ML19332C424

Application for Amend to License NPF-62,consisting of Change Packages LS-87-056,PS-88-021,LS-88-043 & LS-89-017.Changes Include Addition of Note to Tech Spec 4.6.1.1.b Re Verifying Valve Positions During Cold Shutdown

ML19332C424
Person / Time
Site:	Clinton
Issue date:	11/20/1989
From:	Hall D ILLINOIS POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML19332C425	List: ML19332C424 ML19332C429
References
DPH-0695-89, DPH-695-89, GL-89-14, U-601548, NUDOCS 8911280109
Download: ML19332C424 (13)

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x.- .8 8E.100a J i/LLIN0/8 POWER COMPANY; M&

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November 20, 1989

@ 4 g 10CFR50.90. ,

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T.g iDocket No.;50-461- j

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.i Subjects Clinton' Power Station n>

L'- Proposed Amendment of Facility i W,L-g Oneratina License No. NPF-62 i 1' 1

Dear' Sir:

- N-W L1 Pursuant.to-.10CFR50.90, Illinois Power Company - (IP) h ,

.hereby= applies lfor.aniamendment of' Facility' Operating License t No. ~NPF-62:: fori Clinton- Power: Station. This request:for . -;

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-amendment consists-of.four separatecchanges.to tho' Technical ~ y l- V . Specifications. . A ' summary of the changas'is provided in "Attachmentf2y A' complete, detailed description and .;

7 justification,.. including a~ Basis For No Significant Hazards

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consideration,3is provided for each of the proposed' changes-.in l: ,

N ---Attachment'3.. In, addition, an affidavit supporting the facts

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m ' set.forthIin this letter and its attachments is providedlin 4 Attachment l'.: ,

l at IP has reviewed the proposed Operating License changes L% '

.against the criteria'of-10CFR51.22 for environmental ljf ' considerations. The-proposed changes do not involve a- 1 j; significant hazards consideration, or significantly increase  ;

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the.amountsLor change the types of etfluents.that may be  ;

, releasadioffsite, nor do they significantly increase.

, .individualior cumulative occupational radiation exposures. i p Based: on the foregoing, IP concludes' that the proposed F 1

'. operating License changes meet the criteria given in

,, ' 10CFR51.22 (c) (9) - for: a' categorical exclusion from the  ;

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requirement for-an Environmental Impact Statement.

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- Sincerely yours, g:o C ,

f 'i D. P. Hall g0i Senior Vice President b, i\

8911280109 891120 05000461 io,*'LPDR +o ADOCK PDC 3-> y2"[ p $ ._. ._ .

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l> b- - U- 601548 l-L47-89 ( 11- 20)-LP ,

8E.100a TBE/krm  ;

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cc: NRC Clinton Licensing Project' Manager NRC Resident Office  !

' Regional Administrator, Region III, USNRC-Illinois Department of Nuclear Safety 4

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Att2chmsnt 1-to U-601548

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STATE OF ILLINOIS COUNTY OF DEWITT Donald P ' Hall, being first duly sworn, deposes and says:

That he is Senior Vice-President of Illinois Power Company; 1 that the proposed License Amendment has been prepared under his supervision and direction; that he knows the contents thereof; and that to the best of his knowledge and belief said request and the facts contained therein are true and correct.

DATED: This(([bday of November 1989 Signed: ,

Donald P. Hall -l Subscribed and sworn to before me this 2/) day of l

November 1989.

L kllb4AL 0 nsu Notary Public l

My Commission Expires:

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'0FFICIAL SEAL

• l Debert L Bean l Metary Pitiis. State of taineis I by Commiteien E$res 10/V90 l

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Attachcint 2 i to U-601548 ,

Page 1 of 1 ,

i Sn==ary of Technical Soecification Channes  !

This-is a summary listing and description of all 4 change packages.

Please-refer to_each change package for a complete description and justification _ including the Basis For No Significant Hazards Consideration.

Packare No. Descriotion LS87-056 This package.contains changes proposed for  ;

the ACTION statement under the LCO for the Self Test System (STS) that would permit a ,

longer out-of-service time during shutdown / refueling conditions and permit the allowed out-of-service time (for automatic l operation) to be exceeded 'f manual control .,

of the STS can be used to continue STS testing of the applicable logic.

