05000382/LER-1997-013, :on 970407,refueling Machine Failed to Meet TS Requirements.Caused by Failure to Assure Refueling Machines Circuitry Design Complied W/Ts.Software Controlling Overload Protection Features,Upgraded

:on 970407,refueling Machine Failed to Meet TS Requirements.Caused by Failure to Assure Refueling Machines Circuitry Design Complied W/Ts.Software Controlling Overload Protection Features,Upgraded

ML20140H023
Person / Time
Site:	Waterford
Issue date:	05/07/1997
From:	Gaudet T ENTERGY OPERATIONS, INC.
To:
Shared Package
ML20140H004	List: 05000382/LER-1997-013, :on 970407,refueling Machine Failed to Meet TS Requirements.Caused by Failure to Assure Refueling Machines Circuitry Design Complied W/Ts.Software Controlling Overload Protection Features,Upgraded
References
LER-97-013, LER-97-13, NUDOCS 9705120286
Download: ML20140H023 (7)

LER-1997-013, on 970407,refueling Machine Failed to Meet TS Requirements.Caused by Failure to Assure Refueling Machines Circuitry Design Complied W/Ts.Software Controlling Overload Protection Features,Upgraded

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(ii) 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(iv), System Actuation 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability
3821997013R00 - NRC Website

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i NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 31E00104 1499 EXPlRES 04/30/98 ESTIMATED BURDEN PER RESPONSE TO COMPLY WrrH THl3 MANDATORY D4 FORMATION COLLECTION REQUEST: 50.0 HRS. REPORTED LESSONS LEARNED ARE LICENSEE EVENT REPORT (LER) go,"gAlE Q,

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RECORDS MANAGEMENT BR ANCH (T 6 F33), U S. NUCLEAR REGULATORY COMM8%10N, (See reverse for required number of WASHINGTON. OC 20W>0001. AND TO THE PAPERWORK REDUCTION PROJECT 0150 digits / characters for each block) 0% OUICE Of MANAGEMENT AND BUDGET, WASHNGTON, DC 2M3 F ACUB Y NAAM (1)

DOCKII NUMtsFB (2)

PAGt $3a 05000 3M 1 OF 6 WATERFORD STEAM ELECTRIC STATION UNIT 3 TITLi 64)

REFUELING MACHINE FAILED TO MEET TECHNICAL SPECIFICATION REQUIREMENTS EVENT DATE (5)

LER NUMBER (6)

REPORT DATE (7)

OTHER FACILITIES INVOLVED (8)

FACILITY NAME DOCKET NUMBER SI0U ES MONTH DAY YEAR YEAR MONTH DAY YEAR NU N

N/A 05000 f ACluYY NAME DOCKET NUMDER 04 07 97 97 ~ 013

~ 00 05 07 97 N/A 05000 OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 6: (Check one or more) (11)

MODE (9)

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20.2201(b) 20.2203(a)(2)(v)

X 50.73(a)(2)(i) 50.73(a)(2)(vm) 20.2203(a)(1) 20.2203(a)(3)(i) 50.73(a)(2)(ii) 50.73(a)(2)(x)

POWER LEVEL (10) 100 20.2203(a)(2)D) 20.2203(a)(3)(ii) 50.73(a)(2)(m) 73.71 20.2203(a)(2)Di) 20.2203(a)(4) 50.73(a)(2)(iv)

OTHER 20.2203(a)(2)(m) 50.36(c)(1) 50.73(a)(2)(v)

Specify in Abstreet below 20.2203(a)(2)(sv) 50.36(c)(2) 50.73(a)(2)(vii)

UCENSEE CONTACT FOR THIS LER (12)

Nmt TtLEPHONE NUMBER Hnclude Area Cocol TIM GAUDET, LICENSING MANAGER (504)739-6666 COMPLETE ONE UNE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

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CAUSE

SYSTEM COMPONENT MANUFACTURER

CAUSE

SYSTEM COMPONENT MANUFACTURER ON SUPPLEMENTAL REPORT EXPECTED (14)

MONTH DAY YEAR EXPECTED YES SUBMtW ON NO (If yes. complete EXPECTED SUBMISSION DATE).

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ABSTRACT (Limit to 1400 spaces,i.e., approximately 15 eingle-spaced typewntten lines) (16)

On April 7,1997, engineering personnel determined the Refueling machine's fuel mast and Control Element Assembly (CEA) mast have elevation zones during extension and retraction of their hoist assemblies which do not have overload protection provided. This condition is contrary to Technical Specification 3/4.9.6 which requires both the fuel mast and the CEA mast to have operable overload protection features prior to use. The zones where no overload protection was provided are associated with the areas where load transitions occur during extension and retraction of the mast assemblies. The zones were engineered into the design to prevent erroneous readings during the load transitions.

Additionally, the Surveillance Procedure which validates the minimum lift capacity of the CEA hoist was inadequate. The procedure required a load test be performed by raising the CEA hoist to the upper limit and then using a hand wheel to generate a load of 1600 pounds, which does not ensure that the hoist motor can lift it's minimum load capacity. The corrective action for these two conditions consists of a modification to the refueling machine overload protection software to eliminate the bypass feature for the load transition zones, and a revision to the Surveillance Procedure which requires test weights to be used when testing the lifting capacity of the CEA hoist. These conditions did not compromise the health and safety of the public.

