1CAN080902, Arkansas Nuclear One, Unit 1, Response to Request for Information Regarding Steam Generator Tube Integrity During Break in Upper Hot Leg Piping: Difference between revisions

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{{Adams
#REDIRECT [[1CAN080902, Response to Request for Information Regarding Steam Generator Tube Integrity During Break in Upper Hot Leg Piping]]
| number = ML092530659
| issue date = 08/31/2009
| title = Arkansas Nuclear One, Unit 1, Response to Request for Information Regarding Steam Generator Tube Integrity During Break in Upper Hot Leg Piping
| author name = Walsh K T
| author affiliation = Entergy Operations, Inc
| addressee name =
| addressee affiliation = NRC/Document Control Desk, NRC/NRR
| docket = 05000313
| license number = DPR-051
| contact person =
| case reference number = 1CAN080902, TAC MD7178
| document type = Letter type:
| page count = 7
| project = TAC:MD7178
| stage = Response to RAI
}}
 
=Text=
{{#Wiki_filter:1CAN080902  
 
August 31, 2009
 
U.S. Nuclear Regulatory Commission
 
Attn: Document Control Desk
 
Washington, DC  20555
 
==SUBJECT:==
Response to Request for Information Regarding Steam Generator Tube Integrity During Break in Upper Hot Leg Piping  
 
Arkansas Nuclear One, Unit 1
 
Docket No. 50-313
 
License No. DPR-51
 
==REFERENCES:==
: 1. NRC letter dated July 31, 2009, "Arkansas Nuclear One, Unit No. 1 -
Individual Plant Actions Re:  Pressurized-Water Reactor Owners
 
Group Topical Report BAW
-2374, Revision 2, "Risk-Informed Steam Generator Tube Thermal Loads due to Breaks in Reactor Coolant System Upper Hot Let Large-Bore Piping""
(1CNA070901) (TAC No.
MD7178)  2. Entergy letter dated August 14, 2008, "Response to Request for Additional Information Regarding Technical Specification Changes
 
and Analyses Relating to Use of Alternate Source Term"
 
(1CAN080801) (TAC No. MD7178)
 
==Dear Sir or Madam:==
 
By letter dated July 31, 2009 (Reference 1), the NRC requested Babcock & Wilcox (B&W)
 
licensees provide information relating to once-through Steam Generator (SG) tube loads under
 
conditions resulting from postulated breaks in reactor coolant system (RCS) upper hot leg large-
 
bore piping. The letter contained six questions and also requested further dialogue with
 
Arkansas Nuclear One, Unit 1 (ANO-1) to determine impact, if any, on the ANO-1 request to
 
adopt an Alternate Source Term (AST), currently under NRC review. Applicable NRC and
 
ANO-1 personnel participated in a conference call on August 6, 2009 to discuss appropriate
 
responses and the AST submittal. As a result of the call, Entergy Operations, Inc. (Entergy) is
 
providing a response to the questions presented in the NRC July 31, 2009 letter (Reference 1)
 
in Attachment to this letter and is also providing a revised response under separate cover to
 
Question 3 of the Response to Additional Informat ion (RAI) as previously provided in Entergy letter dated August 14, 2008 (Reference 2).
 
Entergy Operations, Inc.
1448 S.R. 333 Russellville, AR  72802
 
Tel  479-858-7721 Kevin T. Walsh Vice President, Operations A rkansas Nuclear One
 
1CAN080902 Page 2 of 2
 
There is one new commitment included in Attachment 2 of this letter.
 
If you have any questions or require additional information, please contact David Bice at
 
479-858-5338.
 
I declare under penalty of perjury that the foregoing is true and correct. Executed on
 
August 31, 2009.
 
Sincerely,
 
Original signed by K. T. Walsh
 
KTW/dbb
 
Attachments:
: 1. Response to Request for Information Regarding Steam Generator Tube Integrity During Break in Upper Hot Leg Piping 2. List of Regulatory Commitments
 
cc: Mr. Elmo Collins Regional Administrator
 
U. S. Nuclear Regulatory Commission
 
Region IV 
 
612 E. Lamar Blvd., Suite 400 Arlington, TX 76011-4125 NRC Senior Resident Inspector
 
Arkansas Nuclear One
 
P.O. Box 310
 
London, AR 72847
 
U. S. Nuclear Regulatory Commission
 
Attn: Mr. Kaly Kalyanam
 
MS O-8 B1
 
Washington, DC  20555-0001
 
Mr. Bernard R. Bevill
 
Arkansas Department of Health
 
Radiation Control Section 4815 West Markham Street Slot #30 Little Rock, AR 72205
 
Attachment to 1CAN080902 Response to Request for Information Regarding Steam Generator Tube Integrity During Break in Upper Hot Leg Piping
 
Attachment to 1CAN080902
 
Page 1 of 2
 
Response to Request for Information Regarding Steam Generator Tube Integrity During Break in Upper Hot Leg Piping By letter dated July 31, 2009, the NRC requested that within 30 days from the date of the letter, each Babcock and Wilcox (B&W) licensee submit a letter providing plans to address the
 
following items resulting from the June 25, 2009, public meeting (Agencywide Documents
 
Access and Management System (ADAMS)
Accession No. ML091820001), regarding once-through steam generator (SG) tube loads under conditions resulting from postulated breaks in
 
reactor coolant system (RCS) upper hot leg large-bore piping. The Entergy Operations, Inc.,
(Entergy) responses for Arkansas Nuclear One, Unit 1 (ANO-1) are included below. ANO-1 is a
 
