ML18064A620
| ML18064A620 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 02/20/1995 |
| From: | Haas K CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML18064A621 | List: |
| References | |
| NUDOCS 9502230292 | |
| Download: ML18064A620 (4) | |
Text
consumers Power KurtM. Haas Plant Safety and Licensing Director POWERINli MICHlliAN"S PllOliRE55 Palisades Nuclear Plant: 27780 Blue Star Memorial Highway, Covert, Ml 49043 February 20, 1995 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT PRESSURE-TEMPERATURE LIMITS TECHNICAL SPECIFICATIONS CHANGE REQUEST REVISED PAGES AND JUSTIFICATION OF PRIMARY COOLANT PUMP STARTING CRITERION On October 5, 1994, Consumers Power Company submitted a Technical Specifications change request (TSCR) proposing revised Primary Coolant System Pressure-Temperature limits.
Our letter of February 10, 1995 provided additional information on the proposed changes requested by the NRR reviewer, Mr Chu Liang.
During his continuing review of that request, Mr. Liang asked for additional information about the basis for proposed Primary Coolant Pump (PCP) starting criterion 3.l.lh(4).
During the review of our analysis following Mr. Liang's questions, it was discovered that for a PCP start at the combination of:
- 1)
The maximum heatup or cooldown rate allowed by specification 3.1.2 for the existing Primary Coolant System (PCS) temperature,
- 2)
The maximum pressure allowed by Figure 3-1 or 3-2 for that temperature and heatup or cooldown rate,
- 3)
The maximum allowable difference between steam generator temperature and PCS temperature, and
- 4)
The maximum LTOP setting allowed by Figure 3-4, it could not be concluded from analysis that, for all initial temperatures, PCS pressure would not have exceeded the LTOP pressure limit.
Due to the requirements of plant procedures and the conservatism applied in actually setting the LTOP setpoint curve, these conditions would not have existed simultaneously under any expected plant conditions.
A revised, more restrictive, Figure 3-4 is attached to assure that the Technical Specifications only allow a PCP start under conditions which have been shown, analytically, to be acceptable.
Please replace the Figure 3-4 submitted on October 5, 1994 with the attached Figure 3-4.
9502230292 950220 PDR ADOCK 05000255 P
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2 The proposed PCP starting limits are intended to prevent initiation of an unacceptable pressure transient in the PCS due to the initiation of flow through a steam generator which is hotter than the PCS.
If a PCP is started under the limitations of Technical Specification (TS) 3.l.lh(4),
"S/G secondary temperature is < l00°F above T0, and shutdown cooling is isolated from the PCS, and pressurizer level is ~ 57%",
the resulting pressure transient is small, and will be terminated by opening of the Power Operated Relief Valves (PORVs) prior to reaching the PCS pressure limit calculated using ASME.code Case N-514.
The requirement that shutdown cooling is isolated from the PCS assures that this lower pressure system will not be affected by a PCP pump started under the criteria of 3.l.lh(4). If a PCP is started with maximum temperature difference between the associated steam generator and the PCS, and the minimum pressurizer steam space allowed by 3.l.lh(4):
- 1)
The PORVs will be available below 430°F because TS 3.1.8.2 requires two PORVs to be operable with a lift setting less than specified in Figure 3-4 whenever PCS temperature is below 430°F.
TS 3.l.lh(4) is only effective when the PCS is below 430°F, because with the PCS above 430°F, TS 3.1.lh(l) allows PCP starting without reliance on the limitations of TS 3.l.lh(4).
- 2)
The PORV stroke time is short enough that, with the specified steam spa~e in the pressurizer, the PORVs will reach full open before the PCS pressure exceeds 105% of the.PORV opening setpoint.
This upper limit for the pressure peak was analyzed by the following steps:
a)
The maximum PCS temperature and volume increases were calculated to ensure that the pressurizer would not go solid.
b)
The rate of PCS pressure increase was calculated using expected heat transfer coefficients, pump heat input, and system volume.
The ideal gas law, with constant specific heat, was used to estimate the effect that compressing the pressurizer steam space would have on PCS pressure.
c)
The rate of PCS pressure increase was compared to the PORV stroke time.
The pressure rise during PORV stroke time is less than 5%.
- 3)
The pressure rise will be terminated when the PORVs reach full open because the volumetric flow rate of even a single open PORV, relieving steam, greatly exceeds the calculated PCS expansion rate.
- 4)
The pressurizer water level will not reach the PORVs because the PCS volume increase due to the heat added from the steam generator is not sufficient to fill the specified pressurizer steam space.
- 5)
The resultant pressure peak will remain below the transient pressure limit allowed by ASME Code Case N-514.
There is no combination of PCS temperature and allowable heat-up or cool-down rate (LCO 3.1.2) where the maximum permissible LTOP setting of Figure 3-4 is above the associated Appendix G pressure limit of Figures 3-1 or 3-2.
The pressure peak, as discussed above, is limited to 105% of the LTOP setting limit and thereby less than 105% of the Appendix G pressure limit.
The allowable transient pressure limit, using Code Case N-514, is 110% of the Appendix G pressure limit.
Therefore, the starting of a PCP, as allowed by proposed TS 3.l.lh(4) will not cause PCS pressure to exceed allowable limits.
3 The change to Figure 3-4 proposed in this letter does not affect the conclusions of the No Significant Hazards analysis submitted in our October *5, 1994 letter on this subject.
SUMMARY
OF COMMITMENTS This letter contains no new commitments or revisions to former commitments.
Kurt M. Haas Director, Plant Safety & Licensing CC Administrator, Region III, USNRC Resident Inspector, Palisades State of Michigan Attachment
CONSUMERS POWER COMPANY To the best of my knowledge, the contents of this Technical Specifications change request, describing PCP starting criterion and LTOP setting requirements, are truthful and complete.
By ~~~'-'------="'-c:/----"'.. L-~.
~-~--
Robert A. Fenech; Vice President Nuclear Operations Sworn and subscribed to before me this dO ~ day of
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Alora M. Davis, Notary Public Berrien County, Michigan (Acting in Van Buren County, Michigan)
My commission expires August 26, 1999 1995.