ML20065S115

Rev 2 to ON-120 Bases, Fuel Handling Problems

ML20065S115
Person / Time
Site:	Limerick
Issue date:	12/06/1990
From:	PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:
References
ON-120-BASES, NUDOCS 9012200084
Download: ML20065S115 (7)

Text

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NATE 12./10/90 14.39 NRMS DOCUMENT CONTROL FORM SEGUENCE # 390004443C PROCEDURES - APPROVED ORIGINALS

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ATTACHED .S A COPY OF:

PROCEDNO ON-120 DA3ES REVISION OOD r ' 12/06/90 UEONT ROLLED: LIDRARY, INPO, NUNEZ O

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9012200084 901206 Cy.{

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l ON-120 BASES, Rev. 2

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PHILADELPHIA ELECTRIC COMPAN ( pfcfD LIMERICK GENERATING STATION 3900044430 ON-120 BASES PUEL HANDLING PROBLEMS 1.0 SYMPTCMS 1.1 Unanticipated rise in SRM count rate during Puel Handling (Criticality). (Step 2.1)

SRM count rate will increase incrementally as fuel bundles are added to the core; however, a sustained, continuing increase in count rate is an unanticipated increased which indicates criticality.

1.2 Fuel Ploor Area Radiation Monitor alarms. (Step 2.2)

Self explanatory.

1.3 Fuel bundle dropped or damaged. (Step 2.3)

Self explanatory.

1.4 Unanticipated reduction of Reactor Cavity OR Spent Puel Pool Water Level. (Step 2.4)

Self explanatory. s

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+ 2.0 OPERATOR ACTIONS U

2.1 IF criticality occurs while inserting fuel into the core, THEN:

According to SIL No. 372, the most credible identified criticality concern during refueling operations is the possibility of inserting fuel bundles into an area of the core with two adjacent control blades withdrawn for maintenance. This would require bypassing the one-rod-out refueling interlock per Tech. Spec. 3.9.10.2, followed by inadvertently reloading fuel bundles around the withdrawn control blades. Criticality would be expected when the last bundle is loaded around the withdrawn blades.

l According to UFSAR 9.1.2.3.1, the fuel storage racks are designed to prevent criticality even if a bundle is dropped on top of, through or next to the storage racks. Thus, criticality is not a concern when moving a bundle into the storage racks.

2.1.1 Raise fuel assembly from core so it clears upper grid.

-Since the control rods would be withdrawn for

(~~N maintenance, they would be blocked out of service..

(,) - Thus, they would not insert when high flux causes a scram signal. If the control room operator observes SRM count rate increasing due to subcritical multiplication, stopping insertion of the fuel assembly may prevent criticality. Raising the fuel assembly will return the core to a suberitical configuration.

2.1.2 Evacuate Fuel Floor.

Self explanatory.

2.1.3 Inform Shift Supervision. Shift Supervision shall determine disposition of fuel bundle.

Shift Supervision should be aware of any problems associated with reactivity control. Shift Supervision shall be responsible for placing the fuel bundle in a " safe conservative position" when core alterations are suspended dependent on fuel floor accessibility.

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I ON-120 BASES, Rev. 2

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() - 2.1. 4 ' Ensure all insertable control rods are inserted.

The:most probable _ reason for criticality was that fuel ~ assemblies were inadvertently inserted into

.the core 11n an area where at least two adjacent

-control rods were withdrawn. Thus, major errors in--

tracking fuel and control rod locations were-made.

This step ensures _that the core is made as suberitical as:possible'in the short term.

2 .1-. 5 - Notify Health Physics.

Self explanatory.-

2.1.6 Notify Reactor Engineering. ,

Self explanatory.

12 .1 ~. 7 Fuel' handling operations shall:not be resumed until- t

. permission-is~obtained from-Superintendent of '

Operations. <

Self explanatory.

2.2- IF Fuel 1 Floor-Area Radiation-' Monitor. alarms unplanned

'-Q 4.

EUD'is not du'e;to2 object-handled near water surface.which 4

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- is-immediately re-submerged, THEN:

2.2.1- Evacuate Fuel. Floor.

i Selfiexplanatory.

+ . . .

- 2.'2. 21 NotifyfShift-Supervision.

Shift: Supervision sho_uld be: aware-of potential' serious exposure hazards associated:with fuel

, handling.--.

