ML090720462
| ML090720462 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 03/13/2009 |
| From: | Wert L Division Reactor Projects II |
| To: | Madison D Southern Nuclear Operating Co |
| References | |
| EA-09-054 IR-08-009 | |
| Download: ML090720462 (11) | |
See also: IR 05000321/2008009
Text
OFFICIAL USE ONLY - PROPRIETARY INFORMATION
UNITED STATES
NUCLEAR REGULATORY COMMISSION
REGION II
SAM NUNN ATLANTA FEDERAL CENTER
61 FORSYTH STREET, SW, SUITE 23T85
ATLANTA, GEORGIA 30303-8931
March 13, 2009
Mr. Dennis R. Madison
Vice President
Southern Nuclear Operating Company, Inc.
11028 Hatch Parkway, North
Baxley, Georgia 31513
SUBJECT: EDWIN I. HATCH NUCLEAR PLANT, NRC INSPECTION REPORT
05000321/2008009 AND 05000366/2008009 AND PRELIMINARY WHITE
FINDING
Dear Mr. Madison:
On March 10, 2009, the Nuclear Regulatory Commission (NRC) completed an in-office
inspection of the 1B Emergency Diesel Generator (EDG) generator coupling failure which
occurred on July 12, 2008. Additional inspection activities were documented in NRC Special
Inspection Report 05000321/2008008 and 05000366/2008008, which was issued on
September 6, 2008.
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.
Based on the results of this inspection, a finding was identified involving the failure to identify
and correct cracks observed during routine maintenance inspections which resulted in
degradation of the 1B EDG generator coupling. Consequently, the generator coupling failed
during a routine surveillance test causing the 1B EDG to be declared inoperable on July 12,
2008. On July 16, 2008, the generator coupling was replaced and the 1B EDG returned to
service.
This finding was assessed, based on the best available information, including influential
assumptions, using the applicable Significance Determination Process (SDP) and was
preliminarily determined to be a low to moderate safety significance (White) finding. The final
resolution of this finding will convey the increment in the importance to safety by assigning the
corresponding color, i.e., White, a finding with low to moderate increased importance to safety
that may require additional NRC inspections. The dominant accident sequences involved: (1)
Loss of offsite power (LOOP) with loss of emergency power (2) a Transient induced LOOP with
failures of primary containment suppression (PCS) and high pressure coolant injection (HPCI)
(3) LOOP with loss of emergency power, reactor core isolation cooling (RCIC), and HPCI with
failure to recover offsite power and the EDGs. These events ultimately could result in the loss of
all injection due to inability to recover EDGs or offsite power leading to core damage. The
exposure period was a total of 182 days including the 4 day repair interval and the178 day
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SNC 2
interval consisting of the individual success periods. The SDP analysis included an increase in
the EDG common cause fail to run probability due to failure of the 1B EDG. All five Hatch EDGs
were vulnerable to an increased likelihood of coupling failure because all couplings had similar
age related deterioration, environmental conditions and overall operating history. The 1B EDG
coupling experienced a catastrophic failure during voluntary testing while the other couplings
had indications of the same degradation mechanism. As such, the EDG coupling components
met the criteria for common cause treatment in the Risk Assessment of Operational Events
(RASP) Handbook Volume 1 Internal Events (Revision1.01), sections 3.4 pages 3-6. The
NRCs evaluation of the common cause within the SDP analysis recognized that the 1B EDG,
being the swing diesel for Hatch, had approximately 20% more operating hours on its coupling
than the other EDGs; however, the increased common cause probability for the other couplings
was still considered to be applicable for environmental, age and other considerations. The SDP
analysis is included as Enclosure 2.
The finding is also an Apparent Violation (AV) of 10 CFR 50 Appendix B Criterion XVI,
Corrective Action, for failure to identify and correct a condition adverse to quality and is being
considered for escalated enforcement in accordance with the Enforcement Policy. In addition,
this finding is considered to have a cross-cutting aspect related to the identification of issues
P.1(a), as described in the corrective action program component of the problem identification
and resolution cross-cutting area. Accordingly, for administrative purposes, Unresolved Item
05000321, 366/2008008-01 is considered closed. The current Enforcement Policy is included
on the NRCs website at http://www.nrc.gov/about-nrc/regulatory/enforcement/enforce-pol.html.
In accordance with Inspection Manual Chapter (IMC) 0609, we intend to complete our evaluation
using the best available information and issue our final determination of safety significance
within 90 days of the date of this letter. The SDP encourages an open dialogue between the
staff and the licensee; however, the dialogue should not impact the timeliness of the staffs final
determination. 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 approximately 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. The NRC will also issue a press release to announce the conference. If
you decide to submit only a written response, such a submittal should be sent to the NRC within
30 days of the receipt of this letter.
