05000331/LER-2006-002, Regarding Drywell Penetrations Calculations Do Not Account for Thermal Movement
| ML061640263 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 06/01/2006 |
| From: | Vanmiddlesworth G Florida Power & Light Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NG-06-0375 LER 06-002-00 | |
| Download: ML061640263 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(v), Loss of Safety Function |
| 3312006002R00 - NRC Website | |
text
FPL Energy Duane Arnold, LIC 3277 DAEC Road Palo, Iowa 52324 FPL Energy.
Duane Arnold Energy Center June 1, 2006 NG-06-0375 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555--.000V1-Duane Arnold Energy Center Docket 50-331 License No. DPR-49 Vol untary Lice nsee EBtnt'RioDort #2006,-002-00 Please find attached the sul~ject Voluntary Licensee Event Report (LER) submitted in accordance with IAI,CFR 50.73.
Thig letter ciointa'ins the following new commitment:
Complete actions to determine if any past operability concerns existed for the 15 drywell penetrations that have been modified. The past operability evaluations are to be completed by October 31, 2006.
Ga' D. Van Middlesworth Vice President, Duane Arnold, Energy Center FP nrgy ua'n ArnoldtLLC
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EC, USNIAC Resident Inspector, DAEC, USNRC
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"~A~V NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 06/30/2007 (r-2004)
Estimated burden per response to comply with this mandatory collection request:
50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br />. Reore lessons learned are incorporated into the licensing process and fed back to industry. Send comments regarding burden estimate to the Records and FOIAIPrivacy Service Branch (r-5 F52), U.S. Nuclear Regulatory Commission, LICENSEE EVENT REPORT (LER)
WashingtonDC 25-01,or by Itree-alto infocollects@nrc.gov, and to theDes Ofice, Ofic o Inbrmtio an Reulaor Afair, NOB- 022,(3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an Information collection does not display a currently valid 0MB control (See reverse for required number of number, the NRC may not conduct or sponsor, and a person is not required to dig its/characters for each block) respond to, the information collection.
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3 AGE Duane Arnold Energy Center 050 311O
- 4. TITLE Drywell Penetrations Calculations Do Not Account For Thermial Movement
- 5. EVENT DATE
- 6. LER NUMBER 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SQETA RE MOT DA YERFACILITY NAME DJOCKET NUMBER MONTH DAY YEAR YEAR SEUMElALRE MO NT.A YA 05000 F:ACILITY NAME DOCKET NUMBER 033
~ 2
'2M6- ~-0 100-
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- - t- ~-2006 -~
95009
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)
[I 20.2201(b) 0I 20.2203(a)(3)(i) 0 50.73(aX2)(i)(C)
[I 50.73(a)(2Xvii) 1 0 20.2201 (d) 0 20.2203(a)(3)(ii) 0 50.73(a)(2)(ii)(A)
[I 50.73(a)(2)(viii)(A)
O 20.2203(a)(1)
[I 20.2203(a)(4)
El 50.73(a)(2)(Ii)(B)
[I 50.73(a)(2Xviii)(B) 0 20.2203(a2)(2X) 0 50.36(c)(l)(i)(A) 0 50.73(a)(2)(Iii) 0 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL [I 20.2203(a)(2)@i)
[] 50.36(cl)(1)(i)(A) 0 50.73(a)(2)(IvX(A) 0l 50.73(a)(2)(x) o 20.2203(a)(2)(iii)
[I 50.36(CX2) 0l 50.73(a)(2)(v)(A) 0 73.71 (a)(4) oI 20.2203(a)(2)(iv) 050.46(a)X3)(ii) 0l 50.73(a)(2)(v)(B) 0l 73.71(a)(5) 84 [1 20.2203(a)X2)(v) 050.73(a)X2)(i)(A) 0l 50.73(a)(2)(v)(C) 0 OTHER 0l 20.2203(a)(2)(vi)
[I 50.73(a)X2)(i)(B)
El 50.73(a)(2)(v)(D)
Specify in Abstract below
______________or in NRC Form 366A
- 12. LICENSEE CONTACT FOR THIS LER NAME TELEPHONE NUMBER (Include Are Code)
Robert J. Murrell, Licensing Engineering Analyst r,319-851-7900
- - 13.
COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT
CAUSE
SYSTEM COMPONENT IMANU-REPORTABLE
CAUSE
SYSTEM CMOET MANU-REPORTABLE FACTURER TO EPIX FACTURER TO EPIX
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH DAY YEA SUBMISSION 0l YES (If yes, complete 15. EXPECTED SUBMISSION DATE) 0 NO DATEI ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
---6-M-rcil-,-2605,-w-i~-opciain-at84%powr, t-WasiM efiimihd l-a
- - piping c-afciiatioh b "r ht---
Containment Vent Purge Exhaust line., did not account for thermal movement of the Drywell. Specifically, te stress model did not start at the Drywell shell and thermal anchor movements were not applied. The
'~lure to account for thermal movement did not meet the design requirements for Drywell penetrations.
