ML20235J892
| ML20235J892 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 07/08/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20235J885 | List: |
| References | |
| NUDOCS 8707160048 | |
| Download: ML20235J892 (7) | |
Text
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/,,c'g UNITED STATES n
NUCLE AR REGULATORY COMMISSION 2
,1 WASHINGTON. D. C. 20555
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT N0. 6 TO FACILITY OPERATING LICENSE NO. NPF-39 PHILADELPHIA ELECTRIC COMPANY LIMERICK GENERATING STATION,. UNIT I DOCKET N0. 50-352
1.0 INTRODUCTION
By letter dated January 13, 1987 as supplemented on March 25 and April 9, 1987, Philadelphia Electric Company (the licensee) requested an amendment to Facility Operating License No. NPF-39 for the Limerick Generating Station, Unit 1.
The proposed amendment would change the Technical Specifications (TS) to permit the licensee to complete the physical modifications, testing and other actions to facilitate connection of the standby gas treatment system (SGTS) to the refueling floor area.
These changes to the TS would enable the licensee to establish the operability of the SGTS service to the refueling floor area in response to the reovirements of License Condition 2.C(14).
The April 9,1987 submittal provided supplemental information and revised TS Bases pages and did not alter the action noticed in the Federal Register on April 8,1987 or the staff's initial no significant hazards determination.
i The SGTS has been operable in support of the Unit I reactor enclosure secondary containment integrity since the issuance of the Unit 1 operating i
license. A secondary containment completely encloses the Unit 1 and the Unit 2 primary containments and is provided to contain any leakage from the prinary containments for processing by filtration systems prior to release.
The secondary containment is divided into three separate venti-lation zones.
Zones I and II consist of the reactor enclosures.which surround the primary containments of Units 1 and 2, respectively, below the floor at elevation 352 feet.
Zone III consists of the common refueling area above the floor at elevation 352 feet.
A design basis of the secondary containment is that the conditions that could exist following a loss-of-coolant-accident (LOCA) or fuel handling accident require the control of' any fission products that may leak into secondary containment. Accordingly, a standby gas treatment system is provided to collect and exhaust sufficient filtered air from the reactor enclosure or refueling area to maintain a negative pressure in the affected volumes during secondary containment isolation.
The NRC staff concurred in SER Supplement Nos. 2 and 3 with a request by the licensee for a scheduler delay in completion of the connection of 9707160048 G70709 PDR ADOCK 05000352 p
. the SGTS to the refueling flonr area (Zone III).
The staff concurred on the basis that Zone III is completely isolated from the Unit i reactor enclosure secondary containment zone, and that Zone III SGTS operation is relied upon during the fuel handling and that there would be no irradi-ated fuel in the spent fuel pool until the first refueling outage.
The staff also established License Condition 2.C(14) which requires the connection of the refueling floor volume to the SGTS prior to any movement of irradiated fuel. Specifically, it stated:
" Prior to any movement of irradiated fuel within the refueling floor volume the licensee shall complete and test all modifications required to connect the refueling floor volume to standby gas treatment system.
During the interim period, the licensee shall not remove the reactor pressure vessel head prior to the NRC staff review and approval." The staff's review and approval of removal of the primary containment head and certain items connected to the reactor vessel head were addressed as separate items by the staff's letters dated May 12 and May 18, 1987.
2.0 EVALUATION The SGTS modifications for License Condition 2.C(14) necessitates changes to the Limerick Unit No.1 Technical Specifications as follows:
(1) incor-porate the new as-built SGTS capacity, (2) address new as-built SGTS con-figuration, (31 address new system isolation actuations, and (4) delete footnotes which will become obsolete upon completion of the modifications.
The requested modifications will be completed prior to startup from the first refueling outage which began on May 15, 1987.
In order to satisfy the requirements of License Condition 2.C(14), several modifications will be made to the SGTS as indicated belnw.
A new refueling area purge exhaust duct will be connected to the SGTS through two new fail open valves (HV-19 and HV-20). Two new prefilters (0AF-906 and OBF-906) will also be installed in the refueling area purge exhaust lines upstream of the existing SGTS filters. These filters will remove larger airborne particles from the refueling area extending the life of the existing SGTS HEPA filters.
In addition, two new SGTS fans (OAV-163 and OBV-163) with higher capacity (8400 cfm) will replace the existing fans (3000 cfm). The licensee stated in the January 13, 1987 letter that the new fans and common ductwork will meet the current Limerick
" drawdown time" limitation.
This limitation requires that a negative pressure of 0.25 inches water gage be achieved in the secondary containment within 2.?5 minutes with simultaneous drawdown of the Unit I reactor enclosure, Unit 2 reactor enclosure (future), and common (Units 1 and 2) refueling area.
The new fans will be installed in the same room and in approximately the same location as the existing fans. The existing fans will be electrically disconnected and blocked off from the existing duct-work and left in place.
