NRC-89-0048, Application for Amend to License NPF-43,incorporating Tech Specs 3/4.1.5 & 3/4.8.4.5 & Associated Bases Re Standby Liquid Control Sys to Address Use of Sodium Pentaborate Enriched w/Boron-10 Isotope Per ATWS Rule (10CFR50.62)

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Application for Amend to License NPF-43,incorporating Tech Specs 3/4.1.5 & 3/4.8.4.5 & Associated Bases Re Standby Liquid Control Sys to Address Use of Sodium Pentaborate Enriched w/Boron-10 Isotope Per ATWS Rule (10CFR50.62)
ML20247E272
Person / Time
Site: Fermi DTE Energy icon.png
Issue date: 05/11/1989
From: Sylvia B
DETROIT EDISON CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20247E276 List:
References
CON-NRC-89-0048, CON-NRC-89-48 NUDOCS 8905260190
Download: ML20247E272 (14)
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Text

_ _ . - . _ - - -

h. . .

e B. Ralph SyMa senior vice President Detroif _,.e,_,

Edison =="-

May 11,1989 NIC-89-0048 U. S. IAlclear Regulatory Commission Attn: Document Control Desk washington,.D. C. 20555

References:

1) Fermi 2 NIC Docket No. 50-341 NRC License No. NPF-43
2) General Electric Co. , Licensing Topic Report " Anticipated Transient Without Scram; Response to NIC A'IWS Rule,10CFR50.62", NEDE-31096-P-A dated February 1987
3) NRC Letter, " Acceptance for Referencing of Licensing Topical Report NIDE-31096-P" dated October 21, 1986
4) Detroit Edison Letter to' NIC, NIC-80-0241,

" Proposed Technical Specification (Licensing Amendment) Change - Standby Liquid Control System (3/4.1.5)", dated November 14, 1988

Subject:

Proposed Technical Specification Change (License Amendment) - Sta v3by Liquid Control System (3/4.1.5 and 3/4.8.4.5)

Pursuant to 10CFR50.90, Detroit Edison Company hereby proposes to amend Operating License NPF-43 for the Fermi 2 plant by incorporating the enclosed changes to Technical Specifications 3/4.1.5 " Standby Liquid Control (SIC) System" and 3/4.8.4.5 "SLC System Associated Isolation Devices", and their associated Bases. The proposed changes address the use of sodium pentaborate enriched with the Boron-10 isotope to meet the requirements of the Anticipated Transient Without  ;

Scram (A'IWS) Rule,10CFR50.62, paragraph (c) (4) . This rule requires  !

that all BWRs have a SIC System with a mininum flow capacity  ;

equivalent to 86 gpm of 13 weight percent sodium pentaborate '

solution. The proposed changes also correct some inconsistencies _

between ACTION statements. i L-8905260190 890511 8[ M

{DR ADOCK 0500 1 6SN

e' .: USNBC May 11,.1989-NIC-89-0048 Page 2 As' stated in Fermi 2 UFSAR Section 15.8 " Anticipated Transients Without SCPAM", Detroit Edison committed to be in full conpliance with 10CFR50.62 before startup following the second refueling outage. At a -

meeting held between NRR, Region III and Detroit Edison's Management l On February 8,1989, Detroit Edison committed to implement this requirement for the SIC System on an earlier schedule, _ i.e., prior to restart from the first refueling outage. 'Iherefore, we are requesting the approval of this proposed amendment to be effective upon completion of the modification during the Fermi 2 first refueling outage.

On November 14, 1989, Detroit Edison submitted (Reference .4) a proposed amendment on the SIC System which added AcrION statements and a surveillance requirement to Technical Specification 3/4.1.5 and clarified the ACTION statements associated with Technical specification 3/4.8.4.5. Implementing the A'IWS Rule, as specified in this letter and its enclosure, will eliminate the need for most of Reference 4 changes. Thus, this submittal supercedes Reference 4.

Remaining concerns originally addressed by Reference 4 are included in this submittal.