Asa result of the identified discrepancy, an immediate operability determination was completed that coneradedithay h
rwl eerto a
prbebae nmeigAM eto IApni criteria. As a result of an extent of condition review into this issue, all Drywell penetrations were reviewed. This review identified 14 other Drywell penetrations, for a total of 15, requiring modifications to restore them to original design requirements and 16 requiring further analysis. The 15 penetrations requiring modifications were modified during Refueling Outage (RFO) 19, which concluded on May 3, 2005. Of the 16 Drywell penetrations requiring further analysis, 8 were identified that required modifications to reestablish design margins. Operability calculations performed on these 8 Drywell penetrations identified no current or past operability concerns.
As of the date of this LER, no past operability concerns have been identified concerning the 15 Drywell penetrations that were modified during RFO 19. Therefore, this LER is being submitted as a Voluntary Report.
NRC FORM 366(6-2004)
PRINTED ON RECYCLED PAPER NRC FORM 366 (6-2D04)
PRINTED ON RECYCLED PAPERU.S. NUCLEAR REGULATORY COMMISSION~
f7-2001)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
IIDOCKET ENUBR()PG13
_____________________________________________~jNUMBER (2)LENUBR()PG(3 YEA SEQUENTIAL IREVISION Duane Arnold Energy Center II00031 NUMBER INUMBER Page 2 of 3 01001112006 -
02 00 TEXT (If more space is required, use additional copies of NRC Form 366A)
1. Description of Event
On March 18, 2005, while operating at 84% power, it was determined that the installed configuration of the Containment Vent Purge Exhaust line did not account for thermal movement of the Drywell. Specifically, th-e calc-ulation-assd-ci'-tl--w-i'h the-Containment-Vent-Purge Exhaust-line did-not-accountfo tbrh -hermal-or___
pressure related movement of the Drywell in its stress model. The model did not start at the Drywell shell and there were no thermal anchor movements (TAM) or pressure anchor movements (PAM) applied. The failure to account for TAM or PAM did not meet the design requirements for Drywell penetrations. As a result of the identified discrepancy, an immediate operability determination was made that concluded that the penetration was operable based on ASME Section HII, Appendix F acceptance criteria. As a result of an extent of condition review into this issue, all Drywell penetrations were reviewed. This review resulted in 14 other Drywell penetrations, for a total of 15, being identified requiring modifications to restore the Drywell penetrations to their original design requirements and 16 Drywell penetrations requiring fuirther analysis. The 15 Drywell penetrations requiring modifications were modified during RFO 19, which concluded on May 3, 2005.
As of the date of this LER, of the 16 Drywell penetrations requiring further analysis, 8 were subsequently identified as requiring modifications. Formal operability determinations for these 8 drywell penetrations have concluded that no current or past operability concerns exist.
Aý1s of the date of this LER, no past operability concerns with the first 15 Drywell penetrations that were modified during REQ 19 have been identified. However, as noted below, additional actions are underway to determine if any past operability concerns existed with these 15 Drywell penetrations. As documented in FPL Energy Duane Arnold's letter to the NRC, dated April 3, 2006, these additional actions are being taken based on the conclusion that the original basis for operability was non-conservative due to the fact that they__
uitiliz-e-d Appiidii7F' of Se-caoi flfoftfihe7AS9ff C-od~e-7 diio/lir nii~A-Weiii-)Tor-determination of past operability. However, we have concluded that past operability reviews of the affected Drywell penetrations need to utilize a newer version of ASME Section HII, Appendix F which would require C nidratonof TAM and PAM.
ere was no other inoperable equipment at the start of this event that affected this event.
HI. Assessment of Safety Consequences:
Since there are no current or past operability issues identified associated with the Drywell penetrations, there are no safety consequences associated with this event. This conclusion could change based on the results of the past operability analysis currently being performed as discussed in the corrective actions section of this LER.
NRC FO RM 366A 17-2001)U.S. NUCLEAR REGULATORY COMMISSION (7-2001)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1) iDOCKET ENUBR()PG(3
_______________________________________________ftNUMBER (2)LE NU BR()P G
(3 YEA SEQUENTIAL REVISION Duane Arnold Energy Center 05 000 331 UME UBR ae3o 1
2066-02
- - 00 TEXT (If more space is required, use additional copies of NRC Form 366A) 111. Cause of Event:
Plant design documents did not adequately account for TAM or PAM for mechanical piping systems interfacing with Drywell penetrations. Since the calculations were performed as long ago as 25 or more cas f-sio pss~eWe
- - em-xae-as ofthse nt-
IV. Corrective Actions
As stated above, the first 15 Drywell penetrations that were identified were modified during RFO 19 to restore them to their original design requirements. For the 8 penetrations identified subsequent to RFO 19 that require modifications, a modification plan is currently being developed. These modifications are scheduled to be completed prior to the completion of RFO 20 which is scheduled to commence in February 2007.
To preclude fur-ther occurrences similar to what caused this event; Engineering Design Guide DGC-M 100 "Stress Analysis and Support Design of Seismic Category I Piping System" was revised to include guidance to account for Drywell shell movement due to thermal and pressure loading at accident conditions.
Additionally, actions are underway to determine if any past operability concerns existed for the 15 drywell penetrations that have already been modified. The past operability evaluations are to be completed by October 31, 2006.
V. Additional Information
Previous Similar Occurrences:-
A review of LERs at the DAEC over the last 3 years identified no LERs with similar events.
EI IS System and Component Codes:
N/A
Reporting Requirements
This report is being submitted as a voluntary LER.