ML053080243
| ML053080243 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 11/04/2005 |
| From: | Blough A Division of Reactor Safety I |
| To: | Crane C AmerGen Energy Co |
| Lorson R, RI/DRS/PEB, (610) 337-5282 | |
| References | |
| EA-05-199 IR-05-011 | |
| Download: ML053080243 (24) | |
See also: IR 05000219/2005011
Text
November 4, 2005
Mr. Christopher M. Crane
President and CEO
AmerGen Energy Company, LLC
200 Exelon Way, KSA 3-E
Kennett Square, PA 19348
SUBJECT:
OYSTER CREEK NRC EVENT FOLLOWUP INSPECTION REPORT
05000219/2005011; PRELIMINARY WHITE FINDING
Dear Mr. Crane:
On September 23, 2005, the U. S. Nuclear Regulatory Commission (NRC) completed an
inspection of an event that occurred at your Oyster Creek Generating Station on August 6,
2005, involving sea grass intrusion into your intake structure. The enclosed inspection report
documents the inspection findings, which were discussed with Mr. B. Swenson, Site Vice
President, and other members of your staff during an exit meeting held on September 23, 2005.
The inspection examined activities conducted under your license as they relate to safety and
compliance with the Commissions rules and regulations and with the conditions of your license.
The inspectors reviewed procedures, records, investigation and analysis reports and
interviewed personnel.
This report documents one finding that appears to have low to moderate safety significance.
This finding involved the failure to properly utilize the Oyster Creek Emergency Plan (E-Plan)
emergency action level (EAL) matrix during an actual event. This resulted in operators not
recognizing that plant parameters met the EAL thresholds for declaring an unusual event (UE)
and a subsequent Alert. Specifically, a large amount of sea grass had clogged the north side
intake structure screens resulting in a decrease in the intake structure water level.
Subsequently, the intake water level decreased over a period of approximately 60 minutes
meeting the values expected for a UE and then an Alert.
The finding was assessed using the emergency preparedness significance determination
process dated March 6, 2003, as a potentially safety significant finding that was preliminarily
determined to be White (i.e., a finding with some increased importance to safety which may
require additional NRC inspection). The finding appears to have low to moderate safety
significance because a Risk Significant Planning Standard implementation problem occurred
during an actual event. The fact that the shift crew did not recognize Alert conditions prevented
the activation of both onsite and offsite emergency response organizations (ERO). Had the
event degraded further, the onsite ERO could not have been readily available to assist in the
mitigation of the event and the offsite agencies could have been prevented from taking initial
Mr. Christopher M. Crane
2
offsite response measures. Although the shift crew took actions to mitigate the event and the
actual consequences of this event were minimal, the performance problems that caused the
failure to classify, if uncorrected, could result in inadequate protection of the public health and
safety under different circumstances.
Your staff implemented immediate corrective actions, including providing additional guidance to
the operators and operator training on implementation of the E-Plan. Therefore, the finding
does not present an immediate safety concern. We understand that long-term corrective and
preventive measures are being developed.
The finding is an apparent violation of NRC requirements (10 CFR 50.54(q) and 50.47(b)(4))
and is being considered for escalated enforcement action in accordance with the NRC
Enforcement Policy. The current policy is included on the NRCs website at
http://www.nrc.gov; select What We Do, Enforcement, then Enforcement Policy.
We believe we have sufficient information to make a final risk significance determination on this
issue. However, before we make a final decision on this matter, we are providing you an
opportunity to: (1) present to the NRC your perspectives on the facts and assumptions used by
the NRC to arrive at the finding and its significance, at a Regulatory Conference, or (2) submit
your position on the finding to the NRC in writing. If you request a Regulatory Conference, it
should be held within 30 days of the receipt of this letter and we encourage you to submit
supporting documentation at least one week prior to the conference in an effort to make the
conference more efficient and effective. If a Regulatory Conference is held, it will be open for
public observation and a press release will be issued announcing it. If you decide to submit
only a written response, such submittal should be sent to the NRC within 30 days of the receipt
of this letter.
Please contact Mr. Raymond K. Lorson at (610) 337-5282 within 7 days of the date of this letter
to notify the NRC of your intentions. If we have not heard from you within 10 days, we will
continue with our significance determination and enforcement decision and you will be advised
by separate correspondence of the results of our deliberations on this matter.
In addition, this report documents four findings of very low safety significance (Green), one of
which was licensee-identified. Three of the four green findings involved violations of NRC
requirements. However, because of the very low safety significance and because they are
entered into your corrective action program, the NRC is treating those three findings as non-
cited violations consistent with Section VI.A.1 of the NRC Enforcement Policy. If you contest
any non-cited violations 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,
ATTN.: Document Control Desk, Washington DC 20555-0001; with copies to the Regional
Administrator, Region I, the Director, Office of Enforcement, United States Nuclear Regulatory
Commission, Washington, DC 20555-0001; and the NRC Resident Inspector at the Oyster
Creek facility.
In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter, its
enclosure, and your response if any will be made available electronically for public inspection in
the NRC Public Document Room or from the Publicly Available Records (PARS) component of
NRCs document system (ADAMS). ADAMS is accessible from the NRC Web site at
Mr. Christopher M. Crane
3
http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room). Should you
have any questions, please contact Mr. Raymond K. Lorson at (610) 337-5282.
Sincerely,
/RA/
A. Randolph Blough, Director
Division of Reactor Safety
Docket No.
50-219
License No.