Detroit Edison has evaluated the proposed Technical Specifications against the criteria of 10CFR50.92 and determined that no significant hazards consideration is involved. The Fermi 2 Onsite Review Organization has approved and the Nuclear Safety Review Group has reviewed the proposed Technical Specification change and concurs with

'the enclosed determinations. In accordance with 10CFR50.91, Detroit Edison has provided a copy of this letter to the State of Michigan.

If you have any questions, please contact Mr. Gordon Nader at (313) 586-4513.

Sincerely, Enclosure cc: A. B. Davis R. C. Knop W. G. Rogers J. F. Stang Supervisor, Advanced Planning and Review Section, Michigan Public Service Cm1 mission y

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May 11, 1989 E NBC-89-0048 l' Page.3

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I, B. 3ALPH SYLVIA, do hereby ' affirm that the foregoing statenents are based on facts and circumstances which are true and accurate to the best of my knowledge and belief.

l Yes0

v. mon -

Senior Vic resident On this /! day of & ,1989, before me 4

personally appeared B. Ralph Sylviaf g61ng first duly sworn and says that he executed tne foregoing as his free act and deed.

Y h. V227dC>

Notary Public poeALtd A ARMEliA Notoiy Nbile. Monroo County, MI WCommissionEmpiresJan.11.1992 Y0_-_-________=___________.._.____________. _ _ _ _ . _ . _ _ _ _ _ _ _ _ .-_ ____ _ _ ______

Enclorure to

DISCUSSION / SAFETY EVALUATION The current design basis for the Standby Liquid Control (SLC) System is to provide a soluble boron concentration to'the reactor vessel sufficient to bring the reactor to a' cold, Xenon-free shutdown, assuming that withdrawn control rods remain fixed in their rated power pattern. .This system provides a backup capability for the control

' rods. The-system is currently designed to inject enough sodium pentaborate into the reactor. vessel, using one of its two pumps, to bring the reactor from full power to a minimum of 2.67, delta k subcritical condition in approximately 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. However, on July 26, 1984, the code of Federal Regulations was amended to include Section 10CFR50.62, " Requirements for Reduction of Ris' from Anticipated Transients Without Scram (ATWS) Events for Lig.a-Water-Cooled Nuclear Power Plants" (known as the "ATWS Rule"). An ATWS is an expected.

operational transient (such as loss of feedwater, loss of condenser vacuum, or loss of offsite power) which is accompanied by a failure of the reactor trip system (RTS) to shutdown the reactor. The ATWS rule requires specific improvements in the design and operation of commercial nuclear _ power facilities to reduce the. likelihood of failure to shutdown the reactor following anticipated transients, and to mitigate the consequences of an ATWS event.. The ATWS Rule adds l injection rate requirements that exceed the current design basis.

Thus, the purpose of this submittal is to propose Technical Specification requirements that will ensure SLC System compliance with 10CFR50.62 paragraph (c)(4).

Paragraph (c)(4) of 10CFR50.62 states, in part:

"Each BWR must have a SLC System with a minimum flow capacity and boron content equivalent in control capacity to 86 gpm of 13 weight percent sodium pentaborate solution".

This requirement assumes the use of natural Boron which contains 19.8 atom percent of Boron-10. Boron-10, with its large neutron absorption capability, is the active component in sodium pentaborate. The use of sodium pentaborate enriched with the Boron-10 isotope provides a faster negative reactivity insertion rate than the same quantity of standard sodium pentaborate.

Equivalency to the specified ATWS Rule can be satisfied by compensating flow rate, sodium pentaborate concentration and/or Boron-10 enrichment as indicated by the following Equivalency l Equation:

Q

  • M251 # C* E >

C M T3- 19.8 - 1 1

i l

~

-Enclosura to

, , NRC-89-0048 Page 2 1

I J

i Where:

Q = SLC System flow rate, gpm.

