initiation | |||
of the TDAFW system, the period between May 29 and June 25 2009, was not included in the exposure period because the system successfully | |||
completed | |||
increased, weekly, surveillance | |||
testing. The team could not conclude that the stem binding condition | |||
would occur after the pump had been successfully | |||
started and run. Cutset probability | |||
calculation | |||
truncation | |||
was set at 1 E-13. Enclosure | |||
Based upon the above assumptions, the Ginna SPAR model calculated | |||
an increase in internal event contribution | |||
to conditional | |||
core damage probability (CCDP) of 2.9E-6. This low-ta-mid | |||
E-6 delta CCDP value represents | |||
a low to moderate safety significance (White). The dominant internal event sequence involved a LOOP with subsequent | |||
failure of the EDGs (station blackout event), the failure of the TDAFW train and the failure to recover AC power. The Phase 3 SPAR model results correlate | |||
well to the Phase 2 SDP Notebook dominant core damage sequences. | |||
External Events Risk Contribution | |||
The Ginna Probablistic | |||
Safety Assessment (PSA) includes a Level 1 analysis of fires and flooding external events. The PSA summarizes | |||
the fire contribution | |||
as representing | |||
approximately | |||
48% of the total (internal | |||
and external) | |||
core damage frequency, or nearly half of the annualized | |||
risk. The NRC does not have an external event risk model for Ginna. Consequently, the SRA, after review of the licensee's | |||
Individual | |||
Plant Examination | |||
of External Events (IPEEE), utilized the licensee's | |||
external events assessment | |||
to quantify the fire and flooding events risk contribution | |||
for this condition. | |||
Seismic event likelihood | |||
was considered | |||
to be very low and determined | |||
not to be a significant | |||
contributor | |||
to the risk of this condition. | |||
The results of the PSA for this condition | |||
calculated | |||
a CCDP contribution | |||
from fire events at 5E-6 and from flooding at 7E-7. The most significant | |||
fire initiated | |||
core damage sequence involved a spectrum of control room fires, with a failure of automatic | |||
and manual suppression, a failure of the TDAFW pump and a failure of the 'C' standby auxiliary | |||
feed water pump for decay heat removal via the steam generators. | |||
The most Significant | |||
flooding core damage sequence quantified | |||
in the PSA for this condition, Involved flooding in the relay room, failure of the TDAFW pump and a failure to align standby auxiliary | |||
feed water pump for decay heat removal via the steam generators. | |||
Large Early Release Frequency (LERF) Evaluation | |||
The SRA used IMC 0609, Appendix H, "Containment | |||
Integrity | |||
Significance | |||
Determination | |||
Process," to determine | |||
if this finding was a significant | |||
contributor | |||
to a large early release. The Ginna containment | |||
is classified | |||
as a pressurized | |||
water reactor large-dry | |||
containment | |||
deSign. Based upon the dominant sequences | |||
involving | |||
LOOP and station blackout (S80) initiating | |||
events, per Appendix H, Table 5.2, "Phase 2 Assessment | |||
Factors -Type A Findings at Full Power," the failure of the TDAFW pump does not represent | |||
a significant | |||
challenge | |||
to containment | |||
integrity | |||
early in the postUlated | |||
core damage sequences. | |||
Consequently, this finding does not screen as a significant | |||
large early release contributor | |||
because the close-in populations | |||
can be effectively | |||
evacuated | |||
far in advance of any postulated | |||
release due to core damage, Accordingly, the risk significance | |||
of this finding is associated | |||
with the delta CDF value, per IMC 0609, Appendix H, Figure 5.1, and not delta LERF. Risk Assessment | |||
Summary The calculated | |||
total risk significance | |||
of this finding is based upon the summation | |||
of internal and external risk contributions (delta CCDP internal + delta CCDP external (fires and floods).= | |||
delta CCDP total). 2.9E-6 + 5E-6 + 7E-7 = 8.6E-6 delta ceDP. Enclosure | |||
Annualized, this value of 8.6E-6 delta CDF represents | |||
a low to moderate safety significance | |||
or White finding. Licensee's | |||
Risk Assessment | |||
Summary Constellation's | |||
risk assessment | |||
for the given condition, assuming no operator recovery, resulted in a total delta CDF value of 1.028E-5. | |||
This increase in CDF value comprised | |||
of: 4.6E-6 due to intemal events; 0.7E-6 due to intemal flooding events; and 5E-6 fire/external | |||
events. Similar to the NRC internal risk contribution, the largest percentage | |||
of intemal risk was derived from station blackout events. The licensee conducted | |||
refinements | |||
in their modeling to credit additional | |||
recovery options in the event that the TDAFW pump failed. By crediting | |||
these recovery actions, the delta CDF was reduced from 1.028E-5 to 9.2 E-6, or by approximately | |||
10%. The specific recovery actions are as follows: . The potential | |||
for operators | |||
to use standby auxiliary | |||
feedwater (SAFW) pump C, in lieu of the TDAFW pump during fire and flood scenarios | |||
which require use of alternate | |||
shutdown procedures | |||
was modeled. Although use of an SAFW pump is not specifically | |||
called out in these procedures, the procedures | |||
do explicitly | |||
recognize | |||
that if the TDAFW pump is not functioning, a loss of secondary | |||
heat sink will result, and direct operators | |||
to refer to other emergency procedures | |||
for alternate | |||
methods of establishing | |||
a heat sink (see ER-FIRE.1 | |||
step 4.3.4.2, FIRE.2 step 4.3.12, etc.}. In response to this hypothetical | |||
scenario, an operations | |||
Shift Manager (SM) indicated | |||
that upon a failure of the TDAFW to provide flow, a SAFW pump could be manually started by locally opening the service water suction valve to the pump and locally closing the breaker to the pump motor. The steps necessary | |||
to align an SAFW pump to the steam generators (SG) are contained | |||
in emergency | |||
operating | |||
procedures (EOP) Attachment | |||
5.1 'Attachment | |||
SAFW'. Since only Busses 14 and 18 are energized | |||
during ER-FIRE scenarios, SAFW pump C would be used. Following | |||
the May 26th overs peed trip of the TDAFW pump, new section 2.2 was added to procedure | |||
P-15.6, 'Operation | |||
of the TDAFW Pump Trip Throttle Valve.' Revision 00200. This step provides instructions | |||
for a 'slow start' of the TDAFW pump manually, following | |||
an overspeed | |||
trip of the pump, by using the trip throttle valve. This allows for starting of the pump even if the governor control valve is stuck in the full open position following | |||
the overspeed | |||
trip. This procedure | |||
step was successfully | |||
used following | |||
both the May 26th failure and the July 2nd failure. Per Operations | |||
management, the shift managers, who would be directing | |||
use of this procedure, were briefed on the updated procedure | |||
to ensure they were aware that new step was available | |||
for use and understood | |||
how it was to be performed. | |||
A controlled | |||
copy of the procedure | |||
is located at the TDAFW pump for use by the operator. | |||
Since this procedure | |||
was in effect prior to the July failure exposure period (Le., prior to the last successful | |||
TDAFW pump test on June 25, 2009), it is considered | |||
as a recovery for failures of the TDAFW pump. Recovery actions identified | |||
in #1 above were not quantified | |||
by the team however the evaluation | |||
approach appears to be appropriate. | |||
Prior to the licensee crediting | |||
recovery actions identified | |||
in #2 above, the team was able to verify that the procedures | |||
were in Enclosure | |||
place and observed troubleshooting | |||
video in which the licensee started the TDAFW pump with this method. As a result the SRA concluded | |||
that the licensee's | |||
modeling demonstrating | |||
a risk reduction | |||
was appropriate. | |||
Based upon the close comparison | |||
between NRC and Constellation | |||
risk estimates, no sensitivity | |||
analyses were warranted. | |||
The use of V2 to approximate | |||
the exposure time was determined | |||
to be appropriate | |||
for standby or periodically | |||
operated components | |||
that fail due to a degradation | |||
mechanism | |||
that gradually | |||
affects the component | |||
during the standby time period. Inclusion | |||
of the unavailability | |||
time hours, due to troubleshooting | |||
and repairs, is also appropriate | |||
and consistent | |||
with the guidance promulgated | |||
in Risk Assessment | |||
of Operational | |||
Events Handbook, Revision 1.01, dated January 2008. This finding has a cross-cutting | |||
aspect in the area of Problem Identification | |||
and Resolution, Corrective Action Program, because Ginna did not implement | |||
a corrective | |||
action program with a low threshold | |||
for identifying | |||
issues completely, accurately, and in a timely manner commensurate | |||
with their safety | |||
significance. | |||
Specifically, Ginna did not identify issues associated | |||
with corrosion | |||
of the governor control valve within the corrective | |||
actions program. The inspectors | |||
concluded | |||
that the performance | |||
deficiency | |||
is reflective | |||
of current performance | |||
because Ginna had reasonable | |||
opportunities | |||
to identify the issue during troubleshooting | |||
in December 2008 and May 2009. [P.1(a) per IMC 0305] Enforcement: | |||
10 CFR 50, Appendix B, Criterion | |||
XVI, "Corrective | |||
Actions," states, in part, "Measures | |||
shall be established | |||
to assure that conditions | |||
adverse to quality, such as failures, malfunctions, defiCiencies, deviations, defective | |||
material and eqUipment, and nonconformances | |||
are promptly identified | |||
and corrected. | |||
In the case of significant | |||
conditions | |||
adverse to quality, the measures shall assure that the cause of the condition | |||
is determined | |||
and corrective | |||
action taken to preclude repetition." Contrary to the above, after identifying | |||
corrosion | |||
on the TDAFW pump governor control valve stem on April 11, 2005, which is a significant | |||
condition | |||
adverse to quality, Ginna did not take adequate measures to determine | |||
the cause and prevent recurrence. | |||
The cause of the condition | |||
was left uncorrected | |||
and resulted in additional | |||
stem corrosion | |||
that led to binding of the governor control valve and the failure of the TDAFW pump on July 2, 2009. In addition, stem corrosion | |||
was the likely cause of the TDAFW pump failure on May 26, 2009. This issue was entered into Ginna's CAP as CR-:2009-003680 | |||
and CR-2009-004577. | |||
Pending final determination | |||
of significance, this finding is identified | |||
as an AV. (AV 0500024412009008*01: | |||
Inadequate | |||
Corrective | |||
Actions Associated | |||
with the TDAFW Pump Governor Control Valve) 2. Untimely Corrective | |||
Actions Associated | |||
with Steam Admission | |||
Valves Introduction: | |||
A self-revealing | |||
NeVof 10 CFR 50, Appendix B, Criterion | |||
XVI, "Corrective | |||
Actions," was identified | |||
for the failure to establish | |||
adequate measures to correct a longstanding | |||
issue associated | |||
with steam a(]mission | |||
valves leakage. As a result, the leakage most likely contributed | |||
to the build-up of corrosion | |||
on the TDAFW pump governor control valve stem on May 26, 2009 and contributed | |||
to the failure of the TDAFW pump on July 2, 2009. Description: | |||
During a review of failures associated | |||
with the TDAFW pump, the inspectors | |||
noted that the steam admission | |||
valves had a history of leaking. Based on a review of the RCA report, industry operating | |||
experience, and associated | |||
CRs, the Enclosure | |||
inspectors | |||
determined | |||
that the steam admission | |||
valve leakage was a contributing | |||
factor in the development | |||
of corrosion | |||
of the governor control valve and contributed | |||
to the failure of the TDAFW pump on July 2, 2009, and most likely the failure of the TDAFW pump overspeed | |||
trip failure on May 26, 2009. Based on a review of eRs and interviews | |||
of personnel, the inspectors | |||
determined | |||
that the steam admission | |||
valves had been leaking since at least 2005. In July 2005, | |||
documented | |||
that steam admission | |||
valve 3505A was leaking past its seat. However, Ginna did not take or plan any corrective | |||
actions associated | |||
with the issue. By October 2006, steam admission | |||
valve 3505A leakage had increased | |||
such that the TDAFW pump turbine was rotating approximately | |||
100 rpm. Ginna cycled the valve to reduce seat leakage, generated | |||
a work order to repair the valve in May 2008, and conducted | |||
an evaluation | |||
of past operability. | |||
Ginna concluded | |||
that there was no potential | |||
for increased | |||
consequences | |||
with time if the condition | |||
continued. | |||
During the May 2008 refueling | |||
outage, Ginna conducted | |||
a repair of steam admission | |||
valve 3505A. However, this corrective | |||
action was not effective; | |||
by September | |||
2008, the valve was leaking again although at a reduced rate. The inspectors | |||
determined | |||
that Ginna did not recognize | |||
or consider the potential | |||
impact of the steam admission | |||
valve leakage on the governor control valve stem. Immediate | |||
corrective | |||
actions included entering this condition | |||
in the CAP, replacing | |||
the govemor control valve stem, and conducting | |||
weekly monitOring | |||
of the governor control valve during surveillance | |||
to identify any potential | |||
for stem binding. Additionally, the steam admission | |||
valves were inspected | |||
and re-worked | |||
and the govemor control valve was Inspected | |||
during the fall 2009 outage. Ginna will continue to monitor the governor control valve under an enhanced TDAFW surveillance | |||
program to ensure TDAFW pump operability. | |||
Planned corrective | |||
actions include replacing | |||
the stem admission | |||
valves in May 2011. Analysis: | |||
The performance | |||
deficiency | |||
is that Ginna did not adequately | |||
address deficiencies | |||
associated | |||
with steam admission | |||
