ML20203P696
| ML20203P696 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 04/28/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20203P693 | List: |
| References | |
| TAC-59696, TAC-59697, TAC-60710, TAC-60711, NUDOCS 8605080040 | |
| Download: ML20203P696 (5) | |
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4.h UNITED STATES y
NUCLEAR REGULATORY COMMISSION s
i WAS6HNGTON, D. C. 20066 S
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION 4
RELATED TO AMENDMENT NO.56 TO FACILITY OPERATING LICENSE NPF-9
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AND AMENDMENT NO.37 TO FACILITY OPERATING LICENSE NPF-17 l
DUKE POWER COMPANY T
MCGUIRE NUCLEAR STATION, UNITS 1 AND 2 INTRODUCTION By letter dated January 10, 1986, Duke Power Company (the licensee) proposed j
amendments to the operating licenses for McGuire Nuclear Station, Units 1 and 7
b 2, which would modify the Technical Specification 3.4.1.2, " Reactor Coolant -
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System - Hot Standby," by increasing by one the number of reactor coolant i
leops required to be operable and in operation for Mode 3 (hot standby). By F
letter dated September 6,1985, the licensee proposed amendments which would j
correct the channel trip logic of the Containment Pressure Control Syst.ani g
(CPCS) in Specification Table 3.3-3 " Engineered Safety Features Actuation h
System (ESFAS) Instrumentation"; clarify CPCS table headings within Tables t
3.3-3, 3.3-4 "ESFAS Instrumentation Trip Setpoints" and 4.3-2 "ESFAS Instru-mentation Surveillance Requirements" consistent with the corrected logic; g
u revise CPCS setpoints in Table 3.3-4; and rephrase the requirements of i
Surveillance Specifications 4.6.2c and 4.6.5.6.2 by referencing the revised.
Table 3.3-4.
The NRC staff has evaluated these proposed changes.
EVALUATION l,,
Reactor Coolant Loops for Hot Standby y
Prior to these amendments, Specification 3.4.1.2, required as a' limiting condition for operation that at least two of the four reactor coolant loops H
be operable and at least one of these be in operation.
(A reactor coolant 's T
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" loop" includes its primary piping, steam generator'and reactor coolant pump).
These amendments increase by one the number of reactor coolant loops required to be operable and in operation for Mode 3 (hot standby). Bases 3/4.4.1, D
" Reactor Coolant Loops and Coolant Circulation" is similarly changed to state
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that "in MODE 3, two reactor coolant loops provide sufficient heat removal capability for removing decay heat; however, single failure considerations require that three loops be OPERABLE." An addition to the ACTION statement for Specification 3.4.1.2 requires that with only one reactor coolant loop in operation, the operator is to restore at least two loops to operation within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or open the Reactor Trip System breakers.
Technical Specification 3.4.1.2 previously stated that when operating in Mode 3, at least two reactor coolant loops were to be operable, but only one of
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these two loops was required to actually be operating. This was inconsistent U
with the FSAR safety analyses which assume that either two or all four of the j'
reactor coolant pumps are operating. The limiting accidents when in Mode 3 i
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operation are steamline break, rod ejection, and control rod bank withdrawal y
from subcritical conditions. The licensee notes that Westinghouse has performed calculations which show that the inconsistency between the safety analysis and Technical Specification 3.4.1.2 does not impact the concl'usions presented in
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the FSAR~for the steamline break and rod ejection accidents. However, the licensee also notes that Westinghouse has performed calculations which show L
that the DNB design basis may not be met with only one of the reactor coolant pumps in operation for the bank withdrawal from subcritical event. The change eliminates the inconsistency between the FSAR and Technical Specification 3.4.1.2 by imposing a more restrictive condition on the allowed number of I
l operable or operating reactor coolant loops. The more restrictive condition ensures that sufficient coolant flow is available when operating in Mode 3 so that the DNB design bases are met for all operating conditions and postulated accidents in Mode 3 including the limiting DN8 accident, control rod bank l
withdrawal from subcritical conditions. The change to the specification, including the additional ACTION statement and the changes to the Bases, result in a McGuire specification which is identical to that previously reviewed and accepted by the NRC for a similar plant, the Catawba Nuclear Station.
