05000323/LER-2019-001, Containment Spray Inoperable in Mode 4
| ML20029E862 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 01/29/2020 |
| From: | Gerfen P Pacific Gas & Electric Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| DCL-20-005 LER 2019-001-00 | |
| Download: ML20029E862 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v), Loss of Safety Function |
| 3232019001R00 - NRC Website | |
text
Pacific Gas and Electric Cmnpanyf' January 29, 2020 PG&E Letter DCL-20-005 Paula Gerten Site Vice President Diablo Canyon Power Plant Mail code 104/6/605 P.O. Box 56 Avila Beach, CA 93424 805.545.4596 Internal: 691.4596 Fax: 805.545.4234 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 10 CFR 50.73 Docket No. 50-323, OL-DPR-82 Diablo Canyon Power Plant, Unit 2 Unit 2 Licensee Event Report 2019-001-00, Containment Spray Inoperable in Mode 4
Dear Commissioners and Staff,
Pacific Gas and Electric Company (PG&E) hereby submits the enclosed Diablo Canyon Power Plant (DCPP) Unit 2 Licensee Event Report (LER) regarding a condition in which the containment spray pumps 2-1 and 2-2 were inoperable during Mode 4. PG&E is submitting this LER in accordance with 10 CFR 50. 73(a)(2)(v)(D) as an event or condition that could have prevented fulfillment of a safety function.
PG&E makes no new or revised regulatory commitments (as defined by NEI 99-04) in this report. All corrective actions identified in this letter will be implemented in accordance with the DCPP Corrective Action Program.
This event did not adversely affect the health and safety of the public.
dqmg/51057622 Enclosure cc/enc:
Scott A. Morris, NRC Region IV Administrator Christopher W. Newport, NRC Senior Resident Inspector Balwant K. Singal, NRR Senior Project Manager INPO Diablo Distribution A
member of the STARS Alliance Callaway
- Diablo Canyon
- Palo Verde
- Wolf Creek
NRC FORM U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 03/31/2020 366
, the NRC may not conduct or sponsor, and a
...... fr.
oerson is not reauired to resoond to the information collection.
. Page Diablo Canyon Power Plant, Unit 2 05000323 1 OF4
- 4. Title Containment Sorav lnooerable in Mode 4
- 5. Event Date
- 6. LER Number
- 7. Report Date
- 8. Other Facilities Involved Sequential Rev Facility Name Docket Number Month Day Year Year Month Day Year Number No.
05000 11 30 2019 2019
- - 001
- - 00 01 29 2020 Facility Name Docket Number 05000
- 9. Operating Mode
- 11. This Reoort is Submitted Pursuant to the Requirements of 10 CFR §: (Check all that apply) 4 0 20.2201 (b)
D 2O.22O3(a)(3)(i) 0 5O.73(a)(2)(ii)(A)
D 5O.73(a)(2)(viii)(A) 0 20.2201 (d)
D 2O.22O3(a)(3)(ii) 0 5O.73(a)(2)(ii)(B)
D 5O.73(a)(2)(viii)(B)
D 2O.22O3(a)(1)
D 2O.22O3(a)(4)
D 5O.73(a)(2)(iii)
D 5O.73(a)(2)(ix)(A)
D 2O.22O3(a)(2)(i) 0 5O.36(c)(1)(i)(A)
D 5O.73(a)(2)(iv)(A)
D 5O.73(a)(2)(x)
- 10. Power Level D 2O.22O3(a)(2)(ii) 0 5O.36(c)(1)(ii)(A)
D 5O.73(a)(2)(v)(A)
D 73.71 (a)(4)
D 2O.22O3(a)(2)(iii)
D 5O.36(c)(2)
D 5O.73(a)(2)(v)(B)
D 73.71(a)(5) 000 D 2O.22O3(a)(2)(iv)
D 5O.46(a)(3)(ii)
D 5O.73(a)(2)(v)(C)
D 73.77(a)(1)
D 2O.22O3(a)(2)(v) 0 5O.73(a)(2)(i)(A) 181 50. 73(a)(2)(v)(D)
D 73.77(a)(2)(ii)
D 2O.22O3(a)(2)(vi) 0 5O.73(a)(2)(i)(B)
D 5O.73(a)(2)(vii)
D 73.77(a)(2)(iii) 0 5O.73(a)(2)(i)(C)
D Other (Specify in Abstract below or in NRC Form 366A
- 12. Licensee Contact for this LER Licensee Contact li'ephone Number (Include Area Code)
!David Madsen
~05-545-6192 Cause System Component Manufacturer Reportable To ICES
Cause
System Component Manufacturer Reportable To ICES
- 14. Supplemental Report Expected Month Day Year D Yes (If yes, complete 15. Expected Submission Date) ~ No
- 15. Expected Submission Date Abstract (Limit to 1400 spaces, i.e., approximately 14 single-spaced typewritten lines)
On November 30, 2019, at 1100 PST, with Unit 2 in Mode 4, Operations identified that both trains of containment spray had been made inoperable (DC control power removed) earlier in the day, at approximately 0237 hours0.00274 days <br />0.0658 hours <br />3.918651e-4 weeks <br />9.01785e-5 months <br /> as part of preparations for a planned Mode 5 entry.
