ML17328A365

Workshop on Sharing Operating Experience from Rigging, Lifting and Load Handling Events - Temporary Overhead Crane Failure at Arkansas Nuclear One Presented to IAEA

ML17328A365
Person / Time
Site:	Arkansas Nuclear
Issue date:	11/30/2017
From:	Geoffrey Miller NRC/RGN-IV/DRP/RPB-D
To:
Miller G
References
48869, ML13158A242, ML14083A409
Download: ML17328A365 (23)

Text

Temporary Overhead Crane Failure at Arkansas Nuclear One Workshop on Sharing Operating Experience from Rigging, Lifting and Load Handling Events IAEA Headquarters 27-30 November 2017 ADAMS Accession Number ML17328A365 1

Outline

• Overview of site and planned lift

• Discussion of the event

• Response actions

• Lessons learned (some confirmed)

• Recovery

• References 2

Overview Arkansas Nuclear One Russellville, Arkansas 3

Unit 1 Stator Replacement Computer Modelling Lift Move Stator weight ~525 tons Travel path ~90 ft (27 m) horizontal

(~477,000 kg) ~29 ft (9 m) vertical 4

Unit 1 Stator Replacement Animation of Planned Lift Train Bay Tripods H-frame U1 Stator 5

Event Summary Sunday, March 31 0639: Lift begins 0750: Crane fails, immediate loss of offsite power to Unit 1 (switchgear damaged), Unit 2 reactor coolant pump trip (vibration-induced) and reactor trip, fire piping ruptured 0923: Breaker failure from water leakage causes Unit 2 partial loss of offsite power and loss of instrument air to both units 1033: Notification of Unusual Event Declared Saturday, April 6 Offsite power restored to Unit 1 using temporary modifications 6

7 8

NRC Response

• Senior Resident Inspector immediately responded to control room on site

• Emergency response mode decision

• Coordination with OSHA

• Performed risk evaluation of event to determine inspection response

• Augmented Inspection Team (second-highest reactive inspection) commenced April 8

• Repair/recovery inspections prior to restart 9

Cause Evaluation

• From NRC Augmented Inspection Team Follow Up Inspection Report:

- The overhead temporary hoisting assembly was not properly designed

- The associated calculation was not reviewed

- The assembly was not load tested 10

Lessons Learned

• Personnel Safety for Suspended Loads

- Be aware the area of impact could be more than beneath the suspended load from falling hoist/crane members or other damaged equipment

- Installed/available cameras can be used to limit observers in the area 11

12 Lessons Learned contd

• Collateral Damage Possible from Chain Reaction Events

- Water from ruptured piping

- Power failures

• Expect Complications to Response and Recovery

- Blocked access routes

- Personnel injuries/fatalities 13

14 15 Lessons Learned contd

• Full Consideration of Plant Risk

- Watch for complacent attitudes associated with high consequence/low probability events

• Control of Vendors and Contractors

- In U.S., the licensee retains ultimate responsibility

- Additional contractor organizations may be needed for technical review

• • For inspectors: know how the licensee verifies compliance 16

17 Lessons Learned contd

• Inspector Response to Significant Events Involving Fatalities/Injuries

- Maintain awareness of operator mindset

• Significant emotional event

• Licensee management actions to ensure operators remain focused on tasks

- Be familiar with alternate access routes within the plant

- Coordination with other government agencies 18

Lessons Learned contd

• Maintain Open and Frequent Internal and External Communications

- Coordinate with public affairs representatives and other local/federal government agencies

- Social media a significant and increasing factor: help public affairs representatives stay in front 19

Damaged Stator Removal 20

Turbine Deck Repair 21

Load Test of Replacement Crane 22

References

• NRC Event Number 48869; Notification of Unusual Event Declared Due to a Breaker Explosion in the Protected Area

• Arkansas Nuclear One - NRC Augmented Inspection Team Report 05000313; 05000368/2013011 (ADAMS ML13158A242)

• Arkansas Nuclear One - NRC Augmented Inspection Team Follow Up Report 05000313; 05000368/2013012 (ADAMS ML14083A409)

• Information available on the NRC website www.nrc.gov

• Investigation of the March 31, 2013 Temporary Overhead Crane Collapse At Arkansas Nuclear One Power Plant In London/Russellville, AR - OSHA (www.osha.gov/doc/engineering/pdf/2013_r_04.pdf) 23