On the basis of the Westinghouse analyses, our prior review on Catawba, and because the effect of the change is to increase the margin of safety (i.e.,
l DNB ratio), we find the licensee's requested changes acceptable.
j Containment Pressure Control System A.
Logic 4
t Prior to these amendments Item 5 of Table 3.3-3 listed the CPCS as having four channels per train with 2-out-of-four trip logic and at least three j
channels were required to be operable. This was inconsistent with the 1
j actual system logic as described in FSAR Section 7.6.16 and accepted by l
t SER 7.6.2 because each of t'ie four channels has a different function in i
the operation of the CPCS. Each of the pressure switches provides a start i
permissive /temination signal to one or two of the following components:
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Containment Spray Pump, Containment Air Return Fan, Hydrogen Skimer Fan, Containment Air Return Damper, Hydrogen Skimer Inlet Valve, and Contain-a ment Spray Isolation Valves. ~herefore, in order to assure proper oper-ation of the CPCS, all four channels must be operable. Accordingly, Table 3.3-3 is revised by these amendments to reflect that there are two trains of four channels each, and that all eight channels are required to be operable, or action in accordance with a new " Action 26" statement referenced by the table is required. The new Action 26 requires that with any of the eight channels inoperable, the operator is to place the in-e i
operable channel (s) in the start pemissive mode within one hour and apply the action statement applicable to the effected component (s) (i.e., for Containment Spray components, apply the action statement of Specification 3.6.2; for the Containment Air Return components or the Hydrogen Skimmer components, apply the action of Specification 3.6.5.6).
New Action 26 re-places Action 19 which was inappropriate for the actual CPCS system logic.
3 Action 19 stated that:
"With the number of OPERABLE channels one less than the Total 1
Number of Channels, STARTUP and/or POWER OPERATION may' proceed i
provided the following conditions are satisfied:
a.
The inoperable channel is placed in the tripped condition within one hour, and b.
The Minimum Channels OPERABLE requirement is met; however.
the inoperable channel may be bypassed for up to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> for surveillance testing of other channels per Specification 4.3.11 and Specification 4.3.2.1" Also, a previous footnote referenced in Table 3.3-4 in conjunction with Actiorf 19, which granted relief from the provisions of Specification 3.0.4, is not referenced in conjunction with new Action 26.
e Prior to these amendments. Item 6 of Tables 3.3-3, 3.3-4 and 4.3-2 designated the heading (i.e., functional unit) " Containment Pressure Control System," and included as subheedings, "a. Start Pemissive" and "b. Temination." These amendments combine the two subheadings and main heading into a single heading (, " Containment Pressure Control System Start Pemissive/Temination SP/T)," or (for Table 3.3-3) just " Con-tainment Pressure Control System." The previous tubheadings were misleading)because they implied that separate instrument channels (and bi-stables were provided for the start pemissive and for the temination functions.
In reality, each CPCS instrument channel provides both the start and temiration functions.
No change in system intent or operation is associated with this change.
Rather, the revised heading represents a clarification consistent with the actual installed system as described in FSAR Section 7.6.16 and as accepted by the NRC staff in SER Section 7.6.2.
B.
Setpoints The function of the CPCS is to preclude underpressurization of the containment. As described in FSAR Section 7.6.16 and accepted in SER Section 7.6.2, the CPCS interlocks with the containment spray and containment air return / hydrogen skimmer systems to prevent operation when containment pressure is below approximately 0.25 psig. As con-tainment pressure increases, the CPCS provides a start permissive signal to allow operation of the Engineered Safety Features (containment spray and air return systems). The setpoint (containment high-high pressure, Item 4c of Table 3.3-4) for these ESF systems is less than or equal to 2.9 psig; the CPCS start pemissive may occur at any containment pressure below 2.9 psig (but at or above about 0.25 psig) and will not affect system operation.