B&W designed commercial nuclear power facility.
: 1. Confirmation that its justification for continued operation for addressing tube integrity following a large break loss-of-coolant accident (LBLOCA) remains valid. (All B&W
 
licensees)
Response:
 
A condition report (CR-ANO-1-2000-00149) that identified the issue with steam generator
 
tube integrity following a large break Loss of Coolant Accident (LBLOCA), including an
 
operability evaluation of the condition, was generated in March 2000. ANO-1 subsequently
 
replaced its steam generators with Areva-designed enhanced once-through steam
 
generators (EOTSGs) during its fall 2005 refueling outage. The EOTSGs include
 
numerous design enhancements that make them more resilient to failure following a
 
LBLOCA, including Inconel 690 tubing, which is not known to be susceptible to
 
circumferential cracking. The EOTSG tubes have been 100% inspected during each of the
 
two refueling outages since their installation and the only degradation observed has been
 
some minor mechanical wear at tube support plates. The operability evaluation associated
 
with the above referenced Condition Report has been reviewed in light of the current
 
ANO-1 EOTSG condition and the elements of that evaluation remain valid, with the
 
exception of the evaluations of tube re-rolls and the mechanical rolled sleeves, neither of
 
which are applicable to the current EOTSG condition. EOTSG operability continues to be
 
assured with ongoing condition monitoring assessments considering LBLOCA conditions.
: 2. Confirmation that compensatory measures, such as changes to emergency operating procedures, have been incorporated into plant procedures and operator training has been
 
performed. (All B&W licensees)
Response:
 
The single compensatory measure with respect to operator action following a Loss of
 
Coolant Accident (LOCA) that results in a steam generator tube rupture (SGTR) is isolation
 
of the "broken" EOTSG(s) to limit loss of containment sump inventory. The ANO-1
 
Emergency Operating Procedure (EOP) for SGTR includes criteria for isolation of a "bad"
 
EOTSG(s), if conditions warrant, and identification of the valves requiring closure in order
 
to establish that isolation. The criteria are set to ensure isolation occurs before entry of
 
liquid into the main steam lines. The EOP steps are included in the Operator continuing
 
training program.
Attachment to 1CAN080902
 
Page 2 of 2
: 3. Confirmation that Title 10 of the Code of Federal Regulations (10 CFR) 50.46(a)(3) reporting requirements have been satisfied. (All B&W licensees)
Response:
The hot leg U-bend LOCA is not considered reportable under 10 CFR 50.46. The break is
 
not limiting for peak fuel centerline temperature (PCT), not limiting for local oxidation, not
 
limiting for hydrogen generation, and not limiting for coolable core geometry. In addition, the break is not reportable for long-term core cooling, because adequate pump net positive
 
suction head (NPSH) is preserved and long-term core cooling is maintained with automatic
 
and EOP-directed follow-up actions to isolate the secondary side of the EOTSGs upon
 
indication of SGTR.
: 4. Confirmation that all LBLOCAs (including those in the candy-cane region) are considered as design basis accidents in the assessments of SG tube integrity following each SG tube
 
inspection. (All B&W licensees)
Response:
All LBLOCAs (including those in the candy-cane region) are currently considered as design basis accidents in the assessments of SG tube integrity following each SG tube inspection.
: 5. Provide a commitment that an analysis will be performed to confirm that the design of the replacement SGs is sufficient to withstand the loads associated with a LBLOCA including
 
the thermal loads associated with a LBLOCA in the candy-cane region of the RCS and to
 
provide the results of that analysis to the NRC by January 31, 2010. (Three Mile Island
 
Nuclear Station, Unit 1, and Arkansas Nuclear One, Unit 1 (ANO-1))
Response:
Entergy is adopting a License Condition to perform an analysis to confirm that the design of
 
the ANO-1 EOTSGs is sufficient to withstand the loads associated with a LBLOCA, including the thermal loads associated with a LBLOCA in the candy-cane region of the
 
RCS. The License Condition is being adopted in association with the ANO-1 Alternate
 
Source Term (AST) request (see Entergy letter dated August 31, 2009, 1CAN080903).
: 6. Commitment to provide the structural limit associated with the most limiting LBLOCA for the replacement SGs as part of the next SG tube inspection report (required by the technical specifications) following completion of the next inspection of the tubes in the replacement
 
SGs, unless previously submitted. (All B&W licensees)
Response:
Entergy will provide the structural limit associated with the most limiting LBLOCA for the
 
ANO-1 EOTSGs as part of the next EOTSG tube inspection report (required by Technical
 
Specification 5.6.7) following completion of the next inspection of the tubes in the ANO-1
 
EOTSGs (see Attachment 2).
 
Attachment 2 to 1CAN080902 List of Regulatory Commitments    to 1CAN080902
 
Page 1 of 1
 
LIST OF REGULATORY COMMITMENTS The following table identifies those actions committed to by Entergy Operations, Inc. (Entergy)
 
in this document. Any other statements in this submittal are provided for information purposes and are not considered to be regulatory commitments.
 
TYPE (Check one)
COMMITMENT ONE-TIME ACTION CONTINUING COMPLIANCE SCHEDULED COMPLETION DATE Entergy will provide the structural limit associated with the most limiting large
 
break Loss of Coolant Accident (LBLOCA)
 
for the Arkansas Nuclear One, Unit 1 (ANO-1) enhanced once-through steam
 
generators (EOTSGs) as part of the next
 
EOTSG tube inspection report (required
 
by Technical Specification 5.6.7) following
 
completion of the next inspection of the
 
tubes in the ANO-1 EOTSGs. Within 180 days after the initial entry into Mode 4 following completion of the next inspection performed in accordance with the Specification 5.5.9, Steam Generator (SG)
Program}}

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