05000289/LER-1917-003, Regarding Primary Containment Declared Inoperable Due to Both Airlock Doors Open Simultaneously
| ML17311A145 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 11/06/2017 |
| From: | Callan E Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| TMl-17-105 LER 17-003-00 | |
| Download: ML17311A145 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 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) 10 CFR 50.73(a)(2)(i) |
| 2891917003R00 - NRC Website | |
text
b "7 Exelon Generation Three Mile Island Unit 1 Telephone 717-948-8000 Route 441 South, P.O. Box 480 Middletown, PA 17057 November 6, 2017 TMl-17-105 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555-0001 THREE MILE ISLAND NUCLEAR STATION, UNIT 1 (TMl-1)
RENEWED FACILITY OPERATING LICENSE NO. DPR-50 DOCKET NO. 50-289
SUBJECT:
LICENSEE EVENT REPORT (LER) NO. 2017-003-00 10 CFR 50.73 "Primary Containment Declared Inoperable Due to Both Airlock Doors Open Simultaneously" This report is submitted in accordance with 10 CFR 50.73(a)(2)(i)(B) and, 10 CFR 50.73(a)(2)(ii)(A) and, 10 CFR 50.73(a)(2)(v)(C). For additional information regarding this Licensee Event Report contact Michael Fitzwater, Sr. Regulatory Engineer, TMI Unit 1 Regulatory Assurance at (717) 948-8228.
There are no regulatory commitments contained in this LER.
Respectively, c~ o.2t~y, E. W. Callan, Jr.
Site Vice President, Three Mile Island Unit 1 Exelon Generation Co., LLC cc:
TMI Senior Resident Inspector Administrator, Region I TMl-1 Senior Project Manager
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2017)
, the httg://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/}
NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Three Mile Island Unit 1 05000289 1 OF 4
- 4. TITLE Primary Containment Declared Inoperable Due to Both Airlock Doors Open Simultaneously
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED YEAR I SEQUENTIAL I REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR NUMBER NO.
MONTH DAY YEAR 05000 FACILITY NAME DOCKET NUMBER 09 05 17 2017 - 003
- - 00 11 06 17 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITIED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (CheckaHthatapp/y)
D 20.2201 (b}
D 20.22os(a)(3)(i}
~ 50.73(a)(2)(ii)(A) 0 50.73(a)(2}(viii)(A)
N D 20.2201 (d)
D 20.22os(a}(3)(ii) 0 50.73(a)(2)(ii)(B) 0 50.73(a)(2)(viii)(B)
D 20.2203(a)(1 >
D 20.22os(a}(4}
D 50.1s(a)(2)(iii) 0 50. 73(a}(2}(ix)(A)
D 20.22os(a)(2}(i) 0 50.36(c)(1 )(i)(A) 0 50.73(a}(2)(iv}(A) 0 50.73(a)(2)(x)
- 10. POWER LEVEL D 20.2203(a)(2)(ii) 0 50.36(c)(1 }(ii}(A) 0 50.73(a)(2)(v)(A)
D 1s.11(a)(4)
D 20.2203(a)(2}(m>
D 50.s6(c)(2) 0 50.73(a)(2}(v}(B) 0 73.71 (a)(5}
- 0 20.2203(a}(2}(iv)
D 5o.46(a)(s)(ii)
~ 50.73(a)(2)(v}(C)
D 1s.n(a)(1>
100 0 20.2203(a}(2}(v) 0 50.73(a)(2)(i)(A}
0 50.73(a}(2)(v)(D)
D 1s.n(a}(2}(i) 0 20.2203(a}(2}(vi)
~ 50.73(a)(2)(i)(B) 0 50.73(a}(2)(vii)
D 1s. n(a)(2)(ii}
0 50.73(a)(2)(i}(C)
D OTHER Specify in Abstract below or in
8. CAUSE OF EVENT
TMl-1 entered its planned maintenance and refueling outage on September 18, 2017. During the period of time at which containment integrity was not required for the plant condition, technicians were able to repeat the failure of the interlock linkage of the PAEH. Maintenance discovered that the PAEH interlock linkage designed to prevent both doors from being opened simultaneously had failed due to a bent ratchet pawl. A weld repair to the ratchet pawl interlock linkage was performed. The interlock linkage preventive maintenance was performed that included linkage adjustment. Testing of the interlock linkage of the PAEH was performed satisfactorily.
An extent of condition was performed on the remaining airlock designated as the Reactor Building Personnel Hatch Airlock. The surveillance and preventive maintenance activities performed on the Personnel Hatch Airlock were all satisfactory. This included testing of the Personnel Hatch Airlock interlock mechanism which was completed satisfactorily.
C. ANALYSIS I SAFETY SIGNIFICANCE This event had no significant impact on public health and safety. TMl-1 was operating at full power when the event occurred. The potential for radioactive material release to the environment was evaluated. The reactor building environmental conditions of pressure and airborne radioactivity were well within operating limits at the time of the event. The resulting consequence for this short duration event is negligible.
Control of the Inner Door of the PAEH was maintained throughout the event. However, the Outer Door of the PAEH was not closed that resulted in a loss of a principal safety barrier (primary containment) and is counted as a safety system functional failure (SSFF) since the event could have prevented fulfillment of a safety function.
D. CORRECTIVE ACTIONS
Actions Completed on the Personnel Airlock of the Equipment Hatch Inner and Outer Doors:
- 1. Reviewed Airlock door operating practices, assigned designated door operators and established backup door indication verification technique prior to re-commencing reactor building entries.
- 2. Performed a weld repair to the pawl on interlock linkage.
- 3. Site Maintenance performed PAEH interlock preventive maintenance, including linkage adjustments.
- 4. Performed interlock door test to verify operability between the two doors.
- 5. PAEH Outer Door seal was repaired.
- 6. Performed Outer Door seal test to verify repairs to door seals.
YEAR 2017 -
SEQUENTIAL NUMBER 003 REV NO.
00
- 7. Performed a satisfactory LLRT of the Personnel Airlock of the Equipment Hatch.
E.
PREVIOUS OCCURENCES
None. Page _4_ of _4_