The previous CPCS trip setpoint in Table 3.3-4 was impractical in that,
the start pemissive and temination botn occurred at the same value of differential containment pressure (0.25 psid), which provided no adjust-ment band about the setpoint. The previous CPCS allowable setpoint in i
Table 3.3-4 was the same value as for the CPCS trip setpoint, which was impractical because it did not provide for nomal variations such as
f instrument drift. Also, the previous CPCS setpoint allowed termination i
of CPCS at any value less than or equal to 0.25 psid and was;" thus, in-i consistent with the FSAR which requires that tennination occur at a value 4
greater than - 1.5 psig (e.g., a termination setpoint of -2.0 would have satisfied the previous technical specification, but not the FSAR).
j Accordingly, these amendments change the CPCS trip 'setpoint in Table 3.3-4 from "less than or equal to 0.25 psid" to a range that is " greater than or equal to 0.3, but not in excess of 0.4 psig". Similarly, the CPCS allow-able value is changed from "less than or equal to 0.25 psid" to a range that is " greater than or equal to 0.25, but not in excess of 0.45 psig".
The CPCS setpoint changes for Table 3.3-4 and some editorial rephrasing are also reflected in the surveillance specifications for the two ESF systems associated with the CPCS logic. Surveillance Specification 4.6.2c previously required that each Containment Spray System periodically be demonstrated operable, in part, by:
"3) Verifying that each spray pump is prevented from starting by the Containment Pressure Control System when the containment i
atmosphere pressure is less than or equal to 0.25 psid,
- 4) Verifying that each spray pump discharge valve is prevented I
from opening by the Containment Pressure Control System when the containment atmosphere pressure is less than or equal to 0.25 psid, and
- 5) Verifying that each spray pump is automatically de-energized F
by the Containment Pressure Control System when the containment l
atmosphere pressure is reduced to less than or equal to 0.25 a
i psid."
i These amendments delete paragraphs 4) and 5) and rephrase 3) to read:
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" Verifying that the Containment Pressure Control System functions within the setpoint limits specified in Table 3.3-4, Item 6."
Similarly, Surveillance Specification 4.6.5.6.2 previously required each Containment Air Return and Hydrogen Skimmer System to periodically be demonstrated operable "by verifying that each air return fan and hydrogen skimmer fan is prevented fro;n starting by the Containment Pressure Control l
System when the containment internal pressure is less than or equal to 0.25 psid relative to the outside atmosphere." The quoted portion of this specification is changed by these amendments to read: "by verifying that the Containment Pressure Control System functions within the setpoint limits specified in Table 3.3-4. Item 6."
l On the basis of our review, we find that the licensee's proposed changes to the l
l headings for Item 6 in Tables 3.3-3, 3.3-4 and 4.3-2, and the rephrasing of Surveillance Specifications 4.6.2c and 4.6.5.6.2 by substitution of functionally equivalent statements, are of an administrative nature and have no adverse im-pact on safety. Therefore, they are acceptable. We find that the other proposed changes are of a corrective nature and more accurately reflect the design and function of the CPCS as previously reviewed and accepted by the NRC.
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c Such corrective changes are necessary for assurance of proper system operation.
The licensee's changes to clarify the required setpoints and allowable values, and the substitution of appropriate action statements, do not significantly change the intent or operation of the CPCS. Therefore, operation.cf the facility in accordance with these amendments does not adversely impact safety, and is, therefore, acceptable.
ENVIRONMENTAL CONSIDERATION These amendments involve changes to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes in surveillance requirements. We have determined that the amendments involve 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 radiation exposure. The NRC staff has made a proposed determination that the amendments involve no signifi-cant hazards consideration, and there has been no public comment on such categorical exclusion set forth in 10 CFR 51.22(c)gibility criteria for finding. Accordingly, the amendments meet the eli (9). Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of these amendments.
CONCLUSION The Commission made proposed determinations that the amendments involve no significant hazards considerations which were published in the Federal Register (51 FR 6822) on February 26,1986, and (51 FR10457) on March 26, 1986, and consulted with the state of North Carolina. No public comments were received, and the state of North Carolina did not have any comments.
We have 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 these amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors: Darl S. Hood, PWR #4 PWR Licensi.ng-A F. Burrows, Electrical, Instrumentation and Control Systems Branch Dated: April 28, 1986 r
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