ML20029B355

Safety Evaluation Supporting Amend 77 to License DPR-22

ML20029B355
Person / Time
Site:	Monticello
Issue date:	02/15/1991
From:	Office of Nuclear Reactor Regulation
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ML20029B354	List: ML20029B353 ML20029B355
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NUDOCS 9103070092
Download: ML20029B355 (7)

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 77 TO FACll1JY OPERATING LICENSE NO. DPR-?2 NORTHERN STATES POWER COMPANY liONTICELLO NUCLEAR GENERATING PLANT DOCKET NO. 50 763

1.0 INTRODUCTION

By letter dated December 13, 1990, the Northern States power Company (the licensee) requested an amendment to the Technical Specifications appended to Facility Operating License No. OPR-22 for the Monticello Nuclear Generating plant.

The proposed amendment would revise pump and valve surveillance testing requirements to be consistent with ASME Section XI code requirements.

The proposed amendment would also eliminate requirements for immediate and more frequent surveillance testing of redundant equipment when equipment is found or made inoperable.

A discussion of each requested change and the NRC staff's evaluation and findings relative to each are addressed in Section 2.0 of this safety Evaluation Report.

2.0 DISCUS $10N AND EVALUATION Addition of General Reauirement for Inservice Testina:

A new subsection

" inservice TestTiig" would be added to Section 4.15 on7 age P29ff. This chan would provide separate paragraphs referencing (a) Inservice inspection (151)ge requirements which apply to pressure vessels and (b) piping and Inservice Testing (151) requirements which apply to pumps and valves.

The new paragraph is similar to the existing 151 requirement but expands and clarifies the IST requirements to incorporate staff-approved fea*Jres of Generic Letter 89-04 and acknowledges that ASME Code requirements are not to be construed as superseding any Technical Specification.

The addition of the proposed new subparagraph is editorial and clarificational, providing a distinction between 151 and IST.

It does not, in itself, modify any operability or testing requirements but serves as a cross-reference applicable to :;/ stems, structures and equipment as invoked elsewhere in the Technical Specifications.

The proposed change is therefore acceptable.

Standby Liquid Control System; Technica' Specifications 3/4.4, Pages 93, 94, 95, and 96 would be revised to (1) renuF sr and retitle paragraphs and make other editorial corrections, and (2) eliminate a requirement that, upon determination that a component is inoperable, additional (intnediate and daily thereafter) testing of redundant components and support equipment.

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2 Item (1) would have no effect on saf ety and is acceptable on that basis.

Item (2) is acceptable on the basis that the normal surveillance test interval and the 7-day allowable out-of-service time (A0T) provide adequate assurance of system reliability and that excessive testing has the potential of reducing degrading equipment and reducing system reliability. Monticello's A0T and test interval are consistent with those prescribed by NUREG-0123 Revision 2

Standard Technical Specifications for General Electric Boiling Water Reactors" (NUREG 0123). The proposed changes are therefore acceptable.

Core Spray System:

Technical Specifications 3/4.5. A, (Pages 101, 102 and 103),

which specif' core spray system operability and test requirements, would be changed to (y) include a cross-reference to the new IST general requiremtt (see 1

above) invoking ASME Section XI requirements, (2) delete statements pertaining to post-maintenance testing, (3) reduce the A0Ts to a value consistent with NUREG 0123 guidance, '4) eliminate a requirement that, upon determination that one of the two subsystems is inoperable. *he redundant core spray subsystem be demonstrated as operable inrnediately and daily thereaf ter and the low pressure coolant injection (LPCI) mode of RHR and the diesel generators be demonstrated operable immediately, and (5) eliminate a requirement that, upon determination t1at both core spray subsystems are inoperable, the LPCI and LPCI support systems be demonstrated operable inrnediately and daily thereaf ter.

Item (1)wouldpermitthemaximumtestintervalforcertainvalvestobe increcsed from monthly to every three months.

This is consistent with ASME code practice and is acceptable on that basis, item (2) eliminates a redundant statemnt, since post-maintenance testing is specified by ASME Section XI and is acceptable on that basis, item (3) reduces the period of time permitted for operating with one core spray subsystem inoperable from 15 days to 7 days, and for operating with both subsystems inoperable from seven days to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

This is consistent with NUREG-0123 guidance and serves to maintain an acceptable level of confidence in system availability in view of the other changes.

Items (4) and (5) would eliminate additional (immediate and daily thereafter) testing currently required only when related equipment is known to be inoperable.

This is based on the position thet the normal surveillance test schedule provides a high level of confidence in system operability, and that excessive testing has the potential to degrade equipment performance. The proposed changes are acceptable based on consistency with ASME Section XI and NUREG-0123 Revision 2 (StandardTechnicalSpecifications).

Low Pressure Coolant injection System:

Technical Specification 3/4.5.B Pages 104 and 105 would be changed in a manner similar to the above core spray changes.

