ML20059C260
| ML20059C260 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 09/09/1993 |
| From: | Martin T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Cooper R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML20059C243 | List: |
| References | |
| NUDOCS 9311010069 | |
| Download: ML20059C260 (27) | |
Text
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ATTACHMENT 1 s
UNITED STATES NUCLEAR REGULATORY COMMISSION E
o
-f REGloN l 47S ALLENDALE ROAD
[
KING oF PRUSSIA, PENNSYLVANIA 19406-1415 o
September 9, 1993 Docket No. 50-271 Richard W. Cooper, II, Director, Division of Reactor Projects
-MEMORANDUM FOR:
Wayne M. Hodges, Director, Division of Reactor Safety Charles W. Hehl, Director, Division of Radiation Safety and Safeguards Thomas T. Martin, Region Administrator FROM:
AUGMENTED INSPECTION TEAM CH ARTER FOR REVIEW
SUBJECT:
OF THE FUEL H ANDLING EVENTS AT VERMONT YANKEE Due to fuel handling incidents on September 3 and 9,1993 at Vermont Yankee, I have determined that an Augmented Inspection Team (AIT) inspection should be conducted to verify the circumstances and evaluate the significance of these events.
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The Division of Reactor Safety (DRS) is directed to conduct the AIT with James Beall as the Further, DRS, in coordination with the Division of Reactor Projects. is Team Leader.
responsible for the timely issuance of the' inspection report, the identification and p potentially generic issues, and the identification and completion of any enforcemen j
warranted as a result of the team's review.
i Enclosed is the charter for the Augmented Team delineating the scope of this inspection. The inspection shall be conducted in accordance with NRC Management Directive (MD) 8 Inspection Manual 0325, Inspection Procedure 93800, Regional Office instruction 101 Revision 2 and this memorandum. The bases for this inspection, per MD 8.3, are: (1) the staff's need to fully understand the causes of the events; and, (2) the staff's need to determ if there are potential generic issues worthy of staff action associated with these events.
Preliminary information indicates that each event was caused by human error due, in part, deficiencies in training, procedure clarity, and possibly human factors.
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Thomas T. Martin Regional Administrator i
Enclosures:
1.
Augmented Inspection Team Charter 2.
Team Membership l
9311010069 931021-i PDR ADOCK 05000271 G
2 cc w/encis:
J. Taylor, EDO J. Sniezek, OEDO T. Murley, NRR J. Partlow, NRR J. Calvo, NRR C. Rossi, NRR D. Dorman, PD I-3, NRR F. Miraglia, NRR C. McCracken, NRR F. Rosa, NRR W. Russell, NRR J. Richardson, NRR A. Thadani, NRR B. Grimes, NRR J. Roe, NRR E. Jordan, AEOD D. Ross, AEOD V. McCree, OEDO W. Kane, DRA, RI R. Cooper, DRP, RI W. Lanning, DRP, RI J. Linville, DRP, RI J. Beall, DRS, RI (Team leader)
E. Kelly, DRP, RI C. Hehl, DRSS, RI S. Shankman, DRSS, RI H. Eichenholz, SRI - Vermont Yankee W. Butler, PD l-3, NRR W. Ruland, DRS, RI J. Durr, DRS, RI W. Hodges, DRS, RI L. Bettenhausen, DRS, RI K. Abraham, PAO, RI M. Miller, SLO, RI v
ENCLOSURE 1 VERMONT YANKEE NUCLEAR POWER STATION FUEL IIANDLING ERRORS AUGMENTED INSPECTION TEAM (AIT) C11 ARTER The general objectives of this AIT are to:
Develop a detailed sequence of events related to both events, from September 3 through 1.
9.
Determine the specific circumstances and causes of the apparent operator errors that 2.
occurred during refueling operations on September 3 and 9,1993.
3.
Determine and evaluate any changes (specifically Plant Design Change 92-11 implemented in Spring 1993) made in the design, maintenance, testing, or operation of the refueling bridge including hoist, grapple and operator controls. Also included is associated training for such modifications.
Evaluate the human factors aspects of both events, including: (a) command and control, 4.
and communications; (b) human performance factors, such as staffing, overtime, and schedule; and, (c) human-systems interfaces such as with console design.
Assess the safety significance, including existing damage to the affected fuel assemblies.
5.
Determine the adequacy of Vermont Yankee's maintenance and troubleshooting practices 6.
for refueling equipment, including vendor interface and control.
7.
Evaluate Vermont Yankee's corrective actions and management controls following the September 3rd event, as they relate to the second September 9th event, particularly on-the-job training.
