ML20005E521
| ML20005E521 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 12/28/1989 |
| From: | PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20005E517 | List: |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.E.4.2, TASK-TM NUDOCS 9001080064 | |
| Download: ML20005E521 (15) | |
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ATTACHMENT l-
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PEACH-' BOTTOM-ATOMIC POWER STATION UNITS 2 AND 3 t
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Docket Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 TECHNICAL SPECIFICATION CHANGE: REQUEST NO. 88-18
" Addition of the High-High' Radiation Trip' Signal per Item II.E.4.2(7) of NUREG-0737"'
Supporting Information for Changes - 15 pages P
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Docket Nos. 50-2771 I
50-278 t
4 License'Nos. DPR-44 DPR-56 Philadelphia Electric Company, Licensee under Facility Operating Licenses DPR-44 and DPR-56 for the Peach Bottom Atomic
-Power' Station"(PBAPS); Unit Nos. 2 and 3,. requests that the
. Technical' Specifications contained in Appendix A of the, Operating-Licenses be amended.
. Proposed changes to the Technical Specifications are
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.i indicated by vertical bar i n the margin of the pages contained in
Attachment:
2 and listed here:
75, 84, 93, 97, 182, 183 and 200.
J' Licensee proposes to revise the Technical Specifications
-to reflect a modification to the primary containment isolation system (PCIS) at the Peach Bottom Atomic Power Station Units 2
.and'3 which adds-a high-high radiation trip signal from the main L
L stack radiation monitors to the control circuit of the containment vent and purge isolation valves.
This modification-is being implemented to meet the requirement of item II.E.4.2(7) of NUREG-0737, " Clarification of TMI Action Plan Requirements",
g, dated October 31, 1980.
l The modification has been completed on Units 2 and 3.
Item II.E.4.2(7) of NUREG-0737 provides a requirement that containment vent and purge isolation valves must close on a
'high-high radiation signal.
Additionally, guidance was provided to this requirement by the NRC to the BWR Owner's Group in a
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2 Dockot Nos. 50-277 50-278 l'
License Nos. DPR '
DPR-56 M
F letter dated May 7, 1986, which stated that lines of 2" diameter l
or smaller need not be-isolated on a radiation signal.
Implementation of this requirement involved adding a signal from the main stack radiation monitors to the control circuit for the F'
containment vent and purge isolation valves greater than 2" diameter.
This Amendment Application identifies the proposed changes which-result from'the implementation of this requirement at the Peach Bottom Atomic Power Station Units 2 and 3.
Licensee-requests that the proposed changes be effective upon-date'of amendment issuance for Unit 2 and Unit 3.
Description of Changes:
Licensee. proposes the following changes to the Technical Specifications:
1 (1) Add the main stack radiation monitoring-trip function to l
Table 3.2.D (Pg. 75, " Radiation Monitoring Systems that
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' Initiate and/or Isolate Systems").
This addition to Table i
3.2.D will include the trip function (" Main Stack Monitor"),
the trip level setting (" Upscale, <106 cps"), the number L
- of instrument channels provided by design ("2 Inst.
Channels"), and the minimum number of operable instrument channels ("1").
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Docket Non. 50-277-50-278-r
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License Nos. DPR-44 DPR-56 As 6 result'of' adding the new trip function which is composed of two instrument channels, it is necessary to revise Note 1 of Table 3.2.D by deleting the words: "there shall be'two, l
operable or. tripped instrument channels per trip system."
Licensee proposes to replace these words with: "the specified number-of instrument channels shall be operable or placed in the tripped' condition."
e As an administrative change which will improve the clarity of
- this table, reference to Note 1 has been added to the. heading of Table 3.2.D, " Minimum No. of Operable Instrument' Channels".
Additionally, for this new trip function, action statement C is' included if the minimum number of operable instrument channels ~can not be met.
