ML18054B006
| ML18054B006 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 09/22/1989 |
| From: | Berry K CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML18054B007 | List: |
| References | |
| TAC-72889, NUDOCS 8909280090 | |
| Download: ML18054B006 (6) | |
Text
consumers Power Kenneth W Berry Director PDWERINli NllCHlliAN'S PRDliRESS Nuclear Licensing General Offices: 1945 West Parnall Road, Jackson, Ml 49201 * (517) J88-1636 September 22, 1989 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -
TECHNICAL SPECIFICATION CHANGE REQUEST -
LOW TEMPERATURE OVERPRESSURE PROTECTION (LTOP) -.
VARIABLE SETPOINT - REVISION 1 (TAC NO. 72889)
)
On September 12, 1989, Consumers. Power Company.submitted the original version of this Technical Specification Change Request.
This Revision 1 submittal is being made to supply additional Technical information requested by the staff and to incorporate information received after September 12, 1989 fr.om our consultant.
The revised information changed the PORV opening area vers~s time relationship from that assumed in our September 12, 1989 submittal.
Thus the analyses used to determine the PORV setpoint and the allowable temperature difference between the Steam Generator and the PCS had to be be revised.
Ghanges.from the September 12, 1989 submittal are marked with two hashmarks.
The attached proposed change to the Palisades Technical Specifications is
- necessary to permit use of a variable Power Operated Relief Valve (PORV) setpoint for Low Temperature Overpressure Protection (LTOP) and thus increase the operating margin during plant heatup and cooldown.
An ancillary improvement is increasing the temperature range in which the HPSI system is available to inject cooling water in the event of a loss of primary system integrity.
We plan to install the variable LTOP (VLTOP) control during the imminent fall 1989 maintenance outage and, at the same time, install larger PORVs and Block Valves.
The larger valves increase the flow capacity to enhance once-through-cooling capability and allow HPSI operability at lower temperatures.
The Palisades Fall 1989 Maintenance Outage is planned to begin on October 1, 1989 and end on November 15, 1989.
We plan to restore the Primary Coolant System pressure boundary on or about November 1, 1989.
Therefore we request that approval of this Change Request be issued before November 1, 1989.
If for some unforeseen reason this project must be delayed until the next outage of sufficient duratiom, we request the effective date of this change coincide with the plant startup following the.installation outage
- OC0889-010l~MD01-NL04 A CMS ENERGY COMPANY II II
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II II II II II II II II
Nuclear Regulatory Commission Palisades Plant TSCR - Low Temperature Overpressure Protetion - Revision 1 September 22, 1989 Attachment I contains.proposed Technical Specification pages as they will appear when this request is approved.
Attachment II contains the existing Technical Specification pages marked up to reflect the proposed changes.
2 Attachments III, IV and V contain reference engineering analyses which
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determine the maximum temperat~r~ difference between the steam generators
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and the PCS shown in Section 3.1.lh, the points used to plot the
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pressure/temperature curves (Figures 3-1, 3-2, and 3-3) in Section 3.1.2,
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and the variable LTOP curve in Section 3.1.8.
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Kenneth W Berry
- Director, Nuclear Licensing CC Administrator, Region III, NRC NRC Resident Inspector - Palisades Attachments OC0889-0101-MD01-NL04
CONSUMERS POWER COMPANY Docket 50-255
- Request for Change to the_Technical SP-~cificcitioTIS License DPR-20 For the reasons hereinafter set forth, it is requested that the Technical Specifications contained in the Provisional Operating License DPR-20, Docket 50-255, issued to Consumers Power Company on October 16, 1972, for the Palisades Plant be changed as described in Section I below:
I. Changes A.
Section 3.1.1.h is changed to specify the necessary.precautions to be taken prior to initiating forced circulation when the secondary temperature is higher than the PCS temperature.
B.
The Basis for Section 3.1 has been changed to explain the new requirements of Section 3.1.1.h.
1 C.
The heatup and cooldown limits in Section 3.1.2 have Qeen changed in accordance with the new limits of Figures 3~1 and 3-2.
The same rates for heatup or cooldown with shutdown cooling isolated are specified to simplify operational requirements.