valve leakage in that the leakage likely resulted in accelerated | |||
corrosion | |||
of the governor control valve and contributed | |||
to the failure of the TDAFW pump. The finding is more than minor because it is associated | |||
with the equipment | |||
performance | |||
attribute | |||
of the Mitigating | |||
Systems cornerstone | |||
and affects the cornerstone | |||
objective | |||
to ensure the availability | |||
and reliability | |||
of systems that respond to initiating | |||
events to prevent undesirable | |||
consequences. | |||
Specifically, leakage through the steam admission | |||
valves can res.ult in continuous | |||
wetting of the governor control valve stem and lead to or accelerate | |||
corrosion | |||
of the governor control valve. This could result in a stem binding of the govemor control valve and failure of the TDAFW pump. The inspectors | |||
evaluated | |||
the significance | |||
of this finding using IMC 0609, Attachment | |||
4, "Phase 1 -Initial Screening | |||
and Characterization | |||
of Findings." The finding is of very low safety significance | |||
because it is not a design or qualification | |||
deficiency, did not represent | |||
a loss of a safety function of a system or a single train greater than its TS allowed outage time, and did not screen as potentially | |||
risk Significant | |||
due to external events. The inspectors | |||
determined | |||
that the steam admission | |||
valve leakage was not a direct cause of the failure of the TDAFW pump overspeed | |||
events. The steam admission | |||
valve leakage was a contributing | |||
factor in the development | |||
of governor control valve stem corrosion | |||
and contributed | |||
to the failure of the TDAFW pump. Enclosure | |||
This finding has a cross-cutting | |||
aspect in the area of Problem Identification Resolution, Corrective | |||
Action Program, because Ginna did not thoroughly | |||
problems such that the resolutions | |||
address causes and extent of conditions, r:eecessary, in a timely manner, commensurate | |||
with their significance. | |||
Ginna did not thoroughly | |||
evaluate the potential | |||
effect of the steam admission leakage on the governor control valve performance. | |||
The inspectors | |||
determined | |||
that issue is reflective | |||
of current licensee performance | |||
because each time the issue identified | |||
and a CR was generated | |||
represented | |||
an opportunity | |||
for Ginna to | |||
evaluate the issue and assign appropriate | |||
corrective | |||
actions. [P.1 (c) per IMC Enforcement: | |||
10 CFR Part 50, Appendix B, Criterion | |||
XVI, "Corrective | |||
Actions," states, in part. "Measures | |||
shall be established | |||
to assure that conditions | |||
adverse to quality, such as failures, malfunctions, deficiencies, deviations, defective | |||
material and equipment, and nonconformances | |||
are promptly identified | |||
and corrected." Contrary to this requirement, from at least July 2005 to July 2, 2009, Ginna did not established | |||
adequate measures to correct longstanding | |||
steam admission | |||
valves leakage and/or minimize the impact of the leakage on the TDAFW pump governor control valve performance. | |||
As a result, leakage I*I through the steam admission | |||
valves contributed | |||
to the corrosion | |||
of the governor valve and contributed | |||
to the failure of the TDAFW pump on July 2, 2009 and most the failure of the TDAFW pump on May 26, 2009. Because this violation | |||
is of very safety significance (Green) and Ginna entered this issue into their CAP for resolution CR-2009-003680 | |||
and CR-2009-004577, this violation | |||
is being treated as an consistent | |||
with the NRC Enforcement | |||
Policy. (NCV 0500024412009008-02: | |||
Corrective | |||
Actions Associated | |||
with Stearn Admission | |||
Valve | |||
2.2 Review of Operating | |||
Experience | |||
a. Inspection | |||
ScoQe The team reviewed operating | |||
experience | |||
involving | |||
TDAFW pump failures and taken by the Ginna staff to identify and address these types of failures. | |||
In addition, team examined the specific issues associated | |||
with governor control valve stem to assess any new generic issues of industry interest for prompt communication dissemination. | |||
As part of this evaluation, the inspectors | |||
reviewed pertinent | |||
operating | |||
experience, Ginna's response to NRC Information | |||
Notices, and | |||
key plant | |||
b. Findings and Observations | |||
No Findings of Significance | |||
Identified. | |||
The inspectors | |||
determined | |||
that there were no new generic issues identified | |||
as a result of this event. However, the inspectors | |||
noted that Ginna missed opportunities | |||
to utilize industry operating | |||
experience | |||
to identify precursors | |||
associated | |||
with this event and to conduct effective | |||
troubleshooting. | |||
Specifically, following | |||
the discovery | |||
of corrosion | |||
on the exposed portion of the TDAFW pump govemor control valve stem in May 2005, Ginna did not enter this issue in to their CAP. As a result Ginna missed an opportunity | |||
to revisit operating | |||
experience | |||
from NRC IN 94-66 conceming | |||
governor control valve stem binding. In several examples in NRC IN 94-66, sites that experienced | |||
governor control valves stem binding identified | |||
stem corrosion | |||
following | |||
valve disassembly. | |||
Ginna Enclosure | |||
had originally | |||
determined | |||
that NRC IN 94-66 was not applicable | |||
to Ginna because the governor control valve was of a different | |||
configuration | |||
and material as those discussed | |||
in the IN and that corrosion | |||
of the stem had not been previously | |||
identified. | |||
Although this may have been a reasonable | |||
assessment | |||
during the original review of the NRC IN 94-66 in 1994, the inspectors | |||
determined | |||
that once corrosion | |||
of the stem was identified | |||
in'May 2005, Ginna missed an opportunity | |||
to revisit this operating | |||
experience. | |||
In addition, as discussed | |||
in Section 2.1.2 of this report. Ginna did not utilize Industry operating | |||
experience | |||
in evaluating | |||
a condition | |||
associated | |||
with steam admission | |||
valve leakage. NRC IN 94-66, other industry operating | |||
experience, and the vendor technical | |||
manual stated that steam admission | |||
valve leakage is a cause related to governor control valve stem binding. However, Ginna did not consider the impact of steam admission | |||
valve leakage on the governor control valve performance. | |||
Finally, the inspectors | |||
noted that Ginna missed opportunities | |||
to incorporate | |||
industry operating | |||
experience | |||
during troubleshooting | |||
efforts during the May 2009 TDAFW pump failure. NRC IN 94-66 discussed | |||
several examples where a freedom of motion test was performed | |||
to test for stem binding with the governor control valve linkage disconnected | |||
and hydraulics | |||
not applied. However, during the May 2009 event, Ginna missed an opportunity | |||
to conduct this test and consequently, missed an opportunity | |||
to potentially | |||
identify the failure mode prior to the July 2, 2009, overspeed | |||
trip. Ginna captured these issues in their CAP under CR-2009-003680 | |||
and CR-2009-004577 | |||
.. 2.3 Review of Root Cause and Extent-ot-Condition | |||
a. Inspection | |||
Scope The team evaluated | |||
the adequacy of Ginna's RCA and completed | |||
interim corrective | |||
actions. In addition the team evaluated | |||
the adequacy of Ginna's initial extent of condition | |||
for the TDAFW pump failures. | |||
The team reviewed plant drawings, procedures, and associated | |||
system modifications. | |||
In addition, the team conducted | |||
a walkdown of the TDAFW system and interviewed | |||
key Ginna personnel. | |||
b. Findings and Observations | |||
Introduction: | |||
The inspectors | |||
identified | |||
an NCV of 10 CFR 50, Appendix B, Criterion | |||
III, "Design Control," for the failure to establish | |||
measures to ensure that a modification | |||
performed | |||
on the governor control valve bushing was a suitable application | |||
of materials | |||
for the TDAFW pump. Description: | |||
During the troubleshooting | |||
and repair of the TDAFW pump in July 2009, Ginna incorrectly | |||
evaluated | |||
that a vendor service bulletin allowed for larger bushing clearance | |||
than was prescribed | |||
in their current technical | |||
documents. | |||
Since there was overlap between the station technical | |||
information | |||
and the vendor service bulletin, Ginna decided to increase the clearance, by lapping the bushings, to reduce the likelihood | |||
that corrosion | |||
products would cause the stem to bind. To increase the clearance, Ginna removed some of the hardened layer on the bushing. During a review of the RCA, the inspectors | |||
determined | |||
that Ginna did not consider the potential | |||
impact of removing some ot the hardened layer on the corrosion | |||
rate of the governor control valve. The inspectors | |||
noted that by removing some of the hardened layer, the material property of the bushing could have been changed and/or additional | |||
micro-cracks | |||
could have been created or exposed that could increase the corrosion | |||
rate or potentially | |||
cause other Enclosure | |||
problems such as | |||
galling. The inspectors | |||
noted that if the corrosion | |||
rate is greater than predicted, then planned corrective | |||
actions may not be adequate to maintain the TDAFW pump operable. | |||
Additionally, the team was concerned, that by increasing | |||
the stem to bushing clearances, the stem would be susceptible | |||
to larger steam exposure and that this could further accelerate | |||
the corrosion. | |||
Following | |||
concerns raised by the inspectors, Ginna initiated | |||
CR-2009-005959 | |||
to ensure that all possible consequences | |||
of lapping the TDAFW pump control valve bushing were fully evaluated. | |||
In addition, Ginna assigned corrective | |||
actions to inspect the control valve bushing during the fall 2009 refueling | |||
outage. During performance | |||
of the refueling | |||
inspection | |||
under WO C90623685, pitting of the stem and corrosion | |||
of the bushings were observed. | |||
Constellation | |||
initiated | |||
and noted that the corrosion | |||
of the bushings appeared to have been caused by the lapping of the bushing to achieve the desired clearance | |||
between the stem and the bushings. | |||
The development | |||
of corrosion | |||
on the bushing reduced the margin that was predicted | |||
to ensure adequate stem movement. | |||
Immediate | |||
corrective | |||
actions following | |||
the inspection | |||
of the governor control valve during the fall 2009 refueling | |||
outage included entering this condition | |||
in the CAP and refurbishing | |||
the governor control valve with a new stem and bushing. Analysis: | |||
The performance | |||
deficiency | |||
is that Ginna failed to establish | |||
measures to ensure that a modification | |||
performed | |||
on the governor control valve bushing was a suitable application | |||
of materials | |||
for the TDAFW pump. The finding is more than minor because it is associated | |||
with the equipment | |||
performance | |||
attribute | |||
of the Mitigating | |||
Systems cornerstone | |||
and affects the cornerstone | |||
objective | |||
to ensure the availability | |||
and reliability | |||
of systems that respond to initiating | |||
events to prevent undesirable | |||
consequences. | |||
Specifically, lapping of the valve bushing resulted in an unanticipated | |||
corrosion | |||
mechanism | |||
of the governor control valve that impacted the reliability | |||
of the TDAFW pump. The inspectors | |||
evaluated | |||
the Significance | |||
of this finding using IMC 0609, Attachment | |||
4, "Phase 1 -Initial Screening | |||
and Characterization | |||
of Findings." The finding is of very low safety significance | |||
because it is not a design or qualification | |||
deficiency, did not represent | |||
a loss of a safety fUnction of a system or a single train greater than its TS allowed outage time, and did not screen as potentially | |||
risk significant | |||
due to external events. The inspectors | |||
determined | |||
that this finding has a cross-cutting | |||
aspect in the area of Human Performance, Decision Making, because Ginna did not make a safety-significant | |||
or risk-significant | |||
decision using a systematic | |||
process, especially | |||
when faced with uncertain | |||
or unexpected | |||
plant conditions, to ensure safety was maintained. | |||
Specifically, Ginna did not use a systematic | |||
process such as an engineering | |||
evaluation | |||
to properly evaluate the potential | |||
impact of removing some of the hardened layer of the bushing. [H.1(a) per IMC 0305] Enforcement: 10 | |||
CFR 50, Appendix B, Criterion | |||
III, "Design Control" states, in part, "Measures | |||
shall also be established | |||
for the selection | |||
and review for suitability | |||
of application | |||
of materials, parts, equipment, and processes | |||
that are essential | |||
to the related functions | |||
of the structures, systems and components." Contrary to the requirements, in July 2009, Ginna failed to establish | |||
measures to ensure that a modification | |||
performed | |||
on the governor control valve bushing was a suitable application | |||
of materials | |||
for the TDAFW pump. Specifically, lapping of the valve bushing resulted in an unanticipated | |||
corrosion | |||
mechanism | |||
of the governor control valve that had the Enclosure | |||
potential | |||
to impact the performance | |||
of the TDAFW pump if not corrected. | |||
Because this violation | |||
is of very low safety significance (Green) and Ginna entered this issue into their CAP for resolution | |||
as CR-2009-006765, this violation | |||
is being treated as an NCV consistent | |||
with the NRC Enforcement | |||
Policy. (NeV 05000244/2009008-03: | |||
Failure To Establish | |||
Design Control Measures Associated | |||
With The Turbine Driven Auxiliary | |||
Feedwater | |||
Pump Governor Control Valve) 2.4 Risk Assessment | |||
of the As-Found Condition | |||
a. Insoection | |||
Scope Prior to the initiation | |||
of the Special Inspection | |||
Team, the Region I SRA performed | |||
a CCDP assessment | |||
which conservatively | |||
bounded the potential | |||
risk significance | |||
