View source for BECO-87-036, Requests Continued Review & Approval of 870119 Application to Change Tech Spec 4.7.B.2.a Re Reduction of Differential Pressure from 8 to 6 Inches in Control Room High Efficiency Air Filtration Sys,Per NRC .Related Info Encl

{{Adams
| number = ML20212D178
| issue date = 02/25/1987
| title = Requests Continued Review & Approval of 870119 Application to Change Tech Spec 4.7.B.2.a Re Reduction of Differential Pressure from 8 to 6 Inches in Control Room High Efficiency Air Filtration Sys,Per NRC .Related Info Encl
| author name = Lydon J
| author affiliation = BOSTON EDISON CO.
| addressee name = 
| addressee affiliation = NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
| docket = 05000293
| license number = 
| contact person = 
| document report number = BECO-87-036, BECO-87-36, NUDOCS 8703040077
| document type = CORRESPONDENCE-LETTERS, INCOMING CORRESPONDENCE, UTILITY TO NRC
| page count = 4
| project = 
| stage = Request
}}

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8057GW EDfSON
                                                 ,                            General Offices 800 Boylston streen Boston, Massachusetts 02199 y
February 25, 1987 BECo 87-036
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James M. Lycon
       'i                               tin Chief U.S.operduclofficerear Regulatory Commission Attn: ' Document Control-Desk                               e Ha'shington, DC              20555                                   g                         g N                    ~ .
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                      >                                  J                                        ;              Docket 50-293 3                                  .,
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* Supplemental Information on Proposed Technical M       -                                      Specification Change to Section 4.7.B.2.a, s
3 Control Room High! Efficiency Air Filtration System

==Dear Sir:==

On January 19. 1987, Boston Edison Company (BECo) made application to change technical specification (TS) 4.7.B.2.a such that the existing surveillance criteria was 'aised   r         from a differential pressure of 3 inches of water to 6 i                            inches. Additionally, the change added wording which clarified that this acceptance could be demonstrated through the use of a procedural Surve based g                      on the. data point of 6" of water at 1000 cfm.                                               1 By letter of January 29,198f, the NRC informed us that the "3 inches" requirement was the result of a typographical error, and that "8 inches" was correct and to be used. The technical specifications were accordingly i                     ' modified.                    <                                      f.       ,
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t          'We h'erein request the, continued review and approval of our January 19, 1987 request.                                                       ].
We have reviewed the proposal in view of the January 29, 1987 change, and
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conclude that it is now more conservative than our original proposal because the reduction from 8" to 6" of water provides an earlier action level for filter replacement than our current 4.7.B.2.a.
For your convenience we have provided an amended Supporting Information and No Significant Hazards Considerations Analyses as an attachment to this letter.
This reflects the conservative direction engendered by the change of January 29, 1987.
B702040077 870225 DR      ADOCK O                3                                g4           h'
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==Attachment:==
Revised Supporting Information and and No Significant Hazards Conditions Analyses O
3 cc: See next page                                                                                     AD,b

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BOSTON EDISON COMPANY Februar 25 1987 U.S.Nucfear*RegulatoryCommission Page 2 cc:  U.S. Nuclear Requiatory Commission Region I 4                         631 Park Avenue King of Prussia, PA 19406 Senior NRC Resident Inspector Pilgrim Nuclear Power Station Robert M. Hallisey, Director Radiation Control-Program Mass. Dept. of Public Health 150 Tremont Street F-7 Boston, MA 02111 1
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Attachment Supporting Information and No Significant Hazards Condition's Ar.alyses The proposed change provides a tolerance to the test success criteria for CRHEAF by allowing the use of a procedural curve relating differential
    -pressure to 1000 cfm as bounded by TS 3.7'.B.2.d.      The change also reduces the differential pressure criteria from 8 to 6 inches of water.
The Code of Federal Regulations,10CFR50.91 requires that at the time a licensee requests an amendment, it must provide to the Commission its analysis using the standards in 10CFR50.92, about the issue of no significant hazards consideration. Therefore, in accordance with 10CFR50.91 and 10CFR50.92 the following analysis has been performed.
: 1. Operating Pilgrim Station in accordance with the proposed amendment will not involve a significant increase in the probability or consequences of an accident previously evaluated.
The CRHEAF creates a positive pressure in the Control Room, using air from which it has filtered out radioiodines and particulates. Currently, TS 4.7.B.2.a requires that at least once every 18 months a pressure drop of less than 8 inches of water be demonstrated across the filters at a flow rate of 1000 cfm. TS 3.7.B.2.d requires that CRHEAF fans operate within 1000 cfm 10%. The system is designert to provide a positive Control Room pressure if the fans can provide a flow rate of 900 to 1100 cfm and the filters are not plugged. Vendor information indicates that filter degradation from plugging is indicated by a differential pressure of 3 inches or greater of water across each HEPA filter. Therefore, when measured across two HEPA filter elements, and the rest of the CRHEAF cc,ponents which create differential pressure, a differential of less than 6 inches of water demonstrates that HEPA plugging has not reached action levels. Hence, if the fans can generate 900 to 1100 cfm to satisfy 3.7.B.2.d and has a pressure drop across the filter trains less than 6 inches at 1000 cfm or the calculated equivalent, sufficient flow exists to provide a positive pressure in the Control Room. Therefore, the purpose of the CRHEAF as a mitigator of the results of an accident will not be impaired by this proposed change. Hence, allowing the differential pressure of 6 inches of water 1000 cfm to be established at flow rates between 900 and 1100 cfm in conformance with a calculated procedural acceptance curve will not involve a significant increase in the probability or consequences of an accident previously analyzed.
: 2. Operating Pilgrim Station in accordance with the proposed amendment will not create the possibility of a new or different kind of accident from any accident previously evaluated.
l The purpose of CRHEAF is to mitigate the consequences of certain accidents by filtering out radiolodines and particulates from air which is then used to maintain a posit 1/e pressure in the Cor. trol Room. The amendment allows a tolerance by allowing a calculated value, based on 6 inches of water at 1000 cfm, to be used for demonstrating that the filter train elements are not plugged. The flow range for the calculated value is 900 - 1100 cfm, determined by existing TS 3.7.B.2.d.

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The change to 6 inches of water from 8 is in compliance with vendor information, and is more conservative because the action level-for the filters is reached earlier. The change of these criteria therefore is consistent with the design and-fan capabilitiesuof the system, and does not degrade the system's ability to perform its designed function of providing positive pressure in the Control ~ Room with filtered air; therefore.-operating Pilgrim in accordance with the proposed change will not create the possibility of a new or different kind of accident from any accident previously evaluated.
: 3. Operating Pilgrim Station in accordance with the proposed amendment will not involve a significant reduction in the margin of safety.
The proposed change does not reduce the CRHEAF's ability to perform'its designed function of creating a positive pressure in the Control Room with filtered air. Hence, accident analyses which take credit for CRHEAF as a mitigator are not affected and the safety margin remains the same.
Therefore, the operation of Pilgrim in accordance with the proposed amendment to TS 4.7.B.2.a will not involve a significant reduction in the margin of safety.
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