Explicitly excluded from this charter are the recovery plans and radiological precautions 8.
associated with eventual removal of the first dropped assembly.
Prepare a report document ng the results of this review for signature by the Regional 9.
Administrator within 30 days of the completion of the inspection.
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I ENCLOSURE 2 VERMONT YANKEE AIT MEMBERSHIP James Beall, AIT Leader, Division of Reactor Safety (DRS), Region I (RI)
Arthur Burritt, Operations Engineer, DRS, R1 Thomas Shediosky, Project Engineer, DRP, RI Paul Harris, Resident Inspector, Vermont Yankee G. West, Engineering Psychologist, NRR Other NRC personnel, consultants, or contractors will be engaged in this ATT, as needed.
E ATTACHMENT 2 Persons Contacted Vermont Yankee Nuclear Power Corporation L. Amirault Training Instructor, SRO J. Bazenas Reactor Engineer (General Electric)
M. Benoit RE&C Manager
- B. Buteau Engineering Director J. Cihak Reactor Engineer
- R. Clark Quality Assurance Director D. Deere Operations Training Instructor D. Faulstich Senior Program Manager (General Electric)
- E. Harms Operations Training Supervisor N. Jennison ACRO M. Newsom Reactor Engineer (General Electric)
K. Oliver SCRO B. Perry Auxiliary Operator B. Pichette SCRO R. Ramsdell Human Factors Engineer
- D. Reid Vice President, Operations R. Shuman ACRO A. Siciak ACRO R. Sojka Operations Support Manager M. Tessier Electrical Engineer
- R. Wanczyk Manager, Vermont Yankee Station United States Nuclear Regulatory Commission
- 2. Cooper Director, Division of Reactor Projects H. Eichenholz Senior Resident Inspector S
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- Denotes those present at the exit meeting on September 21,1993, attended by the public and news media. The team also held discussions with other licensee management, operations, maintenance, engineering and quality assurance personnel.
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NITACIIMENT 3 Sequence of Events for the Vermont Yankee Refueling Incidents Event 1: On September 3 at 12:23 p.m., during fuel move 233 fuel assembly LYN-831 inadvertently uncoupled from the fuel grapple while being removed from the core position 21-14 to sipping can #1. LYN 831 fell approximately 8 feet back into core position 21-14.
Event 2: On September 9 at 4:10 a.m., during fuel move 388, fuel assembly LYV-667 was in transport from core position 25-34 to fuel sipping can #2, and was inadvertently lowered into the double blade guide inserted in the center of the core. LYU-667 was then moved to fuel sipping can #2.
3-4/88 The single J-hook grapple was replaced by the double J-hook design 8/19/93 Joy Stick Modification installed 8/27/93 1:00 p.m.
Commenced reactor shutdown 6:10 p.m.
RMS - Startup 10:00 p.m.
All rods inserted, RMS - Refuel 8/28/93 5:33 a.m.
Rx coolant temp <212 degrees F 8/29/93 1:20 p.m.
Rx vessel head removed 6:00 p.m.
Commenced CRD maintenance 8/31/93 6:45 p.m.
Secondary Containment Capability check 9:45 p.m.
Commenced refueling interlocks per OP 4102 i
2 9/1/93 6:40 a.m.
Completed refueling interlocks 9:40 a.m.
Commenced fuel moves, NRC questions the lack of a 50.59 for a TM installed on CR 26-39 position indicator.
11:55 a.m.
Refueling secured pending analysis of TM 93-49.
6:55 p.m.
VY removed TM 93-49 and replaced the connector pin for CR 26-39. Corrective maintenance completed for CR 26-39.
7:35 p.m.
Completed refueling interlocks.
7:58 p.m.
Commenced fuel moves 9/2/93 1:40 p.m.
Refueling secured, air hose uncoupled 2:35 p.m.
Commenced fuel moves, following repair of the air hose.
10:50 p.m.
Refueling secured, due to a broken power cable for the grapple.
9/3/93 3:15 a.m.
Commenced fuel moves, following repair of the power cable.
12:23 p.m.
LYN-831 uncoupled from the fuel grapple and dropped back into core position 21-14. A shudder was felt by Operators l A and IB on the refuel bridge. The SCRO heard a hissing noise. The grapple closed light was energized. No bubbles or debris were observed. No radiation detectors alarmed.
The RP tech replaced the iodine cartridge with a new one.
The bridge and grapple was left in the " failed" position. The refuel floor was evacuated.
12:30 p.m.
