ML042450672

Proposed Amendment Re. Control Rod Operability

ML042450672
Person / Time
Site:	Oyster Creek
Issue date:	08/31/2004
From:	Tam P NRC/NRR/DLPM/LPD1
To:	David Helker, Robillard D AmerGen Energy Co
References
TAC MC3309
Download: ML042450672 (3)

Text

From:

Peter Tam To:

David Helker; David Robillard Date:

8/31/04 7:45AM

Subject:

Oyster Creek - Proposed Amendment re. Control Rod Operability (TAC MC3309)

Dave:

We are reviewing your application dated 5/20/04. Our reviewer, Tanya Ford, has developed the following questions for discussion in a teleconference.

(1) Page 4 of 7 of the application states that maintenance is normally performed on more than one control rod at the same time.

a. Please explain what normal hydraulic control unit (HCU) maintenance consists of.

b. According to current plant HCU maintenance practice procedures, is there a maximum number of control rods permitted to be valved out-of-service at the same time while undergoing maintenance? Is this number expected to remain the same or increase with the proposed changes?

c. Of the total number of controls rods permitted to be valved out-of-service during the maintenance period, how many of these rods are fully inserted? Is this number expected to remain the same or increase with the proposed changes?

(2) TS 3.2.B.4 defines an inoperable control rod as one that cannot be moved with control rod drive pressure. During maintenance of the HCU, more than one control rod is valved out-of-service and therefore cannot be moved with control rod drive pressure. The staff believes that any control rod not capable of being moved with control rod drive pressure is considered inoperable. Furthermore, the intent of TS 3.2.B.4 is not only directed at stuck rods but all inoperable control rods. In the case of partially or fully withdrawn control rods undergoing maintenance, their safety functions are not capable of being met since while valved out-of-service they are not able to be fully inserted with control rod drive pressure in the event a reactor scram is needed. You proposed to revise the first sentence of TS 3.2.B.4 by adding the phrase "In service" in front of "control rods." This statement may be misleading and possibly states that partially or fully withdrawn control rods are considered operable even when valved out-of-service. For clarification, please consider the definition of an "in service" control rod as opposed to an operable control rod. Please explain why partially or fully withdrawn control rods valved out-of-service for maintenance should still be considered operable based on the definition of operability on TS page 1.0-1.

(3) The Standard Technical Specification-General Electric Plants (STS), BWR/4, NUREG-1433, Revision 3, applies the control rod operability requirements to "withdrawn stuck control rods" and "inoperable" control rods. You stated that the STS excludes operable control rods, valved out-of-service for on-line maintenance from consideration as inoperable control rods. The staff may not agree that operable control rods, valved out-of-service for on-line maintenance are excluded from inoperable control rods based on STS LCO 3.1.3.C which addresses control rods that are inoperable for reasons other than LCOs 3.1.3.A and 3.1.3.B (stuck rods). The staff believes that control rods valved out-of-service for maintenance fall

under LCO 3.1.3.C are still considered inoperable. Therefore, please justify how the proposed clarification change (Proposed Change 1) is consistent with the content of the current STS.

(4) Technical Specification (TS) 3.2.B.4 requires the plant to shutdown with more than six control rods valved out-of-service. Please explain what has changed in the previous maintenance practice or plant operation that now generates a problem in meeting the limit of six allowable inoperable control rods stated in TS 3.2.B.4 and triggers the accelerated control rod exercise requirement of surveillance requirement (SR) 4.2.D.

(5) TS 3.2.B.4 states that inoperable control rods shall be valved out-of-service, in such positions that Specification 3.2.A is met. Since more than one control rod is normally undergoing maintenance at the same time, please demonstrate that Specification 3.2.A can still be met even with the proposed additional number of control rods fully inserted and valved out of service during maintenance. It must be confirmed that shutdown margin can still be maintained without the assistance of negative reactivity from the fully inserted control rods valved out-of-service during the maintenance period.

(6) Page 3 of 7 of your application states "for control rods that exhibit less than optimum positioning performance, corrective maintenance on their HCUs is scheduled. Additionally, other components will be scheduled for proactive maintenance based on vendor and industry experience." Please give examples of vendor and industry experiences causing a need for proactive maintenance on the HCUs.

(7) Also Page 3 of 7 of your application states "Considering the limited duration of the scheduled power reductions, normally more than one control rod is removed from service at the same time to perform HCU maintenance."

a. Please state the duration of the scheduled power reductions at which HCU maintenance is performed.

b. At what reduced power level is the HCU maintenance performed?

This e-mail aims solely to prepare you and others for the requested teleconference, during which we will discuss disposition of the above questions. It does not state an official NRC staff position, nor does it formally convey a request for additional information.

Peter S. Tam, Senior Project Manager Project Directorate I-1 Division of Licensing Project Management Office of Nuclear Reactor Regulation e-mail: pst@nrc.gov Tel.: 301-415-1451 CC:

Tanya Ford Mail Envelope Properties (413464C5.483 : 10 : 20510)

Subject:

Oyster Creek - Proposed Amendment re. Control Rod Operability (TAC MC3309)

Creation Date:

8/31/04 7:45AM From:

Peter Tam Created By:

PST@nrc.gov Recipients Action Date & Time owf2_po.OWFN_DO Delivered 08/31/04 07:45AM TNF CC (Tanya Ford)

Opened 08/31/04 08:55AM exeloncorp.com Transferred 08/31/04 07:45AM david.helker (David Helker)

David.Robillard (David Robillard)

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