ML20154M623

Application for Amend to License NPF-36,consisting of License Change Application 12,revising Tech Specs to Change Method for Determining Setpoint for Main Control Room Vent Radiation Monitors

ML20154M623
Person / Time
Site:	Shoreham File:Long Island Lighting Company icon.png
Issue date:	05/24/1988
From:	Leonard J LONG ISLAND LIGHTING CO.
To:
Shared Package
ML20154M614	List: ML20154M623 ML20154M632 SNRC-1452, Forwards Application for Amend to License NPF-36,consisting of License Change Application 12,revising Tech Specs to Change Method for Determining Setpoint for Main Control Room Vent Radiation Monitors
References
NUDOCS 8806020023
Download: ML20154M623 (3)

Text

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i .', LONG ISLAND LIGHTING COMPANY Operating License NPF-36 Docket 50-322 License Change Application 12 This License Change Application requests modification to Operating License NPF-36 for the Shoreham Nuclear Power Station to change the method for determining the setpoint for the main control room vent radiation monitors.

The request and supporting documentation is contained in Attachments 1 to this License Change Application.

Long Island Lighting Company By b N' Joh D. Leon'ard, Jr. 1 Vice President - Nuclear O perations Subscribedandsworntobeforemethis28_thdayofMay1988.

JAMES A. LITTLE NOTARY PUBLIC. State of New York No. 4886267, Suffolk Cou

,. Term Expires May 18,19 *'

Qant A Notar f Nsw' York l

l My Commission Expires: 77L04//,/989 V

8806020023 DR 880524 ADOCK 05000322 DCD

F r*

SNRC-1452

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Attachment 1 Page 1 of 2 Attachment 1 To License Change Application 12

1.0 DESCRIPTION

OF CHANGE Change the alarm / trip setpoint and measurement range of the main control room vent radiation monitors, item 1 of Technical Specification Table 3.3.7.1-1 as identified in Exhibit A.

2.0 REASON FOR CHANGE 2.1 The current method for determining the setpoint for these monitors is:

Setpoint f$ 2 x Background This current methodology has an inherent weakness. The lower the background the lower the setpoint and the higher the probability of false alarms. These false alarms can be attributed to electronic parameters of the instruments or a change of the background radiation level. This change in setpoint methodology is needed to reduce the number of spurious control room alarms and enable the affected instruments to perform their intended function effectively.

2.2 The change in the instrument range will correct an inconsistency between the Technical Specification and the design basis of the instrument as described in Updated Safety Analysis Report.

3.0 BASIS FOR NO SIGNIFICANT HAZARDS FINDING The proposed license change does not involve a significant hazards consideration because operation of the Shoreham Nuclear Power Station - Unit 1, in accordance with this change, would not:

(1) involve a significant increase in the probability or consequences of an accident previously evaluated. These monitors only detect airborne radioactivity in the control room inlet ducts. The possibility of detecting radiation levels in these ducts will not be reduced by this change.

(2) create the possibility of an accident that is different than any already evaluated in the USAR. The setpoint of these monitors has no effect on plant equipment other than the alarm itself.

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..,- SNFC-1452 Attachment 1 Page 2 of 2 (3) involve a significant reduction in margin of safety.

For the upper portions of the expected background range, the margin of safety will be increased, because the new methodology results in a lower setpoint for this portion of the expected range. There will be a slight reduction in the margin of safety for the lower portion of the expected background range (0-60 cpm). This reduction in the margin of safety has been determined to be insig-nificant, because the monitors will alarm at dose rates well below the 0.2 mr/hr control room design limit, resulting in a maximum dgse rate increase to control room personnel of 1.4x10 mr/hr.

The Commission has provided guidance concerning the appli-cation of standards for determining whether a significant hazards consideration exists by providing certain examples (48 FR 14870) of amendments that are considered not likely to involve significant hazards consideration. Example (vi) relates to changes which either may result in some increase in the probability or consequences of an accident or a reduction in a safety margin, but where the results of the change are within acceptance criteria: for example, a change due to a small refinement of a previously used calculational model or design method. In this case, the proposed change described above is similar to example (vi). The proposed change is a refinement of a calculational method, which may result in a reduction in the margin of safety, but the reduction is insignificant because the monitors will alarm at dose rates well below previously established design limits.

Therefore, based upon the above considerations and analyses, LILCO has determined that this proposed change does not involve a significant hazards consideration.

4.0 TIMING OF CHANGE Since this proposed technical specification change will require a number of station procedure changes, LILCO requests that it become effective upon issuance of the update procedures.

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