2.-2.3 _ Notify. Health Physics.

Self explanatory.-

n 2.2'.4 ' Notify Reactor-Engineering ~ .

Selftexplanatory,

' 2.2.5 Fuel handling operations shall not be-resumed-until-permission is obtained'from Superintendent of Operations.

( 'Self explanatory.

l ON-120 BASES, Rev. 2

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) 2.3 IP fuel bundle is dropped or damaged, THEN:

A spent fuel bundle and the fuel grapple assembly falling as two separate, independent units from their respective fully raised heights into the reactor core is a limiting fault accident analyzed in UFSAR section 15.7.4. Operator actions are specified in UPSAR 15.7.4.2.2. The actions listed in this procedure cover the specified actions; however, the steps of directing personnel to the decontamination area, assessing potential radiation doses, and implementing additional radiological controls are considered to be implicit in the Health Physics Notification step.

If a spent fuel bundle is damaged by fuel handling such that it jeopardizes the structural integrity of the bundle, there is potential for consequences similar to the dropped fuel bundle.

If a new fuel bundle (or any heavy object) is dropped into the fuel pool or refueling cavity, it may cause damage to spent fuel by striking it directly or indirectly. It is prudent to follow this procedure whenever structural damage to spent fuel may have occurred, whether by dropping spent

, fuel, new fuel or other heavy objects or by other handling s of spent fuel.

2.3.1 Evacuate Fuel Ploor.

Self explanatory.

2.3.2 Inform Shift Supervision. Shift Supervision shall determine disposition of damaged bundle.

t Shift Supervision should be aware of potential serious exposure hazards associated with fuel handling. Shift Supervision is responsible for placing a damaged fuel bundle in a " safe conservative position" when core alterations are suspended.

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-A is,) 2.3.3 Ensure Normal Ventilation is isolated AND SGTS is initiated.

IP a single fuel rod is dropped THEN a Refuel Floor isolation need not be initiated unless requested by Health Physics.

Initiating SGTS is a preemptive action anticipating a fission gas release potentially associated with a dropped fuel bundle.

Industry experience has shown that if a non-failed rod is dropped, there are no adverse affects on the fuel rod and no release of fission gases. Also, should a failed rod break-up, there is no release ,

of fission gas since all of the fission gas has already been released in the reactor _ vessel.

2.3.4 IF spent fuel damage results in refueling area  ;

ventilation isolation (Alert) -

OR major damage to spent fuel is observed (Site Emergency),

THEN implement "The Emergency Plan" (EP-101).

Self explanatory.

() 2.3.5 Notify Health Physics.

Self explanatory.

2.3.6 -Notify Reactor Engineering.

Self explanatory.

-2.3.7 Before allowing entrance - Fuel Floor area, a ,

careful study of conditions, radiation levels, etc., shall be performed.

Self explanatory.

2.3.8 Fuel handling operations shall not be resumed until permission is obtained from Superintendent of ,

Operations.

Self explanatory.

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.l ON-120 BASES, Rev. 2 Page 6 of 6

' ' ' ' l,. JGH/smk llh 2.4 IF unanticipated decrease of Reactor Cavity OR Spent Fuel Pool water level occurs, TifEN:

2.4.1 Notify Shift Supervision.

Shift Supervision should be aware of potential serious exposure hazards associated with fuel handling.

2.4.2 Perform SS3.0.A, Response to Low Level.

This system procedure gives detailed actions to initiate makeup, determine and correct the cause of the low level condition in the reactor well or fuel storage pool, and it addresses the potential health physics hazard due to items stored above the fuel storage racks as level drops.

2.4.3 Notify Health Physics of possible radiation hazard on Refuel Floor OR Elevation 313'.

Self explanatory.

2.4.4 Suspend all core component transfer operations:

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a. Return any core component being transferred to its nearest storage location in Fuel Storage Pool OR Core,

b. IP any Fuel Preparation Machine is loaded, THEN reposition it to its full down position.

Self explanatory.

2.4.5 IF water is lost to below fuel level in Spent Fuel Pool (Site Emergency),

THEN implement "The Emergency Plan" (EP-101).

Self explanatory.

2.4.6 Fuel handling operations shall not be resumed until permission is obtained from Superintendent of Operations.

Self explanatory.

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