The heating rate with shutdown cooling MOV3015 and MOV3016 OPEN is limited to ensure not exceeding the capacity of the shutdown cooling system relief valves.
The maximum pressurizer heatup rate has been changed to 200°F per hour with shutdown cooling isolated, and 60°F per hour with shutdown cooling MOV3015 and MOV 3016 OPEN.
D.
Figures 3-1, 3-2, and 3-3 have been revised by using refined calculation methods defined in Regulatory Guide 1.99 Revision 2 to allow higher pressures at a given temperature.
E.
The Basis for Section 3.1.2 has been changed to describe the method of calculation used for Figures 3-1, 3-2 and 3-3.
F.
An explanation of the method for calculating the hourly average cooldown rate has been added to the Basis of Section 3.1.2.
G.
Section 3.1.8 has been changed and Figure 3-4 added to allow the use of a variable PORV setpoint for LTOP.
Section 3.1.8 has also be~n changed to reflect protection of the primary coolant system only.
Protection for the shutdown cooling system is afforded by its_
insta+led r~lief valves, and by the limitations of sections 3.1.1.h,
- 3. 1. 2. a & c, and 3~ 3. 2 g.
H.
Section 3.1.8.c has been deleted since a dedicated operator is not required with a variable PORV setpoint.
I.
Sections a and b of the action requirement of Section_3.1.8 have been changed to reflect the operation of the new PORV.-
(The valve, not only the valve pil9t as with the existing valves, can be electrically held OPEN.)
OC0889-0101-MD01-NL04
2 J.
A paragraph which explains the curve in Figure 3-4 has been added to the Basis for Section 3.1.8.
In addition, a method of opening the J'ORV s to provide a. v~nt pa t.li is explain_~d.
K.
Sectiori 3.3.2.g has been completely revised to take advantage of the higher pressure limit~ ~llowed by the new PORV setpoints specified in proposed Section 3.1~8 (see page changes).
L.
The Basis 0£ Section.3.3 has been changed to reflect the changes to Section 3.3.2.g.
The par~graph explaining the need for a dedicated operator has been deleted.
M.
Section 4.1.1.c has been changed to delete the word "pilot" because the new PORVs can be held open electrically.
N.
Section 4.6.1.b has been changed.to coincide with the changes to Section 3.1. 8 (see page changes).
O.
The last paragraph of the Basis for Section 4.6 has been changed.to conform with the conditions required by the proposed Section 3.1.8.
II.
Discussion Installing a variable PORV setpoint control for the Palisades Plant is a major goal in accomplishing the objective of providing a larger operating margin during heatup and cooldown.
Concurrent with this effort, other programs to increase reactor vessel (RV) life, comply with the block valve criteria of NUREG-0737, and decrease the probability of core melt risk outliers have resulted in actions which have resulted in less fluence for certain areas of the RV (using twice burned fuel and metallic rods in the fuel adjacent to longitudinal welds), installation of new PORV block valves, and installation of larger block valves and PORVs.
Recognizing the appropriate fluence accumulation rates for longitudinal and circumferential welds, new low leakage fuel management, and using refined calculational methods have result~d in new pressure/temperature limits.shown in Figures 3-1, 3-2, and 3-3.
Changes to the calculation method involved:
(1) Using Regulatory Guide 1.99 Revision 2 instead of Regulatory Guide 1.99 Draft Revision 2 resulted in calculating shift at 1/4 t and 3/4 t by using the fluence and 3/4 t instead of using the ~RTNDT surface and 3/4 t.
the ~RTNDT temperature attenuation at 1/4 t attenuation at 1/4 t (2)'-- The stress intensity *factor coefficients* were reeva-luated *using the - *
- vessel radii at 1/4 t and 3/4 t.
(3) Temperature and pressure measurement inaccuracy was not included.
Installation of larger PORVs and block valves will reduce the pressure overshoot when postulating inadvertent mass injection by the charging and HPSI systems and the overall result will be (1) to permit HPSI operability down to 260°F, (2) permit initiation of forced PCS
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OC0889-0101-MD01-NL04
circulation under limited conditions when the steam generator tempera-ture is higher than the PCS cold leg temperature, and (3) provide ample once.:--through-coolJng_ :wheJ:i one }'ORV :is. :tnope;i;-i:ible_.