The specific technical specification changes for l
the SGTS are evaluated in the following subsections.
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1 2.1 Deletion of Primary Containment Isolation Signals l
The licensee proposed deletion of the isolation signals "R" (refueling area ventilation exhaust duct radiation high) and "T" (outside atmosphere to refueling area differential pressure low) from the primary containment isolation sections of Technical Specification Tables 3.3.2-1,
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3.3.2-2, 3.3.2-3, and 4.3.2.1-1.
This proposal results in no physical or hardware changes to the primary containment isolation system. The R and T signals provide a primary and secondary containment isolation function only for a potential fuel handling accident during the refueling mode of operation.
The Limerick secondary containment is divided into three (3) isolated ventilation zones.
Zones 1 and 2 consist of the reactor enclosures which surround the primary containments of Unit No. I and Unit No. 2, respectively.
Zone 3 consists of the common refueling area.
Thus, the refueling area constitutes a distinct zone of the secondary containment and does not communicate with the reactor enclosure secondary containment.
In the current Limerick Technical Specifications, R and T isolation signals appear in both primary and secondary containment isolation sections.
These isolation signals are presently required to be operable during Modes 1, 2, and 3 in the primary containment isolation section but are required to be operable only durinc Mode * (refueling) in this secondary containment isolation section.
The licensee stated in the referenced letter that deletion of the R and T isolation signals from the primary containment isolation section will prevent possible confusion among the plant operators because of the, inconsistent operability requirements and that inclusion of R and T signals in the primary containment isolation section appears to have been an inadvertent oversight during the development of the Limerick Technical Specifications because they are not part of the primary containment i
isolation function for accidents in Modes 1, 2, and 3.
The staff has l
reviewed this and agrees with the licensee's evaluation and therefore, finds deletion of the R and T isolation signals from the primary contain-ment isolation TS section to be acceptable.
2.2 Addition of Clarification to Isolation Signals The licensee proposed the addition of footnote (a) to the isolation signal-column on TS page 3/4 3-15 and clarification of footnotes (a) and (c) on TS page 3/4 3-16.
These changes are needed because the SGTS serves both the refueling area ventilation exhaust (zone 3) and the drywell purge exhausts (zone 1 and 2). Therefore, the R and T signals will still actuate certain primary containment isolation valves (e.g., drywell purge supply and exhaust valves, drywell hydrogen / oxygen sample valves) following accidents during refueling.
Footnotes (a) and (b) clarify these operational features and therefore, the staff finds the addition and clarification to be acceptable.
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2.3 Manual Initiation Signals The licensee proposed to revise the manual initiation signals on TS pages 3/4 3-15, 3/4 3-22, 3/4 3-26, and 3/4 3-31.
These changes revise the current manual initiation isolation signal to be either from the Peactor Enclosure or the Refueling Area upon completion of the SGTS modifications.
The staff finds this revision to be consistent with the system design and, therefore, acceptable.
2.4 Addition of Isolation Signals The licensee proposed to add R and T isolation signals on TS pages 3/4 3-16, 3/4 6-22, and 3/4 6-?6 and delete notes 25 and (b) on TS pages 3/4 6-43, 3/4 6-22, 3/4 6-26, 3/4 6-49, and 3/4 6-51, respectively.
The current note 25 and (b) on page 3/4 6-43 and 3/4 6-49 states:
" Isolation capability upon refueling floor high radiation (signal R in Specification 3.3.2, Table 3.3.2-1) and low differential pressure (signal T in Specification 3.3.2, Table 3.3.2-1) will be added [by the end of the first refueling outage (Note 25)], [ prior to handling irradiated fuel in the refueling area secondary containment (Note (b)].
In accordance with these notes, isolation signals R and T were added where the note is referenced on TS pages 3/4 6-22, 3/4 6-26, 3/4 6-49 and 3/4 6-51, respectively. Accordingly, Note 25 and Note (b) were deleted from pages 3/4 6-43, 3/4 6-49, and 3/4 6-51 as they become obsoleta upon completion of the SGTS modifications.
Isolation signals R and T were also added to Note C on TS page 3/4 3-16 since these signals will become functional (actuate the SGTS) upon completion of the modifications.
The staff finds these changes to be consistent with the SGTS modifications and, therefore acceptable.
2.5 Drywell Purge Exhaust and Suppression Pool Purge Exhaust Isolation Valve The licensee proposed the addition of a new note (Note 33) on TS page 3/4 6-43 for the drywell purge exhaust and suppression pool purge exhaust valves which are called out on TS pages 3/4 6-22 and 3/4 6-26 to incorporate the fact that these valves are both primary containment and refueling area secondary containment isolation valves.
The staff finds the change to be consistent with the SGTS modifications and, therefore, acceptable.