M251 = ratio of the mass of water in the reactor and H recirculation system at hot rated conditions of the ,

reference plants and Fermi 2, lbs (Equals 1 for Fermi 2). j C = sodium pentaborate concentration, weight percent. l E = minimum Boron-10 enrichment, atom percent, j This equivalency position is consistent with References 2 and 3 Utilization of Boron-10 enrichment, in order to comply with the specified ATWS Rule, has the advantages of not requiring any hardware modifications (only alarm setpoint adjustments) and of maintaining the current one pump functional requirement. This latter advantage allows one of the two SLC pumps to remain a standby pump which maintains the reliability of the system and increases the functional capability of the system.

Fermi 2 will meet the ATWS Rule by increasing the enrichment of Boron-10 to a-minimum of 65 atom percent. The current design of the SLC System is sufficient to handle the increased enrichment of sodium pentaborate solution, because the enriched boron solution is chemically similar to the current solution. (As specified in Reference 2, this is the main advantage of using the enrichment alternative to comply with the ATWS Rule.) Using an enriched solution will not change any of the key SLC System process parameters (i.e., flow rate, discharge pressure, required NPSH, etc...). HoNever, the SLC System tank level alarm setpoints will be lowered because a lesser volume of sodium pentaborate solution is required. A reduced storage tank volume of enriched sodium pentaborate is acceptable because the same amount of Boron-10 (the active component in sodium pentaborate) will be available for injection.

Detroit Edison's basis for selecting the proposed solution's enrichment and concentration was not solely based on compliance with the ATWS Rule. As shown above, the Equivalency Equation is based on SLC pump capacity, sodium pentaborate concentration and Boron-10 enrichment. The proposed solution was selected to meet the ATWS Rule and to allow for a reduction in its concentration. A concentration reduction lowers the solution's saturation temperature (the temperature at which precipitation begins). The proposed solution's maximum concentration saturation teaporature is 40 F. Per the UFSAR Section 9.4.8.1, the Plant's Heating System is designed to limit the minimum temperature inside the Reactor Building, Auxiliary i Building, Turbine Building, Radwaste Building and other miscellaneous facilities to 65 F. (The Reactor Building houses all the SLC equipment which contain sodium pentaborate). This allows for a 25 F u

Enclosure to

, , NRC-89-0048

Page 3 temperature margin between the Reactor Building's Heating System design basis minimum temperature and the proposed solution's maximum saturation temperature. This margin is considerably greater than the margin (5 - 10 F) between the maintained solution temperature and .

the solution's saturation temperature specified as necessary in l Reference 2. This' temperature margin can be maintained by the '

non-safety related Plant Heating System when Reactor Building heat loads and/or ambient temperatures are not sufficient to maintain the Reactor Building minimum design air temperatures. The Reactor Building is heated by steam from the Plant Heating Sl/ stem's Auxiliary Boilers. There are two Auxiliary Boilers. If one boiler fails the other boiler can be placed in-service if it-is not already in-service. If both boilers are in-service and one fails, steam can be diverted from less significant load (s) (e.g., Radwaste Building) to the Reactor Building. Furthermore, per UFSAR Section 9.4.8.2 permanent fuel oil, feedwater, and steam line connections are provided so that a portable boiler can be connected to the existing system to supply steam in a timely manner in the event both boilers fail. Thus, the proposed solution can be maintained above its saturation temperature independent of the existing heat tracing and tank heaters.

The existing routine (once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) surveillance requirements, hat verify the sodium pentaborate solution temperature, have been revised to address the proposed solution's saturation temperature change. .The existing margin (8U F) between the existing surveillance requirement's temperature limit and the existing solution's maximum concentration saturation temperature has been retained. (This margin is consistent with Reference 2). If the solution's temperature falls below these Technical Specification limits, the SLC System would be declared inoperable and a plant shut down would be initiated within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> per ACTION statement 3 1.5.a.2. The control room low temperature alarm setpoints for the SLC tank heater and piping will also be adjusted to maintain an adequate margin considering uncertainties associated with instrument accuracies, drift and calibration effects. Actuation of these alarms will initiate an immediate investigation of the problem and subsequent corrective action initiation. Therefore, as a backup to the proposed solution's low saturation temperature and the Plant Heating System, routine surveillance requirements and control room alarms effectively prevent precipitation concerns without relying on the existing SLC tank heaters and heat tracing.