PS 88 021 The "**" note associated with Specification 4.6.1.1.b allows valves located in the drywell, containment or steam tunnel to have their position verified (closed) during each COLD SHUTDOWN instead of once per 31 days as required for other valves. This package-incorporates 2 particular, additional valves which are not located in the drywell, containment or steam tunnel into the "**"

note.

LS88-043 This package is being submitted to revise the ,

value for the secondary containment minimum free volume specified in Technical Specification 5.2.3.

LS-89-017 This package is being submitted in accordance with Generic Letter 89-14 to revise Technical Specification 4.0.2 to remove the 3.25 limit for surveillance interval extensions.

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The following packages (in order) comprise Attachment 3. ='

l ..t, LS87-056 (12 pages)

PS88-021'(4 pages).

LS-88 043 (2 pages) 1 LS-89 017 (7 pages)  ;

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Background

As described in Section 7.2 of the Safety Evaluation Report (SER) for ,

Clinton (NUREG-0853), the design for Clinton Power Station uniquely includes a Self Test System (STS) that injects short-duration test pulses t in the solid state Nuclear System Protection System (NSPS) logic and verifies proper response of the logic to various input combinations. The STS is an overlay system and maintains surveillance over all NSPS circuitry which includes the logic associated with the reactor protection system, ,

emergency core cooling systems, the containment and reactor vessel i

-isolation control system, and other safety systems. The primary purpose of the STS is to improve the availability of the NSPS by optimizing the time to detect and determine the location of a failure in the system. Failure ,

location can be traced to the module or printed circuit card level via the associated plant computer (diagnostic) terminal.

A more detailed description of the STS and an explanation of the testing +

process performed by the STS appears in Supplement 2 of the Clinton SER '

(SSER 2). In particular, this supplement describes the test-pulse test sequence automatically performed by the STS and how plant personnel can i interface with the STS through the plant computer via an associated terminal. It also describes how the STS is used to perform or supplement surveillance testing required by the Technical Specifications for the affected applicable NSPS-relat.ed systems.

The following observations and conclusions by the NRC staff are excerpted from Section 7.2.3.3 of SSER 2:

The NRC staff notes that the STS used to automatically test the Clinton solid state NSPS circuitry offers several advantages over conventional surveillance testing methods. For example, the circuitry is continually being checked, as opposed to checking once a month or less. This will reduce the time to detection of failed components and lead to increased plant availability as well as increased protection system reliability. Another significant 1 advantage of the STS is that the test circuitry is hard wired in place...

(In addition) the NRC staff concludes that use of the STS installed at Clinton to perform certain surveillance testing required by the plant Technical Specifications is acceptable... A combination of STS I and conventional tests will be necessary to accomplish complete end- l to-end overlap testing of the NSPS circuitry to verify its ,

operability... [ Appropriate) Technical Specifications will be l developed by the staff and the applicant during the Technical l Specification review. It should be noted that there will be l Technical Specification limiting conditions for operation and I surveillance requirements on the STS itself as well as the NSPS circuits.

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-A Limiting Condition for Operation (and Surveillance Requirement) was '

subsequently incorporated into the CPS Technical Specifications as '

Specification-3/4.3.10 " Nuclear System Protection System - Self Test System". The. Limiting condition for Operation (LCO) section of the Specification requires the STS to be OPERABLE and operating in the fully automatic mode-(for all four divisions) during OPERATIONAL CONDITIONS (or modes) 1, 2, 3, 4 and 5.- ACTION requirements for restoring the STS to automatic operation are also specified under the LCO.

The STS normally operates such that it automatically performs testing of all four NSPS divisions in a continuous, cyclic manner. Upon detection of a failure, the STS. ceases operating in this fully automatic mode. If the failure occurs, for example, in one particular division, the STS test sequence can be restarted such that-the STS is restored to automatic operation for the remaining three divisions. Once the failure is corrected, the STS can then be restored to fully automatic operation for all four divisions. These essentially are the actions, along with imposed ,

time-limits, that are required by the ACTION statement currently specified under the LCO for-the STS. Specifically, the ACTION requires that-with the STS not operating in the fully automatic mode, corrective action must be initiated within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to restore the STS to automatic operation for the maximum number of_ divisions available within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (per part "a" of the ACTION statement). It must also be restored to fully automatic operation (for all four divisions) within 30 days or the plant must be shut down (per part "b" of the ACTION statement).

