ML20073D345

Proposed Tech Spec Section 3/4.4.5, Steam Generators, Attachment F,Page 2

ML20073D345
Person / Time
Site:	Byron
Issue date:	09/17/1994
From:	COMMONWEALTH EDISON CO.
To:
Shared Package
ML20073D333	List: ML20073D330 ML20073D345
References
NUDOCS 9409270158
Download: ML20073D345 (1)

Text

.

s -

O 600. This represents a savings of approximately $5.2M in plugging and sleeving f repair cos'ts alone. In addition, IPC implementation saves a minimum of 24 days in critical path outage time and eliminates the associated replacement heatpower costs.

l Also, permitting these tubes to remain in service maximizes RCS flow and transfer area availability and minimizes RCS loop asymmetries and loss of rated thermal power.

Comed proposes to amend the following Byron Technical Specification: .

t Specification 3/4.4.5 REACTOR COOLANT SYSTEM-STEAM GENERATORS This proposed lic+nse amendment request will modify Specification 3.4.5 to allow an eddy current bobbin coil probe voltage-based steam generator tube support plate IPC to be applied for Byron Unit 1. Technical Specification Bases Sectionj 3/4.4.5, STEAM GENERATORS will also be modified to reflect these changes.

1. The proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated. J

' Consistent with Regulatory Guide (RG) 1.121, " Basis for Plugging Degraded PWR Steam Generator Tubes," Revision 0, August 1976, the traditional depth-based criteria for SG tube repair implicitly ensures that tubes accepted for continued service will retain adequate structural and leakage integrity during normal operating, transient, and postulated accident conditions. It is recognized that defects in tubes permitted to remain in service, especially l

cracks, occasionally grow entirely through-wall and develop small leaks.

Limits on allowable primary-to-secondary leakage established in Technical Specifications ensure timely plant shutdown before the structural and l leakage integrity of the affected tube is challenged.

The proposed license amendment request to implement voltage amplitude  ;

SG tube support plate interim Plugging Criteria for Byron Unit 1 Cycle 7 '

meets the requirements of RG 1.121. The IPC methodology demonstrates l that tube leakage is acceptably low and tube burst is a highly improbable l event during either normal operation or the most limiting accident e.ondition, l Requesting a single cycle a postulated main steam line break,(MSLB) event. l applicability is more conservative than the guidance contained in the draft Generic Letter on voltage-based repair criteria issued for comment on August 12,1994.

Adequate SG tube leakage integrity during normal operating conditions is assured by limiting allowable primary-to-secondary leakage to 150 gpd per SG or 600 gpd total. Currently, this limit is administratively controlled.

I F-2 9409270159 PDR 940923 P nDDCK 05000454 PDR ____--__ _ _____- _ - -- - -