Please contact Mr. Scott Shaeffer at (404) 562-4521 within 10 business days of the date of your
receipt of this letter to notify the NRC of your intentions. If we have not heard from you within 10
business 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.
Since the NRC has not made a final determination in this matter, no Notice of Violation is being
issued for this inspection finding at this time. In addition, please be advised that the number and
characterization of the apparent violation may change as a result of further NRC review.
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SNC 3
In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and
enclosure 1 will be made available electronically for public inspection in the NRC Public
Document Room or from the NRC=s document system (ADAMS), accessible from the NRC Web
site at http://www.nrc.gov/reading-rm/adams.html.
Sincerely,
/RTM RA for/
Leonard D. Wert, Jr., Director
Division of Reactor Projects
Docket Nos.: 50-321, 50-366
License Nos.: DRP-57, NPF-5
Enclosures: 1. NRC Inspection Report 05000321/2008009 and 05000366/2008009
2. SDP Phase 3 Summary (OFFICIAL USE ONLY - PROPRIETARY
INFORMATION)
cc w/encl.: (See page 4)
cc w/o encl. 2: (See page 4)
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_________________________ X SUNSI REVIEW COMPLETE /SMS/
OFFICE RII:DRP RII:DRP RII:EICS RII:DRP RII:DRP RII:EICS RII:DRS
SIGNATURE JAH /via email/ TXL /RA/ SMS /RA/ JTM /RA/ CFE /via email/ GMD /via email/
NAME JHickey TLighty SSparks SShaeffer JMunday CEvans GMcDonald
DATE 03/10/2009 03/10/2009 03/11/2009 03/13/2009 03/11/2009 03/10/2009
E-MAIL COPY? YES NO YES NO YES NO YES NO YES NO YES NO YES NO
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SNC 4
cc w/encl:
Jeffrey T. Gasser Cynthia Sanders
Executive Vice President Program Manager
Southern Nuclear Operating Company, Inc. Radioactive Materials Program
P.O. Box 1295 Department of Natural Resources
Birmingham, AL 35201-1295 4220 International Parkway
Suite 110
L. Mike Stinson Atlanta, GA 30354
Vice President
Fleet Operations Support Reece McAlister
Southern Nuclear Operating Company, Inc. Executive Secretary
P.O. Box 1295 Public Service Commission
Birmingham, AL 35201-1295 244 Washington Street, SW
Atlanta, GA 30334
David H. Jones
Vice President Chairman
Engineering Appling County Commissioners
Southern Nuclear Operating Company, Inc. County Courthouse
P.O. Box 1295 69 Tippins Street, Suite 201
Birmingham, AL 35201-1295 Baxley, GA 31513
Moanica Caston Mr. K. Rosanski
Vice President and General Counsel Resident Manager
Southern Nuclear Operating Company, Inc. Oglethorpe Power Corporation
Bin B-022 Hatch Nuclear Plant
P.O. Box 1295 P.O. Box 2010
Birmingham, AL 35201-1295 Baxley, GA 31515
cc w/o encl: Senior Engineer
Laurence Bergen Power Supply
Oglethorpe Power Corporation Municipal Electric Authority of Georgia
2100 East Exchange Place 1470 Riveredge Parkway NW
P.O. Box 1349 Atlanta, GA 30328-4684
Tucker, GA 30085-1349
Arthur H. Domby, Esq.
Troutman Sanders
Nations Bank Plaza
600 Peachtree Street, NE, Suite 5200
Atlanta, GA 30308-2216
Dr. Carol Couch
Director
Environmental Protection
Department of Natural Resources
2 Martin Luther King Drive, S.E.
Suite 1152 East Tower
Atlanta, GA 30334
OFFICIAL USE ONLY - PROPRIETARY INFORMATION
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SNC 5
Letter to Mr. Dennis Madison from Leonard D. Wert, Jr. dated March 13, 2009
SUBJECT: EDWIN I. HATCH NUCLEAR PLANT, NRC INSPECTION REPORT
05000321/2008009 AND 05000366/2008009 AND PRELIMINARY WHITE
FINDING
Distribution w/encl:
C. Evans, RII
L. Slack, RII EICS
OE Mail
RIDSNRRDIRS
PUBLIC
R. Martin, NRR
D. Wright, NRR
B. Westreich, NSIR (hard copy w/encl)
E. McNiel, NSIR (hard copy w/encl)
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OFFICIAL USE ONLY - PROPRIETARY INFORMATION
U.S. NUCLEAR REGULATORY COMMISSION
REGION II
Docket No.: 05000321, 05000366
Report No.: 05000321/2008009 and 05000366/2008009
Licensee: Southern Nuclear Operating Company, Inc.