The action for this condition is to: " Cease purgingsof primary containment, and close vent and purge valves greater than 2 inches in diameter."
.'2 ) - The main stack trip function is required to be operable only when the contajnment is purging through the SGTS and containment integrity is required.
Therefore, a' Note (3) will be added to Table 3.2.D (p. 75),-which will correspond to the new trip function
(" Main Stack Monitor"), that will state: "This trip function is required to be operable only.
Docket Nos. 50-277
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License Nos.;DPR-44 DPR-56 when the containment is purging through the SGTS and-containment integrity.is required.
If.both radiation.
E monitors are out of service, action chal'1 be taken as indicated in Note 2, (C)."
u 3)..The Section.3.2 Bases (p. 93) of the Technical Specifications' i
concern' protective instrumentation.
As a result of the addition of the new trip function,.a paragraph will be added which states: "Two channels of nonsafety-related radiation L
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monitors:are.provided in.the main stack.
Trip signals from these monitors are required only when purging the containment through the SGTS;and containment integrity is required.
The-trip signals isolate primary containment vent and purge valves greater than 2 inches in diameter to prevent accidental releases of radioactivity offsite when the valves are open.
This signal is added to fulfill the requirements of item II.E.4.2(7) of NUREG-0737."
l (4) Add the main stack radiation monitoring trip function to Table 4.2.D (P. 84, " Minimum Test & Calibration Frequency for Radiation Monitoring Systems").
This addition 9111 specify the calibration and testing frequency for this new trip function.
This proposed addition will provide the instrument channels (" Main Stack. Monitor"), the instrument. functional test frequency ("once/3 months"), the calibration frequency u-
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Docket Nos. 50-277-50-278-1 License Nos. DPR 44 y.
'("once/12 months as described in 4.8.C.4.a") and an instrument check frequency-("once/ day").
p 5)
The Section 4.2 Bases (P. 97) of-the Technical Specifications concern protective instrumentation.
As a result of the addition of'the new trip function, a paragraph will be added which states:
" Radiation monitors in the main stack which initiate containment isolation are not safety-related and are required only during containment purging through the SGTS and when-containment integrity is required, an activity which occurs-infrequently.
Therefore, a twelve (12) month l
q calibration interval is appropriate."
6)
Add to.the " NOTES POR TABLE No.
3.7.1" (P. 183) the main stack radiation monitoring trip function.
This note will be added to the Group-3 isolation signals and will state: " Main stack high-high radiation during containment purging through p
SGTS (vent and purge valves greater than two inches in
-diameter only)".
t I-Administrative changes to pages 182 and 183 are being L
requested to improve format.
These changes are relocating
" GROUP 3:
The valves in Group 3 are actuated by any one of the following conditions:" from the bottom of page 182 to the 1 l
Docket Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 top of'page_183 and adding the heading " NOTES FOR TABLE-NO.
3.7.l'(Cont'd)" to the top of page 183.
- 7) : Add to'the Section 3.7.D & 4.7.D Bases-(p. 200) a statement which identifies that the new' isolation signal will isolate
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the containment vent and purge isolation valves.
Therefore,
-the Bases will be modified to state: "These valves are 3-isolated on reactor low water level (538"), high drywell
. pressure, reactor building ventilation high radiation which would; indicate a possible accident and necessitate primary containment isolation, or refueling floor ventilation high radiation which would indicate a possible refueling accident or main stack high-high radiation (a nonsafety-related signal) during containment purging through SGTS in-accordance with Section 3.8.C.8a."
Additionally, as noted in the " Safety Assessment", the main stack high-high radiation signal will only be activated upon the positioning of certain valves and there is flow through the standby gas treatment system.
Therefore, the Section 3.7.D & 4.7.D Bases, which describes the Group 3 isolation signal, will also be modified to state: "The group 3 isolation signals, with the exception of main stack high-high radiation, also " isolate" the reactor building and start the Standby Gas Treatment System".