Slight rise in stack gas 1 and 2 rate, 80 cpm to 140 cpm (peak at 180 cpm); Air sample at the 318 ft indicated very slight increase in Xe-133 (0.1 mr/hr). Drywell radiation surveys were normal. Hourly sampling of reactor cavity water indicated increase in Xe-133, Cs-134, and Iodine.
12:39 p.m.
Drywell evacuated 12:50 p.m.
Unusual Event declared, based on OE 3125, General Criteria.
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3 1:45 p.m.
Licensee and NRC conference call: assembly rescated in the proper position and orientation; minor stack gas increases had been observed in the past during sipping and refueling; no previous dropped fuel bundles at site; refuel floor continuous air sampler saw no increase in background or airborne.
2:05 p.m.
PRO submitted, event notifications completed 2:50 p.m.
Secondary containment capability check performed 3:15 p.m.
Licensee management meeting; PORC reviewed the event.
Initial inspections revealed no damage to the grapple. One fuel channel dog ear was bent the other was loose on the fuel assembly upper spider. All chemistry samples were trending down and expected to be normal within 5-6 hours. Iodine at 3E-3 dacs; root cause in progress.
3:30 p.m.
Unusual Event terminated, based on OE 3125 criteria and a PORC recommendation.
3:40 p.m.
NRC Operations Center notified 7:00 p.m.
Licensee and NRC conference call; both parties agreed to hold refueling until NRC inspection of initial moves was performed.
9/5/93 11:25 p.m.
Secondary containment capability check performed 10:35 p.m. TM 93-53 installed on the refuel grapple 1:30 a.m.
Completed refueling pre-requisites 2:25 p.m.
Commenced fuel moves 9/8/93 1:10 a.m.
Refueling secured, rotation of the grapple operator console causes " grapple closed" to go out. Emergency work order initiated.
3:40 a.m.
Commenced refueling, corrective maintenance completed,...
grapple limit switches adjusted.
9:55 a.m.
Refueling secured, outage manager concerned about inadequate documentation of the maintenance performed on the limit switch.
4 11:20 a.m.
Refueling authorized by licensee management following review of the limit switch corrective maintenance.
1:00 p.m.
Commenced fuel moves 1:50 p.m.
Refueling secured due to noise in the take-up reel. Work order initiated.
2:40 p.m.
Commenced fuel moves, completed troubleshooting of the take up reel. Licensee unable to identify the cause of the noise.
9/9/93 4:10 a.m.
Refueling secured due to the inadvertent lowering of fuel bundle LYV-667. During transfer of the bundle to the sipping container the grapple would not ungrapple. A hand-held mechanical tool also couldn't open the grapple. The fuel bundle was repeatedly reseated, without freeing the grapple and the control room was notified. The grapple finally operated and an emergency work order was initiated.
4:45 a.m.
LYV-667 in sip can, commenced grapple, bail, and double blade guide inspections.
5:30 a.m.
Plant management halted fuel handling activities.
10:30 a.m.
Licensee secured all refueling activities Licensee task team chartered to review both refueling incidents with the plant manager as the team leader.
9/10/93 NRC Augmented Inspection Team arrived onsite.
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ATTACIIMENT 4 HUMAN FACTORS WEAKNESSES 1.
Visibility of 12 bel for Joystick: The up label for the joystick control of the grapple was obscured by the rubber base of the joystick, if visible at all, with the refueling platform operator positioned directly in front of the control. This weakness was inconsistent with NUREG-0700 guidelines: " Concealment - 12bels should not be covered or obscured by other units in the equipment assembly" [ guideline 6.6.2.4(b)],
and " Controls - 12bels should be visible to the operator during control actuation"
[ guideline 6.6.2.4(c)].
2.
Grapple Open/Close Switch: The grapple open/close switch had a metal cover over it which obscured its open and close label. This weakness was inconsistent with NUREG-0700 guideline 6.6.2.4(c): " Controls - 12bels should be visible to the operator during control actuation."
3.
Demarcation Line: A black 1-inch wide demarcation line had been drawn with a magic marker between the system stop light and the grapple closed light. This weakness was inconsistent with NUREG-0700 guideline 6.6.6.2: " Permanence -
Lines of demarcation should be permanently attached." The team noted that the licensee had installed a permanent plastic demarcation line as part of corrective action.
4.
Grapple On/Off Light Switch: A danger tag was taped over the grapple on/off light switch and its label because the light attached to the grapple was burned out. This tag obscured the adjacent right label 6.e., frame) for the monorail switch. This weakness was inconsistent with the following NUREG-0700 guidelines: 6.6.5.1(h): " Adjacent Devices - Tag-outs should not obscure any adjacent devices or their associated labels"
[ guideline 6.6.5.l(h)], and " Obscuration - Tag-outs should not obscure the label associated with the non-operable device" [ guideline 6.6.5.l(c)].