3 The existing~LTOP limits of Section 3.1.8 result from limitations set by the pressure limit of the SQutdown Cooling System and existing instrumen-tation capability. Protection for the Shutdown Cooling (SDC)
System by the new PORVs will not be required, since limits proposed for sections 3.1.1 h, 3.1.2 a and c, and 3.3.2 g. will ensure that challenges to the SDC System pressure boundary are within the capacity of the SDC System Relief valves.
The setpoints of the SDC System relief valves will be adjusted as necessary to provide the necessary overpressure protection without reliance on the new PORVS.
New instrumentation which can be programmed to open the PORVs at a large number of pressure/temperature combinations will be installed to permit the higher PORV setpoints in proposed Section 3.1.8.
Simultaneous installation of the new variable LTOP instrumentation and the larger PORV flowpath will result in. a consolidated training module for operating personnel.
Figure 3-4 in Section 3.1.8 shows the maximum PORV pressure setpoint at various temperatures.
The values on that curve are the 10CFR50 Appendix G values minus analyzed pressure overshoot.
The actual PORV setpoints will be below and to the right of the curve to allow for instrument inaccuracy, setpoint error and measurement error.
Proposed Section 3.3.2.g retains requirements that r~cognize the limitations of the Shut.down Cooling (SDC) System pressure boundary.
When the SDC system is not isolated from the PCS, HPSI operability is.*
not allowed.
However when the SDC system is isolated, full HPSI.
operability is allowed down to 260°F and both HPSI trains are required
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- to be operable above 325°F.
Analysis of No Significant Hazards Consideration Consumers Power Company finds that activities associated with this Change Request involve no significant hazards, and, accordingly, a no significant hazards determination per 10CFR50.92(c) is justified.
The following evaluation supports that finding.
../
Evaluation
- 1.
Involve*a*significant increase-in the probability-or consequences* of *an** accident *previously -evaluated*
There are three previously evaluated conditions which could result in the 10CFR50 Appendix G limits being exceeded~- They are mass injection by the charging and/or HPSI systems or a heat injection by initiating forced circulation when the steam generator temperature is higher than the PCS cold leg tempera-ture.
These conditions have been postulated and analyzed under the conditions proposed by this Change Req~est and under no conditions will the Appendix G limits (Fig. 3~1, 3-2, and 3-3) be exceeded.
Therefore the consequences of an accident previously evaluated are not increased.
The HPSI operability OC0889-0101-MD01-NL04
4 range has been increased to provide additional low temperature ECCS availability. If inadvertent HPSI pump operation would occur, Appendix G limits would not he violated.
Therefore there is no increase in th~ probability or consequences of an accident previously evaluated.
- 2.
Create the-possibility of*a*new or different-kind-of accident from** any accident previously -evaluated.
This proposed change only increases allowable PCS pressure/
temperature relationships in specified temperature rang~s and allows HPSI operability over a larger temperature range.
Therefore it does not create the possibility of a new or different kind of accident.
- 3.
Involve a significant reduction*in a margin of-safety.
The margin of safety is the difference between the stress at which the PCS pressure boundary.would fail and the stress permitted by 10CFR50 Appendix G.
This proposed specification change does not change the stress allowed by 10CFR50 Appendix G and ensures that the stress allowed by 10CFR50 Appendix G will not be exceeded.
Therefore, it does not involve a reduction in the margin of safety.
III. Gonclusion The Palisades Plant Review Committee has reviewed this Technical Specification Change Request and has determined that this change does not involve an unreviewed safety question and therefore involves no significant hazards consideration *. This change has been reviewed by the Nuclear Safety Services Department.
A copy of this Technical Specification Change Request has been sent to the State of Michigan official designated to receive such Amendments to the Operating License.
CONSUMERS POWER COMPANY To the best of my knowledge, inform~tion and belief, the contents of this submittal are truthful and complete.
By~~a.
David P Hoffman, Nuclear Operations Sworn and subscribed to before me this 22th day of September 1989.
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Elaine E Buehrer, Notary Public Jackson County, Michigan My commission expires October 31, 1989 OC0889-0101-MD01-NL04