Enclosure:
Inspection Report 05000219/2005011
w/Attachments A and B
cc w/encl:
Chief Operating Officer, AmerGen
Site Vice President, Oyster Creek Nuclear Generating Station, AmerGen
Plant Manager, Oyster Creek Generating Station, AmerGen
Regulatory Assurance Manager, Oyster Creek, AmerGen
Senior Vice President - Nuclear Services, AmerGen
Vice President - Mid-Atlantic Operations, AmerGen
Vice President - Operations Support, AmerGen
Vice President - Licensing and Regulatory Affairs, AmerGen
Director Licensing, AmerGen
Manager Licensing - Oyster Creek, AmerGen
Vice President, General Counsel and Secretary, AmerGen
T. ONeill, Associate General Counsel, Exelon Generation Company
J. Fewell, Assistant General Counsel, Exelon Nuclear
Correspondence Control Desk, AmerGen
J. Matthews, Esquire, Morgan, Lewis & Bockius LLP
Mayor of Lacey Township
K. Tosch, Acting Assistant Director of Radiation Programs, State of New Jersey
Chief, Bureau of Nuclear Engineering, NJ Dept. of Environmental Protection
R. Shadis, New England Coalition Staff
N. Cohen, Coordinator - Unplug Salem Campaign
W. Costanzo, Technical Advisor - Jersey Shore Nuclear Watch
E. Gbur, Chairwoman - Jersey Shore Nuclear Watch
E. Zobian, Coordinator - Jersey Shore Anti Nuclear Alliance
J. Picciano, Acting Regional Director, FEMA Region II
Mr. Christopher M. Crane
4
Distribution w/encl: (VIA E-MAIL)
S. Collins, RA
M. Dapas, DRA
R. Bellamy, DRP
R. Fuhrmeister, DRP
M. Ferdas, DRP, Senior Resident Inspector
J. DeVries, DRP, Resident OA
S. Lee, RI OEDO
R. Laufer, NRR
T. Colburn, NRR
J. Boska, NRR
ROPreports@nrc.gov
Region I Docket Room (with concurrences)
M. Johnson, OE
S. Figueroa, OE
M. Elwood, OGC
K. Farrar, ORA , RI
D. Holody, EO, RI
R. Urban, ORA, RI
C. ODaniell, ORA, RI
R. Kahler, NSIR/EPD
S. LaVie, NSIR/EPD
A. Blough, DRS
R. Lorson, DRS
N. McNamara, DRS
DOCUMENT NAME: E:\\Filenet\\ML053080243.wpd
SISP Review Complete: NSP (Reviewers Initials)
After declaring this document An Official Agency Record it will be released to the Public.
To receive a copy of this document, indicate in the box: "C" = Copy without attachment/enclosure "E" = Copy with attachment/enclosure "N" = No copy
OFFICE
RI/DRS
RI/DRS
RI/DRP
RI/DRS/SRA
RI/OE
NAME
NMcNamara (NTM)
RLorson(NSPfor)
RBellamy (RLF for) WCook (WLS for)
RUrban (RJU)
DATE
11/01/05
11/01/05
11/01/05
11/02/05
11/01/05
OFFICE
NSIR/EPD
RI/DRS
NAME
LaVie (via email)
ABlough (ARB)
DATE
11/02/05
11/04/05
OFFICIAL RECORD COPY
Enclosure
U. S. NUCLEAR REGULATORY COMMISSION
REGION I
Docket No.
50-219
License No.
Report No.
Licensee:
AmerGen Energy Company, LLC (AmerGen)
Facility:
Oyster Creek Generating Station
Location:
Forked River, New Jersey
Dates:
August 25, 2005 - September 23, 2005
Inspectors:
Nancy T. McNamara, Emergency Preparedness Inspector
Jeffrey Herrera, Resident Inspector, Oyster Creek
Steven Dennis, Operator Licensing Examiner
Andrew Rosebrook, Project Engineer
Approved by:
Raymond K. Lorson, Chief
Plant Support Branch 1
Division of Reactor Safety
ii
Enclosure
TABLE OF CONTENTS
Page
SUMMARY OF FINDINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
1.0
EVENT DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1
Event Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2.0
PLANT RESPONSE: PERSONNEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.1
Operator Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3.0
EMERGENCY PREPAREDNESS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1
Emergency Response Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.0
EVENT ROOT CAUSES AND CAUSAL FACTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.1
Root Causes Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.0
Licensee-Identified Violations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.0
Meetings, including Exit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
ATTACHMENT A: SUPPLEMENTAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1
ATTACHMENT B: SEQUENCE OF EVENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1
iii
Enclosure
SUMMARY OF FINDINGS
IR 05000219/2005-011; 08/25/2005 - 09/23/2005; Oyster Creek Generating Station; Event
Followup Inspection; Emergency Classification.
The report covered an event followup inspection by three regional inspectors and one resident
inspector. Four Green findings, three of which were non-cited violations (NCVs), and one
apparent violation (AV) with preliminary White significance were identified. The significance of
most findings is indicated by their color (Green, White, Yellow, Red) using Inspection Manual
Chapter (IMC) 0609, Significance Determination Process (SDP). The NRCs program for
overseeing the safe operation of commercial nuclear power reactors is described in NUREG-
1649, Reactor Oversight Process, Revision 3, dated July 2000.
A.
NRC-Identified and Self Revealing Findings
Cornerstone: Initiating Events
Green. A self-revealing non-cited violation (NCV) of Technical Specification 6.8.1 was
identified for failure to follow an abnormal operating procedure that resulted in the loss
of the No. 1 North Intake Service Water Pump, the No.1 Emergency Service Water
system and the associated containment spray heat exchangers. The licensee took
immediate corrective actions which included the issuance of standing orders to reinforce
managements expectations and provided interim guidance related to the shortcomings
of the shift crews performance.
This finding is greater than minor because the failure to follow the abnormal procedure
impacted the control rooms ability to adequately monitor intake levels and impacted
prompt operator response actions due to decreasing intake level. This finding is
associated with the cornerstone objectives of Initiating Events, Mitigating Systems and
Containment Barriers Cornerstones. The attributes affected are protection against
external factors such as loss of heat sink, equipment performance in availability and
reliability, human performance in human error (pre-event), containment structure system
and component and barrier performance. The cause of the finding is related to the
cross-cutting element of human performance (personnel). (Section 2.0)
Cornerstone: Emergency Preparedness (EP)
Preliminary White. An NRC-identified apparent violation (AV) of 10 CFR 50.47(b)(4)
was identified. This AV, which has low to moderate safety significance, occurred
because the Oyster Creek E-Plan EAL matrix was not properly utilized to determine if a
plant parameter met the EAL threshold for declaring an emergency classification. This
resulted in not recognizing during an actual event, that plant parameters met the EAL
thresholds for declaring a UE and a subsequent Alert. Immediate corrective actions
were taken in which shift crews were retrained on the implementation of E-Plan
requirements.
