05000261/LER-2017-001

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LER-2017-001, Auxiliary Feedwater System Actuation During Surveillance Testing
H. B. Robinson Steam Electric Plant, Unit No. 2
Event date: 04-03-2017
Report date: 06-02-2017
Reporting criterion: 10 CFR 50.73(a)(2)(iv)(A), System Actuation
LER closed by
IR 05000261/2017002 (25 July 2017)
2612017001R00 - NRC Website
LER 17-001-00 for H.B. Robinson, Unit 2, Regarding Auxiliary Feedwater System Actuation During Surveillance Testing
ML17152A326
Person / Time
Site: Robinson Duke energy icon.png
Issue date: 06/01/2017
From: Kapopoulos E J
Duke Energy Progress
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
RNP-RA/17-0040
Download: ML17152A326 (5)


comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to 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 reqtrred to respond to, the information collection H. B. Robinson Steam Electric Plant, Unit No. 2 2017 00

BACKGROUND

The Auxiliary Feedwater (AFW) System[BA] can provide feedwater to the steam generators[SG] for decay heat removal if main feedwater is not available or steam generator level is not adequate. The system provides feedwater from any one or combination of three AFW pumps[P], two are motor-driven pumps and the third is steam driven. The two motor-driven pumps are supplied power from the emergency buses[BU] E-1 and E-2. The steam-driven pump can be operated independent of electrical power where steam produced from decay heat drives the turbine[TRB].

10 CFR 50.72 and 10 CFR 50.73 requires events to be reported in which one of the specified systems actuates either manually or automatically. This requirement is based on the premise that these systems are provided to mitigate the consequences of a significant event and, therefore: (1) they should work properly when called upon, and (2) they should not be challenged frequently or unnecessarily.

The event described below is reportable under 10 CFR 50.72(b)(3)(iv)(A), any event or condition that results in valid actuation of any of the systems listed in paragraph (b)(3)(iv)(B) of this section except when the actuation results from and is part of a pre-planned sequence during testing or reactor[RCT] operation. Consequently, an 8-hour notification was made on 4/3/2017 to the Nuclear Regulatory Commission (NRC) Operations Center (EN No. 52662). The event is also reportable under 10 CFR 50.73(a)(2)(iv)(A), any event or condition that resulted in manual or automatic actuation of any of the systems listed in paragraph (a)(2)(iv)(B) of this section, except when: (1) the actuation resulted from and was part of a pre-planned sequence during testing of reactor operation; or (2) the actuation was invalid and; (i) occurred while the system was properly removed from service; or (ii) occurred after the safety function had been already completed. This criterion requires a 60-day licensee event report be submitted within 60-days of the event date.

EVENT DESCRIPTION

On 4/3/2017 H. B. Robinson Steam Electric Plant, Unit No. 2 (HBRSEP2) was in Mode 3 at zero percent power with the 'B' MFW pump in service. Turbine trip logic surveillance testing was in progress per Maintenance Surveillance Test (MST)-551, Turbine Trip Logic Channel Testing. During performance of the test the AFW system actuated when the only running main feedwater (MFVV) pump was tripped as part of the test. The following sequence of events provides a concise chronological description of the operation of plant equipment surrounding the safety system actuation.

Date: Time: Event:

4/3/2017: 1952 -'A' and 'B' Reactor Trip Breakers[BKR] closed for MST-551, Turbine Trip Logic Channel Testing.

2155 - MFW pump 'B' tripped as a result of MST-551 section 7.6 performance causing an AFW system actuation. 'A' and 'B' motor-driven AFW pumps started as required.

2201 - 'B' AFW pump was secured in accordance with OP-402, Auxiliary Feedwater System.

2237 - 'B' MFW pump was started in accordance with OP-403, Feedwater System.

2242 - 'A' AFW pump was secured in accordance with OP-402.

CAUSAL FACTORS

The guidance (Step 7.6.1) in MST-551, Turbine Trip Logic Channel Testing, directed the balance of plant (BOP) licensed operator to ensure that the AFW defeat switches[33] for 'A' and 'B' trains were in the DEFEAT position. The BOP licensed operator documented completion of Step 7.6.1 without looking at the switch positions as required by the MST procedure. This inadequate procedure adherence is the direct cause of the event.

001 comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infocollects.Resource@nrcgov, and to the Desk Officer, Office of Information and Regulatory Affairs 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 s not requred to respond to, the information collection H. B. Robinson Steam Electric Plant, Unit 05000- 261 001 00 No. 2 2017 - -

CORRECTIVE ACTIONS

Completed:

1. MST-551 was suspended.

2. 'B' MFW pump was restarted.

3. AFW pumps were secured.

4. BOP operator was relieved of his licensed operator duties and submitted to post-event testing.

5. The BOP operator received a formal remedial training package on procedure adherence.

SAFETY ANALYSIS

The actuation of the AFW system during surveillance testing was valid, and the system responded to plant conditions as designed. There is no safety consequence as a result of this event. The cause was attributed to inadequate procedure adherence and not due to any equipment failures. This event resulted in no impact to the health and safety of the public

ADDITIONAL INFORMATION

An operating experience (OE) search was conducted and there is one prior event at HBRSEP2 involving inadvertent actuation of the AFW system within the past three years. This actuation was due to inadequate procedural guidance rather than inadequate procedure adherence, and was reported via LER 2016-005-01.

Energy Industry Identification System (EIIS) codes for systems and components relevant to this event are identified in the text of this document within brackets [ ].