5.
Grapple Closed Light Indication: The grapple closed light was located vertically on the front, lower area of the left panel of the refueling platform console. Whereas, the grapple open and close switch was located vertically on the front, upper area of the right panel of the console. This weakness was inconsistent with the following NUREG-0700 guidelines: " Sequence - controls and displays [ indications] which are use together during a normal task sequence should be grouped together" [ guideline 6.8.2.1(a)]; " Frequency of Use - frequently used controls and displays should be arranged to reduce search time and minimize the potential for during use" [ guideline 6.8.2.l(b); " Functional Considerations - functionally related controls and displays should be grouped together when they are use together to perform tasks related to a specific function..." [ guideline 6.8.2.l(c)]; and " Proximity - a visual display that will be monitored during control manipulation should be located sufficiently close that an 4
2 operator can read it clearly and without parallax from a normal operating posture"
[6.9.1.19(a). With regard to the last guideline, interview results indicated that in a normal standing position it was difficult to see (i.e., parallax) the grapple closed light indication without shifting to a lowered position.
The label for the grapple closed light was placed below the indication light. This weakness was inconsistent with NUREG-0700 guideline 6.6.2.l(a): " Normal Placement - labels should be placed above the panel element (s) they describe."
6.
Monorail Frame and Console Switch: The labels for the monorail switch (either frame or console) were positioned diagonally. This weakness was inconsistent with NUREG-0700 guideline 6.6.2.3: " Horizontal Orientation - (1) Labels should be oriented horizontally so that they may be read quickly and easily from left to right.
(2) Although not normally recommended, vertical orientation may be used only where space is limited. Improperly oriented labels can lead to confusion and cause delays in location and identification of important controls and/or displays."
7.
Verbal Communication: As a result of background noise, verbal communication on the refueling platform was degraded at distances of approximately 6-8 feet or greater from speaker and listener using normal voice levels. This weakness was inconsistent with NUREG-0700 guideline 6.1.5.5(a): " Background Noise - Background should not impair verbal communication between any two points in the primary operating area.
Verbal communications between these points should be intelligible using normal or slightly raised voice levels." Further, NUREG-0700 guideline 6.1.5.5(b) indicates:
" Limit - Background noise levels should not exceed 65 dB(A)." No noise level measurements were obtained during the onsite inspection.
8.
Weaknesses identified From Interviews: During interviews with refueling platform personnel, the following weaknesses were identified: (1) it was difficult to impossible to simultaneously hold a hand-held telephone in one hand and binoculars in another hand, while reading a procedure; (2) no procedure on the bridge; the units for grapple load (pounds) and depth indication or z-indication (inches) were not provided on digital displays; (3) operators complained about the trolley left/right switch because the switch was pushed in the opposite direction than the trolley travels which was confusing and could lead to operator error; (4) operators indicated that the position of the pointer for the forward / reverse control for the refueling platform control was unrelated to its direction; (5) the up and down joystick control for the grapple could be inadvertently actuated when attempting to manipulate the platform forward and reverse control to its left.
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ATTACIIMENT 5 September 3,1993: Post-Event Itadiological Summary Radiation Leveh Drywell (DW) 318 ft level
- 115 mr/hr (background)
Reactor Building (RB) 345 ft level - 15 mr/hr (background)
Reactor Water Clean Up room
- normal Spent Fuel Pool Cooling
- normal Instrument initial P_cak Post-oeak Trend Stack Gas 1 30 cpm 140 cpm 110 cpm down Stack Gas 2 80 cpm 225 cpm 180 cpm down RB ventilation exhaust Gaseous 250 cpm 460 cpm 310 cpm down Paniculate 200 cpm none NA NA Surface Contamination Levels RB 345 ft - < Sk dpm/100 cm (normal during refueling operations) 2 RB 345 ft - no detectable alpha l
Reactor Cavity Water Chemistry (uCi/ml)
Isotope 8:10 a.m.
12:45 pm.
1:45 n.m.
2:45 p.m.
3:45 n.m.
Iodine 133 7.7E-5 7.7E-5 8.6E-5 7.7E-5 8.3E-5 Xenon 133 5.6E-5 4.4E-3 2.1E-3 1.8E-3 1.4E-3 Cesium 134 6.0E-5 1.4E-4 1.0E-4 1.2E-4
- 1. l E-4 i
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ATTACHMENT 6 I
NUCLEAR REGULATORY COMMISSION-VERMONT YANKEE AUGMENTED INSPECTION TEAM EXIT i
SEPTEMBER 21,1993
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PURPOSE OF AN AIT i
A.