Descriotion of Pronosed Change Based on Clinton's operatin5 experience with the STS and its associated Technical Specification, Illinois Power Company (IP) proposes to revise the Limiting Condition for Operation (LCO) section of the CPS Technical Specification for the STS. (Changes are also proposed for the associated

' BASES.) IP-requests this revision to resolve two concerns: (1) the current ACTION statement under the LCO (Technical Specification 3.3,10) doe's not adequately or appropriately prescribe what action should be taken when the LCO cannot be met during shutdown / refueling conditions, and (2) the ACTION c does not allow for the fact that, in lieu of being able to operate in the L automatic mode, the STS can be manually operated to perform testing l comparable in degree to what it does when operating automatically.

Following is a detailed discussion of these two concerns and their resolutions in terms of proposed changes to the CPS Technical Specifications.

l The first concern is what ACTION should be taken when the STS is not operating in the fully automatic mode during shutdown or refueling conditions (Modes 4 or 5). Specifically, what action should be taken if the STS cannot be restored to operation in the fully automatic mode within the required time limit, and what is an appropriate time limit for shutdown / refueling conditions? The ACTION currently specified states that with the STS "not restored to fully automatic operation within 30 days, be in at least HOT SHUTDOWN within the next 12 hcurs and COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />." The ACTION appears to only address the situation in which the STS is not operating in the fully automatic mode during power operation because the ACTION requires the plant to be shut down. It is not

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Page 3 of 12 clear, for example, what action should be taken if the STS cannot be .,

restored to fully automatic operation within the required time limit during refueling conditions. Some ACTION should be required since the LCO is applicable during refueling and shutdown conditions.

In addition, although the LCO for the STS requires the STS to be OPERABLE ,

and operating in the fully automatic mode during OPERATIONAL CONDITIONS 1 ,

2, 3, 4' and 5, the time allowed by the current ACTION statement to restore the STS to fully automatic operation during cold shutdown / refueling conditions is no different than that allowed during OPERATIONAL CONDITIONS 1, 2, 3. If consideration is given to the number of demands placed on the NSPS nssociated systems (such as the reacter protection system, emergency core cooling system and the nuclear steam supply shutoff system) during Modes 4 and 5 relative to Modes 1, 2, 3, it appears that imposing the same AC' LION time. limit for all of these modes is overly conservative. That is, n longer ACTION time limit for restoring the STS to fully automatic operation should be permitted for Modes 4 and 5 relative to the time limit ,

established for Modes-1, 2, 3.

With respect to the second concern, the only provision allowed by the current ACTION is to permit a period of time for restoring the STS to fully automatic operation before a plant shutdown must be initiated. Manual operation of the STS is not recognized. Although to date, Clinton personnel have always been able to' restore fully automatic operation within the required time, operating experience has shown that automatic operation of the STS can be halted under certain conditions that are not easily or quickly corrected or cleared. A provision for manually controlling the STS should be included in the ACTION to reduce the potential for a plant shutdown that would seem to be unnecessary in view of the fact that CPS personnel can perform manual STS testing that is equivalent in scope to '

automatic STS testing.

Automatic operation of the STS is halted upon detection of a failure in any part of the logic being tested. This includes portions of the logic which would not impact safe operation of the facility, logic within the STS itself, or portions of the-logic and hardware not required to be operabIv v under certain conditions. Such nuisance failures can consequently prevent 7 i

the STS from performing automatic testing. Although most logic cturd failures can be corrected quickly (by simply replacing the card), nuisance failures caused by lifted leads, de-energized circuits or busses and equipment failurea, for example, cannot always be corrected or resolved as quickly. Even routine testing and repairs of equipment and components during shutdown / refueling conditions can result in a detected nuisance l failure and consequently prevent the STS from operating in the automatic l mode [at least for the affected division (s)). In some cases, it has been necessary to temporarily clear " tag-outs" in order to allow the STS to operate in the fully automatic mode and thus meet the requirements of the ACTION statement currently specified under Specification 3.3.10.

