ML20216A791
| ML20216A791 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 06/23/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20215M404 | List: |
| References | |
| NUDOCS 8706260386 | |
| Download: ML20216A791 (3) | |
Text
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UNITED STATES
[\\ 3 g [,,g NUCLEAR REGULATORY COMMISSION E
WASHINGTON, D. C. 20555 V
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.101 TO FACILITY OPEATING LICENSE NO. DPR-35 l
BOSTON EDISON COMPANY PILGRIM NUCLEAR POWER STATION DOCKET NO. 50-293 i
1.0 INTRODUCTION
j By letter dated January 19, 1987, as supplemented February 25, 1987, Boston Edison Company transmitted, a proposal to change the Pilgrim Technical Specifications. The licensee has proposed (1) to decrease the pressure drop across the filter unit in the Control Room High Efficiency Air Filtration j
(CRHEAF) system to 6 inches of water (currently the Technical Specification specifies less than 8 inches of water), and (2) to add a 10 percent tolerance
( 10%) to the air flow rate to be used with the filter unit during filter surveillance testing.
2.0 EVALUATION The CRHEAF system provides outside makeup air for pressurizinq the control room following a design basis accident. The CRHEAF system is an engineered safety feature system. The system consists of two redundant filtration units. Each unit contains a heating coil, a prefilter, an upstream HEPA 4
filter, a charcoal adsorber, and a final HEPA filter. Each unit is designed for an air flow intake capacity of 1,000 cfm.
The current Pilgrim Technical Specification Section 4.7.B.2.a specifies that:
"At least once every 18 months the pressure drops across each combined filter train shall be demonstrated to be less than 8 inches of water at 1,000 cfm."
The licensee has proposed to decrease the acceptable pressure drop to 6 inches of water across the filter unit when the air flow rate is 1,000 cfm 10%.
8706260386 870623 PDR ADOCK 050 3
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The staff estimates that the pressure drop across a HEPA filter should be less than 1 inch of. water when the filter is new and operated at rated design air flow capacity. The pressure drop will increase as particulates and dust are collected in the filter. The licensee stated in the referenced letters that the HEPA filter vendor reconinends limiting the maximum allowable pressure drop to 8 inches of water across each HEPA. filter and to 3 inches of water for the filter replacement..Therefore, the proposed pressure drop of less than 6 inches of water across the entire filter unit (one prefilter, two I
HEPA filters, and one charcoal adsorber) is reasonable and acceptable. This
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change is also consistent with the value specified in GE/BWR Standard 1
Technical Specifications (NUREG-0123, Revisions 3 and 4), as well as in 1
Technical Specifications recently issued for other BWRs.
The staff also finds that the addition of a 10 percent tolerance to the air flow rate (i.e.,1,000 cfm 10%) is acceptable, since it is consistent with GE/BWR Standard Technical Specifications. It should La noted, however, that the CRHEAF system at Pilgrim Station is not provided with an air flow indicator and/or a recorder, Instead, the licensee has been utilizing Pitot tube air velocity measuremtnts to estimate the air flow rate..The licensee f
has proposed that the air ilt w rate surveillance requirement of 1,000 cfm 10% will be met by the use m' Pitot tube air velocity measurements in accordance with the plant established calculational procedures.
The staff believes that within this flow range (i.e.,1,000 cfm 10%),the design objectives of the CRHEAF system still can be met (e.g., slight positive pressurization of the control room, air residence time in the charcoal adsorber). Therefore, the staff finds that the licensee's method for determining the air flow rate is acceptable. The revised Section 4.7.2.a of the Pilgrim Technical Specifications will state, in part:... less than 6 inches of water at 1,000 cfm i 10% or the calculated equivalent."
On the basis of the above evaluation, we find that the licensee's proposed Pilgrim Technical Specification changes are acceptable. The bases for acceptance are: (1) proposed Technical Specifications are consistent with recently licensed BWR Technical Specifications as well as BWR Standard Technical Specifications, and (2) proposed Technical Specifications conform j
with acceptable design and operating practices for engineered safety feature 1
ventilation systems.
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3.0 ENVIRONMENTAL CONSIDERATION
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This amendment involves a change in the installation or use of a facility component locat{d within the restricted area as defined in 10 CFR Part 20.
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i a The staff has determined that the amendment involves no signficant increase in the amounts, and no significant change in the types, of any effluents that may
.be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously published a proposed finding that the amendment involves no significant hazards consideration and there has been no public comment on such finding.
Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 951.22(c)(9). Pursuant to 10 CFR $51.22(b), no environmental impact statement or environmental assessment need be prepared in i
connection with the issuance of the amendment.
4.0 CONCLUSION
We have concluded, based on the considerations discussed above, that (1) there l
is reasonable assurance that the health and safety of the.public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations, and the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
J. Lee Dated: June 23, 1987 i