of the degraded condition, assuming the TDAFW pump would fail to star on demand to mitigate the consequences | |||
of an event. The initial CCDP estimate was performed | |||
in accordance | |||
with IMC 0309, "Reactive | |||
Inspection | |||
Decision Basis for Reactors." The SRA used the Ginna SPAR model and associated | |||
GEM to evaluate the potential | |||
risk significance | |||
of this condition. | |||
The results of the IMC 0309 assessment | |||
are documented | |||
in report section 2.1.b.1 above. b. Final Risk Estimate Following | |||
team review and independent | |||
verification | |||
of the degraded turbine driven auxiliary | |||
feed water pump governor control valve, the team concluded | |||
that for approximately | |||
119B hours, the TDAFW pump would not have been capable | |||
of responding | |||
to an event. Consistent | |||
with IMC 0609 conditional | |||
core damage probability | |||
assessment | |||
methodology, this degraded condition | |||
resulted in a loss of operability | |||
or safety function, and therefore | |||
was of low to moderate (B.6E-6) safety significance. | |||
4. OTHER ACTIVITIeS | |||
40A6 Meetings, Including | |||
Exit On August 27 and on October 7,2009 the team presented | |||
the inspection | |||
results to Mr. John Carlin and other members of the R. E. Ginna Nuclear Power Plant staff. The inspectors | |||
verified that none of the | |||
during the inspection | |||
is considered | |||
proprietary | |||
in nature. Enclosure | |||
A-1 ATTACHMENT | |||
A SUPPLEMENTAL | |||
KEY POINTS OF Licensee personnel | |||
J. Carlin, Site Vice President | |||
E. Larson, Plant General Manager D. Crowley, Senior Engineer E. Durkish, Associate | |||
Engineer R. Everett, Supervisor, Primary Systems Engineering | |||
T. Harding, Director, Licensing | |||
R. Ruby, Principal | |||
Engineer, Licensing | |||
P. Swift, Engineering | |||
Manager LIST OF ITEMS OPENED, CLOSED, AND DISCUSSED | |||
Opened 05000244/2009008-01 | |||
Opened/Closed | |||
05000244/2009008-02 | |||
05000244/2009008-03 Failure to Preclude Recurrence | |||
of a Significant | |||
Condition | |||
Adverse to Quality Associated | |||
with the Turbine Driven Auxiliary | |||
Feedwater | |||
Pump Governor Control Valve. (Section 2.1.1) Inadequate | |||
Corrective | |||
Actions Associated | |||
with Steam Admission | |||
Valve Leakage. (Section 2.1.2) Failure to Establish | |||
Design Control Measures Associated | |||
with the Turbine Driven Auxiliary | |||
Feedwater | |||
Pump Governor Control Valve. (Section 2.3) I.IST OF DOCUMENTS | |||
REVIEWED In addition to the documents | |||
identified | |||
in the body of this report, the inspectors | |||
reviewed the following | |||
documents | |||
and records: Corrective | |||
Actions CA-2009-002311 | |||
Condition | |||
Reports CR-2003-2006 | |||
CR-2005-3660 | |||
CR-2006-006029 | |||
CR-2006-006341 | |||
CR-2005-1509 | |||
CR-2005-5513 | |||
CR-2006-006204 | |||
CR-2006-006962 | |||
Attachment | |||
A | |||
CR-2007 -000876 CR-2008-009911 | |||
CR-2009-004590 | |||
CR-2009-005959* | |||
CR-2007-001302 | |||
CR-2009-003680 | |||
CR-2009-004591 | |||
CR-2009-006765* | |||
CR-2008-003687 | |||
CR-2009-004222* | |||
CR-2009-005964 | |||
CR-2008-007541 | |||
CR-2009-004577 | |||
*NRC Identified | |||
During Inspection | |||
Corrective | |||
Action Tracking System CATS R007325 Procedures | |||
AP-FVV.1, Abnormal MFW Pump Flow or NPSH, Revision 01702 PT-16QT-T, Auxiliary | |||
Feedwater | |||
Turbine Pump -Quarterly, Revision 05900 CNG-MN-1.01-1002, Troubleshooting, Revision 0001 CNG-CA-1.01 , Corrective | |||
Action Program, Revision 0001 CNG-CA-1.01-1004, Root Cause Analysis, Revision 0001 CNG-CA-1.01-1005, Apparent Cause Evaluation, Revision 0100 CNG-CA-1.01-1006, Common Cause Analysis, Revision 0001 CNG-CA-1.01-1007, Trending, Revision 0000 CNG-CA-1.01-1010, Use of OE, Revision 0000 IP-CAP-1, Ginna Condition | |||
Reporting, Revision 02800 M-11.5C, Auxiliary | |||
Feedwater | |||
Pump Motor Mechanical | |||
Inspection | |||
and Maintenance, Revision 03000 0-1.1, Plant Heatup From Cold Shutdown to Hot Shutdown, Revision 16301 PT-16Q-T, Auxiliary | |||
Feedwater | |||
Turbine Pump -Quarterly, Revision 05600. Completed | |||
3/14/08,514108,5/5/08,6/11/08,9/4/08, 1213/08, 1214/08, 12111/08, 12/18/08,2/12/09, 5/26/09, 5/28/09 Surveillance | |||
Tests PT-16Q-T, Auxiliary | |||
Feedwater | |||
Turbine Pump -Quarterly, Revision 05600, 03/14/2008 | |||
PT-16Q-T, Auxiliary | |||
Feedwater | |||
Turbine Pump -. Quarterly, Revision 05700, 05/04/2008 | |||
PT-16Q-T, Auxiliary | |||
Feedwater | |||
Turbine Pump _. Quarterly, Revision 05700,05/05/2008 | |||
PT-16Q-T, Auxiliary | |||
Feedwater | |||
Turbine Pump -Quarterly, Revision 05700. 06/11/2008 | |||
STP-0-16-COMP-T, Auxiliary | |||
Feedwater | |||
Turbine Pump -Comprehensive Test, Revision 00000, 06/11/2008 | |||
PT-16Q-T, Auxiliary | |||
Feedwater | |||
Turbine Pump -Quarterly. | |||
Revision 05701, 09/03/2008 | |||
PT-16Q-T, Auxiliary | |||
Feedwater | |||
Turbine Pump -Quarterly, Revision 05701, 12/02/2008 | |||
PT-16Q-T, Auxiliary | |||
FeedwaterTurbine | |||
Pump -Quarterly. | |||
Revision 05701,12103/2008 | |||
PT-16Q-T. | |||
Auxiliary | |||
Feedwater | |||
Turbine Pump _. Quarterly, Revision 05701, 12/04/2008 | |||
PT-16Q-T, Auxiliary | |||
Feedwater | |||
Turbine Pump _. Quarterly, Revision 05702, 12/11/2008 | |||
PT-16Q-T, Auxiliary | |||
Feedwater | |||
Turbine Pump _. Quarterly, Revision 05702, 12/18/2008 | |||
PT-16Q-T, Auxiliary | |||
Feedwater | |||
Turbine Pump -Quarterly, Revision 05801, 01116/2009 | |||
PT -16Q-T, AUXiliary | |||
Feedwater | |||
Turbine Pump -Quarterly, Revision 05801, 02112/2009 | |||
PT-16Q-T, AUXiliary | |||
Feedwater | |||
Turbine Pump _. Quarterly. | |||
Revision 05900,05/26/2009 | |||
PT-16Q-T, Auxiliary | |||
Feedwater | |||
Turbine Pump -Quarterly, Revision 05900,05/28/2009 | |||
STP-0-16-COMP-T, Auxiliary | |||
Feedwater | |||
Turbine Pump -Comprehensive | |||
Test, Revision 00400, 05/28/2009 | |||
Attachment | |||
A | |||
Work Orders W020604989 | |||
W020401907 | |||
Drawings DWG No. 33013-1231, Main Steam System, Revision 37 DWG No. 33013-2285, Motor Driven and Turbine Driven Auxiliary | |||
Feedwater | |||
Pumps Lube Oil Skid, Revision 17 DWG No. LB-112541, Turbine Control and Quick Start System DWG No. T040-001A, TDAFW Control Oil System, Revision 0 DWG No. T040-002A, TDAFW Turbine Trip Valve, Revision 0 DWG No. T040-003A, Auxiliary | |||
and Standby Aux. Feedwater | |||
Systems, Revision 2 DWG No. T040-003B, SAFW System 1-Line Diagram, Revision 0 DWG No. T040-003C, AFW System 1-Une Diagram, Revision 1 DWG No. T040-004A, Auxiliary | |||
Feedwater | |||
Pump Auto Start Signals, Revision 0 DWG No. T830-004A, Blowdown Isolation | |||
Solenoid Control Circuit, Revision 0 Other Documents | |||
Vendor Report, Preliminary | |||
Results of Stem Sticking Failure Mechanisms, July 20, 2009 Vendor Report 09-1929 Part 1, Equipment | |||
Root Cause Analysis of AFWP Control Valve Stem Sticking Problem at Ginna Nuclear Power Station Vendor Technical | |||
Question Response, August 26, 2009 Category I Root Causal Analysis, May and July 2009 Turbine Driven Auxiliary | |||
Feedwater | |||
Pump (TDAFWP) Failures; | |||
Overspeed | |||
Trip During Testing vrD-E9016-4001, Excerpts from EPRI Manual 1007461, Terry Turbine Maintenance | |||
Guide, AFW Application, Revision 000 vrD-G0153-4001, Operating | |||
Instructions | |||
Easy Flow Body Combined Trip Throttle Valve, Revision 2 VrD-W0315-4001, Instructions | |||
For 465 H.P. Non-Condensing | |||
Steam Turbine Serial Number 26635, Revision 000 VrD-W0315-4002, Service Department | |||
Standards | |||
Book No. 10, Field Service Manual, Revision 000 Response to NRC Generic Letter 90-3, Relaxation | |||
of Staff Position In Generic Letter 28, Item 2.2 Part 2 "Vendor Interface | |||
for Safety Related Components, dated September | |||
18, 1990 CATS 10 R04451, Response to NRC IN 94-66, OVERSPEED | |||
OF TURBINE-DRIVEN | |||
PUMPS CAUSED BY GOVERNOR VALVE STEM BINDING CMM-37-19-9519E, Worthington | |||
Turbine Driven Auxiliary | |||
Feedwater | |||
Pump Hydraulic | |||
Governor Control Valve Maintenance | |||
for 9519E, Revision 00200 Constellation | |||
Energy Nuclear Generating | |||
Group Reply to a Notice of Violation; 045 Engineering | |||
Change Package No. ECP-2009-0146, TDAFW Lube Oil Orifice Management | |||
Review Committee | |||
Agenda. August 5, 2009 Purchase Requisition | |||
No. 58686, Dresser-Rand | |||
Valve Stem Technical | |||
Staff Request 97-199, Leakoff from TDAFW Govenor Valve 9519E Management | |||
Review Committee | |||
Agenda, August 5, 2009 Purchase Requisition | |||
No. 58686, Dresser-Rand | |||
Valve Stem Attachment | |||
A | |||
Technical | |||
Staff Request 97-199, Leakofffrom | |||
TDAFW Govenor Valve 9519E Turbine Driven Auxiliary | |||
Feedwater | |||
Pump Preventive | |||
Maintenance | |||
Strategies | |||
Auxiliary | |||
Feed Water System, 1 st Quarter 200S Auxiliary | |||
Feed Water System. 2nd Quarter 200S Auxiliary | |||
Feed Water System. 3rd Quarter 200S Auxiliary | |||
Feed Water System, 4th Quarter 200S Auxiliary | |||
Feed Water System, 1 st Quarter 2009 Operating | |||
Experience | |||
OE-200S-000397 | |||
OE-200S-000607 | |||
OE-200S-000847 | |||
o E-2 0 OS-00S60 OE-2008-001296 | |||
OE-2009-00212 | |||
OE*2009*001178 | |||
Oil Analysis Pump IB Oil Analysis. | |||
2008-03 Pump OB Oil Analysis, 2008-03 Reservoir | |||
Oil Analysis 2008-05 Reservoir | |||
Oil Analysis 2008-08 Reservoir | |||
Oil Analysis 2009-05 Attachment | |||
A | |||
AV CAP CCDP CDF CR DRP EDG GEM ICCDP IMC IN INL *IPEEE LERF LOOP LOSWS NCV NRC NRR PARS PSA RCA SAFW SBO SOP SPAR SRA SCAQ NCV TBD TDAFW TS A-4 LIST OF ACRONYMS Apparent Violation | |||
Corrective | |||
Action Program Conditional | |||
Core Damage Probability | |||
Core Damage Frequency | |||
Condition | |||
Report Division of Reactor Projects Emergency | |||
Diesel Generator | |||
Graphical | |||
Evaluation | |||
Module Incremental | |||
Conditional | |||
Core Damage Probability | |||
Inspection | |||
Manual Chapter Information | |||
Notice Idaho National Labs Individual | |||
Plant Examination | |||
of External Events Large Early Release Frequency | |||
Loss of Off site Power Loss of Service Water System Non Cited Violation | |||
Nuclear Regulatory | |||
Commission | |||
Office of Nuclear Reactor Regulation | |||
Publicly Available | |||
Records Probabilistic | |||
Safety Assessment | |||
Root Cause Analysis Standby Auxiliary | |||
Feedwater | |||
Station Blackout Significance | |||
Determination | |||
Process Standardized | |||
Plant Analysis Risk Senior Reactor Analyst Significant | |||
Condition | |||
Adverse to Quality Non-citied | |||
Violation | |||
To Be Determined | |||
Turbine Driven Auxiliary | |||
Feedwater | |||
Technical | |||
Specification | |||
Attachment | |||
A | |||
8-1 Special Inspection R.E. Ginna Nuclear Power Failure of the Turbine-Driven | |||
Auxiliary | |||
Feedwater (TDAFW) on May 26, 2009 and July 2, Background: | |||
On May 26, 2009, during routine | |||
quarterly | |||
surveillance | |||
testing of the turbine driven auxiliary | |||
feedwater (TDAFW) system, the TDAFW pump tripped on overspeed. | |||
The test was repeated several hours later and the TDAFW pump tripped again on overspeed. | |||
Fluctuations | |||
in oil pressure were observed during the testing. After extensive | |||
troubleshooting, Ginna | |||
identified | |||
a number of issues but no definitive | |||
cause for the overspeed | |||
trips. The lube/control | |||
oil system was drained and cleaned due to the presence of fine particulates; | |||
a pressure pulsation | |||
dampener accumulator | |||
bladder was replaced due to a below normal pressure condition; | |||
the oil pressure regulating | |||
bypass valve was replaced due to potential | |||
cycling; a change to linkage setup was implemented; | |||
governor relay valve, and trip and throttle valve parts were replaced due to out of specification | |||
clearances; | |||
and a miSSing oil line orifice was installed. | |||
Following | |||
these corrective | |||
actions, the system was successfully | |||
tested and declared operable. | |||
Constellation | |||
is completing | |||
a root cause evaluation | |||
and the resident inspectors | |||
continue to conduct baseline inspections | |||
with assistance | |||
from DRS specialists. | |||
Testing of the TDAFW system will be at an increased | |||
frequency | |||
until Constellation | |||
has confidence | |||
that the system is performing | |||
as required. | |||
On July 2, 2009, during the performance | |||
of the increased | |||
frequency | |||
surveillance, the TDAFW pump again tripped on overspeed. | |||
Glnna personnel | |||
discovered | |||
pitting and corrosion | |||
on the stem of the governor control valve during troubleshooting | |||
activities | |||
to restore the pump to operable status. This Special Inspection | |||
Team had raised concerns regarding | |||
corrosion | |||
on the stem of the Governor Control Valve during onsite inspection | |||
activities | |||
the week of June 15, 2009. Basis for the Formation | |||
of the SIT: The failure of the TDAFW pump involved repetitive | |||
failures of this | |||
eqUipment. | |||
There have been three failures of the TDAFW pump since December 2008. On December 2, 2008, a failure was attributed | |||
to inadequate | |||
implementation | |||
of the preventive | |||
maintenance | |||
program. SpeCifically, the governor linkages were not lubricated | |||
in March 2008 which resulted in the pump's inability | |||
to achieve the required flow and pressure in December 2008. On July 2, 2009, the failure was preliminarily | |||
determined | |||
to be caused by pitting on the stem of the Governor Control valve and overly tolerances | |||
causing binding of the stem. Although the specific failure modes (overspeed | |||
trip, inability | |||
to achieve the required flow or pressure) | |||
were different, the underlying | |||
cause of inadequate | |||
or inappropriate | |||
preventive | |||
maintenance | |||
may be the same. Attachment | |||
8 | |||
Based upon best available | |||
information, the Region I Senior Reactor Analyst (SRA) conducted | |||
a preliminary | |||
risk estimate of the May 26 TDAFW pump failure. An incremental | |||
conditional | |||
core damage probability (ICCDP) in the upper E-6 range (8E-6 per the 82 day exposure period), was calculated | |||
using the Ginna SPAR model. assuming that the TDAFW pump would not have started since the last time it passed a surveillance | |||
