05000331/LER-2013-006, Regarding Both Doors in Secondary Containment Airlock Opened Concurrently
| ML14051A351 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 02/14/2014 |
| From: | Richard Anderson NextEra Energy Duane Arnold |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NG-14-0060 LER 13-006-00 | |
| Download: ML14051A351 (4) | |
| 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)(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 |
| 3312013006R00 - NRC Website | |
text
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ýýARNOLD February 14, 2014 NG-14-0060 10 CFR 50.73 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555-0001 Duane Arnold Energy Center Docket 50-331 Renewed Op. License No. DPR-49 Licensee Event Report #2013-006 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
TRichard L. Ande on Vice President, Duane Arnold Energy Center NextEra Energy Duane Arnold, LLC cc:
Administrator, Region III, USNRC Project Manager, DAEC, USNRC Resident Inspector, DAEC, USNRC NextEra Energy Duane Arnold, LLC, 3277 DAEC Road, Palo, IA 52324
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 EXPIRES: 10/31/2013 (10-20 10)
, the (See reverse for required number of NRC may not conduct or sponsor, and a person is not required to respond to, the digits/chiaracters for each block) infonnation collection.
- 3. PAGE Duane Arnold Energy Center 05000331 1 OF 3
- 4. TITLE Both Doors in Secondary Containment Airlock Opened Concurrently
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH DAY YEAR FACILITY NAME DOCKET NUMBER NUMBER NO.
N/A N/A 12 18 2013 2013 006 00 02 14 2014 FACILITY NAME DOCKET NUMBER N/A N/A
- 9. OPERATING MODE II. TH IS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
I 20.2201(b)
[
20.2203(a)(3)(i)
[
50.73(a)(2)(i)(C)
D 50.73(a)(2)(vii) 1
[
20.220 1(d)
[]
20.2203(a)(3)(ii)
[]
50.73(a.)(2)(.ii)(A)
[]
50.73(a)(Z)(viii)(A)
D]
20.2203(a)(1)
D 20.2203(a)(4) 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B)
E]
20.2203(a)(2)0i)
E]
50.36(c)(1)(i)(A)
[]
50.73(a)(2)(iii)
[:]
50.73(a)(2)(ix)(A)
- 10. POWER LEVEL E]
20.2203(a)(2)(ii)
E]
50.36(c)(1)(ii)(A)
EJ 50.73(a)(2)(iv)(A)
ED 50.73(a)(2)(x)
FD 20.2203(a)(2)(iii)
[
50.36(c)(2)
[]
50.73(a)(2)(v)(A)
[
73.71(a)(4) 100%
[D 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
[
50.73(a)(2)(v)(B) 73.7O1(a)(5)
E]
20.2203(a)(2)(v)
[]
50.73(a)(2)(i)(A)
EJ 50.73(a)(2)(v)(C)
VOUOTHER 20.2203(a)(2)(vi) 50.73(a)(2)(i)()
250.73(a)(2)(v)(D)
VOLUNTARY LER
- 12. LICENSEE CONTACT FOR THIS LER NAME Robert J. Murrell, Engineering Analyst TELEPHONE NUMBER (Include Area Code)
(319) 851-7900
- 14. SUPPLEMENTAL REPORT EXPECTED El YES (If yes, complete 15. E.\\PECTE'ID SUBIA.,IIIOND-DTE)
ABSTRACT (Limit to 1400 spaces, i.e., approximately' 15 single-spaced O'peitritten Iiles)
On December 18, 2013, while operating at 100% power, two workers opened doors concurrently when entering a secondary contailnment access airlock. Both individuals realized that this was not allowed and closed their respective door; however, the result was a brief inoperability of secondary containment integrity. This resulted in an 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> reportable event. The Resident Inspector was notified, and Event Notification 49657 was made pursuant to 10 CFR 50.72(b)(3)(v)(C) due to a condition at the time of discovery that prevented the fulfillment of the Secondary Containment safety function.
The apparent cause of the event was determined to be excess strength of a permanent magnet on one of the doors. The monthly surveillance test will be revised to check the permanent magnet for proper adjustment and to adjust it as needed.
This event did not result in a safety system functional failure. There were no radiological releases associated with this event.
NRC FORM 366 (10-20101 PRINTED ON RECYCLED PAPER NRC FORM 366 (10-2010)
PRINTED ON RECYCLED PAPER (If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A) (17) containment integrity is not achieved until 10 seconds following an isolation signal.
The interlock is not credited as performing a safety function. It is used to prevent inadvertent openings and should be maintained to ensure reliable operation.
This event did not result in a safety system functional failure. There were no automatically or manually initiated safety system responses.
III.
Cause of Event
An Apparent Cause Evaluation was completed. The evaluation identified the apparent cause of Door-225 and Door-227 being open at the same time as excess permanent magnet strength. After the permanent magnet was adjusted, the interlock was able to prevent both doors from opening.
IV.
Corrective Actions
An operational check of the Secondary Containment door interlocks is performed monthly via STP 3.6.4.1-02, Secondary Containment Airlock Verification. STP 3.6.4.1-02 will be revised to check the permanent magnet for proper adjustment by verifying that the red interlock light(s) turn OFF as close to when the door latches as possible. The permanent magnet will then be adjusted as needed.
V.
Additional Information
Previous Similar Occurrences:
A review of DAEC Licensee Event Reports from the past 5 years did not identify any similar occurrence.
A review of the corrective action program identified additional occurrences of airlock conditions causing momentary secondary containment inoperability - one additional occurrence in 2013 and eight occurrences in 2012.
ElIS System and Component Codes:
IEL Interlock
Reporting Requirements
This event is being reported as an event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to control the release of radioactive material, 10CFR50.73(a)(2)(v)(C).PRINTED ON RECYCLED PAPER