The finding is greater than minor because it is associated with the EP cornerstone
attribute of response organization (RO) performance (actual event response). It affects
the cornerstone objective of ensuring the capability to implement measures to protect
the health and safety of the public during an emergency. The licensee did not use the
Oyster Creek E-Plan EAL matrix when plant parameters met the EAL thresholds for
iv
Enclosure
declaring a UE and a subsequent Alert. As a consequence, both the onsite and offsite
EROs were not activated during actual Alert conditions. Had the event degraded
further, the onsite ERO would not have been readily available to assist in the mitigation
of the event and the offsite agencies could have been prevented from taking initial
offsite response measures. This finding is of low to moderate safety significance
because it constituted a failure to implement a Risk Significant Planning Standard during
an actual event in which plant conditions met an Alert. The cause of the finding is
related to the cross-cutting element of human performance (personnel). (Section 3.1)
Green. A self-revealing NCV of 10 CFR 50.47(b)(2) was identified in which state and
local agencies were not notified within 15 minutes after declaring a UE. The licensee
immediately re-trained shift managers in the offsite notification process and proper
completion of the notification form.
This finding is greater than minor because it affects the RO performance (actual event
response) attribute of the EP cornerstone. Failure to notify offsite agencies in a timely
manner impacts the EP cornerstone objective of ensuring that the licensee is capable of
implementing adequate measures to protect the public health and safety during an
emergency. Timely offsite notifications enable state and local agencies to make
decisions for taking initial offsite response measures that could affect the general public.
This finding is of very low safety significance because it was a failure to implement a
Risk Significant Planning Standard during an actual event associated with the
notification of a UE. The cause of this finding is related to the cross-cutting element of
human performance (personnel). (Section 3.1)
Cornerstone: Miscellaneous
Green. The inspectors identified a green finding for ineffective corrective actions in that
the root cause analysis team did not correctly identify the amount of time Alert
conditions existed during the August 6, 2005, event. AmerGen initiated some of their
immediate corrective actions and their analysis of the significance of this event based on
the Alert lasting for five minutes when it actually lasted for approximately 45 minutes.
The licensee confirmed the error, revised the root cause analysis report and entered this
issue into their corrective action program.
The finding was more than minor because if left uncorrected, it could have resulted in a
more significant safety concern. Specifically, failure to accurately identify information
pertaining to operating events can lead to deficiencies in corrective actions. Because
this finding does not involve a violation of regulatory requirements, this finding is not
suitable for SDP evaluation, but has been reviewed by NRC management and is
determined to be a finding of very low safety significance. The cause of the finding is
related to the cross-cutting element of problem identification and resolution. (Section
4.0)
B.
Licensee-Identified Findings
A violation of very low safety significance, which was identified by the licensee has been
reviewed by the inspector. Corrective actions taken or planned by the licensee has
been entered into the licensees corrective action program. The violation and corrective
action tracking number are listed in Section 5.0 of this report.
Enclosure
REPORT DETAILS
1.0
EVENT DESCRIPTION
1.1
Event Summary: During the evening of August 5, 2005, Oyster Creek had a higher than
normal level of sea grass build up on the north side of the intake structure. AmerGen
dispatched a team to clear the intake structure screens of the grass. By 1:57 a.m., on
August 6, 2005, conditions had deteriorated resulting in a control room alarm due to
high traveling water screen differential pressure. AmerGen determines the intake water
level from a differential pressure reading via a gas bubbler at the screen wash control
panel located at the north side of the intake structure. There is no indicator in the
control room for monitoring intake level; therefore, operators have to rely on the
information being communicated from personnel in the field. At 2:35 a.m., the level was
reported at <1.4 pounds per square inch gauge (psig) which required the shift crew to
enter Abnormal Operating Procedure (ABN), No. 32, Abnormal Intake Level. Based
on water level, Procedure ABN-32 required operators to monitor the intake water level
every 15-minutes and to refer to the Oyster Creek E-Plan to evaluate the plant
parameter against the EAL matrix. Operators did not monitor intake water level as
required and also did not refer to the E-Plan EAL matrix at the time the procedure
directed.
At approximately 3:05 a.m, the control room was notified that conditions had further
degraded. The sea grass caused a trash rack on each of the three bays of the north
side of the intake structure to collapse. This placed a heavy load on each of the north
side traveling water screens and caused the screens shear pin to break. The three
screens on the south side were not affected during the event. Water level downstream
of the screens on the north side lowered due to the operation of two circulating water
pumps with the clogged intake. In response to the continued lowering of the north
intake bay level, the operators conducted a rapid reactor power reduction to 75% power
and tripped one of the two operating circulation pumps taking a suction form the north
intake bay. This action decreased the possibility of a reactor scram due to low
condensers vacuum conditions and reduced the water flow across the north intake bay
traveling screen, allowing level downstream of the screens to increase.
The level reduction in the north intake bay rendered the No. 1 Emergency Service Water
Pump, the No. 1 Emergency Service Water (ESW) system and associated containment
spray heat exchangers inoperable. The shift crew entered technical specification
Limiting Condition for Operation (LCO) 3.4.C.3 and continued to reduce power. It was
reported to the control room at 3:10 a.m., that the differential pressure level was 0.5 psig
and rising slowly. Sometime between 2:35 a.m. and 3:05 a.m., plant parameters had
met the thresholds for declaring a UE and a subsequent Alert. However, since the
operators had not instituted level monitoring or entered the E-Plan, they were not
cognizant that plant parameters had met the EAL thresholds for making an emergency
declaration.
At 3:35 a.m., the shift technical advisor (STA), who had been supervising the activities
at the intake structure in the capacity of the field supervisor, returned back to the control
room. The STA reviewed the E-Plan EAL scheme and requested a confirmation of the
current intake water level which was reported at 0 psig. Apparently, the water level did
not recover on a consistent upward trend as initially believed at 3:10 a.m. This was due
to the second circulating water pump still operating, causing the water level to fluctuate
2
Enclosure
up and down. The STA informed the shift manager that the Alert threshold had been
met. At 3:45 a.m., with power reduced to 44%, the second circulating water pump was
secured and all north side intake loads were transferred to the south side intake
structure or removed from service. At that time, the intake water level recovered to 2.7
psig, which no longer met the Alert conditions.
