05000391/LER-1917-005, Regarding Unplanned Emergency Core Cooling System Injection Into the Reactor Coolant System Due to Personnel Error
| ML18025B349 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 01/25/2018 |
| From: | Simmons P Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 17-005-00 | |
| Download: ML18025B349 (7) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3911917005R00 - NRC Website | |
text
Tennessee Valley Authority, Post Office Box 2000, Spring City, Tennessee 37381 January 25, 2018 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Watts Bar Nuclear Plant, Unit 2 Facility Operating License No. NPF-96 NRC Docket No. 50-391 10 CFR 50.73
Subject:
Licensee Event Report 391/2017-005-00, Unplanned Emergency Core Cooling System Injection into the Reactor Coolant System due to Personnel Error This submittal provides Licensee Event Report (LER) 391/2017-005-00. This LER provides details concerning an incident where an unplanned injection into the reactor coolant system occurred when the flow path from a centrifugal charging pump was not properly isolated. This condition is being reported as a system actuation in accordance with 10 CFR 50. 73(a)(2)(iv)(A).
There are no regulatory commitments contained in this letter. Please direct any questions concerning this matter to Kim Hulvey, WBN Licensing Manager, at (423) 365-7720.
Enclosure cc: See Page 2
U.S. Nuclear Regulatory Commission Page2 January 25, 2018 cc (Enclosure):
NRC Regional Administrator - Region II NRC Senior Resident Inspector - Watts Bar Nuclear Plant
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 0313112020 (04-2017)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Watts Bar Nuclear Plant, Unit 2 05000391 1 OF 5
- 4. TITLE Unplanned Emergency Core Cooling System Injection into the Reactor Coolant System due to Personnel Error
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED I
SEQUENTIAL I REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER NO.
MONTH DAY YEAR N/A FACILITY NAME DOCKET NUMBER 11 26 2017 2017 - 005
- - 00 01 25 2018 N/A
- 9. OPERATING MODE 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
D 20.2201(b)
D 20.2203(a)(3)(i)
D 50. 73(a)(2)(ii)(A)
D 50. 73(a)(2)(viii)(A)
D 20.2201(d)
D 20.2203(a)(3)(ii)
D 50. 73(a)(2)(ii)(B)
D 50. 73(a)(2)(viii)(B) 5 D
D D
D 20.2203(a)(1) 20.2203(a)(4)
- 50. 73(a)(2)(iii)
- 50. 73(a)(2)(ix)(A)
D 20 2203(a)(2)(i)
D 50 36(c)(1 )(i)(A)
~ 50. 73(a)(2)(iv)(A)
D 50. 73(a)(2)(x)
- 10. POWER LEVEL D 20.2203(a)(2)(ii)
D 50 36(c)(1 )(ii)(A)
D 50. 73(a)(2)(v)(A)
D 73 71 (a)(4)
D 20.2203(a)(2)(iii)
D 50.36(c)(2)
D 50. 73(a)(2)(v)(B)
D 73. 71 (a)(5)
D 20.2203(a)(2)(iv)
D 5046(a)(3)(ii)
D 50. 73(a)(2)(v)(C)
D 73 77(a)(1) 0 D 20.2203(a)(2)(v)
D 50. 73(a)(2)(i)(A)
D 50. 73(a)(2)(v)(D)
D 73. 77(a)(2)(i)
D 20.2203(a)(2)(vi)
D 50.73(a)(2)(i)(B)
D 50. 73(a)(2)(vii)
D 73. 77(a)(2)(ii)
D 50. 73(a)(2)(i)(C)
D OTHER Specify in Abstract below or in 2017 005 F.
Method of discovery of each Component or System Failure or Procedural Error
The issue was identified by operations personnel as a result of increasing pressurizer level.
G. Failure Mode and Effect of Each Failed Component There was no equipment failure associated with this event.
H. Operator Actions
Upon identifying rising pressurizer level, the BIT outlet valve 2-FCV-63-25 was closed and its associated breaker was opened.