Utilizing the proposed solution will allow the SLC heat tracing circuits to be disconnected. However, the_SLC tank heaters will remain because they will be required for mixing during addition of enriched sodium pentaborate and/or water into the SLC tank to ,

establish the required solution operating parameters. l i

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Enclosure to NRC-89-0048 Page 4 Subsequent to the NRC review of this system (as documented in Safety Evaluation Report. Supplement #5 - NUREG 0798), Detroit Edison proposed Technical Specification 3/4.8.4.5 to ensure the reliability and availability of the system by periodic testing of the SLC non-class 1E isolation devices. Technical Specification 3.8.4.5 currently requires OPE 1ABLE SLC circuit breakers'for pumps A and B, tank heaters A and B, and heat tracing circuits A and B. The intent of Specification 3/4.8.4.5 is to maintain the.SLC isolation devices such that their failure will not degrade other SLC components. .However, ACTION statement 3.8.4.5.b must be entered if one or more of the above breakers is inoperable. This ACTION statement. requires, in addition to removing the breaker from service, that'the SLC System be declared inoperable. The ACTION statement that must be entered with the SLC System declared inoperable is 3 1.5.a.2 (or 3 1.5.b.2 depending on the plant's OPERATIONAL CONDITION). Thus, in accordance with action statement 3 1.5.a.2 a plant shutdown must be initiated within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> if any one of the SLC System circuit breakers listed in Technical Specifications 3.8.4.5 becomes inoperable.

There are two problems with ACTION statement 3 8.4.5.b. The first problem is that it is overly conservative to declare the entire SLC System inoperable and shutdown the plant (or insert all insertable control rods), in a relatively short period of time, when a redundant component is inoperable. An example of this problem is the inconsistency that exists between existing ACTION statements 3 1.5.a.1 and 3 8.4.5.b. ACTION 3 1.5.a.1 allows seven days to return one SLC pump to operability, should its motor circuit breaker fail. ACTION 3 8.4.5.b allows only eight hours to return the SLC pump to operability, should the same breaker fail, because this_ ACTION statement declares the entire SLC System inoperable and subsequently invokes ACTION 3 1.5.a.2.

The second problem with ACTION 3.8.4.5.b is that it currently invokes ,

ACTION statement 3 1.5.a.2 (or 3 1.5.b.2 depending on the plant's i OPERATIONAL CONDITION) when a SLC tank heater and/or heat tracing i circuit breaker (s) becomes inoperable. Since no ACTION statements exist for these components other than ACTION statement 3 1.5.a.2 (or 3 1.5.b.2 depending on the plants OPERATIONAL CONDITION), a plant shutdown must be initiated as previously discussed. The heat tracing circuits are not a concern because this proposed amendment deletes [

them. The SLC tank heater's circuit breakers will not be deleted because they will be required (infrequently) when mixing enriched sodium pentaborate and/or water into the SLC tank to establish the i required solution operating parameters. However, operation of the SLC  !

System will not routinely depend on these tank heaters to maintain the proposed solution above its saturation temperature. Therefore, a provision needs to be established to prevent entering ACTION statement i

Enclorure to ,

,, , NRC-89-0048 J Page 5

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3 1.5 for an inoperable SLC tank heater circuit breaker that will only be'used for mixing..

To correct both of the above specified problems ACTION statement 3.8.4.5.b has been modified and a footnote added. ACTION statement 3.8.4.5.b has been modified.to require that only the affected component has to be declared inoperable as a result of an inoperable circuit breaker. This change will allow the applicable component level ACTION statement of Technical Specification 3 1.5 to apply, not the " generic" system level ACTION statement. The footnote will prevent entering the system level ACTION statement of Specification 3 1.5 for an inoperable tank heater circuit breaker (s).- A component level ACTION statement for Specification 3 1.5 is not necessary for an inoperable tank heater, provided the tank heater's circuit breaker is removed from service, because the tank heater will not be required to

-maintain the proposed solution above its saturation temperature. The existing provisions'of ACTION 3 8.4.5.b ensure that an inoperable tank heater circuit breaker is removed from service.