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Dockst Nos. 50-277 50-278-License Nos. DPR-44 1
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DPR-56 8). Add to the Group 3 isolation signal description in the Section 3.7.D & 4.7.D Bases (p. 200) a-description of the new j
main stack radiation mon 3toring trip function.
This
~ description will state: "The main stack high-high radiation signal' (which is nonsafety-related in accordance' with IJUREG-0737) will isolate only those vent and purge valves which are-greater than two inches in diameter during containment purging."
Safety Assessment Plant Modification 664 modifies the primary containment isolation-system-(PCIS) at Peach Bottom Atomic Power Station Units 12 and 3 by adding a high-high radiation isolation signal 1
-from-the main stack radiation monitors to the control circuit for the. containment vent and purge isolation valves.
This change is required by. item II.E.4.2(7) of NUREG-0737, " Clarification of TMI Action Plan Requirements."
This isolation signal is redundant-to the' isolation signal derived from the reactor vessel low water level and high drywell pressure signals.
This high-high radiation isolation signal is activated.
only when valves AO 2506 and 2507* or valves 2511 and 2512* are open and there is flow through the standby gas treatment system.
This ensures that the trip signal affects only the unit which is - - - -
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5 Dock @t'Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 1
'l purging through the standby gas treatment system and containment j
integrity is required.
i In-a-letter to the BWR Owner's Group dated May 7, 1986, the'NRC clarified that lines of 2" diameter or smaller need not beilsolated on:a radiation signal provided that an analysis be performed to show that.the operators, within 30 minutes, assess.
and isolate leakages that would not cause other isolation signals.
This analysis has been completed and shows that the J
operators can make this assessment within the required time.
The following valves (greater than 2" diameter) close whenever the
, main stack radiation level exceeds the'high-high trip point:
Valve Number
l Drywell and Torus Inlet Nitrogen Purge AO 2520 Drywell Air and Nitrogen Purge AO 2521A Torus Air Purge Outboard l
i AO 2521B Torus Air and Nitrogen Purge Inboard AO 2506 Drywell Inboard 18" Vent AO 2507 Drywell Outboard 18" Vent AO 2511 Torus Inboard 18" Vent AO 2512 Torus Outboard 18" Vent _
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Docket Nos. 50-277 50-278 License Nos. DPR-44 1
DPR-56 9
- Unit 2 valve numb:
are given.
Valve numbers in Unit 3 have a 3 in the first digit in place of the 2.
Previous to modification 664, a common circuit (Group 3
-isolation) was used for isolation of the above valves, isolation of the reactor building, and starting the standby gas treatment system (SGTS).
The circuit has been divided so that the logic for isolation of.the reactor building and starting the standby gas treatment system remains unchanged.
1 In accordance with the criteria established by the Nuclear Regulatory Commission la NUREG-0737, the radiation monitors are nonsafety-related.
The SGTS flow-switch is also nonsafety-related.
This flow switch is used to determine flow through the SGTS.
The interface between the nonsafety-related radiation monitors, the nonsafety-related SGTS flow switch and the safety-related PCIS circuitry is through the use of safety related relays located in the Panels 20Cl2 and OOC 14.
The valve limit switch signals are obtained from safety-related relays in p
Panel 2OCO3 (30CO3).. The valve limit switch determines the positien of the valves.
The above features ensure that the PCIS circuitry is isolated from all credible failures of the radiation monitors that could have an adverse affect on the operation of
'the PCIS.
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.The-high-high radiation setpoint maintains the offsite radiation-dose below the 10 CPR 100 limits as required by the Nuclear Regulatory Commission.
Since the two main stack radiation monitors are common to both units, the output of one radiation monitor is used in the i
logic for the inboard. isolation valves in both units and the output of.the other radiation monitor is used in the logic for
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the outboard isolation valves in both units.
u This modification also adds two keylocked bypass switches on panel 20COSA (Unit 2) and 30C05A (Unit 3), one in eachrof the two PCIS logic channels.