This problem may be alleviated and adequate NSPS availability can be '

maintained by including a provision for manually controlling the STS in the ACTION statement under the Limiting Condition for Operation for the STS.

In the " manual mode", the computer terminal associated with the STS can be utilized to manually direct the STS to perform tests on individual cards

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'E U 601543 l LS-87 036 Page 4 of 12 l and'the interconnecting wiring when the STS would otherwise perform no testing at all as it is " locked out" of the automatic mode. By manually stepping.the STS through such testing..all essential cards and ,

interconnecting wiring which would normally be tested during automatic l operation of the STS can continue to be tested by the STS, but the- failed

• cards or nuisance failures which caused the STS to cease operating in the automatic mode must be acknowledged, evaluated, repaired, or bypassed as appropriate while the STS is manually operated. Appropriate action would be taken, including any required by the Technical Specifications, for the affected system or instrumentation associated with the failed card or condition if, for example, that card could not be manually tested or the condition prevented a certain card (s) from being tested.

To permit performing manual STS testing in the manner described above, IP proposes _to revise the ACTION statement under Specification 3.3.10. The proposed revision would permit the option of performing such testing in lieu of taking further ACTION (such as shutting down the plant) if fully automatic STS operation cannot be restored within the allowed time. As ,

indicated below, the required frequency for performing manual STS testing would be different for Modes 1, 2, 3 than it is for Modes 4, 5.

Another major change proposed for the Technical Specification ACTION statement is to. divide the ACTION into two parts so that the action , ;

required for Modes 1, 2, 3 is separate from the action required for Modes e 4, 5. This is required to incorporate different manual test frequencies as mentioned above, to incorporate different time limits for restoring the STS

.to automatic operation, and to provide a final action for Modes 4 and 5 if the:STS cannot be restored to automatic operation within the applicable time limit and manual testing cannot be performed. (Justification for these changes, including the results of analyses that have been performed, is provided later.in the " Justification for Proposed Changes" section of this package.)

In total, the specific changes proposed for the ACTION statement under Specification 3.3.10 (indicated on pages 9 and 10 of this package) are as follows:

1) Divide the current ACTION statement into two parts (new parts a.1 and a.2) to provide separate ACTIONS for Modes 1, 2, 3 relative to Modes 4, 5. Part "a" of the current ACTION statement would effectively remain unchanged as it is equally applicable for all applicable OPERATIONAL CONDITIONS (i.e., 1, 2, 3, 4 and 5).

2) Incorporate (into new part a.2 of the ACTION statement) a revised time limit of 90 days for restoring the STS to fully automatic operation during Modes 4 and 5 based on additional analyses recently performed by General Electric. The time limit of 30 days for Modes 1, 2, 3 would remain unchanged (in new part a.1 of the ACTION statement).

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3) Incorporate the provisions for manually operating the STS to perform testing of the BSPS circuitry not. being tested automatically when the STS cannot be: restored to fully automatic operation within the specified time' limit. The frequnney for performing the manual testing would be at least once per 7 days for Modes 1, 2, 3 and at .

least once per 90 days for Modes 4 and 5 (also based on the above-

mentioned analyses). _

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4) Incorporate an appropriate final action to be taken in Modes 4 and 5 if the STS is not restored to fully automatic operation (within 90 days)'and manual testing cannot be performed as required. The action required would be to suspend CORE ALTERATIONS and all operations with '!

a potential for draining the reactor vessel, verify all insertable control rods to be fully inserted and lock the reactor modo switch in ,

the shutdown position within one hour.  ;

As noted earlier, applicable changes are also proposed for the associated l BASES. ._A marked up copy of the BASES page, including new-text to be added, is provided as pages 11 and 12 of this package, i Justification for Pronosed Chances

.The proposed revision to the ACTION statement to permit manual operation of the STS for performing testing of the NSPS logic is an operation not -

specifically described in the SER (since it was. assumed that the STS would normally be operating in the automatic mode), although human interface via

• the plant computer terminsi is discussed. IP feels that the provision for utilizing the STS in the manual mode when the STS is not operating in the .

fully automatic mode is an option which may be exercised in lieu of shutting down the plant (from Modes 1, 2, 3) and which, if performed at an appropriate frequency, will still support an acceptable availability of the NSPS-associated systems for all applicable modes (i.e., 1, 2, 3, 4 and 5).