Facility: Edwin I. Hatch Nuclear Plant
Location: Baxley, GA
Dates: July 12, 2008 - March 10, 2009
Inspectors: J. Hickey, Senior Resident Inspector (Section 4OA5, 4OA6)
P. Niebaum, Resident Inspector (Section 4OA5, 4OA6)
G. MacDonald, Senior Reactor Analyst (Section 4OA5)
T. Lighty, Project Engineer (Section 4OA5)
Approved by: Scott M. Shaeffer, Chief
Reactor Projects Branch 2
Division of Reactor Projects
OFFICIAL USE ONLY - PROPRIETARY INFORMATION
Enclosure 1
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SUMMARY OF FINDINGS
IR 05000321,366/2008-009; 7/12/2008-3/10/2009; Edwin I. Hatch Nuclear Plant; Unit 1; Other
Activities.
The report transmits the results of the NRCs preliminary assessment of the 1B Emergency
Diesel Generator coupling failure. One Apparent Violation with potentially low to moderate
safety significance (White) was identified. The significance of most findings is indicated by its
color (Green, White, Yellow, or Red) using Inspection Manual Chapter (IMC) 0609, ASignificance
Determination Process@ (SDP). Findings for which the SDP does not apply may be Green or
assigned a severity level after management review. The NRC's program for overseeing the safe
operation of commercial nuclear power reactors is described in NUREG-1649, AReactor
Oversight Process.
Cornerstone: Mitigating Systems
C TBD. A self-revealing apparent violation of 10 CFR 50, Appendix B, Criterion XVI,
Corrective Action, was identified for failure to promptly identify and correct a condition
adverse to quality. Since 1988, the licensee had observed cracks in the glands of the EDG
couplings, but did not identify the cracking was an indication of coupling degradation.
Therefore, no condition report was written to identify and correct the condition adverse to
quality. Consequently, the 1B coupling developed higher than normal vibration on July 12,
2008, during a routine surveillance which prompted the licensee to declare the 1B EDG
The failure to promptly identify and correct a condition adverse to quality for the
observed degraded condition of the 1B EDG coupling is a performance deficiency.
This finding is more than minor because it was associated with the Equipment
Performance attribute of the Mitigating Systems cornerstone and adversely affected
the objective in that there was no reasonable assurance the 1B EDG could meet its
mission time. This finding was assessed using the applicable SDP and preliminarily
determined to White because there was a calculated risk increase over the base
case between 1E-5 and 1E-6. The dominant sequences included (1) LOOP with
loss of emergency power (SBO), success of RCIC, successful depressurization,
failure to recover offsite power and the EDGs within 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />, and failure of firewater
injection due to repressurization caused by inability to operate SRVs without DC
power (2) a Transient induced LOOP with failures of PCS and HPCI, successful
depressurization and failure of all injection due to inability to recover EDGs or offsite
power and (3) LOOP with loss of emergency power, RCIC, and HPCI with failure to
recover offsite power and the EDGs. The HPCI system is failed in the model with
loss of room cooling due to SBO. The exposure period was a total of 182 days
including the 4 day repair interval and the 178 day interval consisting of the
individual success periods.
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Enclosure 1
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REPORT DETAILS
4. OTHER ACTIVITIES
4OA5 Other
(Opened) Apparent Violation (AV) 05000321,366/2008009-001, 1B EDG Coupling Failure
a. Inspection Scope
The inspectors conducted a review and significance evaluation of the failure of the 1B
b. Findings
Introduction. A self-revealing apparent violation of 10 CFR 50, Appendix B, Criterion
XVI, Corrective Action, was identified for failure to promptly identify and correct a
condition adverse to quality. Since 1988, the licensee had observed cracks in the glands
of the EDG couplings, but did not identify the cracking was an indication of coupling
degradation. Therefore, no condition report was written to identify and correct the
condition adverse to quality. Consequently, the 1B coupling developed higher than
normal vibration due to coupling degradation on July 12, 2008, during a routine
surveillance which prompted the licensee to declare the 1B EDG inoperable.
Description. On July 12, 2008, the 1B EDG was manually shutdown due to excessive
vibration and declared inoperable. As part of the troubleshooting effort, vibration
monitoring equipment was installed for an unloaded maintenance run of the 1B EDG on
July 14, 2008. This run was stopped after approximately 45 minutes due engine block
vibration levels exceeding an operational limit recently supplied by the EDG vendor.
Post-event inspections by the licensee identified several cracks of the rubber gland on
both the diesel engine flywheel side and the generator side of the coupling. It was later
determined that the cause of the excessive vibration was the age-related cracks in the
rubber gland of the EDG coupling. Subsequent to the 1B EDG coupling vibration issues,
the licensee replaced all five EDG couplings. During the root cause analysis, the
licensee determined that cracks on the 2C EDG coupling had been observed as early as
1988 and similar cracks had been seen on the other EDG couplings. However, these
conditions were not documented during routine maintenance inspections and no
condition report was written to identify this condition adverse to quality. As the condition
was not identified, corrective actions were not taken to address the degraded conditions.