test on March 5 until May 26 (82 days). The dominant core damage sequence was a station blackout (LOOP with failure of both EDGs,) with no TDAFW and failure to recover offsite power or an EDG in one hour. Based upon the preliminary | |||
conditional | |||
core damage probability | |||
estimate of upper E-6 range, in accordance | |||
with IMC 0309, this event falls within the region for a Special Inspection | |||
Team. Oblectives | |||
of the Special Inspection: | |||
The objectives | |||
of the special inspection | |||
are to review and assess: (1) | |||
Constellation's | |||
planning and execution | |||
of the risk significant | |||
work activities | |||
on the TDAFW system; (2) equipment | |||
issues related to the TDAFW testing; and (3) Constellation's | |||
response to this significant | |||
equipment | |||
failure. To accomplish | |||
these objectives, the following | |||
will be performed: Evaluate the adequacy and completeness | |||
of the maintenance | |||
on the TDAFW system, including | |||
preventive | |||
maintenance, procedural | |||
guidance, maintenance | |||
testing, and supervisory | |||
oversight. Evaluate Constellation's | |||
application | |||
of pertinent | |||
industry operating | |||
experience | |||
and evaluation | |||
of potential | |||
precursors, including | |||
the effectiveness | |||
of any actions taken in response to the operating | |||
experience | |||
or precursors. Evaluate the adequacy of Constellation's | |||
response to the TDAFW system failures, including | |||
Constellation's | |||
cause analysis and completed | |||
interim corrective | |||
actions. Evaluate the adequacy of Constellation's | |||
initial extent of condition | |||
for the TDAFW failures, as appropriate. Evaluate the failure modes for potential | |||
generic implications | |||
including | |||
the need for generic communications | |||
Additionally, the team leader will review lessons learned from the Special Inspection | |||
and, if appropriate, prepare a feedback form on recommendations | |||
for revising the reactor oversight | |||
process (ROP) baseline inspection | |||
procedures | |||
in order to proactively | |||
identify the issues and causes involved with the event. Guidance: | |||
Inspection | |||
Procedure | |||
93812, "Special Inspection", provides additional | |||
guidance to be used by the Special Inspection | |||
Team. Team duties will be as described | |||
in Inspection | |||
Procedure | |||
93812. The inspection | |||
should emphasize | |||
fact-finding | |||
in its review of the circumstances | |||
surrounding | |||
the event. It is not the responsibility | |||
of the team to examine Attachment | |||
B | |||
the regulatory | |||
process. Safety concerns identified | |||
that are not directly related to the event should be reported to the Region I office for appropriate | |||
action. The Team will conduct an entrance meeting and begin the inspection | |||
on June 8,2009. While on site, the Team Leader wi" provide daily briefings | |||
to Region I management, who will coordinate | |||
with the Office of Nuclear Reactor Regulation, to ensure that all other parties are kept informed. | |||
A report documenting | |||
the results of the inspection | |||
should be issued within 45 days of the completion | |||
of the inspection. | |||
This Charter may be modified should the team develop significant | |||
new information | |||
that warrants review. Attachment | |||
8 | |||
}} |
Revision as of 20:37, 30 January 2019
ML093160122 | |
Person / Time | |
---|---|
Site: | Ginna |
Issue date: | 11/12/2009 |
From: | David Lew Division Reactor Projects I |
To: | Carlin J T Ginna |
Clifford J W | |
References | |
EA-09-249 IR-09-008 | |
Download: ML093160122 (29) | |
See also: IR 05000244/2009008
Text
UNITED STATES NUCLEAR REGULATORY
COMMISSION
REGION I 475 ALLENDALE
ROAD KING OF PRUSSIA, PA 19406-1415
November 12, 2009 EA-09-249
Mr. John T. Carlin Vice President, RE. Ginna Nuclear Power Plant RE. Ginna Nuclear Power Plant, LLC 1503 Lake Road Ontario, New York 14519
RE. GINNA NUCLEAR POWER PLANT -NRC SPECIAL INSPECTION
TEAM REPORT 05000244/2009008;
PRELIMINARY
WHITE FINDING Dear Mr. Carlin: On June 16-20, 2009, and August 24-27,2009, the U.S. Nuclear Regulatory
Commission (NRC) conducted
the onsite portions of a special inspection
at RE. Ginna Nuclear Power Plant. office inspection
reviews were conducted
in the intervening
weeks. The enclosed report documents
the inspection
team's findings and observations
which were discussed
with you and others members of your staff on August 27, 2009, during a preliminary
exit briefing, and on October 7, 2009, during the final exit meeting. The special inspection
was conducted
in response to a turbine driven auxiliary
feedwater (TDAFW) pump overspeed
trip on May 26, 2009. The team included a subsequent
trip on July 2,2009 into its inspection
scope. The NRC's initial evaluation
of this condition
satisfied
the criteria in NRC Inspection
Manual Chapter 0309, "Reactive
Inspection
Decision Basis for Reactors," for conducting
a special inspection.
The basis for initiating
this special inspection
is further discussed
in the inspection
team's charter that is included in this report as Attachment
B. The inspection
examined activities
conducted
under your license as they relate to safety and compliance
with the Commission's
rules and regulations
and with the conditions
of your license. The inspectors
reviewed selected procedures
and records, observed activities, and interviewed
personnel.
This letter transmits
one self-revealing
finding that, using the reactor safety Significance
Determination
Process (SOP), has preliminarily
been determined
to be White, a finding with low to moderate safety significance.
The finding is associated
with the failure to preclude recurrence
of a significant
condition
adverse to quality associated
with the corrosion
of the governor control valve of the turbine driven auxiliary
feedwater (TDAFW) pump, that led to a failure of the TDAFW pump during surveillance
testing on July 2, 2009 and was the likely cause of the overspeed
trip on May 26, 2009. Following
the July test failure, Ginna replaced the
J. Carlin 2 governor control valve stem and conducted
weekly monitoring
of the governor control valve during surveillance
testing to identify any potential
for stem binding. In addition, corrective
actions included a follow-up
inspection
of the governor control valve during the fall 2009 refueling
outage. There is no immediate
safety concern present due to this finding
because the system is now operable and the long term corrective
actions are being implemented
in Ginna's corrective
action program. The final resolution
of this finding
will be conveyed in a separate correspondence.
As discussed
in the attached Inspection
report. the tinding is also an apparent violation
of NRC requirements.
specifically, 10 CFR Appendix B, Criterion
XVI. "Corrective
Actions." and is therefore
being considered
for escalated
enforcement
action in accordance
with the Enforcement
Policy, which can be found on the NRC's Web site at http://www.nrc.gov/readingrm/doc-collections/enforcementl.
Following
a discussion
of the preliminary
safety Significance
of this finding during the initial exit briefing on August 27,2009. a phone call was held between Glenn Dentel, Branch Chief, Division of Reactor Projects.
and yourself on October 1. 2009. During this call, you indicated
that R.E. Ginna Nuclear Power Plant does not contest the characterization
of the rIsk significance
of this finding, and therefore
you have declined to further discuss this issue at a Regulatory
Conference
or provide a written response.
Please note that by declining
to request a Regulatory
Conference
or submit a written response, you relinquished
your right to appeal the final SOP determination.
in that by not doing either, you would not meet the appeal requirements
stated in the Prerequisite
and Limitation
sections of Attachment
2 of IMC 0609. You will be advised by a separate correspondence
of the results of our deliberations
on this matter. In addition.
the report documents
two findings of very low safety significance (Green). The findings involved violations
of NRC requirements.
However, because of the very low safety significance
and because they are entered into your corrective
action program (CAP). the NRC is treating these findings as non-cited
violations (NeVs) consistent
with Section VI.A.1 of the NRC Enforcement
Policy. If you contest any NCV in this report, you should provide a response within 30 days of the date of this inspection
report, with the basis for your denial, to the Nuclear Regulatory
Commission, A TIN.: Document Control Desk, Washington, DC 20555-0001;
with copies to the Regional Administrator, Region I; the Director, Office of Enforcement;
and the NRC Resident Inspector
at R.E. Ginna. In addition.
if you disagree with the characterization
of any finding in this report, you should provide a response within 30 days of the date of this inspection
report. with the basis for your disagreement, to the Regional Administrator, Region I, and the NRC Resident Inspector
at R.E. Ginna Nuclear Power Plant. The information
you provide will be considered
in accordance
with Inspection
Manual Chapter 030? In accordance
with 1 0 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and its enclosure, and your response (if any) will be available
electronically
for public inspection
in the
J. 3 NRC Public Document Room or from the Publicly Available
Records (PARS) component
of the NRC's document system (ADAMS). ADAMS is accessible
from the NRC Web Site at http://www.nrc.gov/reading-rm/adams.html(the
Public Electronic
Reading Room). Sincerely, ,/;I,/;tJ--fbr-Division of Reactor Projects Docket No.: 50-244 License No.: DPR-18
Inspection
Report 05000244/2009008
w/Attachment
A: Supplemental
Information
w/Attachment
B: Special Inspection
Charter cc w/encl: Distribution
via ListServ
J. 2 NRC Public Document Room or from the Publicly Available
Records (PARS) component
of the NRC's document system (ADAMS). ADAMS is accessible
from the NRC Web Site at httg:llwww.nrc.gov/reading*rm/adams.html(the
Public Electronic
Reading Room). Sincerely, IRAJ James W. Clifford for: David C. lew, Director Division of Reactor Projects Docket No.: 50-244 License No.: DPR-18
Inspection
Report 05000244/2009008
w/Attachment
A: Supplemental
Information
w/Attachment
B: Special Inspection
Charter cc w/encl: Distribution
via
SUNSI Review Complete:
gtd (Reviewer's
DOCUMENT NAME: G:\DRP\BRANCH1\Ginna\TDAFW
SIT\AED Track Changes Ginna Report Rev 4 After declaring
this document "An Official Agency Record" it will be released to the To receive I!I copy of this document, indicate in the box: "C' =Copy without attachmenVenclosure "e" =Copy with attaclhmentlenclosure "N";:; No co ML093160122
RI/ENF OFFICE RI/DRS RI/DRP NAME CCahill/cc*
JClifford/jwc
DATE 10/21109 11/05/09 *see prior concurrence
OFFICIAL RECORD COpy Distribution
w/encl: S. Collins, RA (R10RAMaii
Resource)
ROPreports@nrc.gov
M. Dapas, ORA (R10RAMaii
Resource)
D. Lew, DRP (R1DRPMaii
Resource)
J. Clifford, DRP (R1DRPMail
Resource)
l. Trocine, RI OEDO RidsNrrPMREGinnaResource
RidsNrrDorlLpl1-1
Resource G. Dentel, DRP N. Perry, DRP J. Hawkins, DRP K. Kolaczyk, DRP, SRI S. Kennedy, DRP, SRI L. Casey, DRP, RI M. Rose, DRP, OA D. Bearde, DRP
Docket License Report Team
Approved U.S. NUCLEAR REGULATORY
REGION 50-244 DPR-18 05000244/2009008
Constellation
Energy, R. E. Ginna Nuclear Power Plant, LLC R. E. Ginna Nuclear Power Plant Ontario. New York June 15-19, 2009 and August 24-27.2009
C. cahill, Senior Reactor Analyst, Division of Reactor Safety S. Kennedy, Senior Resident Inspector, Division of Reactor Projects K. Kolaczyk, Senior Resident Inspector, Division of Reactor Projects J. Bream, Project Engineer.
Division of Reactor Projects Glenn T. Dentel, Chief Projects Branch 1 Division of Reactor Projects
2 SUMMARY OF FINDINGS IR 05000244/2009008;
06/15-19/2009
and 08/24-2'712009;
R. E. Ginna Nuclear Plant; Special Inspection
Team Report. The report covered two on-site inspection
visits and related in-office
inspection
activities
by a special inspection
team consisting
of a Senior Reactor Analyst. two Senior Resident Inspectors.
and one Project Engineer.
One apparent violation (A V) with potential
for greater than Green safety significance
and two Green findings were identified.
The significance
of most findings is indicated
by its color (Green. White, Yellow, or Red) using Inspection
Manual Chapter (lMC) 0609, "Significance
Determination
Process." Findings for which the significance
determination (SDP) process does not apply may be Green or be assigned a severity level after NRC management
review. The NRC program for overseeing
the safe operation
of commercial
nuclear power reactors is described
in NUREG-1649, "Reactor Oversight
Process," Revision 4, dated December 2006. NRC Identified
and Self-Revealing
Findings Cornerstones:
Mitigating
Systems Preliminary
White: A self-revealing
apparent violation (A V) of 10 CFR 50, Appendix B, Criterion
XVI, uCorrective
Actions," was identified
for the failure to preclude recurrence
of a signIficant
condition
adverse to quality (SCAQ) associated
with the Turbine Driven Auxiliary
Feedwater (TDAFW) pump governor control valve. Specifically, after identifying
corrosion
of the govemor control valve stem in April 2005, Ginna did not take adequate corrective
actions to preclude the recurrence
of corrosion
which led to the binding of the gave mar control valve and failure of the TDAFW pump on July 2,2009. In addition, the inspectors
concluded
that governor control valve stem binding was the likely cause of the failure of the TDAFW pump on May 26,2009. The overspeed
trip of the TDAFW pump on May 26. 2009. was originally
determined
by Ginna to be failure of the governor control system relay valve. Governor control valve stem corrosion
is a SCAQ because corrosion
of the stem can IHad to governor control valve stem binding and failure of the TDAFW pump as discussed
in NRC Information
Notice (IN) 94-66: "Overspeed
of Turbine-Driven
Pumps Caused by Governor Valve Stem Binding" and other related industry operating
experience
documents.
Immediate
corrective
actions inCluded entering this condition
in the corrective
action program (CAP). conducting
a root cause analysis (RCA). replacing
the governor control valve stem, and conducting
weekly monitoring
of the governor control valve during surveillance
testing to identify any potential
for stem binding. In addition, corrective
actions included a follow-up
inspection
of the governor control valve during the fall 2009 refueling
outage. Ginna will continue to monitor the govemor control valve under an enhanced TDAFW surveillance
program to ensure TDAFW pump operability.
