05000410/LER-2020-002, Failure to Meet Technical Specification MSIV Stroke Times
| ML20129J906 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 05/05/2020 |
| From: | Tierney T Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NMP2L2732 LER 2020-002-00 | |
| Download: ML20129J906 (7) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 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) |
| 4102020002R00 - NRC Website | |
text
</ Exelon Generation,~,
NMP2L2732 May 5, 2020 U.S. Nuclear Regulatory Commission ATIN: Document Control Desk Washington, DC 20555-0001 Nine Mile Point Nuclear Station, Unit 2 Renewed Facility Operating License No. NPF-69 Docket No. 50-41 O 10 CFR 50.73
Subject:
NMP2 Licensee Event Report 2020-002, Failure to Meet Technical Specification MSIV Stroke Times In accordance with the reporting requirements contained in 10 CFR 50.73(a)(2)(v)(C}, please find enclosed NMP2 Licensee Event Report 2020-001, Manual Scram due to an Electro-Hydraulic Control Fluid Leak on the Turbine Control System.
There are no regulatory commitments contained in this letter.
Should you have any questions regarding the information in this submittal, please contact Brandon Shultz, Site Regulatory Assurance Manager, at (315) 349-7012.
Respectfully,
~
a., t*o,.1A,{,/).,Jp Todd A. Tierney_.---,-,
Plant Manager, Nine Mile Point Nuclear Station Exelon Generation Company, LLC TAT/DJW
Enclosure:
NMP2 Licensee Event Report 2020-001, Manual Scram due to an Electro-Hydraulic Control Fluid Leak on the Turbine Control System cc:
NRG Regional Administrator, Region I NRG Resident Inspector NRC Project Manager
Enclosure NMP2 Licensee Event Report 2020-001 Manual Scram due to an Electro-Hydraulic Control Fluid Leak on the Turbine Control System Nine Mile Point Nuclear Station, Unit 2 Renewed Facility Operating License No. NPF-69
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150*0104 EXPIRES: 03/31/2020 (04-2017)
, the htt1:1://www.nrc.govlreadlng-rm/doc-collectlons/nuregs/slaff/sr1022/r3l)
NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
1, FACILITY NAME
- 2. DOCKET NUMBER
- 3. PAGE Nine Mile Point Unit 2 05000410 1 OF 5
- 4. TITLE Failure to Meet Technical Specification MSIV Stroke Times
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED YEAR I SEQUENTIAL I REV FACILllY NAME DOCKET NUMBER MONTH DAY YEAR NUMBER NO;*
MONTH DAY YEAR N/A N/A FACllllY NAME DOCKET NUMBER 03 06 2020 2020
- 002
- - 00 05 05 2020 NIA NIA
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: {Check all that apply)
D 20.2201(bl D 20.2203(al(3HI>
D 50.73(a)(2)(il)(A)
D 50.73(a)(2)(viii)(A) 4 D 20.2201 (d>
D 20.2203(al(3Hii>
D 50.73(a)(2)(il)(B)
D 50.73(a)(2)(vili)(B)
D 20.2203(aic1 >
D 20.2203(a)(4>
D so.13(a)(2J(m>
D 50.73(a)(2)(1x)(A)
D 20.2203(al(2Hi>
D 50.36(c)(1)(i)(A)
D 50.73(a)(2)(iv)(A)
D 50.73(a){2)(x) 1 O. POWER LEVEL D 20.2203(a>c2>111i D 50.36(c)(1)(ii)(A)
D 50.73(a)(2)(v)(A)
D 13.11caH4l D 20.2203(aJ(2)cm>
D so.3scc>c2l D 50.73(a)(2)(v)(B)
D 73.71 (a)(S)
D 20.2203(a)(2)(iv)
D so.4s(alC3Hli>
181 50.73(a)(2)(V)(C)
D 73.n(a)(1) 000 D 20.2203(a)(2)(v)
D 50.73(a)(2)(i)(A)
D 50.73(a)(2)(v)(D)
D 13.11(a)(2J(il D 20.2203(a)(2)(vl)
D 50.73(a)(2)(i)(B)
D 50.73(a)(2)(vii)
D 13.11(a)(2Jcni D 50.73(a)(2)(i)(C)
D OTHER Specify in Abs1ract below or in D. DA TES AND APPROXIMATE TIMES OF MAJOR OCCURRENCES AND OPERATOR ACTIONS:
The dates, times, and major occurrences and operator actions for this event are as follows.
