ML20197B123
| ML20197B123 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 10/16/1986 |
| From: | COMMONWEALTH EDISON CO. |
| To: | |
| Shared Package | |
| ML20197B116 | List: |
| References | |
| NUDOCS 8610280061 | |
| Download: ML20197B123 (9) | |
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LIMITING CONDITION FOR OPERATION SURVEILLANCE REQUIREMENT 3.3 REACTOR COOLANT SYSTEM (per unit) 4.3 REACTOR COOLANT SYSTEM (per unit)
- 1. Operational Components 1. Operational Components A. Reactor Coolant Loops and Coolant A. Reactor Coolant Loops and Coolant Circulation Circulation
- 1. a. All Reactor Coolant Loops shall 1. The reactor coolant loops shall be be OPERATING. verified to be OPERATING and
- b. Startup of one inactive circulating reactor coolant at i unisolated loop will not be least once per shif t.
performed at levels greater than l 25%.*
i l APPLICABILITY: Modes 1 and 2**
i ACTION: With less than the above required reactor coolant loops OPERATING, be in at least HOT SHUTDOWN within one hour.
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- 2. All Reactor Coolant Loops shall be 2. The reactor coolant loops shall be OPERATING. verified to be OPERATING and circulating reactor coolant at least APPLICABILITY: Mode 3*** once per shift.
ACTION: With less than the above required reactor i coolant loops OPERATING, immediately open the reactor trip breakers or de-energize both rod drive M.G. sets. '
- This power level is contingent upon the results of inactive loop startup tests performed under carefully l
controlled conditions. If the results of these tests indicate that startup can only be safely performed from a lower power level, the value of 25% will be replaced with this new power level. Startup of an inactive
! loop will not be performed on a robtine basis until the controlled startup tests are evaluated.
- See Special Test Exception 3.23.1
"** With 1) reactor trip breakers closed, and 2) a rod drive M.G. set energized.
8610280061 861016
! 0824t/0874t hDR ADOCK05000g3 73 TSC 84-10
LIMITING CONDITION FOR OPERATION SURVEILLANCE REQUIREMENT l 3.3.1.A. 3. At least two of the Reactor Coolant Loops 4.3.1.A. 3. a. The required reactor coolant pumps, if
, shall be OPERABLE with at least one of the not in operation, shall be determined il OPERABLE loops OPERATING.# OPERABLE once per week by verifying d
correct breaker alignments and indicated power availability.
l APPLICABILITY: Mode 3*
ACTION: b. At least one cooling loop shall be
- a. With less than the above verified to be OPERATING and
{
required reactor coolant loops circulating reactor coolant at least
- OPERABLE, restore the required once per shif t.
. loops to OPERATING status within ,
! 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in HOT SHUTDOWN c. Verify at least once per shif t that 1) l with Tavg < 350*F, within the the reactor trip breakers are open, or i next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. 2) both rod drive M.G. sets are de-energized.
i b. With no reactor coolant loop in operation suspend all operations involving a reduction in boron concentration of the Reactor Coolant System and immediately initiate corrective action to return the required coolant loop to operation.
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- With 1) Reactor trip breakers open, or 2) both rod drive M.G. sets de-energized.
- All reactor coolant pumps may be de-energized for up to one hour provided: 1) no operations are permitted that wcald cause dilution of the reactor coolant system boron concentration, and 2) core outlet temperature is maintained at least 10*F below saturation temperature.
0824t/0874t 73a TSC 84-10
LIMITING CONDITION FOR OPERATION SURVEILLANCE REQUIREMENT l 3.3.1. A. 4. At least two of the six heat removal loops 4.3.1.A. 4. a. The required reactor coolant pump (s), l (four reactor coolant loops
- and two if not OPERATING, shall be determined residual heat removal loops) shall be to be OPERABLE once per week by OPERABLE. At least one of these loops verifying correct breaker alignments l shall be OPERATING.# and indicated power availability.
- APPLICABILITY
- Mode 4 b. The required steam generator (s) shall be determined OPERABLE by verifying ACTION: secondary side wide range water level
- a. With less than the above to be greater than or equal to 17% at required loops OPERABLE, least once per shif t.
immediately initiate corrective action to return two loops to c. At least one heat removal loop shall be OPERABLE status as soon as verified to be in operation and possible; be in COLD SHUTDOWN circulating reactor coolant at least j within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Once per shift.
- b. With no heat removal loop in d. With no heat removal loop in operation l 1 operation: the core exit temperature shall be j -
- 1) Suspend all operations monitored utilizing data from 2 or more
- involving a reduction in core exit thermocouples. The frequency
- boron concentration of the of temperature readings shall be i Reactor Coolant System and; adequate to insure that the temperature will not increase above the 10*F
- 2) Immediately initiate subcooling limit between temperature i corrective action to return readings.