Although the shift manager recognized that the Alert no longer existed, he erroneously
believed that conditions still met the criteria for a UE. Therefore, at 4:03 a.m., the shift
manager declared a UE based on low intake level.
The designated on-shift communicator, who was performing other assigned duties at
the rad waste building and the intake structure, returned to the control room at 4:11 a.m.
The communicator attempted to contact the State of New Jersey via the automatic ring-
down phone which was found to be out of service. The communicator contacted the
state manually and completed the notification by 4:26 a.m., followed by the notification
to the NRC. At 7:55 a.m., AmerGen terminated the UE.
There were no injuries or radiation release associated with this event.
The licensee performed a root cause analysis and identified several operator
performance problems which were related to: inadequate communications; not
recognizing the significance of the degrading conditions; lack of teamwork; and,
inadequate command and control. Short and long-term corrective actions to prevent
recurrence were being developed as a result of the root cause analysis.
2.0
PLANT RESPONSE: PERSONNEL
Cornerstone: Initiating Events
2.1
Operator Performance
a.
Inspection Scope
The inspectors reviewed and assessed licensed operator performance during an actual
event which occurred on August 6, 2005, due to low intake water level. The inspectors
reviewed and evaluated the operators use and adherence to abnormal and emergency
procedures during transient mitigation and subsequent plant operations. The inspectors
interviewed licensed operators involved in the event to assess operator performance
during the transient. Documents reviewed included the following:
1.
operator logs;
2.
normal and abnormal operating procedures;
3.
Exelons corporate event investigation team report; and
4.
AmerGens prompt investigation report.
b.
Findings
Introduction. A self-revealing Green NCV of Technical Specification 6.8.1 was identified
for failure to follow an abnormal operating procedure that resulted in the loss of the No.
3
Enclosure
1 North Intake Service Water Pump, the No.1 ESW system and the associated
containment spray heat exchangers.
Description. During the August 6, 2005, event, control room operators did not establish
a plan to monitor the intake water level as directed by Procedure ABN-32. They never
stationed an individual to specifically monitor the intake level every 15 minutes as
directed by the procedure. This led them to miss a significant drop in level between
2:35 a.m. and 3:05 a.m., which met the UE and Alert classification thresholds. The
failure to follow procedure ABN-32, directly impacted the operators ability to track, trend
and recognize the degrading conditions. This resulted in the loss of the No. 1
Emergency Service Water Pump, the No. 1 ESW system, the associated containment
spray heat exchangers and missed entry into the E-Plan EALs. Refer to Sections 1.0
and Appendix B for additional details of the actions taken by the shift crew while
mitigating the event.
Immediate corrective actions were taken in that the licensee issued standing orders
reinforcing managements expectations and provided interim guidance related to the
shortcomings of the shift crews performance. Long-term corrective actions to prevent
recurrence were being developed as a result of the root cause analysis.
Additionally, the root cause analysis identified previous corrective action items (CAP
Nos. 02003-2361, 02004-0165, and 02004-0123), regarding communication challenges
with respect to the monitoring of intake level from the control room. AmerGen proposed
that a modification to add a control room indicator for recording the intake level be made
to resolve reliance on verbal communications between the control room and operators in
the field. The enhancement was never made a priority or scheduled for implementation
and had remained open since 2003.
Analysis. In accordance with IMC 0612, Appendix B, Issue Disposition Screening, the
inspectors determined that this finding was more than minor because the failure to
follow the abnormal procedure impacted the control rooms ability to adequately monitor
intake levels and impacted prompt operator response actions due to decreasing intake
level. Specifically, operators did not adequately monitor intake levels for degrading
intake conditions which rendered the No. 1 Emergency Service Water Pump, the No. 1
ESW system and associated containment spray heat exchangers inoperable.
The finding is associated with the Initiating Events cornerstone objective to limit the
likelihood of those events that upset plant stability and challenge critical safety functions
during power operations. The attributes affected include protection against external
factors such as loss of heat sink, equipment performance availability and reliability, and
human performance. The finding is also associated with the Mitigating Systems
cornerstone objective to ensure the availability, reliability, and capability of systems that
respond to initiating events to prevent undesirable consequences (i.e., core damage).
The attributes affected include protection against external factors such as loss of heat
sink, equipment performance in availability and reliability, and human performance error
(pre-event). In addition, the finding is associated with the Barrier Integrity cornerstone
objective to provide reasonable assurance that physical design barriers protect the
public from radionuclide release caused by accidents or events. The attributes affected
included containment structure system, and component and barrier performance. The
4
Enclosure
cause of the finding is related to the cross-cutting element of human performance
(personnel).
In accordance with IMC 0609, Appendix A, "Significance Determination of Reactor
Inspection Findings for At-Power Situations," the inspectors conducted a significance
determination process (SDP) Phase 1 screening and determined that this finding
required a Phase 2 approximation based upon the finding affecting the Initiating Events,
Mitigating Systems, and Containment Barriers Cornerstones. The inspectors conducted
a Phase 2 evaluation using the Risk-Informed Inspection Notebook for Oyster Creek
Nuclear Generating Station, Revision 1. The inspectors made the following
assumptions: the duration of the low intake water level event was less than one hour,
accordingly, the Table 1, < 3 days column was used to assign Initiating Event
Likelihood; the special initiator worksheet Table 3.10, "Loss of Intake Water Pump Pit
(TIW)" was used for the Phase 2 approximation; the initiating event likelihood value was
increased by one order of magnitude, in accordance with IMC 0609, Appendix A,
Attachment 2 Rule 1.3; and no operator recovery credit was provided. The approximate
change (increase) in core damage frequency as a result of this performance deficiency
was mid E-9, or of very low risk significance (Green). The most dominant core damage
sequence involved a loss of intake water to pump pit, followed by the failure of an
electromatic relief valve (stuck open) and subsequent failure of the low pressure
injection system. For the short duration of the actual event, the adjacent intake bay was
unaffected, and thus, ensured the availability of the redundant trains of mitigating
equipment.
