ML20035A977
| ML20035A977 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 03/22/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20035A967 | List: |
| References | |
| NUDOCS 9303300300 | |
| Download: ML20035A977 (5) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REL ATED TO AMENDMENT NO.161 TO FACILITY OPERATING LICENSE NO. DRP-71 AND AMENDMENT NO.192TO FACILITY OPERATING LICENSE NO. DPR-62 CAROLINA POWER & LIGHT COMPANY BRUNSWICK STEAM ELECTRIC PLANT. UNITS 1 AND 2 DOCKET NOS. 50-325 AND 50-324 i
1.0 INTRODUCTION
By letter dated January 12, 1993, as supplemented February 8, March 1, and March 17, 1993, the Carolina Power & Light Company (the licensee or CP&L) submitted a request for changes to the Brunswick Steam Electric Plant, Units 1 and 2 (BSEP), Technical Specifications (TS). The February 8, 1993, letter provided clarifying information; the March 1, 1993, letter provided updated TS pages and made an editorial change to reflect the more conservative guidance of Generic Letter 88-13; and, the March 17, 1993, letter provide updated TS pages and marked-up TS pages detailing all the changes requested.
None of the three supplemental letters altered the proposed no significant hazards consideration made in the February 11, 1993, Federal Reaister Notice.
The licensee proposed five changes to the TS Sectica 3/4.3.5.5, Chlorine Detection System, and to Section 3/4.7.2, Control 1-m Emergency Filtration System, and to their associated Bases sections to reflect changes made to the i
actuation logic in the control building emergency ventilation system (CBEVS) chlorine detection logic to revise the present f ail-safe design to a single-failure proof design. The modification of the logic requires revision of the Limiting Condition for Operation (LCO) Action Statements and Surveillance Requirements in the TS to reflect the increased number of detectors being installed in each detection trip system of the CBEVS and the new type of detection equipment. Additionally, deficiencies in the Applicability requirements, as well as a lack of requirements for the radiation protection and smoke protection instrumentation in the CBEVS, are corrected.
One of the principal design objectives of the control building heating, ventilation and air conditioning (CBHVAC) system is to permit continuous occupancy of the control room emergency zone under both normal operating conditions and under the postulated design basis events throughout the life of the plant.
The CBHVAC system must function to provide protection to the operators for three type events:
a radiation event, up to and including a design basis accident (e.g., main steam line break cccident, refueling -
accident, control rod drop accident, or loss-of-coolant accident (LOCA)); a toxic gas ? vent (e.g., the complete rupture of the 55-ton chlorine tank car located nar the service water building, or a slow leak lasting for an i
extended period of time); and an external smoke event.
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. l The CBEVS is designed to meet the criteria of General Design Criterion 19.
Additionally, the system has been designed using the guidance of Regulatory Guide 1.95, Revision 1.
Commitments have also been made to design the CBEVS to meet the single failure criteria described in IEEE 279-1971, with exception noted in the Control Room Habitab'lity Analysis, Revision 2, dated February 1983.
During a radiation event, the CBHVAC system is designed to automatically isolate and enter the radiation protection mode on a control room intake high radiation signal. Thus, the area radiation monitoring system automaticaily realigns to the emergency mode of operation. The normal fresh air inlet closes, and, at approximately the same time, the emergency air filtration units begin operation, recirculating control room air and providing filtered makeup air to minimize contaminated build-up and provide positive pressure in the control room environment.
The CBHVAC system responds to an external smoke event in a manner similar to that of a radiation event.
In the event of a chlorine release, the CBHVAC system enters a full recirculation mode, with no outdoor air intake. The emergency filtration trains do not start, since the filters quickly become saturated and, thus, may be damaged by the presence of chlorine.
Protection for chlorine gas events overrides any concurrent, ongoing or subsequent radiation or smoke initiation signals. The override design offers protection to operations personnel in the control room for the most immediate life-threatening event by providing protection against potentially fatal chlorine gas releases. This protection is required any time the chlorine tank car is within the exclusion area.
