05000321/LER-1917-006, Regarding Manual Scram Initiated Due to Inoperable Intermediate Range Monitors
| ML17170A072 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 06/19/2017 |
| From: | Vineyard D Southern Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-17-1114 LER 17-006-00 | |
| Download: ML17170A072 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 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)(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)(v), Loss of Safety Function 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) |
| 3211917006R00 - NRC Website | |
text
Da)rid R. Vineyard Hatch Nuclear Plant Southern Nuclear Vtee Pres!Oent-Plant Hatch 11028 Hatch Parkway North
~ey.~ 31513 June 19, 2017 Docket No.:
50-321 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Edwin I. Hatch Nuclear Plant Unit 1 LEA 2017-006-00 912 537 5859 tel 912 366 2077 tax NL-17-1114 Manual Scram Initiated Due to Inoperable Intermediate Range Monitors Ladies and Gentlemen:
In accordance with the requirements of 10 CFR 50.73(a}(2}(iv}(A), Southern Nuclear Operating Company (SNC) hereby submits the enclosed Licensee Event Report.
This letter contains no NRC commitments. If you have any questions, please contact Greg Johnson at (912) 537-5874.
Respectfully submitted, f}JVJ{tr---
David R. Vineyard Vice President - Hatch DRV/jcb Enclosure: LER 2017-006-00
U.S. Nuclear Regulatory Commission NL-17-1114 Page2 Cc:
Regional Administrator, Region II NRR Project Manager-Hatch Senior Resident Inspector-Hatch RTYPE: CHA02.004
Edwin I. Hatch Nuclear Plant Unit 1 LER 2017-006-00 Manual Scram Initiated Due to Inoperable Intermediate Range Monitors
NRC FORM366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2018 (06-2016)
Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />
,........ '!\\.
LICENSEE EVENT REPORT (LER)
Reported lessons learned are incorporated into the licensing process and fed back to industry.
~~ i Send comments regarding burden estimate to the FOIA, Privacy and Information Collections (See Page 2 for required number of digits/characters for each block)
Branch (T -5 F53), U.S. Nuclear Regulatory Commission. Washington, DC 20555-0001, or by e-mail
~..... :.r to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory (See NUREG-1 022, R.3 for instruction and guidance for completing this fonn Affairs, NEOB-1 0202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control htto:llwww.nr~;.gov/reading-nn/s;!~-collections/numg§:!~taff/llr1022/r~
number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
.PAGE Edwin I. Hatch Nuclear Plant Unit 1 05000321 1 OF3
- 4. TITLE Manual Scram Initiated Due to Inoperable Intermediate Range Monitors
- 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 19 2017 FACILITY NAME DOCKET NUMBER 04 20 2017 2017
- - 006
- - 00 6
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: Check all that apply) 0 20.2201(b) 0 20.2203(a)(3)(i) 0 50.73(a)(2)(ii)(A) 0 50.73(a)(2)(viii)(A) 4 0 20.2201 (d) 0 20.2203(a)(3)(ii) 0 50.73(a)(2)(ii)(B) 0 50.73(a)(2)(viii)(B) 0 20.2203(a)(1) 0 20.2203(a)(4) 0 50.73(a)(2)(iii) 0 50.73(a)(2)(ix)(A) 0 20.2203(a)(2)(i) 0 50.36(c)(1)(i)(A) 181S0.73(a)(2)(iv)(A) 0 50.73(a)(2)(x)
- 10. POWER LEVEL 0 20.2203(a)(2)(ii) 0 50.36(c)(1)(ii)(A) 0 50.73(a)(2)(v)(A) 0 73.71(a)(4) 0 20.2203(a)(2)(iii) 0 50.36(c)(2) 0 50.73(a)(2)(v)(B) 0 73.71(a)(5) 0 20.2203(a)(2)(iv) 0 50.46(a)(3)(ii) 0 50.73(a)(2)(v)(C) 0 73.77(a)(1) 0 0 20.2203(a)(2)(v) 0 50.73(a)(2)(i)(A) 0 50.73(a)(2)(v)(D) 0 73.77(a)(2)(i) 0 20.2203(a)(2)(vi) 0 50.73(a)(2)(i)(B) 0 50.73(a)(2)(vii) 0 73.77(a)(2)(ii) 0 50.73(a)(2)(i)(C) 0 OTHER Specify '"Abstract below or In NRC Form 366A
- 12. LICENSEE CONTACT FOR THIS LER ICENSEE CONTACT
~~LEPHONE NUMBER (Include Area Code)
Edwin I. Hatch/Jimmy Collins-Licensing Supervisor 912-537-2342
- 13. COMPLETE ONE UNE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT
CAUSE
SYSTEM COMPONENT MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT MANU-REPORTABLE FACTURER TOEPIX FACTURER TO EPIX
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH DAY YEAR 0 YES (If yes, complete 15. EXPECTED SUBMISSION DATE)
[8] NO SUBMISSION DATE ABSTRACT (Umit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
On April 20, 2017 at 2345 EST with Unit 1 in Mode 4 at 0 percent rated thermal power, the Unit 1 Reactor Mode Switch was taken from the REFUEL to the SHUTDOWN position per Technical Specification (TS} Limiting Condition for Operation (LCO} 3.1 0.4, Required Action A.2.2, due to having no operable intermediate range monitors (IRMs} in one quadrant of the reactor vessel because of maintenance activities. All control rods had been previously inserted, therefore no control rod motion occurred when the mode switch was positioned to SHUTDOWN.