Theproposedchangesinclude(1)reducingtheA0TforeninoperableLpCI injection valve from 30 days to 7 days (2) reducing the A0T for two inoperable LPCI-injection valves from 7 days to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> (3) reducing the A0T for an inoperable drywell spray loop from 30 days to 7 days, (4) elimination of text which is redundant to ASME Section XI pertaining to post-maintenance testing, (5) additun of a cross-reference to the new Section 4.15.B paragraph discussed above, and (6) elimination of additional (inunediate and daily thereaf ter) testing currently required only when related equipment is known to be inoperable.

The A0T applicable when two LPCI pumps are inoperable is currently seven days and would not be changed.

The corresponding A0T prescribed by NUREG-0123 is 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

The longer A0T for Monticello is acceptable based on the provision of

-S-an existing additional limitation that both core spray subsystems be operable in this condition. Otherwise, these changes are similar to those for the core spray system as described above and are acceptable on the same basis.

Containmant Heat Removal System: The containment heat removal function is provided by the residual heat removal (RHR) system using coolant provided by the -

residual heat removal service water (RHRSW) system. Technical Specification 3/4.5.C, Pages 106 and 107, which specifies the Limiting Conditions for Operation and the Surveillance Requirements for the RHRSW system would be changed to (1) provide a cross-reference to the new Section 4.15.B paragraph discussedabove,(2)eliminatetextwhichisredundanttoASMESectionXI pertaining to post-maintenance testing, and (3) eliminate additional (immediate and daily thereaf ter) testing currently required only when related equipment is known to be inoperable. The current A0T applicable when one RHRSW subsystem is inoperable is seven days.

The licensee's application indicates a desire to retain this A0T.

However, it is the staff position that a 7-day A0T is appropriate when one pump in either or both subsystems is inoperable, but when two pumps in the same subsystem are inoperable a 72-hour A0T should be applied.

On December 28, 1990, the NRC staff contacted the licensee's staff (T. Parker and M. Vik) and discussed this issue. The licensee's representatives readily accepted the staff position and verbally amended the application accordingly, items (1) and (2) are editorial changes having no safety significance.

Item (3), together with the reduced A0T applicable for the condition when two RHRSW pumps in the same CSF division are inoperable, will provide greater assurance that core and containment cooling systems will be available if required.

The applicant's proposed RHRSW technical specification revisions (as amended in the telecon) are acceptable based on consistency with NUREG-0123 guidance.

High pressure Core Cooling Capability:

Technical Specification 3/4.5.D. Page 108 would be revised to (1) invoke by cross-reference the new specification 4.15.B discussed above, (2) eliminate a requirement for immediate operability tests of the core spray systems, reactor coolant injection (RCIC) s LPCI subsystems when the high pressure core injection system (HPCI)ystem and is deter-mined to be inoperable, and (3) revise the A0T for the HPCI system from seven days to 14 days.

Item (1)willresultincertainvalveIsl/operabilitytestintervalsbeing changed from monthly to every three months. This is consistent with the requirements of ASME Section XI and is acceptable.

Item (2)issimilarto changes propw 4d for the core spray system described above and is similarly acceptable based on the position that the normal test intervals provide a high le# sf confidence in system operability, and that excessive testing has the r:

al to degrade equipment performance, item (3)allowsthelicenseea

!aer A0T for periods of HPCI inoperability.

The 14-day A0T is acceptable based on consistency with NUREG-0123.

A 14-day A0T represents the staff

-position for HPCI A0Ts applicable to facilities in which the total operable ECCS capability is composed of two trains of two redundant core spray systems, i

two redundant (or loop-select type) LPCI systems, and an automatic depressur-ization system (ADS), with the additional provision of an independent 1

turbine-driven RCIC system.

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Automatic Pressure Relief System: The proposed amendment would revise Section 3/4.5.E relating to the ADS. The A0T for inoperability of one valve would be changed from seven to 14 days. The A0T for the case of more than one inoperable valves would be changed from 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. A requirement to imediately, and weekly thereafter, demonstrate HPCI operability would be deleted.

These changes are consistent with NUREG-0123. The proposed A0Ts and elimination of additional HPCI testing are acceptabits on a similar basis as those changes proposed to related systems as described above.

Reactor Core Isolatics C)oling System: The proposed amendment would revise 3/4.5.F Pages Ill, llla (to be eliminated) and 112), relating to the RCIC sy s tem.

Proposed changes include (1) pump operability and flow rate test req)uirements would be changed to cross-reference the new 4.15.B described above, (2 the A0T for the RCIC s restrictive) 14 days, (3) ystem would be changed from 15 days to (a more a statement that the A0T applies only if the HPCI system is operable would be deleted and (4) a requiren'ent to imediately, and daily thereafter, demonstrate HPCI system operability would also be deleted.

1 Item (1)issimilartochangesproposedforothersystemsdescribedaboveand is acceptable en similar basis.

Item (2) brings the A0T into conformance with currentstaffguidance(NUREG-0123)andisalsoacceptable.