The finding is more than minor because it is associated
with the equipment
performance
attribute
of the Mitigating
System cornerstone
and affects the cornerstone
objective
to ensure the availability, reliability, and capability
of systems that respond to initiating
events to prevent undesirable
consequences.
Specifically.
stem corrosion
caused binding of the governor control valve and led to the failure of the TDAFW pump. This finding was assessed using IMC 0609 and preliminarily
determined
to be White (lOW to moderate safety significance)
based on a Phase 3 analysis with a total (internal
and Enclosure
external contributions)
calculated
conditional
core damage frequency (CCDF) of B.6E-6. This finding has a cross-cutting
aspect in the area of Problem Identification
and Resolution, Corrective
Action Program, because Ginna did not implement
a corrective
action program with a low threshold
for identifying
issues completely, accurately, and in a timely manner commensurate
with their safety significance
P.1(a} per IMC 0305]. Specifically, Ginna did not identify issues
with corrosion
of the governor control valve within the corrective
action program. (Section 2.1.1) Green: A self-revealing
non-cited
violation (NCV) of 10 CFR 50, Appendix B, Criterion
XVI, "Corrective
Actions," was identified
for the failure to establish
adequate measures to correct a longstanding
issue associated
with steam admission
valves leakage. As a result, the leakage most likely contributed
to the build-up of corrosion
on the TDAFW pump governor control valve stem and contributed
to the failure of the TDAFW pump on May 26, 2009, and on July 2, 2009. The steam admission
valves had been leaking since at least 2005. However, G.inna did not take adequate measures to correct the leakage or minimize the impact of the leakage on governor control valve performance.
Immediate
corrective
actions included entering this condition
in the corrective
action program, conducting
a root cause analysis, replacing
the governor control valve stem, and conducting
weekly monitoring
of the governor control valve during surveillance
testing to identify any potential
for stem binding. Additionally, the steam admission
valves were inspected
and re-worked
and the governor control valve was inspected
during the fall 2009 outage. Ginna will continue to monitor the governor control valve under an enhanced TDAFW surveillance
program to ensure TDAFW pump operability.
Planned corrective
actions include
the steam admission
valves in May 2011. The finding is more than minor because it is associated
with the equipment
performance
attribute
of the Mitigating
Systems cornerstone
and affects the cornerstone
objective
to ensure the availability
and reliability
of systems that respond to initiating
events to prevent undesirable
consequences.
Specifically, leakage through the steam admission
valves can result in continuous
wetting of the governor control valve stem and lead to or accelerate
corrosion
of the governor control valve. This could result in a stem binding of the governor control valve and failure of the TDAFW pump. The inspectors
evaluated
the signifiCance
of this finding using IMC 0609, Attachment
4, "'Phase 1 -Initial Screening
and Characterization
of Findings." The finding is of very low safety significance
because it is not a design or qualification
deficiency, did not represent
a loss of a safety function of a system or a single train greater than its technical
speCification (TS) allowed outage time, and did not screen as potentially
risk Significant
due to external events. This finding has a cross-cutting
aspect in the area of Problem Identification
and Resolution, Corrective
Action Program, because Ginna did not thoroughly
evaluate problems such that the resolutions
address causes and extent of conditions, as necessary, In a timely manner, commensurate
with their significance
[P.1 (c) per IMC 0305]. Specifically, Ginna did not thoroughly
evaluate the potential
effect of the steam admission
valve leakage on the governor control valve performance. (Section 2.1.2) Green: The inspectors
identified
an NCVof 10 CFR 50, Appendix B. Criterion
III, "Design Control," for the failure to establish
measures to ensure that a modification
performed
on the governor control valve bushing was a suitable application
of materials
for the TDAFW pump. During a review of the RCA associated
with the TDAFW pump failures, the inspectors
noted that Ginna did not consider the potential
impact of Enclosure
removing some of the hardened layer of the bushing on the corrosion
rate of the governor control valve. Following
concerns raised by the inspectors, Ginna inspected
the governor control valve bushing during the fall 2009 refueling
outage and observed corrosion
of the bushings.
Ginna noted that the corrosion
of the bushings appeared to have been caused by the lapping of the bushing to achieve the increased
clearance
between the stem and the bushings.
Immediate
corrective
actions following
the inspection
of the governor control valve during the fall 2009 refueling
outage included entering this condition
in the CAP and refurbishing
the governor control valve with a new stem and bushing. The finding is more than minor because it is associated
with the equipment
performance
attribute
of the Mitigating
System cornerstone
and affects the cornerstone
objective
to ensure the availability, reliability, and capability
of systems that respond to initiating
events to prevent undesirable
consequences.
Specifically, lapping of the valve bushing resulted in an unanticipated
corrosion
mechanism
of the govemor control valve that impacted the reliability
of the TDAFW pump" The inspectors
evaluated
the significance
of this finding using IMC 0609, Attachment
4. "Phase 1 Initial Screening
and Characterization
of Findings." The finding is of very low safety significance
because it is a design or qualification
deficiency confirmed not
to result in the loss of operability
or functionality.
The inspectors
determined
that this finding has a cross-cutting
aspect in the area of Human Performance, Decision Making. because Ginna did not make a safety-significant
or risk-significant
decision using a systematic
process, especially
when faced with uncertain
or unexpected
plant conditions, to ensure safety was maintained
H.1(a) per IMC 0305]. Specifically, Ginna did not use a systematic
process such as an engineering
evaluation
to properly evaluate the potential
impact of removing some of the hardened layer of the bushing. [H.1 (a) per IMC 0305] (Section 2.3) Licensee Identified
Violations
None Enclosure
REPORT DETAILS 1. INTRODUCTION
1.1 Background
and Event Description
On May 26, 2009, and July 2, 2009, the TDAFW pump tripped on overspeed
during the performance
of surveillance
testing activities.
These were the second and third times the TDAFW pump had failed a surveillance
test in a six month period. The previous test failure occurred on December 2, 2008, when the TDAFW pump failed to develop acceptable
discharge
pressure during a quarterly
surveillance
test. Details surrounding
the December test failure including
Ginna corrective
actions are discussed
in NRC Integrated
Inspection
Report 50-244/2009002.
Following
each of the three test failures, Ginna declared the TDAFW pump inoperable
and entered the limiting Condition
for Operation
for TS 3.7.5 "Auxiliary
Feedwater." Following
the May 26, 2009, test failure, Ginna troubleshooting
activities
were focused on the TDAFW lubricating
oil system where system pressure oscillations
were noted by test personnel
prior to the pump overspeed
trip. As part of the troubleshooting
efforts, the TDAFW lubricating
oil system was drained and refilled with fresh oil, filters in the lubrication
system were examined and replaced, and several components
in the lubricating
oil system including
the relay and pressure regulating
valves were replaced.
Additionally
the turbine governor linkage was adjusted to original specifications
outlined in the vendor technical
documents.
Although several out of speCification
and missing components
were identified
during this troubleshooting
effort, a definitive
cause for the surveillance
failure was not identified.
Nevertheless, following
the successful
completion
of post maintenance
testing activities, Ginna declared the TDAFW pump operable and commenced
an augmented
surveillance
testing program for the TDAFW pump that tested the pump on a weekly basis. On July 2, 2009, another TDAFW pump overspeed
failure occurred when the pump was undergoing
the augmented
testing program. Troubleshooting
activities
following
this failure were focused on the turbine control system, which did not appear to have functioned
properly during the test. Accordingly, the turbine control and relay valves were disassembled
and inspected, and the governor linkage system was adjusted.
Additionally.
the lubricating
oil system was flushed and examined for particulates.
However, unlike the May 26 failure, these troubleshooting
activities
identified
a definitive
cause, a stuck governor control valve stem, that resulted in the surveillance
test failure. Visual inspection
of the stem, which had become bound to its bushing and had to be forcibly removed, revealed corrosion
buildup where the stem contacted
the upper valve bushing. To restore the control valve to an operable status, Ginna replaced the valve stem and increased
the bushing clearances
to dimensions
specified
by the Ginna TDAFW pump inspection
procedure.
The pump was successfully
tested and declared operable subject to an augmented
testing program. Ginna assigned an RCA team to investigate
the surveillance
test failures.
The Ginna RCA team concluded
that the primary root cause of the failure of the governor contrOl valve to control turbine speed on July 2,2009, was binding caused by a corrosion
mechanism
that occurred between the valve stem and the valve bushings.
The RCA team also concluded
that stem binding appeared to be an intermittent
problem and that Enclosure
station members missed opportunities
to identify the failure mode during previous surveillances
and failures.
As such, the RCA team determined
that governor control valve stem binding could not be ruled out as a possible failure mode during the December 2008 and the May 2009 TDAFW pump failures.
At Ginna's request, an independent
vendor reviewed the issues associated
with the governor control valve stem binding to determine
the failure mechanism
that was the cause of the TDAFW pump overspeed
trips. The vendor determined
that the most likely cause of the corrosion
of the governor control valve stem was fresh-water
corrosion (Langelier
corrosion)
that was the result of galvanic interactions
between the nitrided case and the base material of the governor control valve stem. The vendor considered
several variables
that contributed
to the corrosion
mechanism
such as material composition
of the stem and bushing, stem-to-bushing
clearance, steam admission
valve leakage, and TDAFW pump surveillance
frequency
and duration.
1.2 Special Inspection
Scope The NRC conducted
this inspection
to gain a better understanding
of the circumstances
involving
trips during surveillance
testing on May 26, 2009, and on July 2,2009. The inspection
team used NRC Inspection
Procedure
93812, "Special Inspection," as a guide to complete their review. Additional
inspection
and review activities
were outlined in the special inspection
team charter, provided as Attachment
B. The special inspection
team reviewed procedures, corrective
action documents, work orders, engineering
analyses, and the root cause evaluation
prepared by Ginna. In addition.
the team conducted
equipment
walkdowns
and interviewed
key plant personnel
regarding
the discovery
and resolution
of the condition.
A list of site personnel
interviewed
and documents
reviewed are provided in Attachment
A to this report. 1.3 Preliminary
Conditional
Risk Assessment
Using IMC 0309, "Reactive
Inspection
Decision Basis for Reactors," IMe 0609, "Significance
Determination
Process," and the Ginna Standardized
Plant Analysis Risk (SPAR) model in conjunction
with the Graphical
Evaluation
Module (GEM). the Region I Senior Reactor Analyst (SRA) evaluated
the increase in conditional
core damage probability
for the failure of the TDAFW pump. Based on the nature of the failure and the subsequent
trip on an instrumented
diagnostic
run, the condition
was evaluated
as being non-recoverable
in the event of actual demand. Based upon best available
information, an incremental
conditional
core damage probability (ICCDP) in the upper E-6 range (8E-6 per the 82 day exposure period), was calculated.
The exposure period was based on the assumption
that the TDAFW pump would not have started since the last time it passed a surveillance
test on March 5 until May 26 (82 days). The dominant core damage sequence was a station blackout (loss of offsite power (LOOP) with failure of both emergency
diesel generators (EDGs), with no TOAFW and failure to recover offsite power or an EDG in one hour. Based upon this conservative
conditional
core damage probability (CCDP) value, and having satisfied
an IMC 0309 deterministic
criterion, the May 26 degraded TDAFW pump Enclosure
condition
fell within the Special Inspection
to Augmented
Inspection
Team range for reactive inspections.
2. SPECIAL INSPECl"ION
AREAS 2.1 Review of Maintenance
a. Inspection
Scope The team evaluated
the adequacy and completeness
of the maintenance
on the TDAFW system, including
preventive
maintenance, procedural
guidance, post-maintenance
testing, and supervisory
oversight.
The team independently
evaluated
selected procedures, preventive
maintenance
strategies.
condition
reports (CRs). system health reports. and associated
work orders. In addition, the team reviewed the RCA, conducted
equipment
walkdowns
and interviewed
key station personnel.
For the weaknesses
identified, the inspectors
verified that appropriate
corrective
actions have been planned or taken. b. Findings and Observations
1. Failure to Preclude Recurrence
of a Significant
Condition
Adverse to Quality Introduction:
A self-revealing
AV of 10 CFR 50, Appendix S, Criterion
XVI, "Corrective
Actions," was identified
for the failure to preclude recurrence
of a SCAQ associated
with the TDAFW pump governor control valve. Specifically, after identifying
corrosion
of the governor control valve stem in April 2005, Ginna did not take adequate corrective
actions to preclude the recurrence
of corrosion
which led to the binding of the governor control valve and failure of the TDAFW pump on July 2, 2009. In addition, governor control valve stem binding was a fikely failure of the May 26, 2009, TDAFW pump overspeed
trip. This finding was preliminarily
determined
to be White. Description:
On April 11, 2005, Glnna conducted
a periodic major inspection
of the TDAFW pump governor control valve under work order #20401907.
During the disassembly
of the valve, mechanics
noted corrosion
in the bushing area of the stem plug. The vendor recommended
replacing
the valve stem and plug due to the corrosion.
However, Ginna did not recognize
stem corrosion
as a condition
adverse to quality and did not initiate a CR in accordance
with station guidance in IP-CAP-1 r "Condition
Reporting." As a result, Ginna did not conduct any further analysis or evaluation
to determine
the cause of the corrosion.
On July 2, 2009, during surveillance
testing, the TDAFW pump tripped due to overspeed. Ginna
formed an Issue Response Team and developed
a comprehensive
troubleshooting
plan to determine
the cause(s) of the failure. The troubleshooting
plan consisted
of all possible failure modes, possible causes of each failure mode, and actions to validate or refute each "failure mode. Upon disassembly
of the governor control valve, the stem was found seized within its bushings and had to be forcibly removed. Visual inspection
showed pitting on the surface of the stem Where it contacted
the upper valve bushing. Following
completion
of the troubleshooting
activities, Ginnaconcluded
that TDAFW pump failure was due to binding of the governor control valve and that the binding was caused by the build up of corrosion
on the valve stem. Enclosure
Governor control valve stem corrosion
is an SCAQ because corrosion
of the stem can lead to govemor control valve stem binding and failure of the TDAFW pump as discussed
of Turbine-Driven
Pumps caused by Governor Valve Stem Binding," and other related industry operating
experience
documents.