The cause of this event was due to flawed technical decision making surrounding maintenance activities related to inoperable I RMs. An inadequate review of TS LCO 3.1 0.4, in part due to the emergent nature of the maintenance activities to restore IRMs to operable status, resulted in Operations' incorrect determination that one of the requirements of TS LCO 3.1 0.4, "Single Control Rod Withdrawal-Cold Shutdown" was not met. The Unit 1 Reactor Mode Switch was therefore placed to the SHUTDOWN position per TS 3.1 0.4, Condition A.2.2.
Corrective actions included ensuring TS Bases 3.1 0.4 language is not ambiguous, issuing an order that requires the shift manager to approve the removal of TS equipment from service for maintenance, and inclusion of this event in licensed operator continuing training.
Event Description
On April 20, 2017 at 2345 EST with Unit 1 in Mode 4 at 0 percent rated thermal power, the Unit 1 Reactor Mode Switch was taken from the REFUEL to the SHUTDOWN position per Technical Specification (TS)
Limiting Condition for Operation (LCO) 3.1 0.4, Required Action A.2.2, due to having no operable intermediate range monitors (IRMs) in one quadrant of the reactor vessel because of maintenance activities. All control rods had been previously inserted, therefore no control rod motion occurred when the mode switch was positioned to SHUTDOWN.
Event Cause Analysis
The cause of this event was due to flawed technical decision making surrounding maintenance activities related to inoperable IRMs. An inadequate review of TS LCO 3.1 0.4, in part due to the emergent nature of the maintenance activities to restore IRMs to operable status, resulted in Operations' incorrect determination that one of the requirements of TS LCO 3.1 0.4, "Single Control Rod Withdrawal - Cold Shutdown" was not met. The requirements of TS LCO 3.1 0.4 dictate that the MODE 5 requirements of TS LCO 3.3.1.1 for operable IRMs be met. In MODE 5, with a control rod withdrawn in a cell containing fuel, TS LCO 3.3.1.1 requires that there be an operable IRM in each quadrant. In this case, since all rods were already inserted, LCO 3.3.1.1 MODE 5 requirements for IRMs were not applicable, thus the LCO 3.1 0.4 requirements for IRMs were met. However, due to the incorrect determination that this requirement of TS LCO 3.1 0.4 was not met, the Unit 1 Reactor Mode Switch was placed to the SHUTDOWN position per TS 3.1 0.4, Condition A.2.2.
Safety Assessment
This event is reportable per 10 CFR 50. 73(a)(2)(iv)(A) as an event that resulted in the automatic actuation of the reactor protection system (RPS).
The IRMs monitor neutron flux from the upper portion of the source range monitor (SRM) range to the lower portion of the power range neutron monitoring (PRNM) range. The IRM system consists of eight IRM channels and detectors that are inserted into the core for a reactor startup and are withdrawn after the reactor mode selector switch is positioned to RUN. The IRM system is divided into two groups of IRM channels arranged in the core. IRM channels "A", "C", "E", and "G" are associated with trip system A of the RPS and IRM channels "B", "D", "F", and "H" are associated with trip system B. There are two IRM channels in each quadrant of the core. The IRM system is capable of generating a trip signal that can be used to prevent fuel damage resulting from abnormal operating transients that occur while operating in the intermediate power range.
There was no change in reactivity and no movement of the control rods occurred since all rods were inserted prior to this event. Therefore, this event is considered to have low safety significance. Page 2 of3 (06-2016)
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2018 f'¥'
j
~.....:.r LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET (See NUREG-1 022, R.3 for instruction and guidance for completing this form http://WNW.nrc.gov/reading-rmldoc-collectionslnuregs/stafflsr1022/r31)
Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />.
Reported lessons teamed are incorporated into the licensing process and fed back to industry.
Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503.1f a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. LER NUMBER Edwin I. Hatch Nuclear Plant Unit 1 05000-321 YEAR I SEQUENTIAL I REV NUMBER NO 2017
- - 006
- - 00
Corrective Actions
The TS Bases were reviewed to ensure there was no ambiguity in the wording of TS Bases 3.1 0.4. A Standing Order was issued to provide direction that the Shift Manager must approve any work that removes TS equipment from service. Additionally, this event will be covered in Licensed Operator Continuing Training.
Previous Similar Events
None. Page 3 of 3