IP recently contracted General Electric to perform an analysis for determining an appropriate manual STS test frequency for all applicable modes. As part of that analysis, the 30 day allowed outage time (A0T),

i.e., the time limit for restoring the STS to fully automatic operation, was reevaluated to determine if it could be extended during +

shutdown / refueling conditions based on reduced NSPS requirements. The analysis performed was an extension of an analysis previously performed that established the 30 day A0T for the STS currently specified in the CPS Technical Specifications (primarily for Modes 1, 2,3).

l l The methodology employed in the original analysis involved the calculation of NSPS associated system unavailabilities as a function of the STS failure l

probability and STS A0T. Results were compared to comparable relay logic

_ results determined in various industry documents.* The analysis examined f the impact of the STS on the availability of the key NSPS systems, i.e.,

the reactor protection system (RPS), the nuclear steam supply shutoff system (NSSSS), and the emergency core cooling system (ECCS). The results L

l *See for example, NEDC-30844, BWR Owners' Group Response to NRC Cencric Letter 83-28, Item 4.5.3, General Electric Company, January 1985.

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of the study indicated that, overall, the availability of the affected systems was relatively insensitive to the availability of the STS, For the  :

RPS a 30 day STS A0T yielded a CPS RPS unavailability that is lower than j relay plant RPS unavailability. (The value obtained for the CPS RPS  !

unavailability was 8.0E 07/ demand.) l l

The new analysis went one step further than the original analysis in that 1 it evaluated the g untial for continued plant operation (during Modes 1 2, 3) given the STS A0T (of 30 days) has been exceeded and manual testing.

by the STS is performed at an appropriate frequency. (Manual STS testing I was determined to perform basically the same function as automatic STS testing except that it is not feasible to perform manual testing at the same frequency as when the STS is operating automatically.) The frequency of manual STS testing of the RPS was determined by calculating the RPS i I

unavailability assuming the automatic STS testing interval is equal to a specified testing interval feasible for manual testing. This approach was used, for example, in the BWR Owners' Group RPS technical specification ,

improvement analysis, NEDC-30851P, "BWR Owners' Group Technical Specifications Improvement Analysis for BWR Reactor Protection System," <

General Electric Company, May 1985.*

The RPS unavailability, given that the essential RPS logic cards are tested once per week, was determined to be 8.7E-07/ demand. The RPS unavailability with the STS totally inoperable for 30 days (i.e., with an AOT of 30 days) was determined to be 3.1E 06/ demand. Combining these results yielded an RPS unavailability of 1.2E-06/ demand. This compared favorably to the relay plant value of 1.3E 06/ demand. It was thus concluded that a 30 day STS A0T and a 1-week manual STS testing interval is acceptable during power operation (Modes 1, 2, and.3). This supports continued plant operation given that the STS A0T is exceeded as long as manual testing of essential NSPS logic cards is conducted at the prescribed frequency.

The second objective of the new analysis was-to evaluate the potential for  ;

extending the 30-day AOT for the STS during shutdown / refueling conditions (and to determine an appropriate manual test frequency for when the I

• NEDC-30851P-A, " Technical Specification Improvement Analyses for BWR Reactor Protection System," was prepared by General Electric on behalf of the BWR Owners' Group as part of the Technical Specification Improvements Program. The report provides the results of an application of reliability analyses to the RPS to justify improvements to the test intervals and l allowed'out-of-service times specified in the BWR Technical Specifications L for the RPS instrumentation. In this study, a reliability model for the l'

BWR-6 solid state (i.e., CPS) RPS was developed for calculation of a base case failure frequency. The study (Section 6.7.1) notes that the STS l

provides an automatic test of the RPS logic at a test interval of less than y one hour [when operating in the automatic mode). However, for the purposes l of the study, the RPS logic test interval was set equal to 1 week.

Although the study focused on the impact of changing channel functional test intervals and allowed out-of-service times for the RPS i instrumentation, it is significant to note that the desired changes to those parameters could be justified (with no significant effect on the overall average RPS failure frequency) with the assumed STS test interval of one week.