Enforcement. Technical Specification 6.8.1 states that written procedures shall be
established, implemented, and maintained covering the items referenced in AmerGens
Appendix "A" of Regulatory Guide 1.33 as referenced in the licensees Quality
Assurance Topical Report. Abnormal procedures are included in Regulatory Guide 1.33. Contrary to the above, the licensees failure to monitor intake level, as required by
procedure ABN-32, led to an untimely response to a degrading condition caused by
heavy grassing at the intake. As a consequence, the No. 1 Intake Service Water Pump,
the No. 1 ESW system and the associated containment spray heat exchangers were
rendered inoperable. However, because the violation was of very low safety
significance and has been entered into the licensees corrective action program under
issue report (IR) 360630, this violation is being treated as a NCV, consistent with
Section VI.A of the NRC Enforcement Policy. (NCV 05000219/2005011-01, Failure to
Follow Procedures)
3.0
3.1
Emergency Response Performance
a.
Inspection Scope
The inspectors reviewed and assessed the licensees performance related to
emergency response and the implementation of the E-Plan during the August 6, 2005,
event. The assessment included interviews with control room operators and plant
personnel who responded to the intake structure to remove the grass. Items reviewed
included the following:
5
Enclosure
operator logs;
abnormal procedures;
Oyster Creek Exelon/AmerGen Radiological Emergency Plan;
emergency plan implementing procedures;
state/local notification forms;
Exelons corporate event investigation team report; and
AmerGens prompt investigation report.
b.
Findings
One NRC-identified preliminary White finding and one self-revealing Green finding are
documented in the section below.
Emergency Classification
Introduction. An NRC-identified apparent violation (AV) was identified of low to
moderate safety significance (White) associated with the emergency classification
during an actual event. AmerGen did not properly utilize the Oyster Creek EAL matrix
which resulted in not recognizing that plant parameters had met the EAL thresholds for
declaring a UE and a subsequent Alert.
Description. Procedure, ABN-32, step four, requires the evaluation of the condition
using the E-Plan EAL matrix, which lists the initiating condition threshold values for
making an emergency declaration. The EAL threshold for intake canal water level
(differential pressure) is <0.94 psig for meeting a UE and <0.50 psig for meeting an
Alert classification. The control room received notification at 2:35 a.m., that the water
level at the north side of the intake structure was measured at <1.4 psig. Sometime
between 2:35 a.m. and 3:05 a.m. plant conditions had met the EAL criteria for declaring
a UE and a subsequent Alert due to the level dropping 1.4 psig to 0 psig. The inspector
determined that the shift manager did not properly utilize the E-Plan EAL matrix as
required by the abnormal procedure, to determine if an emergency classification was
warranted.
The shift manager did not review the E-Plan EAL matrix until approximately 3:40 a.m.,
after being prompted by the STA that plant conditions had met an Alert. Between 3:40
a.m. and 4:00 a.m., the shift manager reviewed the EAL technical basis document and
determined, based on the intent of the EAL, an Alert had been warranted. The shift
manager recognized the Alert no longer existed because the level had recovered to 2.4
psig. However, he erroneously believed the conditions still met the criteria for a UE and
at 4:03 a.m., the shift manager declared a UE based on low intake level.
Analysis. The performance deficiency associated with the response to this actual event
is the Oyster Creek E-Plan EAL matrix was not properly utilized to determine if a plant
parameter met the EAL classification thresholds. Although the intake level exceeded an
EAL threshold sometime between 2:35 a.m. and 3:05 a.m., it was not recognized until
approximately 3:40 a.m., that plant parameters met the EAL threshold for declaring an
Alert. However, an emergency declaration was not made until 4:03 a.m. The inspectors
determined that the licensee should have known of the exceeded EAL threshold by 3:05
a.m., and the delay in recognition and classification could not be reasonably attributed to
6
Enclosure
competing safety-related activities. The inspectors also determined that this finding was
indicative of a cross-cutting weakness in the area of human performance (personnel).
The finding was greater than minor because it is associated with the EP cornerstone
attribute of RO performance (actual event response). It affects the cornerstone
objective of ensuring the capability to implement measures to protect the health and
safety of the public during an emergency. The inspectors reviewed this finding using
IMC 0609, Appendix B, "Emergency Preparedness Significance Determination Process,
Sheet 2, Actual Event Implementation Problem. The finding has low to moderate safety
significance (White) because a Risk Significant Planning Standard implementation
problem occurred during an actual event in that the Oyster Creek E-Plan EAL matrix
was not properly utilized when plant conditions met an Alert. This prevented the
activation of both onsite and offsite EROs during an actual event. Had the event
degraded further, the onsite ERO would not have been readily available to assist in the
mitigation of the event. Additionally, state and local agencies, which rely on information
provided by the facility licensee, could have been prevented from taking initial offsite
response measures.
Immediate corrective actions were taken in that shift crews were re-trained on the
implementation of E-Plan requirements during transient events. Therefore, the finding
does not present an immediate safety concern. Long-term corrective actions to prevent
recurrence were being developed as a result of the root cause analysis.
Enforcement. In accordance with 10 CFR 50.54(q), a licensee authorized to possess
and operate a nuclear power reactor shall follow and maintain in effect emergency plans
which meet the standards in 10 CFR 50.47(b). In accordance with 10 CFR 50.47(b)(4)
a standard emergency classification and action level scheme shall be in use by facility
licensees. State and local response plans call for reliance on information provided by
facility licensees for the determination of minimum initial offsite response measures.
Contrary to the above, between 2:35 a.m. and 3:40 a.m., on August 6, 2005, AmerGen
did not use the Oyster Creek E-Plan EAL matrix during an actual event to determine if
plant parameters met the EAL thresholds for declaring a UE and a subsequent Alert. As
a consequence, AmerGen failed to make an Alert declaration and, as a result, failed to
activate their ERO to assist operators in mitigating the event. Additionally, state and
local agencies, which rely on information provided by the facility licensee, could have
been prevented from taking initial offsite response measures. This finding is identified
as an apparent violation of low to moderate safety significance (White), in accordance
with the NRC Enforcement Policy and was entered into AmerGens corrective action
program as IR 360630. (AV 05000219/2005011-02, E-Plan EAL Matrix Not Reviewed
During Alert Conditions)
Notification of State and Local Agencies
Introduction. A Green self-revealing NCV was identified in that state and local
governmental agencies were not notified within 15 minutes of the declaration of a UE.