LOWEST LEVEL OF NRC INCIDENT INVESTIGATION PROGRAM FOR RESPONSE TO OPERATIONAL EVENTS B.
CONDUCT A TIMELY AND THOROUGH 1
INSPECTION WITH THE EMPHASIS ON FACT-FINDING h
C.
COLLECT AND ANALYZE TIE FACTS TO DETERMINE CAUSE(S) OF THE EVENT a
D.
ASSESS THE SAFETY SIGNIFICANCE OF THE i
EVENT E.
AN AIT DOES NOT DETERMINE WHETHER hTC' RULES WERE VIOLATED OR RECOMAEND ENFORCEMENT ACTION F.
AN AIT DOES NOT ADDRESS THE APPLICABILITY OF GENERIC CONCERNS TO OTHER PLANTS
i AIT MEMBERS j
TEAM LEADER:
J. E. Beall, DRS TEAM MEMBERS:
G. West, Engineering Psychologist, NRR-T. Shedlosky, Project Engineer, DRP P. Harris, Resident Inspector, DRP A. Burritt, Operations Engineer, DRS
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AGENDA AIT CHARTER t
FACILITY DESCRIPTION CH.RONOLOGY
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.I FINDINGS
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AIT CHARTER DEVELOP CHRONOLOGY OF THE EVENTS DETERMINE THE CAUSE(s)
DETERMINE PLANT RESPONSE DETERMINE THE ADEQUACY OF LICENSEE
RESPONSE
DETERMINE GENERIC IMPLICATIONS OF THESE EVENTS i
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l CHRONOLOGY DESIGN CHANGE TO REFUELING BRIDGE DEVELOPED e
PRE-OUTAGE TRAINING CONDUCTED i
MODIFICATION COMPLETED (CONTROLS REWIRED)
REFUELING OUTAGE BEGAN FUEL ASSEMBLY DROPPED, FUEL HANDLING SUSPENDED e
LICENSEE REVIEW AND CORRECTIVE ACTIONS COMPLETED, FUEL HANDLING RESUMED FUEL ASSEMBLY INADVERTENTLY LOWERED ONTO CORE, THEN MOVED TO PLANNED LOCATION FUEL HANDLING SUSPENDED, AIT DISPATCHED e
LICENSEE CORRECTIVE ACTIONS Stop Fuel Handling Additional training, including OJT Enhanced procedure for fuel moves Grapple inspection, testing i
Air system troubleshooting, repairs I
After September 9 incidents, again stopped fuel handling Initiated management team investigation i
UAUbt SEPTEMBER 3,1993 FUEL DROP EVENT BREAKDOWN IN MANAGEMENT CONTROL AND OVERSIGHT OF FUEL HANDLING OPERATIONS REQUIRED SHIFT BRIEFINGS NOT HELD OPERATORS NOT KNOWLEDGEABLE OF ALL PROCEDURE REQUIREMENTS PROCEDURES NOT USED PROCEDURES NOT ADHERED TO REACTOR ENGINEER RESPONSIBLE FOR GRAPPLE CLOSURE VERIFICATION ASSIGNED CONFLICTING COLLATERAL DUTIES LITTLE OR NO INDEPENDENT OVERSIGHT DURING FUEL hah 4) LING h
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CAUSE i
September 9,1993 Fuel Handling Errors 1.
Lowering assembly onto core was an inadvertent operator performance error with two major contributors Controls modification No operator input into change No training on wiring reversal Increase in speed (30 vs previous 20 i
feet per minute) 1
.l Fuel Shuffling procedure Fuel lifted 2-3 feet out of core, then moved horizontally to core center Vertical motion then initiated from 2-3 feet above core
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Little time to correct error (4-6 seconds)
Lower drywell radiation levels represent a risk tradeoff 4
- 2. Continuance of fuel move was a procedure adherence error
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SRO believed he could authorize completion of fuel move Procedure states any unusual or off normal occurrence required halting movement and notifying the shift supervisor Further movement required operations manager permission Neither the licensee line management review nor the management team investigation identified SRO action as procedure non-compliance d
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CONCLUSIONS September 3 event caused by poor management control and oversight widespread procedure non-compliance preponderance of the evidence suggests refuel platform operator performance error rather than a hardware failure little or no management presence during fuel handling activities 4
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f, Initial September 9 incident was caused by inadvertent operator error human factors contributor fuel handling methodology contributor second September 9 incident was caused e
by failure to follow procedures weakness in corrective actions from September 3 event continued weakness in management oversight
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