The specific proposed changes (attached) to Technical Specification 3/4.1.5 and 3/4.8.4.5 are:

o The Technical Specification temperature of 70 F specified in surveillance requirements 4.1.5.a.1 & 3 and the situational test (footnote *) of surveillance requirement 4.1.5.b.1 have been changed to 48 F. This number retains the existing Technical Specification margin between the solution's maximum concentration saturation temperature and the Technical Specification limit, and is consistent with Reference 2 recommendation. References to heat tracing have been deleted from surveillance requirements 4.1.5.a.3, 4.1.5.d.3 and the situational test (footnote **) of surveillance requirement 4.1.5.d.3 because as previously stated the heat tracing circuits will be disconnected. The words

" reactor vessel" have been replaced with " explosive valves" in surveillance requirement 4.1.5.d.3 The piping from the storage tank to the explosive valves contains sodium pentaborate and is required to be routinely flushed. The piping down stream of the explosive valves contains demineralized water. The explosive valves are used to. isolate the sodium pentaborate from the reactor vessel during operation. The temperature requirement has replaced the reference to "both heat tracing circuits have been found to be inoperable" in the situational test (footnote **) of surveillance requirement 4.1.5.d.3 Surveillance Requirement 4.1.5.d.4 has been modified. to specify that it is only required for mixing.

o A new surveillance requirement has been proposed that requires verification (per analysis) of the Boron-10 isotope enrichment at i

Enclorure to NRC-89-0048 Page 6 I

least once per 18 months. The possibility of a loss of enrichment control will be administrative 1y precluded by procurement from a vendor that has a 10CFR50 Appendix B Quality Assurance Program, segregated storage and receipt analysis of boron enrichment. 2 Additionally, the current supply of enriched boric acid will be l converted to enriched sodium pentaborate. This effectively reduces the potential of mistaking natural boron for enriched boron, as enriched sodium pentaborate wlll be supplied as a pre-mixed solid.

o Figure 3 1.5-1 " Sodium Pentaborate Volume / Concentration Requirements" has been revised to reflect the acceptable (ATWS Rule) volume / concentration ranges of sodium pentaborate enriched with Boron-10. As specified on the proposed Figure, the minimum Boron-10 enrichment is 65 atom percent. The technical basis for the proposed Figure is consistent with References 2 and 3, and has l been re-verified by Detroit Edison's Engineering Staff.  !

o The SLC Tank overflow volume has been corrected because of a minor calculational error.

o ACTION statement 3.8.4.5.b has been modified so that only the affected inoperable SLC component has to be declared inoperable.

A footnote has been added to this ACTION statement that will preclude entering the generic system level ACTION statements of Specification 3 1.5 for an inoperable tank heater circuit breaker provided the inoperable breaker is removed from service and this condition is verified every 7 days thereafter.

o The SLC heat tracing circuits have been deleted from Table 3 8.4.5-1 because they will be disconnected. The need to maintain the sodium pentaborate solution above the Reactor Building Heating System's minimum design basis temperature is no longer required because of the proposed solution's low saturation temperature.

o The Bases Sections for Technical Specification 3/4.1.5 and i I

3/4.8.4.5 have been revised. Bases Section 3/4.1.5 has been revised to reflect the ATWS Rule and the new volume / concentration ranges and enrichment requirement. The Bases Section for Technical Specification 3/4.8.4.5 has been revised to specify the proposed design basis of the SLC tank heaters.