! the required heat removal loop to operation.
[
- See section 3.3.2.G for low temperature overpressure protection considerations before starting a reactor coolant pump.
l # All reactor coolant pumps and residual heat removal loops may be de-energized for up to one hour provided:
- 1) no operations are permitted that would cause dilution of the reactor coolant system boron concentration, and 2) core outlet temperature is maintained at least 10*F below saturation temperature.
]
0824t/0874t 73b TSC 84-10
LIMITING CONDITION FOR OPERATION SURVEILLANCE REQUIREMENT
'l 3.3.1. A. 5.
Two residual heat removal (RHR) loops 4.3.1.A. 5. a. The residual heat removal loop l shall be OPERABLE.* At least one of these shall be determined to be in
! loops shall be OPERATING. However, the operation and circulat'in'g' reactor
! requirement for an OPERATING RHR loop may coolant at least once per shift.
- be deleted provided a) no evolutions that With no RHR loop in op'drition the would cause a reduction of the reactor b.
coolant system boron concentration are in core exit temperature shall be 3
progress or initiated, and b) the core monitored utilizing data from 2 or outlet temperature as measured by the core more core exit thermocouples. The exit thermocouples is kept at least 10*F frequency of temperature readings q below saturation temperature. shall be adequate to insure that the temperature will not increase
) APPLICABILITY: Mode 5 above the 10*F subcooling limit between temperature readings.
' ACTION:
- a. With only one of the above required loops OPERABLE, immediately initiate corrective action to return the inoperable loop to OPERABLE status as soon as possible.
- b. With no RHR loop OPERABLE:
- 1) suspend all operations involving a reduction in boron concentration of the Reactor
- Coolant System and; .
1 2) immediately initiate
! corrective action to return both i RHR loops to OPERABLE, status, or operation if necessary, in order to maintain core outlet temperature at least 10*F below i saturation temperature.
- c. The provisions of Specification j 3.0.3 are not applicable.
!
- One RC loop capable of natural circulation may be substituted for one OPERABLE RHR loop. A RHR loop may j still be considered OPERABLE with only one of either the normal or emergency power sources OPERABLE.
j 0824t/0874t l 73c TSC B4-10
Basas: 3.3.1 and 4.3.1 .
Operational Components
, Th2 plant is designed to operate with all reactor coolant loops in operation and maintain DNBR equal to or greater than the applicable design limit DNBR (1) during all normal operations and anticipated transients. In MODES 1 and 2 with one
, reacter coolant loop not in operation this specification requires that the plant be in at least HOT SHUTDOWN within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.
Tha maximum 25% power level stated for startup of an inactive reactor coolant loop is contingent upon the results of insctive loop startup tests performed under carefully controlled conditions. If the results of these tests indicate that
, startup can only be safely performed from a lower power level, the value of 25% will be replaced with this new power level. Startup of an inactive loop will not be performed on a routine basis until the controlled startup ta:ts are cvaluated.
In MODE 3, a single reactor coolant loop provides sufficient heat removal capability to remove decay heat f.as the i reacter. However, for Hot Zero Power (HZP) conditions operation is bounded by the following three accidents: 1) steamline break, 2) rod ejection, and 3) bank withdrawal f rom subcritical. These accidents all assume four reactor coolant pumps in cp ration. For the steamline break and the rod ejection accidents, the operation of only a single reactor coolant pump
. will n3t impact the conclusions presented in the FSAR. But with less than four reactor coolant pumps in operation, the t
4 margin of safety may be reduced during a bank withdrawal accident. (
Reference:
Westinghouse letter, W. J. Johnson to J. S.
Abel, dated June 6, 1984 (CWE-84-579)). To ensure that the plant is maintained in an analyzed condition it is necessary to
- cith2r maintain all four reactor coolant loops in operation, or prevent the bank withdrawal accident from occurring by
! ensuring the reactor trip breakers are open or the rod drive motor generator (M.G.) sets are de-energized. Single failure consid2 rations require two reactor coolant loops OPERABLE for the purpose of decay heat removal.
! In MODES 4 and 5, a single reactor coolant loop or RHR loop provides sufficient heat removal capability for removing decay h at; but single failure considerations require that at least two loops be OPERABLE. Thus, if the reactor coolant loops are not OPERABLE, this specification requires two RHR loops to be OPERABLE.
7h2 operation of one Reactor Coolant Pump or one RHR pump provides adequate flow to ensure mixing, prevent stratification
- and produce gradual reactivity changes during boron concentration reduction in the Reactor Coolant System. The reactivity
' changs rate associated with boron reduction will, therefore, be within the ' capability of operator recognition and control.
J l During MODE 5, one reactor coolant loop capable of providing natural circulation may also be substituted for an OPERABLE j RHR lecp. At least one RHR loop must be OPERABLE at all times.