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DOCKET NJMBER 3 IN ADDIT N TO 05000 3

VARIES PAGE NUMBED 4

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EVENT DATE 2 R BLOCK 7 TOTAL

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3 FOR SEQUENTIAL NUMBER 2 FOR REVISION NUMBER 8 TOTAL

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CHECK BOX THAT APPLIES 15 EXPECTED SUBMISSION DATE 2 PER BLOCK I

.U.S. NUCLEAR REGULATORY COMMISSION 14 9'd i

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET LER NUMBER (6)

PAGE (3)

N BR NUM WATERFORD STEAM ELECTRIC STATION UNIT 3 05 00 2

Op 6 i

TEXT (11 ms.o space is requored, use naditional copies of NRC Form 366A) (17)

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REPORTABLE OCCURRENCE Technical Specification (TS) 3.9.6 establishes overload cutoff limits for the Refueling machine's fuel mast hoist and Control Element Assembly (CEA) mast hoist (DF, Ells Identifier FHM) which must be demonstrated operable prior to movement of fuel or the CEAs. Historically, Waterford 3 had determined that the Refueling machine was operable even though both hoists had design features which bypassed the overload cutoff limits at certain elevation zones when lifting and lowering fuel and control element assemblies. Additionally, the Surveillance Procedure for demonstrating that the CEA hoist is operable did not require the use of an actual test load to demonstrate operability. The lifting capacity of the CEA hoist motor was not being properly demonstrated. These conditions are reportable pursuant to 10 CFR 73(a)(2)(i)(B) as conditions prohibited by TS.

INITIAL CONDITIONS At the time this concern was identified, Waterford 3 was operating in Mode 1 at approximately 100% power. There were no inoperable structures, systems or components that contributed to this event. In addition, no TS Limiting Conditions for Operation were in effect specific to this event.

EVENT DESCRIPTION

Communications with Programmed and Remote Systems Corporation (PAR), the vendor for the Waterford 3 Refueling machine, re/ealed Calvert Cliffs Nuclear Power Plant (CCNF P) staff personnel had identified ibeir Refueling machine's overload interlocks (the engineered features) do not fu!Iy implement CCNPP TS 3/4.9.6.

Communications with the vendor, along with contacting CCNPP personnel, led the Waterford 3 engineering staff to evaluate whether the same condition existed at Waterford 3.

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.U.S. NUCLEAR REGULATORY COMMISSION !

ces L'CENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACIUTY NAME (1)

DOCKET LER NUMBER (6)

PAGE (3)

"ENEn" "w'uN!!

"A" 05000 OF 3

6 Waterford Steam Electric Station Unit 3 382 97 -

013 ~ 00 TEXT lit more space is reqwred, use additional copies of NRC Form 366Al (17)

On April 7,1997, engineering concluded that both the fuel mast and the CEA mast i

have elevation zones during extension and retraction of the hoist assembly which do not have overload protection provided. The zones where no overload protection was provided are associated with the areas where load transitions occur during extension and retraction of the mast assembly. The zones were engineered into the design to prevent expected load transients from exceeding overload interlock values. During evaluation of this condition, another TS related deficiency was identified regarding the adequacy of the Surveillance Procedure which implements the load testing requirement for the CEA mast.

The purpose of the Refueling machine, which consists of a fuel handling mast and a CEA handling mast, is tr, provide a means of handling fuel bundles and CEAs which prevents damage to the fuel, the CEAs, and the reactor core internals and pressure vessel. The fuel mast and the CEA mast are stainless steel cylinders approximately 34 feet long and 22 inches in diameter that house and guide the fuel and CEA hoisting assemblies. The hoist assemblies are telescopically extended and retracted for removal, replacement, and relocation of the fuel assemblies and CEAs. The hoist assemblies consist of an open box which includes a hoist cable connected to a grappling device. The grappling device is lowered and engages the top of the fuel assembly or CEA to be lifted. The fuel assembly or the CEA is then raised into the associated mast. The Refueling machine can then transport the selected assembly to another location.

As the fuel assembly or CEA is being lifted out of or inserted into the core, the load on the hoist cable is monitored at the refueling machine control console to ensure fuel assembly movement is not being restricted. The hoist load is measured by a weighing system (s) which electronically measures the load on the hoist cable and provides input for the overload protection features. These overload protection features are provided by interlock functions which suspend movement of the selected assembly when an overload condition is detected, NBC FORM 386A 14951

eU.S. NUCLEAR REGULATORY COMMISSION essi LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION

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FACIUTY NAME (1)

DOCKET LER NUMBER (6)

PAGE (3)

SuEI' EuES 05000 OF 4

6 Waterford Steam Electric Station Unit 3 382 97 -

013 ~

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TEXT fit more space is reqwred. Use additional copies of NRC Form 366A) U 7)

The weighing system operates in two load zones, when raising or lowering fuel only and when raising or lowering fuel plus the fuel hoist box. Initially as a fuel bundle is being withdrawn from the core, the Reactor Building Storage Racks, or the fuel carrier, the load on the grapple is the weight of the fuel bundle only. When the fuel bundle is being removed from a core location and is fully raised into the fuel hoist box the weight of the fuel hoist is added to the grapple. The overload interlocks are momentarily bypassed at this load transition point. The reverse sequence occurs during the lowering operation.