Description. As stated previously, at 4:03 a.m., the shift manager declared a UE. The
licensee is required to notify state and local governmental agencies within 15 minutes
after making a declaration. However, for reasons unrelated to the delay in making the
7
Enclosure
declaration, the notification to the State and local governmental agencies was not
completed until 4:26 a.m. The completion time exceeded the notification time criterion
by seven minutes.
The following performance and equipment problems were identified as contributing
factors to the untimely notification: the notification form was not completed in a timely
manner; there was a delay in requesting the on-shift communicator to report to the
control room; on-shift communicator was not able to immediately report to the control
room as required by procedure due to other responsibilities; the state/local automatic
ringdown telephone was inoperable; and, the on-shift communicator was not familiar
with the backup notification process. The inspectors determined that the notification
delays could not be reasonably attributed to competing safety-related activities.
Additionally, the completed notification form contained numerous errors and omissions
including an incorrect emergency classification. The form indicated the declaration of an
Alert when, the shift manager had declared a UE.
AmerGen took immediate corrective actions in which they retrained Oyster Creek shift
managers in the offsite notification process and proper completion of the notification
form. Long-term corrective actions to prevent recurrence were being developed as a
result of the root cause analysis.
Analysis. The inspectors concluded that a performance deficiency was identified
associated with timely notification to state and local governmental agencies during an
actual event. AmerGen did not notify state and local governmental agencies within the
required 15 minutes after declaring a UE. The inspectors also determined that this
finding was indicative of a cross-cutting weakness in the area of human performance
(personnel).
This self-revealing finding was greater than minor because it is associated with the EP
cornerstone attribute of RO performance (actual event response). It affects the
cornerstone objective of ensuring the capability to implement measures to protect the
health and safety of the public during an emergency. The inspectors reviewed this
finding using IMC 0609, Appendix B, "Emergency Preparedness Significance
Determination Process, Sheet 2, Actual Event Implementation Problem. Although a
timely notification was not made for either the UE or Alert condition, the inspectors
based the significance evaluation on a UE classification since the shift manager
ultimately declared a UE. The finding has low safety significance (Green) because it
was a failure to implement a risk significant planning standard during an actual event
associated with the declaration of a UE.
Enforcement. In accordance with 10 CFR 50.54(q), a licensee authorized to possess
and operate a nuclear power reactor shall follow and maintain in effect emergency plans
which meet the standards in 10 CFR 50.47(b). In accordance with 10 CFR 50.47(b)(5)
procedures shall have been established for notification of state and local response
organizations. Also,10 CFR Part 50, Appendix E.D.3, states that a licensee shall notify
the state and local governmental agencies within 15 minutes after declaring an event.
Contrary to the above, during the August 6, 2005, event, the licensee declared a UE at
4:03 a.m. and completed the notification to the State and local governmental agencies
8
Enclosure
at 4:26 a.m. Therefore, AmerGen did not notify state and local governmental agencies
within the required 15 minutes after making a declaration. Timely offsite notifications
enable state and local agencies to make decisions for taking initial offsite response
measures that could affect the general public. Since the violation was of very low safety
significance (Green) and since AmerGen entered the deficiency in to their correction
action program under IR 360630, this finding is being treated as an NCV, consistent with
Section VI.A of the NRC Enforcement Policy. (NCV 05000219/2005011-03, Late State
Notification of UE)
4.0
EVENT ROOT CAUSES AND CAUSAL FACTORS
Cornerstone: Miscellaneous
4.1
Root Causes Analysis
a.
Inspection Scope
The inspectors reviewed AmerGens Root Cause Analysis Report, Revision 0 (IR
360630) and interviewed the root cause team leader to assess AmerGens capability to
determine the events causal factors for implementing the appropriate corrective actions
to prevent recurrence. Also the inspector reviewed Oyster Creek Procedure LS-AA-125-
1001, Root Cause Analysis Manual, to determine if the root cause analysis was
conducted in accordance with the procedure.
b.
Findings
Introduction: The NRC identified a green finding for ineffective corrective actions in that
the root cause analysis team did not correctly identify the amount of time Alert
conditions existed during the August 6, 2005, event. AmerGen initiated some of their
immediate corrective actions and their analysis of the significance of this event based on
the Alert lasting for five minutes when it actually lasted for approximately 45 minutes.
Description: NRC inspectors conducted interviews and reviewed operator logs to verify
and validate the licensees event time line and conclusions of the root cause analysis
report. The inspectors identified a significant discrepancy in the licensees event time
line concerning the amount of time the plant was in the Alert condition. The root cause
team had determined that the plant had only been in an Alert condition for a period of
approximately five minutes (3:05 a.m. - 3:10 a.m.) because the level was reported as
slowly rising. However, the NRC inspector discovered during an interview with the STA,
that at 3:35 a.m., the STA requested a pressure level measurement which was reported
at 0 psig. Apparently, the water continued to fluctuate until the second circulating water
pump was secured at 3:45 a.m. The STA stated it was due to this, he recommended to
the shift manager to declare an Alert. Thus, it appears the plant was actually in Alert
conditions for approximately 45 minutes versus the five minutes concluded by the root
cause team.
As a result of the erroneous assumption regarding the duration of the Alert, standing
orders were issued which stated that an event that terminates before identification,
should still be classified and reported, but not declared to implement the E-Plan. They
9
Enclosure
provided further guidance concerning a short spike where conditions rapidly recovered
above the EAL threshold. The appropriate action implied by the briefing, was the event
should have been classified after-the-fact, but not declared.
Based on information provided by the NRC, the licensee issued a revised version of the
root cause report and entered this issue into their corrective action process.
Analysis: A performance deficiency occurred in which AmerGens staff did not properly
determine the amount of time the plant was in an Alert condition as part of a root cause
analysis. Not determining all the significant facts, did not meet the intent of Procedure
LS-AA-125-1001, Root Cause Analysis Manual. The performance deficiency was that
the licensee inaccurately determined the duration that Alert conditions existed during the
August 6, 2005, event, and influenced some of the corrective actions that were
developed to prevent recurrence. The finding was more than minor because if left
uncorrected, it could have resulted in a more significant safety concern. Specifically,
failure to accurately identify information pertaining to operating events can lead to
deficiencies in corrective actions. Specifically, AmerGen initiated some of their
immediate corrective actions and their analysis of the significance of this event based on
the Alert lasting for a short duration. The inspectors also determined that this finding
was indicative of a cross-cutting weakness in the area of problem identification and
resolution.