When the Unit has been in MODE 5 for an extended period of time, decay heat addition to the reactor coolant is very slow.
During these periods, the requirement for an operating RHR pump may be relaxed to require two RHR pumps to be OPERABLE.
' Operation with no forced coolant flow is considered to be an unusual and undesirable mode of plant operation. If it b:comes necessary to interrupt forced coolant flow for testing, maintenance, or any other reason, the Technical a
- 0824t/0874t 77b TSC 84-10 I
Specification will assure that the onset of potential boiling can be detected and core cooling initiated before boiling occurs. The rate of reactor coolant system heatup with no forced flow is estimated to be less than 6*F per minute af ter 1 day, 5'F per minute af ter 4 days, and 3*F per minute af ter 1 month of plant shutdown. This estimate is based on no natural circulation flow through the coolant loops and reactor vessel water level at the centerline of the nozzles.
Th2 reactor vessel head vent system is provided to exhaust noncondensible gases from the reactor vessel that could inhibit nattral circulation core cooling.
0824t/0874t 77c TSC 84-10 l
ATTACMENT 2 EVALUATION OF SIGNIFICANT HAZARDS CONSIDERATION PROPOSED CHANGES TO ZION TECHNICAL SPECIFICATION APPENDIX A - SECTIONS 3.3.1 AND 4.3.1 REACTOR COOLANT SYSTEM DESCRIPTION OF AMENDMENT REOUEST An amendment to the Zion Facility Operating License is proposed to require either the opening of the reactor trip breakers or the de-energization of the rod drive M-G sets during reactor operation in Mode 3 with less than four reactor coolant pumps in operation.
BACKGROUND 10 CPR 50.92 states that a proposed amendment will involve a no significant hazards consideration if the proposed amendment does not:
(1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety.
In addition, the Commission has provided guidance in the practical applica-tion of these criteria by publishing eight examples in 48 FR 14870.
The discussion below addresses each of these three criteria and demonstrates that the proposed amendment involves a no significant hazards consideration.
BASIS FOR NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION Does the proposed amendment (1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety?
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DISCUSSION - ITEM 1 This proposed amendment will result in the removal of an inconsistency between the current Zion Technical Specifications and the existing Zion safety analysis. The current Zion Technical Specifications allows two reactor coolant pumps (RCP) to be operating during M de 3. This results in a potentially nonconservative inconsistency with the existing Zion safety analysis in the event of an uncontrolled rod withdrawal from a wLc.ritical condition. The Zion FSAR assumes that four RCPs are in operation during this postulated event.
The addition of a requirement to either open the reactor trip breakers or de-energize the rod drive M-G sets during reactor operation in >
Mode 3 with less than four reactor coolant pumps in operation will ensure that the assumptions of the Zion safety analysis remain valid. This provides continued assurance that the previously calculated results contained in the Zion FSAR remained bounding for the operation of Zion Station.
Thus, this proposed amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated. Rather, it ensures that the postulated consequences of an uncontrolled rod withdrawal from a subcritical condition remain as stated in the Zion FSAR.
DISCUSSION - ITEM 2 The addition of an additional restriction during operation in Mode 3 has no effect on the reliability or integrity of any of Zion's systems. Rather, this change is intended to prevent the postulated spurious operation of Zion's rod control system while in Mode 3.
The new requirement to require either the opening of the reactor trip breakers or the de-energization of the rod drive M-G sets has no effect on the any of Zion's systems nor on the generation of any external event such as a tornado or flood. This new requirement will not create the possibility of any additional system malfunctions or externally generated events.
Therefore, this proposed amendment cannot create the possibility of a new or different kind of accident from any accident previously evaluated.
DISCUSSION - ITEM 3 The proposed amendment will result in more conservative operation than is currently allowed by the Zion Technical Specifications.
Specifically, the proposed change will require either the opening of the reactor trip breakers or the de-energization of the rod drive M-G sets during reactor operations in Mode 3 with less than four reactor coolant pumps in operation. This is a new requirement that results in more conservative operation.
T The overall intent of this proposed change is to remove the remote possibility of experiencing spurious operation of the rod control system while in Mode 3 with less than four reactor coolant pumps in operation.
This will ensure that Zion Station is always operated within the assumptions contained in the pre-existing Zion safety analysis.
Therefore, this change does not involve a reduction in the margin of safety.
The proposed amendment will result in an additional restriction in the Zion Technical Specifications. Therefore, example (ii) is applicable in this instance. Example (ii):
(ii) A change that constitutes an additional limitation, restriction, or control not presently included in the technical specification: for example, a more stringent surveillance requirement.
Therefore, since the application for amendment satisfies the criteria specified in 10 CFR 50.92 and is similar to examples for which no significant hazards consideration exists, commonwealth Edison Company has made a determination that the application involves no significant hazards consideration.
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