Immediate
corrective
actions included entering this condition
in the CAP, conducting
an RCA, replacing
the governor control valve stem, and conducting
weekly monitoring
of the governor control valve during surveillance
testing to identify any potential
for stem binding. In addition, corrective
actions included a follow-up
inspection
of the governor control valve during the fall 2009 refueling
outage. Because additional
corrosion
was found during this inspection
on September
18, 2009, the control valve was sent to the vendor to be refurbished.
Ginna will continue to monitor the governor control valve under an enhanced TDAFW surveillance
program to ensure TDAFW pump operability.
Ginna also was evaluating
longer term corrective
actions to address the corrosion
including
more frequent governor control valve stem replacement, change of the stem material, and other modifications
to the system design. Planned corrective
actions include replacing
the stem admission
valves in May 2011. The inspectors
noted that governor control valve stem binding also could have been a contributor
to the December 2, 2008, TDAFW pump failure to develop the minimum acceptable
discharge
flow and pressure, and the likely cause of the May 26, 2009, TDAFW pump overspeed
trip. Following
these events, Ginna missed opportunities
to identify potential
stem binding problems after identifying
possible indicators
of this failure mode such as leaking steam admission
valves and rust/corrosion
on the visible portion of the governor valve stem. In addition, during troubleshooting
efforts in May 2009, . Ginna missed an opportunity
to exercise the governor control valve stem with the linkage disconnected
and lube oil pressure not applied. Operating
experience
suggested
that cycling the valve by hand without hydraulics
applied is a prudent action to validate or refute governor control valve stem binding. Analysis:
The performance
deficiency
is that Ginna did not take adequate measures to correct a condition
that had the potential
to impact the operability
of the TDAFW pump. Specifically, after identifying
corrosion
on the governor control valve stem in 2005, Ginna did not take adequate corrective
actions to preclude the recurrence
of corrosion
which led to the binding of the governor control valve and failure of the TDAFW pump. The finding is more than minor because it is associated
with the equipment
performance
attribute
of the Mitigating
System cornerstone
and affects the cornerstone
objective
to ensure the availability, reliability, and capability
of systems that respond to initiating
events to prevent undesirable
consequences.
Specifically, stem corrosion
caused binding of the governor control valve and led to the failure of the TDAFW pump. In accordance
with IMe 0609, Attachment
4, "Phase 1 -Initial Screening
and Characterization
of Findings," a Phase 2 risk analysis was required because the finding represents
an actual loss of safety function of a single train for greater than the TS allowed outage time of 7 days. The Phase 2 risk evaluation
was performed
in accordance
with IMC 0609, Appendix A, Attachment
1, "User Guidance for Phase 2 and Phase 3 Reactor Inspection
Findings for At*,power
Situations." Because the precise time is unknown for the inception
of TDAFW pump inoperability, an exposure time of one-half of the time period (t/2) between discovery (May 26, 2009) to the last successfully
completed
quarterly
surveHlance
test (March 5, 2009) was used. This t/2 exposure time Enclosure
9 equals 51 days. Using Ginna's Phase 2 SDP notebook, pre-solved
worksheets, and an initiating
event likelihood
of 1 year (>30-days
exposure time), the inspector
identified
that this finding is of potentially
substantial
safety significance (Yellow).
The dominant sequence identified
in the Phase 2 notebook involves a loss of offsite power (LOOP), failure of both EDGs, and the subsequent
loss of the TDAFW pump, with the failure of operators
to restore offsite power within 1 hour: LOOP (2) + EAC (3) + TDAFW (0) + REC1 (0) = 5 (Yellow).
In recognition
that the Phase 2 notebook typically
yields a conservative result, a
NRC Region I Senior Reactor Analyst (SRA) performed
a Phase 3 risk assessment
of this finding. The SRA used Ginna's Standardized
Plant Analysis Risk (SPAR) model, Revision 3.45, dated June 2008. and graphical
evaluation
module, in conjunction
with the System Analysis Programs for Hands-On Integrated
Reliability
Evaluations (SAPHIRE).
Version 7, to estimate the internal risk contribution
of the Phase 3 risk assessment.
The following
assumptions
were used for this assessment: Based on the guidance provided in the Risk Assessment
of Operational
Events Handbook, Revision 1.01, the calculated
exposure was determined
to be 1198 hrs. The summation
of this exposeure
time was determined
as follows: One half the exposure time, (tI2), was applied for the period between March 5 -May 26, 2009 The full exposure time, (t). was applied for the unavailability
and troubleshooting
from May 26 -May 29, 2009. One half the exposure time. (tI2), was applied for the period between June 25 -July 2, 2009 The full exposure time, (t), was applied for the unavailability
and troubleshooting
from July 2 -July 5, 2009 To closely approximate
the type of f*lilure exhibited
by the TDAFW pump, the fail to start basic event <AFW-TDP-FS-TDP>
was changed from its baseline failure probability
to 1.0, representing
a 100 percent failure to start condition. Based on the nature of the failure. and no recovery procedures
in place, there was no recovery credit assigned to the May failure. The loss of service water initiating
event frequency (IE-LOSWS)
was increased
from its nominal value of 4.0E-4 to 2.0E*3 to more closely model the risk of a LOSWS at the Ginna station. This is consistent
with Ginna's understanding
of the risk of this event. All remaining
events were left at their nominal failure probabilities. The model was modified by Idaho National Laboratory (INL) to include convolution
correction
factors. Convolving
the failure distribution
eliminates
the simplifying
assumption
that all failure to run events happen at time=O. Inclusion
of this correction
can reduce station blackout (SBO) core damage frequency (CDF) significantly
for plants like Ginna that have low EDG redundancy. Since all observed failures happened upon the initiation
of the TDAFW system, the period between May 29 and June 25 2009, was not included in the exposure period because the system successfully
completed
increased, weekly, surveillance
testing. The team could not conclude that the stem binding condition
would occur after the pump had been successfully
started and run. Cutset probability
calculation
truncation
was set at 1 E-13. Enclosure
Based upon the above assumptions, the Ginna SPAR model calculated
an increase in internal event contribution
to conditional
core damage probability (CCDP) of 2.9E-6. This low-ta-mid
E-6 delta CCDP value represents
a low to moderate safety significance (White). The dominant internal event sequence involved a LOOP with subsequent
failure of the EDGs (station blackout event), the failure of the TDAFW train and the failure to recover AC power. The Phase 3 SPAR model results correlate
well to the Phase 2 SDP Notebook dominant core damage sequences.
External Events Risk Contribution
The Ginna Probablistic
Safety Assessment (PSA) includes a Level 1 analysis of fires and flooding external events. The PSA summarizes
the fire contribution
as representing
approximately
48% of the total (internal
and external)
core damage frequency, or nearly half of the annualized
risk. The NRC does not have an external event risk model for Ginna. Consequently, the SRA, after review of the licensee's
Individual
Plant Examination
of External Events (IPEEE), utilized the licensee's
external events assessment
to quantify the fire and flooding events risk contribution
for this condition.
Seismic event likelihood
was considered
to be very low and determined
not to be a significant
contributor
to the risk of this condition.
The results of the PSA for this condition
calculated
a CCDP contribution
from fire events at 5E-6 and from flooding at 7E-7. The most significant
fire initiated
core damage sequence involved a spectrum of control room fires, with a failure of automatic
and manual suppression, a failure of the TDAFW pump and a failure of the 'C' standby auxiliary
feed water pump for decay heat removal via the steam generators.
The most Significant
flooding core damage sequence quantified
in the PSA for this condition, Involved flooding in the relay room, failure of the TDAFW pump and a failure to align standby auxiliary
feed water pump for decay heat removal via the steam generators.
Large Early Release Frequency (LERF) Evaluation
The SRA used IMC 0609, Appendix H, "Containment
Integrity
Significance
Determination
Process," to determine
if this finding was a significant
contributor
to a large early release. The Ginna containment
is classified
as a pressurized
water reactor large-dry
containment
deSign. Based upon the dominant sequences
involving
LOOP and station blackout (S80) initiating
events, per Appendix H, Table 5.2, "Phase 2 Assessment
Factors -Type A Findings at Full Power," the failure of the TDAFW pump does not represent
a significant
challenge
to containment
integrity
early in the postUlated
core damage sequences.
Consequently, this finding does not screen as a significant
large early release contributor
because the close-in populations
can be effectively
evacuated
far in advance of any postulated
release due to core damage, Accordingly, the risk significance
of this finding is associated
with the delta CDF value, per IMC 0609, Appendix H, Figure 5.1, and not delta LERF. Risk Assessment
Summary The calculated
total risk significance
of this finding is based upon the summation
of internal and external risk contributions (delta CCDP internal + delta CCDP external (fires and floods).=
delta CCDP total). 2.9E-6 + 5E-6 + 7E-7 = 8.6E-6 delta ceDP. Enclosure
Annualized, this value of 8.6E-6 delta CDF represents
a low to moderate safety significance
or White finding. Licensee's
Risk Assessment
Summary Constellation's
risk assessment
for the given condition, assuming no operator recovery, resulted in a total delta CDF value of 1.028E-5.
This increase in CDF value comprised
of: 4.6E-6 due to intemal events; 0.7E-6 due to intemal flooding events; and 5E-6 fire/external
events. Similar to the NRC internal risk contribution, the largest percentage
of intemal risk was derived from station blackout events. The licensee conducted
refinements
in their modeling to credit additional
recovery options in the event that the TDAFW pump failed. By crediting
these recovery actions, the delta CDF was reduced from 1.028E-5 to 9.2 E-6, or by approximately
10%. The specific recovery actions are as follows: . The potential
for operators
to use standby auxiliary
feedwater (SAFW) pump C, in lieu of the TDAFW pump during fire and flood scenarios
which require use of alternate
shutdown procedures
was modeled. Although use of an SAFW pump is not specifically
called out in these procedures, the procedures
do explicitly
recognize
that if the TDAFW pump is not functioning, a loss of secondary
heat sink will result, and direct operators
to refer to other emergency procedures
for alternate
methods of establishing
a heat sink (see ER-FIRE.1
step 4.3.4.2, FIRE.2 step 4.3.12, etc.}. In response to this hypothetical
scenario, an operations
Shift Manager (SM) indicated
that upon a failure of the TDAFW to provide flow, a SAFW pump could be manually started by locally opening the service water suction valve to the pump and locally closing the breaker to the pump motor. The steps necessary
to align an SAFW pump to the steam generators (SG) are contained
in emergency
operating
procedures (EOP) Attachment
5.1 'Attachment
SAFW'. Since only Busses 14 and 18 are energized
during ER-FIRE scenarios, SAFW pump C would be used. Following
the May 26th overs peed trip of the TDAFW pump, new section 2.2 was added to procedure
P-15.6, 'Operation
of the TDAFW Pump Trip Throttle Valve.' Revision 00200. This step provides instructions
for a 'slow start' of the TDAFW pump manually, following
an overspeed
trip of the pump, by using the trip throttle valve. This allows for starting of the pump even if the governor control valve is stuck in the full open position following
the overspeed
trip. This procedure
step was successfully
used following
both the May 26th failure and the July 2nd failure. Per Operations
management, the shift managers, who would be directing
use of this procedure, were briefed on the updated procedure
to ensure they were aware that new step was available
for use and understood
how it was to be performed.
A controlled
copy of the procedure
is located at the TDAFW pump for use by the operator.
Since this procedure
was in effect prior to the July failure exposure period (Le., prior to the last successful
TDAFW pump test on June 25, 2009), it is considered
as a recovery for failures of the TDAFW pump. Recovery actions identified
in #1 above were not quantified
by the team however the evaluation
approach appears to be appropriate.
Prior to the licensee crediting
recovery actions identified
in #2 above, the team was able to verify that the procedures
were in Enclosure
place and observed troubleshooting
video in which the licensee started the TDAFW pump with this method. As a result the SRA concluded
that the licensee's
modeling demonstrating
a risk reduction
was appropriate.
Based upon the close comparison
between NRC and Constellation
risk estimates, no sensitivity
analyses were warranted.
The use of V2 to approximate
the exposure time was determined
to be appropriate
for standby or periodically
operated components
that fail due to a degradation
mechanism
that gradually
affects the component
during the standby time period. Inclusion
of the unavailability
time hours, due to troubleshooting
and repairs, is also appropriate
and consistent
with the guidance promulgated
in Risk Assessment
of Operational
Events Handbook, Revision 1.01, dated January 2008. This finding has a cross-cutting
aspect in the area of Problem Identification
and Resolution, Corrective Action Program, because Ginna did not implement
a corrective
action program with a low threshold
for identifying
issues completely, accurately, and in a timely manner commensurate
with their safety
significance.
Specifically, Ginna did not identify issues associated
with corrosion
of the governor control valve within the corrective
actions program. The inspectors
concluded
that the performance
deficiency
is reflective
of current performance
because Ginna had reasonable
opportunities
to identify the issue during troubleshooting
in December 2008 and May 2009. P.1(a) per IMC 0305] Enforcement:
10 CFR 50, Appendix B, Criterion
XVI, "Corrective
Actions," states, in part, "Measures
shall be established
to assure that conditions
adverse to quality, such as failures, malfunctions, defiCiencies, deviations, defective
material and eqUipment, and nonconformances
are promptly identified
and corrected.
In the case of significant
conditions
adverse to quality, the measures shall assure that the cause of the condition
is determined
and corrective
action taken to preclude repetition." Contrary to the above, after identifying
corrosion
on the TDAFW pump governor control valve stem on April 11, 2005, which is a significant
condition
adverse to quality, Ginna did not take adequate measures to determine
the cause and prevent recurrence.
The cause of the condition
was left uncorrected
and resulted in additional
stem corrosion
that led to binding of the governor control valve and the failure of the TDAFW pump on July 2, 2009. In addition, stem corrosion
was the likely cause of the TDAFW pump failure on May 26, 2009. This issue was entered into Ginna's CAP as CR-:2009-003680
and CR-2009-004577.