This finding is not suitable for significance determination process evaluation, but has
been reviewed by NRC management and is determined to be a finding of very low
safety significance (Green). There was no direct impact on human performance and
equipment reliability, and the NRC intervened so that appropriate corrective actions
could be performed. This issue was entered into the licensees corrective action
program as IR No. 00384615. Because this finding does not involve a violation of
regulatory requirements and has very low safety significance, it is identified as FIN
05000219/2005011-04, Inadequate Root Cause Analysis.
Enforcement: Enforcement action does not apply because the performance deficiency
did not involve an explicit violation of a requirement.
5.0
Licensee-Identified Violations
The following finding of very low significance was identified by AmerGen and is a
violation of NRC requirements which meets the criteria of Section VI of the NRC
Enforcement Policy, NUREG-1600 for being dispositioned as a non-cited violation.
In accordance with 10 CFR 50.47(b)(2), adequate staffing must be provided for
initial facility accident response and maintained at all times. Contrary to the
above, during the August 6, 2005, event, both the STA and on-shift
communicator did not perform their emergency response duties in a timely
manner. This was identified in a root cause analysis report and documented in
the licensees corrective action program as IR 360630. This finding was
considered not more than Green significance because it did not constitute a
failure to meet a risk significant planning standard. The inspectors determined
10
Enclosure
that this finding was indicative of a cross-cutting weakness in the area of human
performance (personnel).
6.0
Meetings, including Exit
On September 23, 2005, the inspector presented the inspection results to Mr. B.
Swenson and other AmerGen staff. The inspector confirmed that no proprietary
information was provided or examined during the inspection.
A-1
Attachment
ATTACHMENT A
SUPPLEMENTAL INFORMATION
KEY POINTS OF CONTACT
Licensee Personnel
J. Kandasamy, Manager, Regulatory Assurance and Licensing
J. Karkoska, Exelon, MAROG EP Manager
K. Poletti, Site EP Manager
R. Detwiler, Plant Operations Manager
J. Freeman, Plant Operations Superintendent
J. Hackenberg, Training Manager
P. Cervenka, Root Cause Team Leader
R. Brown, Prompt Investigation Team Leader
New Jersey State Department of Environmental Protections
R. Russell, Nuclear Engineer, Bureau of Nuclear Engineering (BNE)
D. Zannoni, Supervisor, Nuclear Engineering, BNE
LIST OF ITEMS OPENED, CLOSED, AND DISCUSSED
Opened
EAL Matrix Not Reviewed For Declaring an Alert
(Section 3.1)
Opened and Closed
Failure to Follow Procedures
(Section 2.1)05000219/2005011-03
Untimely State/Local Notification of UE
(Section 3.1)05000219/2005011-04
Inadequate Root Cause Analysis
(Section 4.1)
Discussed
None
A-2
Attachment
LIST OF DOCUMENTS REVIEWED
Procedures
Exelon Standardized Emergency Plan
Oyster Creek Radiological Emergency Plan
Oyster Creek Emergency Plan Implementing Procedures
OP-OC-100, Oyster Creek Conduct of Operations, Revision 4
EPIP-OC-.01, Classification of Emergency Conditions, Revision 14
EP-OC-114-100, State/Local Notifications, Revision 0
EP-OC-112-100, Control Room Operations, Revision 2
OP-AA-106-101-1001, Event Response Guidelines
LS-AA-125-1001, Root Cause Analysis Guidelines
Corrective Action Reports
IR No. 00360630, UE Declared on August 6, 2005 Due to Low Intake Level
IR No. 00360632, Heavy Grassing at Intake Collapses 3 North Intake Grates
IR No. 00360667, Intake Trash Rake Cable Damaged During Grating Collapse
IR No. 00360670, State/Local Phones Found Inoperable in Intake Level Event
IR No. 00360716, Opportunity To Capture Key Decisions in Operator Logs Missed
IR No. 00360956, Returned to Full Power 4.5 Hrs. Prior Than Shown
IR No. 00361537, Suggested Intake Improvements
IR No. 00362061, Problems at Intake Leading to Alert Declaration on 8/6/2005
IR No. 00362269, OCC Critique for Aug 6th Intake Grassing Event
IR No. 00362338, Revised EP-OC-114-100 Attachment 1
IR No. 00362472, Issues w/OC EAL Matrix
IR No. 00362554, Data Supports an Earlier LCO Entry Time for 8/6/5 ESW LCO
IR No. 00362628, Prompt Investigation Not Commenced in a Timely Manner
IR No. 00365568, NOS Identifies Inadequate ABN-32 Procedure Guidance
IR No. 00366205, Latest OC NLO Class did not Receive Shift Comm. DLA
IR No. 00371847, NOS ID Error Likely Situation During OC EAL Change
IR No. 00384615, Root Cause Report Missing Data Point
CAP No. 02003-2361, Plant Required Rapid Reduction in Power Due to Debris
CAP No. 02004-0165, Unexpected Low Intake Level Event on January 16, 2004
CAP No. 02004-0123, UE Declared on January 16, 2004 Due to Low Intake Level
Miscellaneous
Root Cause Analysis, IR Number 360630, dated September 13, 2005, Revision 0
Oyster Creek Prompt Investigation Report
Independent Review Team Assessment, dated August 15, 2005, Rev. 0
State/Local Notification Form for the UE
State/Local Notification Form for Termination of the Event
Memorandum from State of New Jersey, dated August 10, 2005, Oyster Creek Event
Reactor Plant Event Notification Worksheet No. 41899
Event Summary Report
E-Plan EAL Event Termination and Shift Communicator Expectations White Paper
Operations Standing Order Nos. 69 and 70
LS-AA-125-1001, Root Cause Investigation, dated January, 22, 2004, Low Intake Events
A-3
Attachment
LIST OF ACRONYMS
ABN
Abnormal Operating Procedure
Apparent Violation
Corrective Action Process
Emergency Action Level
Emergency Response Organization
Emergency Service Water
IMC
Inspection Manual Chapter
IR
Issue Report
LCO
Limiting Condition for Operation
Non-Cited Violation
NRC
Nuclear Regulatory Commission
Publicly Available Records
Psig
Pounds per Square Inch Gauge
Response Organization
Risk Significant Planning Standard
Significant Determination Process
Shift Manager
Unusual Event
B-1
Attachment
ATTACHMENT B
SEQUENCE OF EVENTS
Entries that appear in italics are notes or observations made by the NRC inspection team.