In addition, the licensee proposed to add the drywell purge exhaust and suppression pool purge exhaust isolation valves to Table 3.6.5.2.2-1 on page 3/4 6-51 as part of the Refueling Area Secondary Containment Automatic Isolation Valves.
This addition is required due to the connection of the refueling area ventilation to the SGTS ductwork which also interfaces with the drywell and suppression pool exhaust purge ductwork.
Further, an error in Table 3.6.5.2.2-1 where the Refueling Area was erroneously titled as Reactor Enclosure in the table subheading has been corrected. The staff finds these proposed changes to be consistent I
with the SGTS modifications and, therefore, acceptable.
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2.6 SGTS Surveillance Requirements The licensee proposed to revise the SGTS Surveillance Requirements as indicated on TS pages 3/4 6-53 and 3/4 6-54 because of modifications to the SGTS. The modifications include the addition of two new prefilters installed in the refueling area purge e>haust lines upstream of the existing SGTS filters which will extend the life of the existing SGTS HEPA filters, and two new SGTS fans with hioher capacity (8400 cfm) to replace the existing fans (3000 cfm).
In addition, Section 4.6.5.1.1.b.3 on TS page 3/4 6-46, Section 4.6.5.1.2.b.3 on TS page 3/4 6-47, and Section 3.6.5.2.2(c) on TS page 3/4 6-50 have been revised to reflect the addition of new slide gate danpers which will be added as part of the SGTS modifications. A new surveillance requirement for the two new prefilters has been added on Item b.4 on TS page 3/4 6-53.
This requirement will specify that the pressure drop across the prefilter should not exceed 0.25 inch water gage while operating at a flow rate of 2400 cfm 10%. Also the pressure drop limit in TS 4.6.5.3.d across the combined HEPA and charcoal adsorber banks is revised to be less than 9.1 inches water gage (currently A.8 inches) while operating the filter train at a flow rate of 8400 cfm 10% (currently 3000 cfm 10%).
Further the footnote on TS page 3/4 6-53 and the system flow rates in Item b.3 are revised to reflect the new SGTS operational modes.
1 No operational changes have been made to the existing SGTS configuration l
with the exception of the increased flow rate from the new fans in order l
to meet the secondary containment drawdown time requirement. The increased SGTS flow rate will also reduce the resident time in the existing 8-inch deep charcoal adsorbers, however, the SGTS will be operated at 8,400 cfm air flow rate only during the drawdown period (2.25 minutes to reach negative 0.25 inches water gage), during which no credit for iodine l
removal is given.
Only after drawdown is completed is the iodine removal credit given (99 percent for elemental, organic, and particulate iodine).
During secondary containment isolation (zone 1, 2 and 3), the maximum inleakage rate will be 3264 cfm. At this flow rate, the residence time in the existing charcoal adsorbers will be approximately 1.1 seconds.
This residence time meets the guidance in Regulatory Guide 1.52, Rev. 1.
The staff therefore, finds the revised SGTS surveillance requirements to be acceptable.
2.7 SGTS Technical Specification Bases Bases Section 3/4 6.5 on TS page B 3/4 6-5 has been revised by the licensee to reflect the SGTS system modifications.
The staff finds the bases to be consistent with the revised system requirements and, therefore, acceptable.
2.8 CONCLUSION
On the basis of the above evaluation, the staff finds that the proposed changes to the Limerick Technical Specifications concerning the SGTS
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modifications are in accordance with Limerick License Condition 2.C(14),
and thus, the staff conclusions in the original Limerick Safety Evaluation Report (NUREG-0991) regarding post-accident fission product control systems are unchanged by the modifications.
The staff, therefore, concludes that the proposed Technical Specification changes are acceptable.
2.9 IMPLEMENTATION The above Technical Specification changes will be implemented prior to startup following the first refueling outage.
Specifically, the revised Technical Specifications will become effective upon initial entry into either Operational Condition 3 or 2 during startup following the first refueling outage.
This implementation is consistent with the requirements of License Condition 2.C(14) and is therefore acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
This amendment involves changes to requirements with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes to the surveillance require-ments. The staff has determined that the amendment involves no significant increase in the amounts, and no significant chance 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 Comission has previously issued a proposed finding that tnis amendment involves no significant hazards consideration and there has been no public coment on such finding. Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement nor environmental assessment need be prepared in connection with the issuance of this amendment.
4.0 CONCLUSION
The staff has concluded, based on the considerations discussed above, that:
(1) there 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 this amendment will not be inimical to the common defense and the security nor to the health and safety of the public.
Prinicipal Contributors: Jay Lee Dated: July 8,1987
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c 4 Local Public Document Room location:
Pottstown Public Library, 500 High Street, Pottstown, Pennsylvania 19464
/s/
Walter R. Butler, Director Project Directorate I-2 Division of Reactor Projects I/II l
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