These switches bypass all PCIS isolation signals to the drywell or torus exhaust valves to permit venting as a means of preventing overpressurization of r
containment during severe accidents.
The bypass switch is interlocked with the individual valve control switch so that both switches' require deliberate operator action before the isolation signal.is bypassed and the valves opened to complete one vent l~
path.
Containment Control Procedure T-102 states that if drywell l
pressure reaches 60 psig, the containment should be vented per I'
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procedure T-200.
In order to vent through the exhaust valves, it is necessary to bypass the containment isolation signal.
This L
action can be completed by use of the bypass switches.
The bypass switches are safety-related and are seismically qualified.
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and1 environmentally qualified for a-mild environment.
The I
switches are keylocked for administrative control and alarmed-J dk when-inLthe bypass mode.
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s InformationiSupporting a Finding of
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No Significant Hazards Consideration i
The: Commission has provided guidance concerning the
. application of the standards for determining whether license
-amendments involve >significant hazards considerations ~by.
providing certain examples:(51 FR 7751).
One of the' examples of t
amendments that are considered not likely-to-involve significant 5
-hazards-considera' tion is "(11) A change that constitutes an
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. additional limitation, restriction, or control not-presently
.i ncludedtin' the technical specifications, e.g., a more stringent g
surveillance' requirement."
The proposed changes to the Technical
-t Specifications' impose additional control not presently included l
in-the Tech'nical Specifications.
The proposed changes to the Peach Bottom operating licenses do not constitute a significant hazards consideration in
'that-they do not:
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Involve a significant increase in the probability or-consequences of an-accident previously evaluated. r
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I License Nos. DPR-44 DPR-56 Vee codification associated with the proposed Technical 1
i Spes4fication changes provide additional means of
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mitigating the consequences of an accident by adding an
' isolation signal not previously part of the plant design.
The addition of this isolation signal enhancos plant safety by adding an additional means of isolating containment.
Implementation of this isolation signal is s
the result of Item II.E.4.2(7) of NUREG-0737 which requires that containment vent and purge isolation valves must close on a high-high radiation signal.
The new nonsafety-related isolation signal is isolated from the safety-related portions of the circuits by qualified relays.
Therefore, the proposed changes do not involve i
a significant increase in the probability or consequences of an accident as previously evaluated in Chapter 14 of the PBAPS Updated Final Safety Analysis Report.
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Create the possibility or a new or different kind of accident from any accident previously evaluated.
-The modification associated with the proposed Technical Specification changes provided additional means of r.itigating the consequences of a plant event by adding,
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50-278 License Nos. DPR-44 5
DPR-56 an isolation signal not previously part of the plant design.
Adding a redundant isolation trip feature does not' create a new accident precursor.
Therefore, the i
proposed changes would not create the possibility of a l
new or different kind of accident from any previously evaluated.
iii) Involve a significant reduction in a margin of safety.
The modification associated with the proposed Technical Specification changes provided additional assurance that the primary containment is isolated during a radiological event.
Consequently, the potential for an offsite radiation release is reduced, resulting in an increased margin of safety.
Information Supporting an Environmental Impact Assessment An environmental impact assessment is not required for the changes proposed by this Application because the changes conform to the criteria for " actions eligible for categorical exclusion" as specified in 10 CFR Sl.22(c)(9).
The Application involves.no significant hazards consideration as demonstrated in the preceding section.
The Application involves no significant change in the types or significant increase in the amounts of any L 1
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l effluents that may be released offsite, and there is no significant increase in individual or cumulative occupational radiation exposure.
conclusion 6
The Plant Operations Review Committee and the Nuclear Revicu Board have reviewed these proposed changes to the Technical Specifications and have concluded that they do not involve unreviewed safety questions or involve Significant Hazards Considerations, and will not endanger the health and safety of the public.
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