I.
Automatically and Manually Initiated Safety System Responses
Upon identifying that flow was being injected into the RCS, the operator isolated the flow path to the RCS.
00 Ill.
CAUSE OF THE EVENT
A The cause of each component or system failure or personnel error, if known.
The cause of this issue is that an Operator improperly used a Caution Order (CO) to determine the configuration of the breaker for the BIT outlet valve.
B. The cause(s) and circumstances for each human performance related root cause.
The cause of this issue is that an Operator improperly used a CO to determine the configuration of the breaker for the BIT outlet valve. This is a personal accountability issue for not properly using the human performance tool Correct Component Verification to validate the current position of the breaker in the field.
IV.
ANALYSIS OF THE EVENT
During preparation for the performance of O-Sl-82-6, "18 Month Loss of Offsite Power With Safety Injection Test - DG 2B-B," it is intended that the BIT outlet valve is closed with power removed by opening its associated breaker. During the pre-test lineups in advance of performance, an Operator improperly used a Caution Order to determine the configuration of the breaker for the BIT outlet valve. A CO tag is provided to identify that a component is in an off normal configuration but does not control configuration.
The breaker had actually been repositioned to closed to support previous plant testing with no reconfiguration required following that testing based on plant conditions. The Operator relied solely on the information present on the CO tag to determine breaker position and did not validate the position in the field.
V.
ASSESSMENT OF SAFETY CONSEQUENCES
The event resulted in an unplanned injection into the RCS which was promptly identified and corrected by operations personnel. All other systems responded as expected and ECCS flow was isolated. Unit 2 Pressurizer level and pressure remained below limits. With the Unit in Mode 5 following refueling, the plant operating crew were able to stop the increase in pressurizer level well in advance of overfilling the pressurizer, therefore there was no safety consequence.
A. Availability of systems or components that could have performed the same function as the components and systems that failed during the event If the BIT outlet valve was unable to be closed, the affected charging pump could have been secured.
B. For events that occurred when the reactor was shut down, availability of systems or components needed to shutdown the reactor and maintain safe shutdown conditions, remove residual heat, control the release of radioactive material, or mitigate the consequences of an accident This event involved a single component during testing. Other means were available to secure ECCS injection.
C. For failure that rendered a train of a safety system inoperable, an estimate of the elapsed time from the discovery of the failure until the train was returned to service Not applicable.
VI.
CORRECTIVE ACTIONS
This event was entered into the Tennessee Valley Authority (TVA) Corrective Action Program and is being tracked under Condition Report (CR) 1362001. ~
A.
Immediate Corrective Actions
Upon identifying rising pressurizer level, the BIT outlet valve 2-FCV-63-25 was closed and its associated breaker was opened.
B. Corrective Actions to Prevent Recurrence or to Reduce Probability of Similar Events Occurring in the Future Corrective actions for this event include revising procedures to ensure the breakers associated with the boron injection flow path will be tagged open during ESFAS testing and that lessons learned related to this event are communicated to operating crews. An evaluation on the use of Caution Orders for off normal equipment positions will be performed.
VII.
PREVIOUS SIMILAR EVENTS AT THE SAME SITE
On May 10, 2017 the 1 B-B Safety Injection (SI) pump discharge isolation valve was discovered closed durina operator rounds as described in LER 390-2017-005. The cause of the mispositioned valve was the 2017 -
005 00 result of an individual failing to follow procedure use and adherence requirements related to the application of Not Applicable during the performance of Emergency Diesel Generator (EOG) Blackout testing. The safety injection pump discharge valve was closed to support the test but was not reopened following the testing. Corrective actions for this event Includes personal accountability actions, revision of the EOG blackout procedures to ensure the SI pump discharge valves are reopened, and additional station focus on procedure use.
This event is similar to the event described in this report. WBN continues to focus on operator human performance as a result of this and prior events.
VIII.
ADDITIONAL INFORMATION
None.
IX.
COMMITMENTS
None. Page _5_ of _5_