05000382/LER-2016-002, Regarding Both Trains of Essential Services Chilled Water Inoperable Due to Failing to Maintain Exiting Chilled Water Temperature in Specification Resulting in Event or Condition That Could Have Prevented
| ML16285A502 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 10/11/2016 |
| From: | Jarrell J Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| W3F1-2016-0059 LER 16-002-00 | |
| Download: ML16285A502 (7) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v), Loss of Safety Function 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)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) |
| 3822016002R00 - NRC Website | |
text
10 CFR 50.73 W3F1-2016-0059 October 11, 2016 U.S. Nuclear Regulatory Commission Attn: Document Control Desk 11555 Rockville Pike Rockville, MD 20852
Subject:
Licensee Event Report (LER) 2016-002-00, Both Trains of Essential Services Chilled Water Inoperable due to Failing to Maintain Exiting Chilled Water Temperature in Specification Resulting in Event or Condition that Could Have Prevented Fulfillment of a Safety Function Waterford Steam Electric Station, Unit 3 (Waterford 3)
Docket No. 50-382 License No. NPF-38
Dear Sir or Madam:
On August 12, 2016, both trains of Essential Services Chilled Water at Waterford Steam Electric Station, Unit 3 (Waterford 3) were inoperable, causing entry into Technical Specification (TS) 3.0.3. This event is reportable pursuant to 10 CFR 50.73(a)(2)(v)(D),
"Event or Condition that Could Have Prevented Fulfillment of a Safety Function of Structures or Systems that are Needed to (D) Mitigate the Consequences of an Accident."
A supplement to LER 2016-002-00 is planned by February 24, 2017 to provide the safety significance determination.
This report contains no new commitments. Please contact John P. Jarrell, Regulatory Assurance Manager, at (504) 739-6685 if you have questions regarding this information.
Sincerely, JPJ/MMZ
Attachment:
LER 2016-002-00 Entergy Operations, Inc.
17265 River Road Killona, LA 70057-3093 Tel 504 739 6685 Fax 504 739 6698 jjarrel@entergy.com John P. Jarrell III Manager, Regulatory Assurance Waterford 3
W3F1-2016-0059 Page 2 cc:
Mr. Kriss Kennedy, Regional Administrator U.S. NRC, Region IV RidsRgn4MailCenter@nrc.gov U.S. NRC Project Manager for Waterford 3 April.Pulvirenti@nrc.gov U.S. NRC Senior Resident Inspector for Waterford 3 Frances.Ramirez@nrc.gov Chris.Speer@nrc.gov
Attachment to W3F1-2016-0059 Licensee Event Report 2016-002-00 (4 pages)
NRC FORM 366 (06-2016)
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (06-2016)
LICENSEE EVENT REPORT (LER)
(See Page 2 for required number of digits/characters for each block)
(See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc/gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
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- 1. FACILITY NAME Waterford Steam Electric Station, Unit 3
- 2. DOCKET NUMBER 05000-382
- 3. PAGE 1 OF 4
- 4. TITLE Both Trains of Essential Services Chilled Water Inoperable due to Failing to Maintain Exiting Chilled Water Temperature in Specification Resulting in Event or Condition that Could Have Prevented Fulfillment of a Safety Function
- 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 DOCKET NUMBER 08 12 2016 2016 -
002
- - 00 10 11 2016 FACILITY NAME DOCKET NUMBER
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 1 20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 20.2201(d) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 20.2203(a)(1) 20.2203(a)(4) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A) 20.2203(a)(2)(i) 50.36(c)(1)(i)(A) 50.73(a)(2)(iv)(A) 50.73(a)(2)(x)
- 10. POWER LEVEL 20.2203(a)(2)(ii) 50.36(c)(1)(ii)(A) 50.73(a)(2)(v)(A) 73.71(a)(4) 100 20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(B) 73.71(a)(5) 20.2203(a)(2)(iv) 50.46(a)(3)(ii) 50.73(a)(2)(v)(C) 73.77(a)(1) 20.2203(a)(2)(v) 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(D) 73.77(a)(2)(i) 20.2203(a)(2)(vi) 50.73(a)(2)(i)(B) 50.73(a)(2)(vii) 73.77(a)(5)(ii) 50.73(a)(2)(i)(C)
OTHER Specify in Abstract below or in revealed infinite resistance at several locations and subsequent testing identified several dead spots. The module had been in service since October 17, 2005. It is located in an area with elevated temperature and humidity.
