05000331/LER-2011-002, Regarding Loss of Ultimate Heat Sink and Completion of Technical Specification Required Shutdown
| ML112840153 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 10/10/2011 |
| From: | Wells P NextEra Energy Duane Arnold |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| NG-11-0381 LER 11-002-00 | |
| Download: ML112840153 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 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)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3312011002R00 - NRC Website | |
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October 10,2011 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555-0001 Duane Arnold Energy Center Docket 50-331 License No. DPR-49 Licensee Event Report #2011-002-00
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DUANE ARNOLD NG-11-0381 10 CFR 50.73 Please find attached the subject report submitted in accordance with 10 CFR 50.73. This letter makes no new commitments or changes to any existing
commitments
Peter Wells Vice President, Duane Arnold Energy Center NextEra Energy Duane Arnold, LLC NextEra Energy Duane Arnold, LLC, 3277 DAEC Road, Palo, IA 52324
NRC FORM 366 (10-2010)
PRINTED ON RECYCLED PAPER NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (10-2010)
LICENSEE EVENT REPORT (LER)
(See reverse for required number of digits/characters for each block)
APPROVED BY OMB NO. 3150-0104 EXPIRES: 10/31/2013 Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />. Reported lessons learned are incorporated into the licensing process and fed back to industry. Send comments regarding burden estimate to the Records and FOIA/Privacy Service Branch (T-5 F52), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to infocollects@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202 (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 OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITY NAME Duane Arnold Energy Center
- 2. DOCKET NUMBER 05000331
- 3. PAGE 1 OF 4
- 4. TITLE Loss of Ultimate Heat Sink and Completion of Technical Specification Required Shutdown
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL NUMBER REV NO.
MONTH DAY YEAR FACILITY NAME N/A DOCUMENT NUMBER 05000 08 11 11 2011 002 0
10 10 11 FACILITY NAME N/A DOCUMENT NUMBER 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(i)(C)
X 50.73(a)(2)(vii) 1 20.2201(d) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 20.2203(a)(1) 20.2203(a)(4) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 20.2203(a)(2)(i) 50.36(c)(1)(i)(A) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL 20.2203(a)(2)(ii) 50.36(c)(1)(ii)(A)
X 50.73(a)(2)(iv)(A) 50.73(a)(2)(x) 20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(A) 73.71(a)(4) 100%
20.2203(a)(2)(iv) 50.46(a)(3)(ii)
X 50.73(a)(2)(v)(B) 73.71(a)(5) 20.2203(a)(2)(v)
X 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(C)
OTHER 20.2203(a)(2)(vi) 50.73(a)(2)(i)(B)
X 50.73(a)(2)(v)(D)
VOLUNTARY LER
- 12. LICENSEE CONTACT FOR THIS LER NAME TELEPHONE NUMBER (Include Area Code)
Robert J. Murrell, Engineering Analyst (319) 851-7900 CAUSE SYSTEM COMPONENT MANU-FACTURER REPORTABLE TO EPIX
CAUSE
SYSTEM COMPONENT MANU-FACTURER REPORTABLE TO EPIX N/A N/A N/A N/A N/A
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH DAY YEAR YES (If yes, complete 15. EXPECTED SUBMISSION DATE)
X NO SUBMISSION DATE ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
On August 11, 2011 at 0008, while operating at 100% power, both trains of River Water Supply (RWS) were declared inoperable due to the failure of river Intake Structure traveling screens. This required entry into Technical Specification (TS) 3.7.2, River Water Supply System and Ultimate Heat Sink, Condition B, Both RWS subsystems inoperable. This Limiting Condition for Operation (LCO) requires that the reactor be in Mode 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and Mode 4 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The LCO was entered because of the high indicated differential pressure on the intake traveling screens and their inability to be rotated. Subsequent inspections of the Intake Structure found several feet of sand in the forebay and pump pit areas. The required action to be in Mode 3 was completed at 1138 with the insertion of a manual scram. Upon inserting the manual scram, reactor water level dropped below 170 inches resulting in Primary Containment Isolation System (PCIS)
Groups 2, 3 and 4 being received. This reactor water level response is considered normal following a reactor scram from power due to void collapse in the reactor vessel. The PCIS isolations all functioned properly. This event was caused by inadequate management of river sediment buildup.
This event is being reported as an Event or Condition that Could Have Prevented Fulfillment of a Safety Function, 10CFR50.73(a)(2)(v)(B and D), a Common-cause Inoperability of Independent Trains or Channels, 10CFR50.73(a)(2)(vii),
and Completion of a TS Required Shutdown, 10CFR50.73(A)(2)(i)(A), reference EN 47142. Additionally, this event was reported under 10CFR50.73(A)(2)(iv)(A), Specified System Actuation, reference Event Notification 47143. There were no actual safety consequences and no effect on public health and safety as a result of this event.
(If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A) (17)
PRINTED ON RECYCLED PAPER
- 3.
Complete the design change to repair spur dikes and perform dredging as necessary to return the river to its desired flow pattern.
V.
Additional Information
Previous Similar Occurrences:
A review of License Event Reports from the past 5 years did not identify any previous similar occurrences.
EIIS System and Component Codes:
BS - Ultimate Heat Sink System
Reporting Requirements
This event is being reported as an Event or Condition that Could Have Prevented Fulfillment of a Safety Function, 10CFR50.73(a)(2)(v)(B and D), a Common-cause Inoperability of Independent Trains or Channels, 10CFR50.73(a)(2)(vii), and Completion of a TS Required Shutdown, 10CFR50.73(A)(2)(i)(A),
reference EN 47142. Additionally, this event was reported under 10CFR50.73(A)(2)(iv)(A), Specified System Actuation, reference Event Notification 47143. There were no actual safety consequences and no effect on public health and safety as a result of this event.