2.0 EVALUATION The licensee proposed five changes to TS Section 3/4.3.5.5, Chlorine Detection System, and to Section 3/4.7.2, Control Room Emergency Filtration System, and their associated Bases sections, to reflect changes made to the actuation logic in the CBEVS chlorine detection logic to revise the present fail-safe design to a single-failure proof design. These five changes will be evaluated as two separate changes to TS Sections 3/4.3.5.5 and 3/4.7.2. Specifically, requested changes 1 and 3 deal exclusively with TS 3/4.3.5.5 and shall be evaluated as one, while requested changes 2 and 4 deal exclusively with TS 3/4.7.2 and, therefore, shall be evaluated together.
Proposed change 5, changing both TS Sections 3/4.3.5.5 and 3/4.7.2, makes only administrative 1
changes to TS Section 3/4.3.5.5 and its associated Bases section; and, as such, the bulk of the proposed change will be evaluated with TS Section 3/4.7.2.
2.1 TS Section 3/4.3.5.5, Chlorine Detection System 2.1.1 Proposed Changes Proposed Change 1 is to revise the LCO, Applicability, Action and Surveillance Requirements sections. The new LC0 section would reflect the addition of four chlorine detectors, a trip subsystem within a trip system, a 7-day LCO Action statement for one chlorine detector of either trip subsystem for either or l
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both trip. system (s) being inoperable, and a requirement fer isolation of the control room environment within one hour with both detectors in a trip subsystem of either trip system inoperable. The Applicability and Action sections would be revised to reference a new Table 3.3.5.5-1, Control Building Emergency Ventilation System Instrumentation. An operational condition requirement is proposed to be added to the Applicability section whenever the chlorine tank car is within the exclusion area. Also proposed is'a revision to the Surveillance Requirements section to increase the channel-calibration frequency from refueling to annual.
Proposed Change 3 adds radiation protection and external smoke protection.
instrumentation associated with the control building emergency ventilation system to the existing TS 3/4.3.5.5, reformats the section into a table format, and renames the section " Control Building Emergency Ventilation System." Also, it revises the LCO, Applicability and Action sections. The new LC0 section would add operability requirements for the radiation protection and external smoke protection instrumentation and reformat the existing requirements into a table. The Applicability section would require.
operability of the chlorine detection instrumentation whenever the chlorine tank car is in the exclusion area and would also require operability of the l
radiation protection and smoke detection instrumentation. Action statements are added to address inoperable chlorine, radiation or smoke detectors.
2.1.2 Evaluation of Proposed Changes The proposal to rename TS Section 3/4.3.5.5, " Control Building Emergency Ventilation System Instrumentation," and to reformat the section into a table' i
format and expand its associated Bases Section, including word and syntax changes, is administrative in nature, similar to the Standard Technical Specifications, and is acceptable.
l The proposed changes expand the scope of the LC0 by adding radiation and external smoke protection instrumentation function requirements, is similar to the requirements in TS 3/4.7.2, and associated with the existing chlorine detection TS.
Since these instruments are only involved in the mitigation of CBEVS design basis events and this change eliminates the need for a TS interpretation for TS 3/4.3.5.5, the proposed change is acceptable.
The proposed changes to the LC0 section reflecting the new configuration of the chlorine isolation instrumentation trip systems and the addition of chlorine detectors does not change any safety settings. The addition of four chlorine detectors and the separation of the instrumentation into two divisions increases the reliability of the system.
The change does not affect-any of the chlorination system piping system or tank car that would be the initiating component of a chlorine release event.
Therefore, the probability of a chlorine tank car rupture analyzed in the Updated Final Safety Analysis Report (UFSAR), Section 6.4.4.2, will not be increased and the results of the analysis remain within the original acceptance criteria.