Extensive troubleshooting performed on Essential Chiller B identified that the as found configuration of the guide vanes was such that when at the minimum (closed) actuator position, the guide vanes were approximately 5% open. This partially open guide vane provided additional cooling, resulting in a low outlet temperature with a high thermostat setting. The linkage and actuator arm were adjusted to ensure full guide vane closure and the set screws were tightened.
REPORTABLE OCCURRENCE This event is reportable pursuant to 10 CFR 50.73(a)(2)(v)(D), "Event or Condition that Could Have Prevented Fulfillment of a Safety Function of Structures or Systems that are Needed to (D) Mitigate the Consequences of an Accident" due to both Essential Services Chilled Water Loops being inoperable.
PREVIOUS OCCURRENCES
A review of Waterford 3s corrective action program and LERs for previous similar events was performed. The following were identified:
CR-WF3-1997-2698: Essential Chiller A chilled water outlet temperature was discovered to be above 42 deg F. Local observation revealed that the compressor inlet vanes [CDMP] would not change position in automatic or manual. Loop A was declared inoperable. The cause was due to a failure of the guide vane actuator. The actuator was replaced. It was also identified that there was no PM strategy for the capacity control modules and therefore new replacement tasks were added at 12 year intervals.
CR-WF3-2005-3270: Essential Chiller AB chilled water outlet temperature was noted to be 48 deg F. Readings indicated oscillating voltage, which was ascribed to a failed part within the capacity control module. The task frequency for capacity control module replacement was changed to 10 years with a 25% grace period based on the known operating experience at the time.
Modules in all chillers were replaced in 2005.
CR-WF3-2006-0191: Essential Chiller B chilled water outlet temperature was observed at approximately 43 deg F. The actuator linkage was observed to have been twisted, in that the top and bottom knuckle connections were not parallel and the guide vane and guide vane actuator shaft arms were no longer at the correct angles with respect to each other. An 18 month PM task was initiated to lubricate the actuator linkage.
CAUSAL FACTORS Essential Chiller A: The direct cause of the elevated chilled water outlet temperature was failure of the chillers capacity control module. The apparent cause is an inadequate PM strategy for replacement of the capacity control module. This apparent cause resulted in this condition by not replacing the module before age related degradation resulted in failure. The contributing cause is the system is not configured with high and low alarms [TA] for exiting Essential Chiller chilled water temperatures. This contributing cause contributed to this condition by delaying identification of the high Essential Chiller A chilled water outlet temperature for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />.
The Apparent Cause Evaluation for Essential Chiller B has not been approved by site management. The causes stated in the following paragraph are those that have been identified in the draft cause evaluation.
Essential Chiller B: The direct cause of the elevated chilled water outlet temperature was incorrect guide vane setup. The incorrect setup resulted in adjusting the thermostat too high. The high thermostat setting prevented the chiller from maintaining outlet temperature less than 42 deg F following a large demand increase. The apparent cause is that inadequate guidance exists
for guide vane actuator linkage setup. This apparent cause resulted in this condition by providing additional cooling due to the partially open guide vane. This resulted in a low outlet temperature with a high thermostat setting.
CORRECTIVE ACTIONS
Essential Services Chilled Water Loop A:
(1) Replace the capacity control module, calibrate, and return the chiller to operation. (complete)
(2) Change the frequency of the capacity control module replacement tasks to 6 years with a 10% grace period. (planned)
(3) Add high and low temperature alarms for chilled water outlet temperature for all chillers. (planned)
Essential Services Chilled Water Loop B:
(1) Adjust linkage and arm correctly and set thermostat. (complete)
(2) Create detailed model work instructions for the correct installation of the Essential Chiller guide vane actuator. (planned)
(3) Establish a procedure for Essential Chiller troubleshooting. (planned)
(4) Revise the post-maintenance tests for all work orders that require removal of the guide vane linkage. (planned)
(5) Add an activity to check the guide vane and actuator arm shaft set screws to the 6 year PM. (planned)
SAFETY SIGNIFICANCE
The safety significance determination is not yet completed. It will be included in the planned update to this LER.
ADDITIONAL INFORMATION
Energy industry identification system (EIIS) codes and component function identifiers are identified in the text with brackets [ ].