The momentary bypassing of the interlocks does not appear to be allowed by the wording of the TS. TS 3.9.6 does not provide for any exceptions to the specified overload protection. Therefore, the operationa! characteristics created by the design features of the hoist assemblies results in a condition prohibited by TS.

Additional reviews by engineering in preparation for the RFO8 Refueling Outage identified potentialinadequacies in Surveillance Procedare OP-903-073 regarding full compliance with the intent of TS surveillanae 4.0.0.2. This TS curveillance states, "The CEA mast used for movement of CEAs r, hall be demonstrated OPERABLE within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> prior to the start of such operations by performing a load test of at least 1600 pounds and demonstrating an automatic load cut oN woan the CEA mast exceeds 1700 pounds." Engineering review revealed that the CEA mast is not tested using an actual test load that creates a load of 1600 pounds. Instead the load test is performed by raising the hoist to the upper limit and then using the hand wheel to generate a load of 1600 pounds. This method of testing the minimum lifting capacity is inconsistent with the testing practice for the fuel mast and has been determined to be inconsistent with common industry practice. Performing the test requirement in this manner, in lieu of using a test load, does not ensure that the hoist motor can lift a load of 1600 pounds.

This testing deficiency regarding the CEA hoist is considered to be a condition prohibited by TS. Engineering review found that the fuel hoist was being tested properly.

The Waterford 3 licensing staff has reviewed the Calvert Cliffs, Unit 2, and St. Lucie, Unit 1, response to this similar condition regarding the operability of their refueling NRC FORM 388A 14951

NHC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION w

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

I DOCKET If MR NUMBER (6)

PAGE (3)

" sus?

Nu'$

05000 OF 5

6 Waterford Steam Electric Station Unit 3 382 97 ~

013 - 00 TEXT (11 more space os required, use additional copies of NRC form 36CA) (17) machine versus compliance with TS requirements. The root cause of this LER condition is the same at all three plants. The overload bypass circuitry was included in the original design of the refueling machines at all three facilities. The discrepancy between the design of the refueling machine and the TS was not identified during the original plant licensing and had existed since that time.

CAUSAL FACTORS Root cause analysis and investigation into the overload bypass issue have identified a failure to assure the refueling machine's circuitry design complied with the TS. The overload bypass circuitry design has been a part of the refueling machine design since initial procurement. A contributing factor was that the bypass feature was included in the original fuel handling system design. Due to a lack of attention to detail, the TS review and acceptance process during original plant licensing, did not identify the discrepancy between the design and the TS.

l Root cause analysis and investigation into the surveillance procedure deficiency identified the preparation of the procedure was inadequate. The procedure preparation was inadequate due to (1) the lack of a weighted test assembly to perform the lift test, and (2), the administrative requirements for preparation and approval of the procedure failed to ensure that the lift capacity of the hoist motor was tested.

CORRECTIVE MEASURES Immediate corrective actions consisted of contacting PAR to obtain additional details of the similar overload bypass issue at CCNPP. The software which controls the overload protection features has been upgraded. Waterford 3 developed and implemented a revision to the control software to accommodate an overload limit in conformance with TS 4/3.9.6. The software modification will establish a overload limit of 3350 pounds for the full travel of the fuel and fuel hoist box assembly and a overload limit of 1700 pounds for the full travel of the CEA and CEA hoist box assembly.

NRC FORW 306A 64951

eU.S. NUCLEAR REGULATORY COMMISSION m

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET LER NUMBER (6)

PAGE (3)

"mE[n" EuS!!

05000 6

OF 6 Waterford Steam Electric Station Unit 3 382 97 -- 013 -- 00 TEXT (11 more space is required, use additional copies of NRC Form 366Al (17)

In response to the inadequate procedure a change was issued to the Surveillance Procedure to add procedure steps for live load testing of the CEA hoist assembly. In prepsration for the RFO 8 Refueling Outage, the CEA hoist assembly was satisfactorily tested and subsequently declared operable in support of CEA movements during the outage.

SAFETY SIGNIFICANCE

Failure to comply with Technical Specification 3/4.9.6 was not a safety significant issue at Waterford 3. The potential for inadvertent criticality and offsite release as a result of refueling machine interlock failures are bounded by existing analyses. The results of the FSAR Chapter 15 safety analysis demonstrate that applicable dose limits are not exceeded as a result of the worst postulated fuel assembly drop. No credit is taken for instrumentation or interlocks on the fuel handling equipment to either prevent or mitigate the consequences of the fuel assembly drop. Therefore, the design feature of the refueling machine which permitted certain elevation zones to be bypassed during fuel movement is not safety related. This event did not compromise the health and j

safety of the public.

SIMILAR EVENTS

There have been no similar events reported as LERs at Waterford 3.

NRC FORM 306A 1499