The proposed changes enhance the overall safety of the system because:

o The changes are being implemented in order to bring Fermi 2 SLC System into compliance with 10CFR50.62 paragraph (c)(4); the methods of achieving this compliance are in accordance with l

Enclosure to

, , NRC-89-0048 ,

Page 7 j General Electric's Topical Report NEDE-31096-P-A (Reference 2) which has been reviewed and accepted by the NRC (Reference 3).

o The functional capability of the system has been increased to provide a faster negative reactivity insertion rate and the original design basis has not been invalidated. 3 k

o Using an enriched Boron-10 solution does not change any of the key q system process parameters because the enriched solution is chemically similar to the currently used standard Boron solution, o The effectiveness of using enriched Baron-10 provides a larger sodium pentaborate solution operating margin. The acceptable bounds for the sodium pentaborate solution reserve volume are increased; this increases the reliability of the system.

o The proposed solutions's maximum concentration saturation temperature has been lowered to 40 F (the proposed nominal design saturation temperature is 37 F). The existing solution's maximum concentration saturation temperature is 62 F. This allows for a 25 F temperature margin between the Reactor Building's Heating System design basis minimum temperature and the proposed solution's maximum concentration saturation temperature.

This margin is considerably greater than the margin (5 F -

10 F) between the maintained solution temperature and the solution's saturation temperature specified as necessary in  ;

Reference 2. Thus, the existing System's heat tracing and tank heaters are not required to maintain the proposed solution above its saturation temperature. Additionally, routine surveillance requirements and control room low temperature alarms ensure that the proposed solution will not fall below its saturation temperature, without entry into the applicable Technical Specification ACTION statement.

o The reliability of the SLC System has been increased because the system is less dependent on active components to perform its required function. The concentration of the proposed solution has been reduced without reducing the solution's effectiveness. The lower concentration reduces the solution's saturation temperature such that reliance on heat tracing circuits and tank heaters is not required to keep the proposed solution from precipitating.

o Potential power cyclic oscillations from uneven mixing of Boron in the co r at high delivery rates is not a concern because of the l steady boron concentration buildup observed in mixing tests, as documented in NEDC-30921. Additionally, References 2 and 3 I

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'., Enclecura to l NRC-89-0048 Page 8 specify that Boron mixing is not a factor in determining equivalency to the ATWS Rule. .

SIGNIFICANT HAZARDS CONSIDERATION In accordance with 10CFR50.92, Detroit Edison has made a determination '

l that the proposed amendment involves no significant hazards considerations. To make this determination, Detroit Edison must establish that operation in accordance with the proposed amendment would 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.

1) The proposed changes do not involve a significant increase in the  ;

probability or consequences of an accident previously evaluated because the functional capability of the system has been increased without changing any of the key process parameters or the system's  !

operation. Using an enriched solution does not change any of the key system process parameters (i.e., flow rates, discharge ,

pressure, required NPSH, etc) because the enriched solution is l chemically and physically similar to the solution currently used.

The changes are being achieved in accordance with General Electric's Topical Report NEDE-31096-P-A (Reference 2). This .

Topical Report has been reviewed and accepted by the NRC 1 (Reference 3). Additionally, the SLC System is not taken credit for.in any of the design bases accidents; it merely provides a  :

backup to other safety-related systems. However, should the SLC System be required to perform its ATWS function, the proposed changes will increase the functional capability of the system such that the reactor will be shut down in approximately half the existing time.

The proposed solution's maximum concentration saturation temperature has been lowered to 40 F compared to the existing j solution's maximum saturation temperature of 62 F (the proposed i nominal design saturation temperature is 37 F). This allows for a 25 F temperature margin between the non-safety Reactor Building Heating System's design basis minimum temperature and the proposed solution's maximum concentration saturation temperature.

This margin is considerably greater than the margin (5 F -

10 F) between the maintained rolution temperature and the

solution's saturation temperature specified as necessary in Reference 2. Thus, the existing system's heat tracing circuits and tank heaters are not required to maintain the proposed solution above its saturation temperature. Routine surveillance l

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Enclorura to-y NRC-89-0048 i Page 9 L requirements and control room low temperature alarms for.the SLC system ensure that the proposed' solution will-not fall below its saturation temperature, without_ entry into the applicable .