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Enclosure 1
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4
In November 2008, the licensee completed voluntary offsite testing on the 1B EDG
coupling to determine if the 1B EDG could meet the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> mission time. The coupling
catastrophically failed about 30 minutes into a fully loaded 2-hour test run. This indicated
that the 1B EDG would not have met its mission time. The failure mechanism was
determined to be age related deterioration of the coupling combined with running the 1B
EDG in its fully loaded condition. This resulted in high stress on the EDG couplings.
However, start-up torque conditions could also have contributed to coupling deterioration.
The 1B EDG had 20% more run time than the other EDGs (approximately 2754 hours0.0319 days <br />0.765 hours <br />0.00455 weeks <br />0.00105 months <br /> vs.
2200 hours0.0255 days <br />0.611 hours <br />0.00364 weeks <br />8.371e-4 months <br />). Therefore, the 1B EDG coupling was considered to be the bounding case
for all the EDGs with regards to run hours. The 1C EDG coupling did not fail during the
full load offsite testing and all other EDG couplings did not exhibit any operational
problems prior to replacement in 2008. However, the EDG couplings had several strong
factors which support common cause treatment including common hardware,
maintenance program, environment, equipment age, operating hours and similar
degradation.
Analysis. The failure to identify and correct a condition adverse to quality for the
observed degraded condition of the 1B EDG coupling is a performance deficiency. This
finding is more than minor because it was associated with the Equipment Performance
attribute of the Mitigating Systems cornerstone and adversely affected the objective in
that there was no reasonable assurance the 1B EDG could meet its mission time. This
finding was assessed using the applicable SDP and preliminarily determined to White
because there was a calculated risk increase over the base case between 1E-5 and 1E-
6. The analysis included an increase in the emergency diesel generator (EDG) common
cause fail to run probability due to all five Hatch EDGs being vulnerable to an increased
likelihood of coupling failure due to degraded couplings. All couplings had similar age
and operating history and one EDG coupling suffered a catastrophic failure while the
other couplings had indications of the same degradation mechanism which meets the
criteria for common cause treatment in the Risk Assessment of Operational Events
(RASP) Handbook Volume 1 Internal Events, sections 3.4 page 3-6. The dominant
sequences included (1) LOOP with loss of emergency power (SBO), success of RCIC,
successful depressurization, failure to recover offsite power and the EDGs within 5
hours, and failure of firewater injection due to repressurization caused by inability to
operate SRVs without DC power (2) a Transient induced LOOP with failures of PCS and
HPCI, successful depressurization and failure of all injection due to inability to recover
EDGs or offsite power and (3) LOOP with loss of emergency power, RCIC, and HPCI
with failure to recover offsite power and the EDGs. The HPCI system is failed in the
model with loss of room cooling due to SBO. The exposure period was the 178 day
interval consisting of the individual success periods and a 4 day repair interval for a total
of 182 days.
Enforcement. 10 CFR 50, Appendix B, Criterion XVI, Corrective Action, states in part
that measures shall be established to assure that conditions adverse to quality are
promptly identified and corrected. Contrary to the above, the licensee failed to promptly
identify and correct a condition adverse to quality. Since 1988, the licensee had
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Enclosure 1
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5
observed cracks in the EDG couplings, but did not identify the cracking as an indication
of coupling degradation. The licensee did not document the conditions during routine
maintenance inspections and no condition report was written to identify and correct this
condition adverse to quality. Consequently, the 1B coupling developed higher than
normal vibration on July 12, 2008, during a routine surveillance which prompted the
licensee to declare the 1B EDG inoperable. In addition, this finding is considered to have
a cross-cutting aspect related to the identification of issues P.1(a), as described in the
corrective action program component of the problem identification and resolution cross-
cutting area. Specifically, that the licensee identifies issues completely, accurately, and
in a timely manner commensurate with their safety significance. URI 05000321,
366/2008008-01, which was opened during the special inspection is considered closed.
Pending final significance determination, this finding is identified as Apparent Violation
(AV) 05000321,366/2008009-01, 1B EDG Coupling Failure.
4OA6 Meetings, Including Exit
On March 10, 2009, the NRC presented the inspection results to Mr. Dennis Madison
who acknowledged the findings.
ATTACHMENT: SUPPLEMENTAL INFORMATION
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Enclosure 1
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SUPPLEMENTAL INFORMATION
LIST OF REPORT ITEMS
Opened
05000321, 366/2008009-01 AV 1B EDG Coupling Failure (Section 4OA5)
Closed
05000321, 366/2008008-01 URI Review of EDG Coupling Root Cause Evaluation (Section
4OA5.3).
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Enclosure 1