Times that appear in italics are due to approximations. All entries were obtained from control
room logs, interviews conducted by both the licensee and the NRC, and event notification
forms.
Initial Plant Conditions (Pre-Event) - 100% Reactor Power
Time
Event
[August 5, 2005]
23:00
Higher than normal levels of grass at intake structure reported to control room.
Plant personnel performed backwashing, raking and screen cleaning in attempts
to keep flow through the intake screens.
[August 6, 2005]
01:57
Received alarm k-5-e Intake Screen P Hi into the control room. This was due
to high traveling water screen differential pressure. Alarm cleared within a few
minutes. This was the operators first indication the grass was impeding water
flow.
02:05
On-shift communicator reports to intake structure from rad waste building
(normal duty station) to assist in removing debris.
02:35
Received alarm k-5-e Intake Screen P Hi for second time. Entered Abnormal
Procedure ABN-32, Abnormal Intake Level. Intake level pressure indicator is
less than 1.4 psig or -2.0 ft mean sea level. ABN-32 requires monitoring the
water level at 15 minute intervals. No monitoring schedule was established. No
review of EAL matrix was performed. (UE threshold is <0.94 psig and Alert
threshold is <0.5 psig.)
02:54
STA leaves control room and reports to the intake structure as field supervisor.
03:00
North side #1 traveling screen grate collapsed, traveling screen pin #1 shear pin
had broken.
03:05
Control room receives report that all three traveling screens had broken shear
pins. Screen damage confirmed. Performed rapid power reduction to 75%
power by reducing reactor recirculation flow. Control room informed that the
intake level instrument for the north side indicated 0 psig on the bubble gage.
Plant conditions for the Alert were reached at this time. Since level was not
monitored it is unknown at what time conditions crossed the threshold for a UE.
B-2
Attachment
03:10
No.1-1 main circulator pump removed from service. This was due to the loss of
all north intake traveling screens. No. 2 NRW SW pump was started and #1
pump was secured.
03:10
Water level is noted to have recovered to 0.5 psig and slowly rising. This was
not reported back to the control room.
0313
No. 1-1 service water pump removed from service. This was due to loss of all
north intake traveling screens.
03:15
A-Reactor Water Cleanup removed from service. This was due to partial loss of
cooling to reactor building closed cooling water system.
03:30
Entered: LCO 3.4.C.3. Unplanned. Risk = Yellow action statement; the reactor
may remain in operation for a period not to exceed 7 days provided remaining
containment spray system loop and its associated emergency service water
system loop each have no inoperable components and are verified daily to be
operable. Emergency service water system no.1 and its associated containment
spray system loop is declared inoperable due to loss of the north side screens.
03:34
STA returned to control room, reviewed plant conditions and EAL matrix.
03:35
STA requested another reading of the water level which is reported at 0 psig.
STA made recommendation to declare an Alert. This was the first time the EAL
matrix was reviewed. Although the level initially recovered at 03:10 hours, it
appears the level continued to fluctuate.
03:40
Power is reduced to 44% to remove loads from north side of intake structure.
03:40
Shift Manager reviewed EAL basis document for clarification on the Alert
classification.
03:45
No.1-2 Main circulation water pump removed from service. All north side intake
loads were transferred to the south side intake structure or removed from
service.
03:50
Control room received report that the lower trash grate at No.1-2 traveling screen
had collapsed - intake structure trash rake was stuck where the grating was
damaged.
03:50
Control room is informed that the intake pressure gauge indicated 2.7 psig and
steady. This indicated that the plant was no longer in a Alert condition.
03:55
Communicator returned to rad waste building to take required 04:00 surveillance
readings.
04:00
No. 1-3 traveling screen returned to service.
B-3
Attachment
04:03
SM assumed the duty of Emergency Director and declared a UE. Shift manager
log stated, The north intake water level had been at EAL for an Alert but had
recovered to level for EAL for a UE. The 15-minute notification clock begins.
04:05
Control Room informs the communicator that he is needed in the control room.
04:08
Station alarm sounded and an announcement was made that a UE was
declared.
04:10
No. 1-2 Traveling screen returned to service.
04:11
Communicator entered control room. Shift manager informed communicator that
plant was at an Alert and de-escalated to a UE.
04:15
Communicator attempted to make the offsite notifications using the automatic
ring-down phones. Phone was out of service. This was due to a storm from the
previous evening had tripped a circuit breaker.
04:20
Communicator manually dialed telephone number. This is the backup method to
the ring-down phone.
04:26
Notification completed.
04:30
Intake trash rake returned to service for screens 4, 5, 6 only. Upper grate on No.
1 bay and middle grates on No. 2 and No. 3 bays had collapsed.
04:43
NRC notified of event.
04:50
No. 1 screen returned to service. All north screens were in service. No. 1 and
No. 2 high pressure and No. 4 low-pressure screen wash pumps were in service.
04:55
No. 1 service water pump returned to service.
0755
UE Terminated.
08:11
Exited procedure ABN-32. This was due to satisfactory intake levels above the
requirements to enter ABN-32.
09:08
Exited LCO: 3.4.C.3. Risk is Yellow. This is due to emergency service water
system No. 1 and its associated containment spray system loop was declared
operable after starting each emergency service water pump in system No. 1 and
verifying pumps responded appropriately to a start and 5 minute run. There was
no indication of any air binding. Discharge pressures, system flows and pump
amps all were normal. The north intake was functionally available but degraded,
and as such pant risk remained at yellow until both the north side intake
collapsed racks were replaced and the plant returned to full power.