Technical Specification ACTION statement.- The SLC heat tracing

. circuits will be disconnected and deleted from the Technical l~ Specifications. . The SLC tank heaters will not be disconnected

.because the heaters will be used for mixing during additiores to-1.

the SLC tank. However, the tank heater will not be required.to maintain the normal solution above its saturation temperature.-

Thus, the reliability of the SLC system has been increased because the system is less dependent on active components to perform its required function.

The SLC temperature surveillance requirements have been changed to reflect the proposed solution's saturation temperature change.

The existing margin (8 F) between the Technical Specification temperature ~ limit and the existing solution's maximum

. concentration saturation temperature has been retained.

The proposed changes to ACTION statement 3 8.4.5.b will reduce unnecessary plant. shutdowns'by allowing the appropriate component level ACTION statement requirements of Technical Specification

.3 1 5:to apply and still ensure that inoperable circuit breakers.

are removed from service. Therefore,:since the proposed changes are enhancing the functional capability and reliability of the system to perform its ATWS function, are in accordance with: .

accepted industry. methods and requirements,'and.are not affecting a' system that is taken credit for.in any of the design bases accidents the probabilities or consequences of an accident previously evaluated are not significantly increased.

2) The proposed changes do not create the possibility of a new or different kind of accident from any accident previously evaluated-because no new failure modes are introduced. The existing design of the SLC System will be sufficient to handle enriched sodium pentaborate solution, because it is chemically and physically-similar to the current solution. Using an enriched solution does not change any of the key system process parameters (i.e., flow rates, discharge pressure, required NPSH, etc)._ Correct enrichment is verified by the addition of a routine surveillance requirement. The current supply of enriched boric acid will be converted to enriched sodium pentaborate. This effectively reduces the potential of mistaking natural boron for enriched boron, as enriched sodium pentaborate will be supplied as a pre-mixed solid. Potential power cyclic oscillations from uneven mixing of Boron in the core at high delivery rates is not a concern because of the steady Boron concentration buildup observed l

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- j Enclo ura to

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NRC-89-0048 Page 10-in mixing tests, as documented in NEDC-30921. Additionally, References 2 and 3 specify that Boron mixing is not'a factor in determining equivalency to the ATWS Rule.

As stated in item 1, the proposed solution's saturation temperature has been reduced such that heat tracing and. tank heater are not required to maintain the proposed solution. The proposed changes to existing surveillance requirements,-the

. Reactor Building Heating System, control room low SLC temperature alarms and the proposed solution's low saturation temperature prevent the introduction of any new failure modes.

3) The proposed changes do not involve a significant reduction in the margin of safety because the proposed changes will increase the functional capability of the system without changing any of the key system process parameters or the system's operation. The changes are being achieved in accordance with generic industry

-criteria that has been previously reviewed.and approved by the NRC (Reference 3). The effectiveness of using enriched Boron provides.

a larger sodium pentaborate solution operating margin. As stated in item 1, the proposed solution's saturation temperature has been reduced such that the heat tracing and tank heaters are not required to maintain the proposed solution. This increases the reliability of the SLC System because the System will be less dependent on active components to perform its required function.

Therefore, since the proposed changes will enhance the functional capability and reliability of the system, are in accordance with accepted industry methods and regulatory requirements, and are within the existing capacities of the system, the proposed changes do not involve a significant reduction in the margin of safety.

Based on the above, Detroit Edison has determined that the proposed amendment does not involve a significant hazards consideration.

ENVIRONMENTAL IMPACT Detroit Edison has reviewed the proposed Technical Specification change against the criteria of 10CFR51.22 for environmental considerations. The proposed change does not involve a significant hazards consideration, nor significantly change the types or significantly increase the amounts of effluents that may be released offsite, nor significantly increase individual or cumulative occupational radiation exposures. Based on the foregoing, Detroit Edison concludes that the proposed Technical Specification meets the criteria given in 10CFR51.22(c)(9) for a categorical exclusion from the requirements for an Environmental Impact Statement.

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'. Enclorura to NRC-89-0048 Page 11 l CollCLUSI0li Based on the evaluation above: 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 proposed amendments'will not be inimical to the common defense and security or to the health and safety of the public.

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