March 4, 2020 at 12:05 - Unit 2 Operators insert a manual reactor scram. Subsequently the decision is made to enter the scheduled refueling outage.
March 5, 2020 at 08:40 - Unit 2 enters Mode 4.
March 6, 2020 at 18:00- MSIV Technical Specification Surveillance 3.6.1.3.7 and 5.5.6 are completed concluding that MSIVs 2MSS*AOV6A, 2MSS*AOV6D and 2MSS*AOV7A are slow and do not meet the maximum required Tech Spec stroke times. The three MSIVs are declared inoperable.
Refueling Outage -The air packs replaced for MSIVs (2MSS*AOV6A, 2MSS*AOV6D and 2MS8*A0V7 A).
March 24, 2020 at 00:05 - MSIVs test satisfactory in accordance with N2-0SP-MSS-CS001
E. METHOD OF DISCOVERY
This event was discovered by Operations during the performance of Tech Spec required surveillance testing.
F. SAFETY SYSTEM RESPONSES:
This LEA concerns a failed Tech Spec surveillance test. No system responses were necessary.
II. CAUSE OF EVENT
The cause of the MSIV failures is being investigated and will be provided in the supplement.
III. ANALYSIS OF THE EVENT
The inoperable MS IVs are reportable under 10 CFR 50. 73(a)(2)(v)(C) as any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to: (C) Control the release of radioactive material. Two of the three valves were in a common Main Steam Line.
YEAR 2020 *
- 3. LER NUMBER SEQUENTIAL NUMBER 002 All design basis accident, transient criteria and regulatory limits remain satisfied with no overall impact to dose and EQ/HELB requirements. This conclusion is based on the following analyses.
- 1. Design Basis Secondary Containment HELB Outside Containment Peak Sub Compartment Pressure and Temperature. The slow closure increases the steam tunnel wall differential pressure due to the extended blowdown. The maximum differential pressure remains within the steam tunnel design margins. Steam tunnel temperature reaches the maximum prior to assumed closure of the MSIVs; therefore, the delay in the closure does not result in a change in peak temperature.
- 2. Design Basis Secondary Containment HELB Piping Outside Containment - Dose rates are substantially below current USAR because the increased mass release attributable to the delayed MSIV closure is substantially offset by the actual iodine concentration.
- 3. Equipment Qualification - The peak pressure envelope is extended from the assumed 9 seconds to 11 seconds. The additional 2 second duration does not result in a significant change in the peak pressure since the rate of pressure increase is mitigated by the large primary relief path through the steam tunnel blowout panels. The peak temperature remains the same with the duration of the peak temperature extended from 5.5 seconds to 11 seconds. The temperature envelope duration was drawn to start to decrease at 9 seconds, the 2 second shift in the peak duration does not represent a significant change that impacts equipment qualification.
REV NO.
00
- 4. Primary containment Peak Pressure and Temperature: The impact on peak containment pressure is defined by the fast closure specification. The slow closure has no impact on the containment peak pressure and temperature since the slow closure results in less total mass energy inside containment.
Based on the above discussion, it is concluded that the safety significance of this event is low, and the event did not pose a threat to the health and safety of the public or plant personnel.
This event does affect the NRC Regulatory Oversight Process Indicator for safety system failures.
IV. CORRECTIVE ACTIONS
A. ACTION TAKEN TO RETURN AFFECTED SYSTEMS TO PRE-EVENT NORMAL STATUS:
The MSIV air packs were replaced and tested satisfactory in accordance with Tech Spec surveillance requirements sections 3.6.1.3.7 and 5.5.6.
B. ACTION TAKEN OR PLANNED TO PREVENT RECURRENCE:
To be provided in the supplement when the cause is completed.
V. ADDITIONAL INFORMATION
A. FAILED COMPONENTS:
MSIVs 2MSS* AOV6A, 2MSS* AOV6D and 2MSS* AOV7 A, Air Packs B. PREVIOUS LERs ON SIMILAR EVENTS:
None C. THE ENERGY INDUSTRY IDENTIFICATION SYSTEM (EIIS) COMPONENT FUNCTION IDENTIFIER AND SYSTEM NAME OF EACH COMPONENT OR SYSTEM REFERRED TO IN THIS LER:
COMPONENT Main Steam Isolation Valves, Air Pack IEEE 803 FUNCTION IDENTIFIER VOP IEEE 805 SYSTEM IDENTIFICATION SB Page _s_ of _s_