05000323/LER-2018-001, Automatic Reactor Trip of Unit 2 Following a Load Rejection

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Automatic Reactor Trip of Unit 2 Following a Load Rejection
ML19030B857
Person / Time
Site: Diablo Canyon Pacific Gas & Electric icon.png
Issue date: 01/30/2019
From: Welsch J
Pacific Gas & Electric Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
DCL-19-007 LER 2018-001-00
Download: ML19030B857 (4)
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LER-2018-001, Automatic Reactor Trip of Unit 2 Following a Load Rejection
Event date:
Report date:
Reporting criterion: 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
3232018001R00 - NRC Website
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text

Pacific Gas and Electric Company'l' January 30, 2019 PG&E Letter DCL-19-007 James M. Welsch Vice President Nuclear Generation and Chief Nuclear Officer Diablo Canyon Power Plant P.O. Box 56 Avila Beach, CA 93424 805.545.3242 E-Mail: JMW1@pge.com 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 Licensee Event Report 2-2018-001-00, Automatic Reactor Trip of Unit 2 Following a Load Rejection

Dear Commissioners and Staff,

Pacific Gas and Electric Company (PG&E) hereby submits the enclosed Licensee Event Report (LER) regarding an automatic reactor trip of Unit 2, which occurred on December 1, 2018. PG&E is submitting this LER in accordance with 10 CFR 50. 73(a)(2)(iv)(A) as an event or condition that resulted in manual or automatic actuation of any of the systems listed in paragraph (a)(2)(iv)(B).

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 Diablo Canyon Power Plant Corrective Action Program.

This event did not adversely affect the health and safety of the public.

Sincerely, dqmg/6192/51006788 Enclosure cc/enc:

Scott A. Morris, NRC Region IV Administrator Christopher W. Newport, NRC Senior Resident Inspector Balwant K. Singal, NRR Senior Project Manager L. John Klos, NRR Project Manager INPO Diablo Distribution A

member of the STARS Alliance Callaway

  • Diablo Canyon
  • Palo Verde
  • Wolf Creek

NRC FORM366 U.S. NUCLEAR REGULA TORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2018)

, the NRC may not conduct or sponsor, and a

      • 1'..

person is not required to respond to, the information collection.

3.Page Diablo Canyon Power Plant, Unit 2 05000 323 1

OF 3

4. Title Automatic Reactor Trip of Unit 2 Following a Load Rejection
5. Event Date
6. LER Number
7. Report Date
8. Other Facilities Involved Month Day Year Year I Sequential I Rev Month Facility Name Docket Number Number No.

Day Year 05000 01 Facility Name Docket Number 12 01 2018 2018 -

001 -

00 30 2019 05000

9. Operating Mode
11. This Report is Submitted Pursuant to the Requirements of 10 CFR §: (Check all that apply) 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) 1 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) 0 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) 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) 100 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)(2)(ii)
50. 73(a)(2)(i)(C)

Other (Specify in Abstract below or in C. Status of Inoperable Structures, Systems or Components that Contributed to the Event There were no inoperable structu~es, systems or components that contributed to the event.

D. Other Systems or Secondary Systems Affected None.

E. Method of Discovery

The event was immediately apparent to plant operators due to alarms and indications associated with the load rejection received in the control room.

F. Operator Actions

Control room personnel responded in accordance with established procedures, confirmed the reactor trip, verified proper engineered safety feature actuations, and stabilized the unit in Mode 3.

G. Safety System Responses The trip was not complex; all safety systems responded as designed.

IV. Cause of the Problem The DCPP Unit 2 trip was caused by the actuation of the DC-SPS logic. PG&E is conducting a root cause evaluation (RCE) and will submit a supplemental Licensee Event Report (LER) following completion of the RCE.

V. Assessment of Safety Consequences

There were no safety consequences as a result of this event. The Operations crew responded to the event in accordance with plant operating procedures. Equipment necessary for Unit 2 decay heat removal was available and operated as required by plant design. Unit 1 was not affected by this event. There was no impact on the health and safety of the public or plant personnel.

VI. Corrective Actions

The ROD logic portion of the DC-SPS circuitry has been disabled and mitigation measures have been implemented, including enhanced communications with the Grid Control Center.

As stated in Section IV, PG&E will submit a supplemental LER following the completion of this RCE. Page 3

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