Pending final determination
of significance, this finding is identified
as an AV. (AV 0500024412009008*01:
Inadequate
Corrective
Actions Associated
with the TDAFW Pump Governor Control Valve) 2. Untimely Corrective
Actions Associated
with Steam Admission
Valves Introduction:
A self-revealing
NeVof 10 CFR 50, Appendix B, Criterion
XVI, "Corrective
Actions," was identified
for the failure to establish
adequate measures to correct a longstanding
issue associated
with steam a(]mission
valves leakage. As a result, the leakage most likely contributed
to the build-up of corrosion
on the TDAFW pump governor control valve stem on May 26, 2009 and contributed
to the failure of the TDAFW pump on July 2, 2009. Description:
During a review of failures associated
with the TDAFW pump, the inspectors
noted that the steam admission
valves had a history of leaking. Based on a review of the RCA report, industry operating
experience, and associated
CRs, the Enclosure
inspectors
determined
that the steam admission
valve leakage was a contributing
factor in the development
of corrosion
of the governor control valve and contributed
to the failure of the TDAFW pump on July 2, 2009, and most likely the failure of the TDAFW pump overspeed
trip failure on May 26, 2009. Based on a review of eRs and interviews
of personnel, the inspectors
determined
that the steam admission
valves had been leaking since at least 2005. In July 2005,
documented
that steam admission
valve 3505A was leaking past its seat. However, Ginna did not take or plan any corrective
actions associated
with the issue. By October 2006, steam admission
valve 3505A leakage had increased
such that the TDAFW pump turbine was rotating approximately
100 rpm. Ginna cycled the valve to reduce seat leakage, generated
a work order to repair the valve in May 2008, and conducted
an evaluation
of past operability.
Ginna concluded
that there was no potential
for increased
consequences
with time if the condition
continued.
During the May 2008 refueling
outage, Ginna conducted
a repair of steam admission
valve 3505A. However, this corrective
action was not effective;
by September
2008, the valve was leaking again although at a reduced rate. The inspectors
determined
that Ginna did not recognize
or consider the potential
impact of the steam admission
valve leakage on the governor control valve stem. Immediate
corrective
actions included entering this condition
in the CAP, replacing
the govemor control valve stem, and conducting
weekly monitOring
of the governor control valve during surveillance
to identify any potential
for stem binding. Additionally, the steam admission
valves were inspected
and re-worked
and the govemor control valve was Inspected
during the fall 2009 outage. Ginna will continue to monitor the governor control valve under an enhanced TDAFW surveillance
program to ensure TDAFW pump operability.
Planned corrective
actions include replacing
the stem admission
valves in May 2011. Analysis:
The performance
deficiency
is that Ginna did not adequately
address deficiencies
associated
with steam admission
valve leakage in that the leakage likely resulted in accelerated
corrosion
of the governor control valve and contributed
to the failure of the TDAFW pump. The finding is more than minor because it is associated
with the equipment
performance
attribute
of the Mitigating
Systems cornerstone
and affects the cornerstone
objective
to ensure the availability
and reliability
of systems that respond to initiating
events to prevent undesirable
consequences.
Specifically, leakage through the steam admission
valves can res.ult in continuous
wetting of the governor control valve stem and lead to or accelerate
corrosion
of the governor control valve. This could result in a stem binding of the govemor control valve and failure of the TDAFW pump. The inspectors
evaluated
the significance
of this finding using IMC 0609, Attachment
4, "Phase 1 -Initial Screening
and Characterization
of Findings." The finding is of very low safety significance
because it is not a design or qualification
deficiency, did not represent
a loss of a safety function of a system or a single train greater than its TS allowed outage time, and did not screen as potentially
risk Significant
due to external events. The inspectors
determined
that the steam admission
valve leakage was not a direct cause of the failure of the TDAFW pump overspeed
events. The steam admission
valve leakage was a contributing
factor in the development
of governor control valve stem corrosion
and contributed
to the failure of the TDAFW pump. Enclosure
This finding has a cross-cutting
aspect in the area of Problem Identification Resolution, Corrective
Action Program, because Ginna did not thoroughly
problems such that the resolutions
address causes and extent of conditions, r:eecessary, in a timely manner, commensurate
with their significance.
Ginna did not thoroughly
evaluate the potential
effect of the steam admission leakage on the governor control valve performance.
The inspectors
determined
that issue is reflective
of current licensee performance
because each time the issue identified
and a CR was generated
represented
an opportunity
for Ginna to
evaluate the issue and assign appropriate
corrective
actions. [P.1 (c) per IMC Enforcement:
10 CFR Part 50, Appendix B, Criterion
XVI, "Corrective
Actions," states, in part. "Measures
shall be established
to assure that conditions
adverse to quality, such as failures, malfunctions, deficiencies, deviations, defective
material and equipment, and nonconformances
are promptly identified
and corrected." Contrary to this requirement, from at least July 2005 to July 2, 2009, Ginna did not established
adequate measures to correct longstanding
steam admission
valves leakage and/or minimize the impact of the leakage on the TDAFW pump governor control valve performance.
As a result, leakage I*I through the steam admission
valves contributed
to the corrosion
of the governor valve and contributed
to the failure of the TDAFW pump on July 2, 2009 and most the failure of the TDAFW pump on May 26, 2009. Because this violation
is of very safety significance (Green) and Ginna entered this issue into their CAP for resolution CR-2009-003680
and CR-2009-004577, this violation
is being treated as an consistent
with the NRC Enforcement
Policy. (NCV 0500024412009008-02:
Corrective
Actions Associated
with Stearn Admission
Valve
2.2 Review of Operating
Experience
a. Inspection
ScoQe The team reviewed operating
experience
involving
TDAFW pump failures and taken by the Ginna staff to identify and address these types of failures.
In addition, team examined the specific issues associated
with governor control valve stem to assess any new generic issues of industry interest for prompt communication dissemination.
As part of this evaluation, the inspectors
reviewed pertinent
operating
experience, Ginna's response to NRC Information
Notices, and
key plant
b. Findings and Observations
No Findings of Significance
Identified.
The inspectors
determined
that there were no new generic issues identified
as a result of this event. However, the inspectors
noted that Ginna missed opportunities
to utilize industry operating
experience
to identify precursors
associated
with this event and to conduct effective
troubleshooting.
Specifically, following
the discovery
of corrosion
on the exposed portion of the TDAFW pump govemor control valve stem in May 2005, Ginna did not enter this issue in to their CAP. As a result Ginna missed an opportunity
to revisit operating
experience
from NRC IN 94-66 conceming
governor control valve stem binding. In several examples in NRC IN 94-66, sites that experienced
governor control valves stem binding identified
stem corrosion
following
valve disassembly.
Ginna Enclosure
had originally
determined
that NRC IN 94-66 was not applicable
to Ginna because the governor control valve was of a different
configuration
and material as those discussed
in the IN and that corrosion
of the stem had not been previously
identified.
Although this may have been a reasonable
assessment
during the original review of the NRC IN 94-66 in 1994, the inspectors
determined
that once corrosion
of the stem was identified
in'May 2005, Ginna missed an opportunity
to revisit this operating
experience.
In addition, as discussed
in Section 2.1.2 of this report. Ginna did not utilize Industry operating
experience
in evaluating
a condition
associated
with steam admission
valve leakage. NRC IN 94-66, other industry operating
experience, and the vendor technical
manual stated that steam admission
valve leakage is a cause related to governor control valve stem binding. However, Ginna did not consider the impact of steam admission
valve leakage on the governor control valve performance.
Finally, the inspectors
noted that Ginna missed opportunities
to incorporate
industry operating
experience
during troubleshooting
efforts during the May 2009 TDAFW pump failure. NRC IN 94-66 discussed
several examples where a freedom of motion test was performed
to test for stem binding with the governor control valve linkage disconnected
and hydraulics
not applied. However, during the May 2009 event, Ginna missed an opportunity
to conduct this test and consequently, missed an opportunity
to potentially
identify the failure mode prior to the July 2, 2009, overspeed
trip. Ginna captured these issues in their CAP under CR-2009-003680
and CR-2009-004577
.. 2.3 Review of Root Cause and Extent-ot-Condition
a. Inspection
Scope The team evaluated
the adequacy of Ginna's RCA and completed
interim corrective
actions. In addition the team evaluated
the adequacy of Ginna's initial extent of condition
for the TDAFW pump failures.
The team reviewed plant drawings, procedures, and associated
system modifications.
In addition, the team conducted
a walkdown of the TDAFW system and interviewed
key Ginna personnel.
b. Findings and Observations
Introduction:
The inspectors
identified
an NCV of 10 CFR 50, Appendix B, Criterion
III, "Design Control," for the failure to establish
measures to ensure that a modification
performed
on the governor control valve bushing was a suitable application
of materials
for the TDAFW pump. Description:
During the troubleshooting
and repair of the TDAFW pump in July 2009, Ginna incorrectly
evaluated
that a vendor service bulletin allowed for larger bushing clearance
than was prescribed
in their current technical
documents.
Since there was overlap between the station technical
information
and the vendor service bulletin, Ginna decided to increase the clearance, by lapping the bushings, to reduce the likelihood
that corrosion
products would cause the stem to bind. To increase the clearance, Ginna removed some of the hardened layer on the bushing. During a review of the RCA, the inspectors
determined
that Ginna did not consider the potential
impact of removing some ot the hardened layer on the corrosion
rate of the governor control valve. The inspectors
noted that by removing some of the hardened layer, the material property of the bushing could have been changed and/or additional
micro-cracks
could have been created or exposed that could increase the corrosion
rate or potentially
cause other Enclosure
problems such as
galling. The inspectors
noted that if the corrosion
rate is greater than predicted, then planned corrective
actions may not be adequate to maintain the TDAFW pump operable.
Additionally, the team was concerned, that by increasing
the stem to bushing clearances, the stem would be susceptible
to larger steam exposure and that this could further accelerate
the corrosion.
Following
concerns raised by the inspectors, Ginna initiated
CR-2009-005959
to ensure that all possible consequences
of lapping the TDAFW pump control valve bushing were fully evaluated.
In addition, Ginna assigned corrective
actions to inspect the control valve bushing during the fall 2009 refueling
outage. During performance
of the refueling
inspection
under WO C90623685, pitting of the stem and corrosion
of the bushings were observed.
Constellation
initiated
and noted that the corrosion
of the bushings appeared to have been caused by the lapping of the bushing to achieve the desired clearance
between the stem and the bushings.
The development
of corrosion
on the bushing reduced the margin that was predicted
to ensure adequate stem movement.
Immediate
corrective
actions following
the inspection
of the governor control valve during the fall 2009 refueling
outage included entering this condition
in the CAP and refurbishing
the governor control valve with a new stem and bushing. Analysis:
The performance
deficiency
is that Ginna failed to establish
measures to ensure that a modification
performed
on the governor control valve bushing was a suitable application
of materials
for the TDAFW pump. The finding is more than minor because it is associated
with the equipment
performance
attribute
of the Mitigating
Systems cornerstone
and affects the cornerstone
objective
to ensure the availability
and reliability
of systems that respond to initiating
events to prevent undesirable
consequences.
Specifically, lapping of the valve bushing resulted in an unanticipated
corrosion
mechanism
of the governor control valve that impacted the reliability
of the TDAFW pump. The inspectors
evaluated
the Significance
of this finding using IMC 0609, Attachment
4, "Phase 1 -Initial Screening
and Characterization
of Findings." The finding is of very low safety significance
because it is not a design or qualification
deficiency, did not represent
a loss of a safety fUnction of a system or a single train greater than its TS allowed outage time, and did not screen as potentially
risk significant
due to external events. The inspectors
determined
that this finding has a cross-cutting
aspect in the area of Human Performance, Decision Making, because Ginna did not make a safety-significant
or risk-significant
decision using a systematic
process, especially
when faced with uncertain
or unexpected
plant conditions, to ensure safety was maintained.
Specifically, Ginna did not use a systematic
process such as an engineering
evaluation
to properly evaluate the potential
impact of removing some of the hardened layer of the bushing. H.1(a) per IMC 0305] Enforcement: 10
CFR 50, Appendix B, Criterion
III, "Design Control" states, in part, "Measures
shall also be established
for the selection
and review for suitability
of application
of materials, parts, equipment, and processes
that are essential
to the related functions
of the structures, systems and components." Contrary to the requirements, in July 2009, Ginna failed to establish
measures to ensure that a modification
performed
on the governor control valve bushing was a suitable application
of materials
for the TDAFW pump. Specifically, lapping of the valve bushing resulted in an unanticipated
corrosion
mechanism
of the governor control valve that had the Enclosure
potential
to impact the performance
of the TDAFW pump if not corrected.
Because this violation
is of very low safety significance (Green) and Ginna entered this issue into their CAP for resolution
as CR-2009-006765, this violation
is being treated as an NCV consistent
with the NRC Enforcement
Policy. (NeV 05000244/2009008-03:
Failure To Establish
Design Control Measures Associated
With The Turbine Driven Auxiliary
Pump Governor Control Valve) 2.4 Risk Assessment
of the As-Found Condition
a. Insoection
Scope Prior to the initiation
of the Special Inspection
Team, the Region I SRA performed
a CCDP assessment
which conservatively
bounded the potential
risk significance
of the degraded condition, assuming the TDAFW pump would fail to star on demand to mitigate the consequences
of an event. The initial CCDP estimate was performed
in accordance
with IMC 0309, "Reactive
Inspection
Decision Basis for Reactors." The SRA used the Ginna SPAR model and associated
GEM to evaluate the potential
risk significance
of this condition.
The results of the IMC 0309 assessment
are documented
in report section 2.1.b.1 above. b. Final Risk Estimate Following
team review and independent
verification
of the degraded turbine driven auxiliary
feed water pump governor control valve, the team concluded
that for approximately
119B hours, the TDAFW pump would not have been capable
of responding
to an event. Consistent
with IMC 0609 conditional
core damage probability
assessment
methodology, this degraded condition
resulted in a loss of operability
or safety function, and therefore
was of low to moderate (B.6E-6) safety significance.