The proposed change maintains the existing operability requirements for the chlorine isolation instrumentation and the same Action statements for loss of redundancy and loss of function of the system. The proposed change is required to reflect i
chlorine detection system configuration changes.so that previously
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unidentified single failures will be eliminated. The proposed change imposes the same Operability requirements as the existing configuration as well as the same Action statements for loss of function and loss of redundancy. Since the detection / isolation components will continue to operate as required and previously unidentified single failures are being eliminated, the proposed change is more conservative than the existing TS and, thus, is acceptable.
The change in the surveillance interval to reflect the new type of sensor is a conservative increase in the interval and will not reduce the reliability of the detection system.
Therefore, the proposed change is acceptable.
2.2 TS Section 3/4.7.2, Control Room Emergency Filtration System 2.2.1 Proposed Change Proposed Change 2 revises the LCO, Applicability and Action sections.
The new LC0 section would add operability requirements for radiation and smoke protection modes and for the chlorine protection mode as defined in TS 4.7.2.d.3 and in the Basis section of 3/4.7.2.
The Applicability section would be expanded to include operational conditions 4, 5, *, and **. The Action section would be replaced with statements applicable to each operational condition.
Proposed Change 4 amends the specific filtration efficiency of TS 4.7.2.b.1 to be consistent with Surveillance Requirements 4.7.2.e and f and the guidance of Generic Letter 83-13.
Proposed Change 5 is to the Surveillance Requirements of TS 4.7.2.d, decreasing the maximum allowable pressure drop across the combined HEPA t
filters and charcoal adsorber banks.
Also, various administrative word changes will be made to TS 3/4.3.5.5 and 3/4.7.2, and to their respective Bases sections, to reflect the changes proposed above.
2.2.2 Evaluation of Proposed Changes The proposal to rename TS Section 3/4.7.2 " Control Room Emergency Ventilation System," and to reformat the section and expand its associated Bases Section, including word and syntax changes, is administrative in nature and is acceptable.
The proposed change expands the scope of the LC0 and is similar to the requirements in the BWR Standard TS section for the main control room environment control system, By adding chlorine, radiation and external smoke protection mode operability requirements, the licensee is ensuring that the control room will remain habitable for operations personnel during and following all credible external hazard events, consistent with previously l
evaluated assumptions and scenarios.
The additional operability requirements for the system during operational conditions 4 and 5 and during movement of i
irradiated fuel assemblies in the secondary containment will be the same_ as in operational conditions 1, 2, and 3.
These added requirements ensure that the control room will remain habitable for operations personnel during and following all credible accident conditions (e.g., fuel handling accidents)
I that are applicable during these operational conditions, and are acceptable.
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Since the proposed change is more conservative than the existing TS, the proposed change is acceptable.
Proposed Change 4, adding efficiency requirements to the Surveillance Requirement, meets the guidance of Generic Letter 83-13, is consistent with the cur rent requirements of TS 4.7.2.e and f and remains bounded by the maximum efficiency assumed in the habitability analyses contained in the Safety Evaluations for the BSEP CBEVS filtration units, which ensures that no General Design Criteria limits will be exceeded, i
Therefore, the proposed change is acceptable.
The proposed change 5, to revise the maximum allowable pressure drop across the filtration train to less than or equal to 5.25 inches of water gauge ensures that the required flow rate can be met with margin for filter loading following an accident.
The proposed change ensures that the system will perform its intended design function and poses no additional operating modes or new credible single failures.
Therefore, the proposed change is acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the State of North Carolina official was notified of the proposed issuance of the amendment. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements. The NRC staff has determined that the amendment involves no significant 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 issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (58 FR 8068). Accordingly, the 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 or environmental assessment need be prepared in connection with the issuance of the amendment.
5.0 CONCLUSION
i The Commission 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, (2) such 5
activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimacal to the common defense and security or to the health and safety of the public.
1 Principal Contributor:
C. E. Carpenter Date: March 22, 1993
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