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• - LS 87 056 Page 7 of 12 extended A0T is exceeded). This seemed possible based on the fact that there are reduced demands or requirements, from an accident point of view, for the NSPS-associated systems during such conditions. To perform this evaluation, the same methodology and fault tree models used in the earlier analysis were used except that the new analysis focused on RPS unavailability as a function of the STS A0T during cold shutdown / refueling conditions. - The primary difference between the STS A0T analyses during power operation and shutdown / refueling is the criterion for acceptable NSPC unavailability.

During shutdown and refueling, the requirements for protective actions for the RPS, ECCS, and NSSSS are reduced from full power operation. As an example, the primary function of the RPS during these operating conditions is to protect against a rod drop or fuel loading accident. The initiating frequencies of these accidents which require the RPS are substantially less than the initiating frequencies of transients requiring scram during power operation. Therefore, the acceptable RPS unavailability can be expected to be higher during shutdown and refueling than during power operation. Based on a review of the_ accident frequencies during shutdown / refueling, it was.

determined that an RPS unavailability of at least one order of magnitude higher than the unavailability during power operation is acceptable during shutdown and refueling. Also, it was established that analysis of the RPS l alone could be used in determining the STS A0T durin5 shutdown and refueling based on the analysis performed previously for the STS A0T. -

The RPS unavailability was evaluated for several different A0Ts and logic test intervals. The results yielded an RPS unavailability of.

1.25E 05/ demand for an STS A0T of three months and a manual RPS logic test interval of three months if the A0T is exceeded (based on a previously determined STS unavailability of 0,15). The calculated RPS unavailability of-1.25E-05/ demand compared favorably to the comparable relay plant value of 1.3E-05/ demand. Therefore, it was concluded that a three-month STS A0T and a three-month logic test interval if the A0T is exceeded is acceptable for the Clinton plant.

The final change to be addressed is the ACTION required during refueling / shutdown conditions when the STS cannot be restored to fully automatic operation and manual testing cannot be performed. In the unlikely event that this situation exists, the ACTION proposed is to place the plant in a condition which minimizes possible challenges to the NSPS (particularly the RPS). The ACTION proposed (i.e., suspending CORE ALTERATIONS and operations with a potential for draining the reactor L vessel, verifying all insertable control rods to be fully inserted and l' locking the mode switch in the Shutdown position within one hour) is based on a review of the ACTIONS required for systems and instrumentation l- associated with the NSPS that are addressed elsewhere in the Technical L Specifications.

l l Basis For No Sirnificant Hazards Consideration According to 10CFR50.92, a proposed change to the license (Technical Specifications) involves no significant hazards consideration if operation L of the facility in accordance with the proposed change would not (1) l involve a significant increase in the probability or consequences of an RFP1:TBE15

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!t accident previously evaluated -(2) create the possibility of a new or . i different kind of accident from any accirlent previously evaluated, or (3)

-involve a significant reduction in a margin'of safety, s (1) The proposed change does not involve a significant increase in the -

probability or_ consequences of an accident previously evaluated-p s because, based on studies previously performed, the proposed change does not significantly reduce the availability of the essential NSPS logic tested by the STS. Under the proposed change,,the STS would-still be-operated (manually) to perform testing at an appropriate -

frequency.for verifying the integrity of the essential NSPS logic. I Therefore, the proposed change does not adversely impact the l capability of the NSPS-associated systems (the RPS, ECCS, CRVICS, I etc.) to perform their intended function for mitigating the 1 consequences of previously evaluated (design basis) accidents. The a probability of occurrence 9 an accident previously evaluated is not 1 increased since the scope of the proposed change is limited only to ,

its (indirect) effect on systems designed to mitigate the consequences'of such accidents.

1 (2) As the proposed change only affects operation of the STS, it involves 1 no changes to the plant design and does not directly affect operation nj of the associated safety systems (RPS, ECCS, CRVICS, etc.). (The 1 STS, including the interface circulty.between the STS and the NSPS logic-it is designed to test, has been designed such that its operation has no affect on the active circuitry of the NSPS.) For. l these reasons and due to its limited scope, the proposed change does i not create the possibility of a new or different kind of accident from any accident previously evalunted.

.(3)- The proposed change does not involve a reduction in a margin of safety previously analyzed so far as a margin of safety applies to I this change. The proposed change involves no changes to plant design ;I and affects no setpoints or margins assumed in any accident analyses. l l

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