4. OTHER ACTIVITIeS
40A6 Meetings, Including
Exit On August 27 and on October 7,2009 the team presented
the inspection
results to Mr. John Carlin and other members of the R. E. Ginna Nuclear Power Plant staff. The inspectors
verified that none of the
during the inspection
is considered
proprietary
in nature. Enclosure
A-1 ATTACHMENT
A SUPPLEMENTAL
KEY POINTS OF Licensee personnel
J. Carlin, Site Vice President
E. Larson, Plant General Manager D. Crowley, Senior Engineer E. Durkish, Associate
Engineer R. Everett, Supervisor, Primary Systems Engineering
T. Harding, Director, Licensing
R. Ruby, Principal
Engineer, Licensing
P. Swift, Engineering
Manager LIST OF ITEMS OPENED, CLOSED, AND DISCUSSED
Opened 05000244/2009008-01
Opened/Closed 05000244/2009008-02
05000244/2009008-03 Failure to Preclude Recurrence
of a Significant
Condition
Adverse to Quality Associated
with the Turbine Driven Auxiliary
Pump Governor Control Valve. (Section 2.1.1) Inadequate
Corrective
Actions Associated
with Steam Admission
Valve Leakage. (Section 2.1.2) Failure to Establish
Design Control Measures Associated
with the Turbine Driven Auxiliary
Pump Governor Control Valve. (Section 2.3) I.IST OF DOCUMENTS
REVIEWED In addition to the documents
identified
in the body of this report, the inspectors
reviewed the following
documents
and records: Corrective
Actions CA-2009-002311
Condition
Reports CR-2003-2006
CR-2005-3660
CR-2006-006029
CR-2006-006341
CR-2005-1509
CR-2005-5513
CR-2006-006204
CR-2006-006962
Attachment
A
CR-2007 -000876 CR-2008-009911
CR-2009-004590
CR-2009-005959*
CR-2007-001302
CR-2009-003680
CR-2009-004591
CR-2009-006765*
CR-2008-003687
CR-2009-004222*
CR-2009-005964
CR-2008-007541
CR-2009-004577
- NRC Identified
During Inspection
Corrective
Action Tracking System CATS R007325 Procedures
AP-FVV.1, Abnormal MFW Pump Flow or NPSH, Revision 01702 PT-16QT-T, Auxiliary
Turbine Pump -Quarterly, Revision 05900 CNG-MN-1.01-1002, Troubleshooting, Revision 0001 CNG-CA-1.01 , Corrective
Action Program, Revision 0001 CNG-CA-1.01-1004, Root Cause Analysis, Revision 0001 CNG-CA-1.01-1005, Apparent Cause Evaluation, Revision 0100 CNG-CA-1.01-1006, Common Cause Analysis, Revision 0001 CNG-CA-1.01-1007, Trending, Revision 0000 CNG-CA-1.01-1010, Use of OE, Revision 0000 IP-CAP-1, Ginna Condition
Reporting, Revision 02800 M-11.5C, Auxiliary
Pump Motor Mechanical
Inspection
and Maintenance, Revision 03000 0-1.1, Plant Heatup From Cold Shutdown to Hot Shutdown, Revision 16301 PT-16Q-T, Auxiliary
Turbine Pump -Quarterly, Revision 05600. Completed
3/14/08,514108,5/5/08,6/11/08,9/4/08, 1213/08, 1214/08, 12111/08, 12/18/08,2/12/09, 5/26/09, 5/28/09 Surveillance
Tests PT-16Q-T, Auxiliary
Turbine Pump -Quarterly, Revision 05600, 03/14/2008
PT-16Q-T, Auxiliary
Turbine Pump -. Quarterly, Revision 05700, 05/04/2008
PT-16Q-T, Auxiliary
Turbine Pump _. Quarterly, Revision 05700,05/05/2008
PT-16Q-T, Auxiliary
Turbine Pump -Quarterly, Revision 05700. 06/11/2008
STP-0-16-COMP-T, Auxiliary
Turbine Pump -Comprehensive Test, Revision 00000, 06/11/2008
PT-16Q-T, Auxiliary
Turbine Pump -Quarterly.
Revision 05701, 09/03/2008
PT-16Q-T, Auxiliary
Turbine Pump -Quarterly, Revision 05701, 12/02/2008
PT-16Q-T, Auxiliary
FeedwaterTurbine
Pump -Quarterly.
Revision 05701,12103/2008
PT-16Q-T.
Auxiliary
Turbine Pump _. Quarterly, Revision 05701, 12/04/2008
PT-16Q-T, Auxiliary
Turbine Pump _. Quarterly, Revision 05702, 12/11/2008
PT-16Q-T, Auxiliary
Turbine Pump _. Quarterly, Revision 05702, 12/18/2008
PT-16Q-T, Auxiliary
Turbine Pump -Quarterly, Revision 05801, 01116/2009
PT -16Q-T, AUXiliary
Turbine Pump -Quarterly, Revision 05801, 02112/2009
PT-16Q-T, AUXiliary
Turbine Pump _. Quarterly.
Revision 05900,05/26/2009
PT-16Q-T, Auxiliary
Turbine Pump -Quarterly, Revision 05900,05/28/2009
STP-0-16-COMP-T, Auxiliary
Turbine Pump -Comprehensive
Test, Revision 00400, 05/28/2009
Attachment
A
Work Orders W020604989
W020401907
Drawings DWG No. 33013-1231, Main Steam System, Revision 37 DWG No. 33013-2285, Motor Driven and Turbine Driven Auxiliary
Pumps Lube Oil Skid, Revision 17 DWG No. LB-112541, Turbine Control and Quick Start System DWG No. T040-001A, TDAFW Control Oil System, Revision 0 DWG No. T040-002A, TDAFW Turbine Trip Valve, Revision 0 DWG No. T040-003A, Auxiliary
and Standby Aux. Feedwater
Systems, Revision 2 DWG No. T040-003B, SAFW System 1-Line Diagram, Revision 0 DWG No. T040-003C, AFW System 1-Une Diagram, Revision 1 DWG No. T040-004A, Auxiliary
Pump Auto Start Signals, Revision 0 DWG No. T830-004A, Blowdown Isolation
Solenoid Control Circuit, Revision 0 Other Documents
Vendor Report, Preliminary
Results of Stem Sticking Failure Mechanisms, July 20, 2009 Vendor Report 09-1929 Part 1, Equipment
Root Cause Analysis of AFWP Control Valve Stem Sticking Problem at Ginna Nuclear Power Station Vendor Technical
Question Response, August 26, 2009 Category I Root Causal Analysis, May and July 2009 Turbine Driven Auxiliary
Pump (TDAFWP) Failures;
Trip During Testing vrD-E9016-4001, Excerpts from EPRI Manual 1007461, Terry Turbine Maintenance
Guide, AFW Application, Revision 000 vrD-G0153-4001, Operating
Instructions
Easy Flow Body Combined Trip Throttle Valve, Revision 2 VrD-W0315-4001, Instructions
For 465 H.P. Non-Condensing
Steam Turbine Serial Number 26635, Revision 000 VrD-W0315-4002, Service Department
Standards
Book No. 10, Field Service Manual, Revision 000 Response to NRC Generic Letter 90-3, Relaxation
of Staff Position In Generic Letter 28, Item 2.2 Part 2 "Vendor Interface
for Safety Related Components, dated September
18, 1990 CATS 10 R04451, Response to NRC IN 94-66, OVERSPEED
OF TURBINE-DRIVEN
PUMPS CAUSED BY GOVERNOR VALVE STEM BINDING CMM-37-19-9519E, Worthington
Turbine Driven Auxiliary
Pump Hydraulic
Governor Control Valve Maintenance
for 9519E, Revision 00200 Constellation
Energy Nuclear Generating
Group Reply to a Notice of Violation; 045 Engineering
Change Package No. ECP-2009-0146, TDAFW Lube Oil Orifice Management
Review Committee
Agenda. August 5, 2009 Purchase Requisition
No. 58686, Dresser-Rand
Valve Stem Technical
Staff Request 97-199, Leakoff from TDAFW Govenor Valve 9519E Management
Review Committee
Agenda, August 5, 2009 Purchase Requisition
No. 58686, Dresser-Rand
Valve Stem Attachment
A
Technical
Staff Request 97-199, Leakofffrom
TDAFW Govenor Valve 9519E Turbine Driven Auxiliary
Pump Preventive
Maintenance
Strategies
Auxiliary
Feed Water System, 1 st Quarter 200S Auxiliary
Feed Water System. 2nd Quarter 200S Auxiliary
Feed Water System. 3rd Quarter 200S Auxiliary
Feed Water System, 4th Quarter 200S Auxiliary
Feed Water System, 1 st Quarter 2009 Operating
Experience
OE-200S-000397
OE-200S-000607
OE-200S-000847
o E-2 0 OS-00S60 OE-2008-001296
OE-2009-00212
OE*2009*001178
Oil Analysis Pump IB Oil Analysis.
2008-03 Pump OB Oil Analysis, 2008-03 Reservoir
Oil Analysis 2008-05 Reservoir
Oil Analysis 2008-08 Reservoir
Oil Analysis 2009-05 Attachment
A
AV CAP CCDP CDF CR DRP EDG GEM ICCDP IMC IN INL *IPEEE LERF LOOP LOSWS NCV NRC NRR PARS PSA RCA SAFW SBO SOP SPAR SRA SCAQ NCV TBD TDAFW TS A-4 LIST OF ACRONYMS Apparent Violation
Corrective
Action Program Conditional
Core Damage Probability
Core Damage Frequency
Condition
Report Division of Reactor Projects Emergency
Diesel Generator
Graphical
Evaluation
Module Incremental
Conditional
Core Damage Probability
Inspection
Manual Chapter Information
Notice Idaho National Labs Individual
Plant Examination
of External Events Large Early Release Frequency
Loss of Off site Power Loss of Service Water System Non Cited Violation
Nuclear Regulatory
Commission
Office of Nuclear Reactor Regulation
Publicly Available
Records Probabilistic
Safety Assessment
Root Cause Analysis Standby Auxiliary
Station Blackout Significance
Determination
Process Standardized
Plant Analysis Risk Senior Reactor Analyst Significant
Condition
Adverse to Quality Non-citied
Violation
To Be Determined
Turbine Driven Auxiliary
Technical
Specification
Attachment
A
8-1 Special Inspection R.E. Ginna Nuclear Power Failure of the Turbine-Driven
Auxiliary
Feedwater (TDAFW) on May 26, 2009 and July 2, Background:
On May 26, 2009, during routine
quarterly
surveillance
testing of the turbine driven auxiliary
feedwater (TDAFW) system, the TDAFW pump tripped on overspeed.
The test was repeated several hours later and the TDAFW pump tripped again on overspeed.
Fluctuations
in oil pressure were observed during the testing. After extensive
troubleshooting, Ginna
identified
a number of issues but no definitive
cause for the overspeed
trips. The lube/control
oil system was drained and cleaned due to the presence of fine particulates;
a pressure pulsation
dampener accumulator
bladder was replaced due to a below normal pressure condition;
the oil pressure regulating
bypass valve was replaced due to potential
cycling; a change to linkage setup was implemented;
governor relay valve, and trip and throttle valve parts were replaced due to out of specification
clearances;
and a miSSing oil line orifice was installed.
Following
these corrective
actions, the system was successfully
tested and declared operable.
Constellation
is completing
a root cause evaluation
and the resident inspectors
continue to conduct baseline inspections
with assistance
from DRS specialists.
Testing of the TDAFW system will be at an increased
frequency
until Constellation
has confidence
that the system is performing
as required.
On July 2, 2009, during the performance
of the increased
frequency
surveillance, the TDAFW pump again tripped on overspeed.
Glnna personnel
discovered
pitting and corrosion
on the stem of the governor control valve during troubleshooting
activities
to restore the pump to operable status. This Special Inspection
Team had raised concerns regarding
corrosion
on the stem of the Governor Control Valve during onsite inspection
activities
the week of June 15, 2009. Basis for the Formation
of the SIT: The failure of the TDAFW pump involved repetitive
failures of this
eqUipment.
There have been three failures of the TDAFW pump since December 2008. On December 2, 2008, a failure was attributed
to inadequate
implementation
of the preventive
maintenance
program. SpeCifically, the governor linkages were not lubricated
in March 2008 which resulted in the pump's inability
to achieve the required flow and pressure in December 2008. On July 2, 2009, the failure was preliminarily
determined
to be caused by pitting on the stem of the Governor Control valve and overly tolerances
causing binding of the stem. Although the specific failure modes (overspeed
trip, inability
to achieve the required flow or pressure)
were different, the underlying
cause of inadequate
or inappropriate
preventive
maintenance
may be the same. Attachment
8
Based upon best available
information, the Region I Senior Reactor Analyst (SRA) conducted
a preliminary
risk estimate of the May 26 TDAFW pump failure. An incremental
conditional
core damage probability (ICCDP) in the upper E-6 range (8E-6 per the 82 day exposure period), was calculated
using the Ginna SPAR model. assuming that the TDAFW pump would not have started since the last time it passed a surveillance
test on March 5 until May 26 (82 days). The dominant core damage sequence was a station blackout (LOOP with failure of both EDGs,) with no TDAFW and failure to recover offsite power or an EDG in one hour. Based upon the preliminary
conditional
core damage probability
estimate of upper E-6 range, in accordance
with IMC 0309, this event falls within the region for a Special Inspection
Team. Oblectives
of the Special Inspection:
The objectives
of the special inspection
are to review and assess: (1)
Constellation's
planning and execution
of the risk significant
work activities
on the TDAFW system; (2) equipment
issues related to the TDAFW testing; and (3) Constellation's
response to this significant
equipment
failure. To accomplish
these objectives, the following
will be performed: Evaluate the adequacy and completeness
of the maintenance
on the TDAFW system, including
preventive
maintenance, procedural
guidance, maintenance
testing, and supervisory
oversight. Evaluate Constellation's
application
of pertinent
industry operating
experience
and evaluation
of potential
precursors, including
the effectiveness
of any actions taken in response to the operating
experience
or precursors. Evaluate the adequacy of Constellation's
response to the TDAFW system failures, including
Constellation's
cause analysis and completed
interim corrective
actions. Evaluate the adequacy of Constellation's
initial extent of condition
for the TDAFW failures, as appropriate. Evaluate the failure modes for potential
generic implications
including
the need for generic communications
Additionally, the team leader will review lessons learned from the Special Inspection
and, if appropriate, prepare a feedback form on recommendations
for revising the reactor oversight
process (ROP) baseline inspection
procedures
in order to proactively
identify the issues and causes involved with the event. Guidance:
Inspection
Procedure
93812, "Special Inspection", provides additional
guidance to be used by the Special Inspection
Team. Team duties will be as described
in Inspection
Procedure
93812. The inspection
should emphasize
fact-finding
in its review of the circumstances
surrounding
the event. It is not the responsibility
of the team to examine Attachment
B
the regulatory
process. Safety concerns identified
that are not directly related to the event should be reported to the Region I office for appropriate
action. The Team will conduct an entrance meeting and begin the inspection
on June 8,2009. While on site, the Team Leader wi" provide daily briefings
to Region I management, who will coordinate
with the Office of Nuclear Reactor Regulation, to ensure that all other parties are kept informed.
A report documenting
the results of the inspection
should be issued within 45 days of the completion
of the inspection.
This Charter may be modified should the team develop significant
new information
that warrants review. Attachment
8