The containment spray pumps are required to be operable (along with the containment fan cooler units (CFCUs)) in Modes 1-4 in accordance with Technical Specification (TS) 3.6.6. With Containment Spray Pumps 2-1 and 2-2 inoperable, TS 3.6.6 Condition F requires immediate entry into TS 3.0.3. Since Unit 2 was in Mode 4, TS 3.0.3 required placing the unit in Mode 5 within 37 hours4.282407e-4 days <br />0.0103 hours <br />6.117725e-5 weeks <br />1.40785e-5 months <br />. At 1125 hours0.013 days <br />0.313 hours <br />0.00186 weeks <br />4.280625e-4 months <br />, both trains of containment spray were returned to operable and TS 3.6.6 and TS 3.0.3 were exited. The five CFCUs remained operable at all times throughout the inoperability of the containment spray pumps.
This event was a result of human error.
There was no impact on the health and safety of the public or plant personnel.
NRC FORM 366 (04-2018)
I. Reportable Event Classification
YEAR 2019 SEQUENTIAL NUMBER
- - 001 This event is being reported in accordance with 10 CFR 50.73(a)(2)(v)(D) and the associated guidance of NUREG-1022, as an event or condition that could have prevented fulfillment of a safety function.
REV NO.
- - 00 Event Notice (EN) 54417 reported this event in accordance with 10 CFR 50.72(b)(3)(ii)(B), as an unanalyzed condition that may have degraded plant safety. However, further engineering review of the event has determined that since all five containment fan cooler units (CFCUs) remained operable during this occurrence, there was not an unanalyzed condition that significantly degraded plant safety and the reporting criterion of 10 CFR 50. 73(a)(2)(ii)(B) is not applicable.
11. Plant Conditions
At the time of the event, Diablo Canyon Power Plant (DCPP) Unit 2 was in Mode 4 (Hot Shutdown) while preparing to enter Mode 5 (Cold Shutdown).
111. Problem Description A. Background Both containment spray pumps are required to be operable by Technical Specification (TS) 3.6.6 in Modes 1-4. The function of the containment spray system is to provide a spray of borated water mixed with sodium hydroxide into the upper regions of containment to reduce containment pressure and temperature, and to reduce fission products from the containment atmosphere during a design basis accident (OBA). Opening the containment spray pump direct current (DC) control power switches rendered both trains of containment spray inoperable.
B. Event Description
During the evening of November 29, 2019, while DCPP Unit 2 was in Refueling Outage 21, preparations were begun to transition Unit 2 from Mode 4 to Mode 5 in response to an equipment issue. Operations prepared for Mode 5 entry by writing necessary clearances, preparing procedures, and hanging configuration control tags. One such action was to disable the containment spray pumps by opening their associated DC control power knife switches. This action, which should have been performed following entry into Mode 5, was completed at approximately 0237 hours0.00274 days <br />0.0658 hours <br />3.918651e-4 weeks <br />9.01785e-5 months <br /> on November 30, 2019, with Unit 2 still in Mode 4. The DC control power was removed from the containment spray pumps as a result of human error. At 1100, the next operating crew (day shift) recognized the error and immediately entered TS 3.6.6 Condition F due to two trains of containment spray being inoperable. TS 3.6.6 Condition F.1 requires immediate entry into TS 3.0.3. Both pumps were restored to operable status on November 30, 2019, at 1125, and TS 3.6.6 and 3.0.3 were exited.
C. Status of Inoperable Structures, Systems or Components that Contributed to the Event Page 2 of 4 (04-2018)
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 3/31/2020 LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET (See NUREG-1022, R.3 for instruction and guidance for completing this form http://www. nrc.qov/readinq-rm/doc-collections/nu regs/staff/sr1022/r30
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. LER NUMBER YEAR Diablo Canyon Power Plant, Unit 2 05000-323 2019 There were no inoperable structures, systems or components that contributed to the event.
D. Other Systems or Secondary Systems Affected None.
E Method of Discovery Self-identified. This condition was discovered by Operations personnel.
F. Operator Actions
SEQUENTIAL NUMBER
- - 001 REV NO.
- - 00 Upon discovery of both trains of containment spray being inoperable in Mode 4, Unit 2 entered TS 3.6.6 Condition F and TS 3.0.3 at 1100 on 11/30/19. Both pumps were restored to operable status, and the associated TS were exited at 1125. The Operations crews responded to this event in accordance with plant operating procedures.
G. Safety System Responses There were no safety system responses as a result of this event. Additionally, all five CFCUs remained operable and available during the period of containment spray inoperability.
IV. Cause of the Problem The DC control power was removed from containment spray pumps as a result of human error.
V. Assessment of Safety Consequences
There were no safety consequences as a result of this event. The event occurred on day 69 of Unit 2 Refueling Outage 21 while preparations were being made to return Unit 2 to Mode 5, with relatively low decay heat in the core. Containment integrity was maintained, and all five containment fans coolers remained operable during this event. Given the Unit 2 conditions at the time, two of the five containment fan coolers would have provided sufficient containment cooling in the event of a loss of coolant.
There was no impact on the health and safety of the public or plant personnel. Page 3 of 4 (04-2018)
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 3/31/2020 LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET (See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r31)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. LER NUMBER YEAR Diablo Canyon Power Plant, Unit 2 05000-323 2019
VI. Corrective Actions
SEQUENTIAL NUMBER
- - 001 REV NO.
- - 00 The containment spray pumps were promptly restored to operable status upon identification of the error. Follow-up corrective actions to prevent recurrence will be managed in accordance with DCPP Corrective Action Program.
VII. Additional Information
There have been no similar events at DCPP in the previous three years. Page 4 of 4