Item (3) deletes superfluous wording and it also acceptable (If both the HPCI and RCIC systems are inoperable, Technical. Specification 3.5.D applies).

Item (4)issimilarto changes proposed for other systems described above and is acceptable on similar basis.

Minimum Requirements for Core and Containment Cooling Capability:

Section 3/4.5.6, Pages 112 and 113 (with IIz to become part of 3/4.5.r) would be revised to (1) delete a condition that the 7-day A0T for an inoperable standby diesel generator applies only if all the low pressure core and containment cooling systems connected to the operable standby diesel generator are operable,

.(2) delete a requirement that no combination of inoperable components in the core and containment cooling systems shall defeat the capability of remaining components to fulfill the core and containment cooling function, and (3) delete a requirement to, upon determining that a standby diesel generator is inoperable, verify operability immediately and daily thereaf ter, of the other standby diesel

. generator and all of its-associated low pressure core and-containment cooling systems. This-statement conflicts with changes proposed to Section 3/4.9.3.a.

Item (1) is' acceptable based on the fact that the requirements contained in t

the text to be_ deleted are already_ encompassed by the individual equipment operability requirements invoked by the definition of " operability" contained-in Section 1.0.L of the Technical. Specifications.

Under the terms of 1.0.L.

if a-standby diesel generator power source is inoperable, no associated system, component or train is considered operable unless the corresponding redundant system, component or-train served by the operable standby diesel power source is operable. Thus, should a standby diesel power source be determined to be inoperable,-while at the same time, there-is an inoperable low pressure core or containment cooling syster, component or train in the division served by the operable standby diesel generator, the entire core or containment cooling function provideo by both divisions of the low pressure core or containment-

5-cooling systems, components or trains is considered inoperable and an equal or more restrictive system, component or train A0T applies (typically 72-hours).

Item (2) is also acceptable, on the buis that the definition of " operability" l

requires that necessary support systems be operable in order for a ' core or containment cooling system to be considered oserable.

Item (3)isacceptable based on the need to maintain consistency wit 1 other Technical Specificctions.

See " Standby Diesel Generators" below.

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_ Standby Gas Treatment System:

Section 3/4,7.B. Pages 166 and 167, of the facility Technical Specifications would be revised to (1) delete the requirement to, upon determining that one train of the SGTS is inoperable, test within two hours, and daily thereafter, the other SGTS train, and (2) delete a statement (4.7.1.b)that,ineventbothtrainsofSGTSareinoperableforsevendays, l

within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> place the facility in a condition for which secondary containment integrity is not required.

Item (1) is acceptable consistent with the previously stated position that normal surveillance test intervals provide L

a.high. level of confidence in systems operability, and that additional testing has the potential to degrade equipment performance.

Item (2)isacceptableon l~

the basis that it eliminates a redundancy. The A0T snacified by 4.7.1.b, to be deleted,-is redundant to statements specified in 3..B.1.

primary Containment Automatic Isolation Valves:

Section 3/4.7.0 would be revised to (1) replace-requirements specifying quarterly full-stroke testing of normally open power operated isolation valves with requirements that these valves be tested pursuant to-the new 4.15.B. and (2) eliminate the specification for post-maintenance testing. These changes are acceptable on-the basis that the Section 3/4.7,0 requirements are redundant to the ASME Section XI code requirements invoked by 4.15.B.

Section 4.15.B specifies appropriate operability and post-maintenance testing requirements.

Standby Diesel Generators:

Section 3/4.9.3.a. Page 201, presently reads:

From and after the date that one of the diesel generators is made or found to tte inoperable for any reason, reactor operation is permissible only during the succeeding seven days unless such diesel generator-is sooner made operable, provided that during such seven days the operable diesel generator shall be demonstrated to be operable immediately and daily thereafter.

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This would be revised to read:

From and after the date'that one of the diesel generators is made or found to be inoperable, reactor operation is permissible only L

during the succeeding-7 days, provided that the operable diesel generator is demonstrated to be operable within 24 hrs.

This test is required to be completed regardless of when the inoperable diesel generator is restored to operability.

The operability of the other diesel generator need not be demonstrated-if the diesel generator inoperability was due to preplanned preventative maintenance or testing.

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These changes would (1) delete the requirement for additional testing of a diesel gentrator solely be:ause the other diesel generator has been deliberately made inoperable for the purpose of planned maintenance or testing, (2) allow, in event a diesel generator is found inoperable, a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period before performing the required testing the other diesel generator.

Surveillance test intervals and A0Ts would not be changed.

1\\em(1)isacceptableonthebasisthatthecurrentsurveillancetestintervals provide a high level of confidence in systems operability, and that the Monticello diesel generators have dem nstrated high reliability.

Item (2) is i

acceptable on the basis of staff pol',ey which has adopted the concept that when a system, structure or component has been intentionally made inoperable for purposes of preplanned maintenance or testing activities, there is no basis to suspect that the redundant component is thereby made less reliable.

It is noted that the 7 day A0T (to be retained) for an inoperable diesel generator is inconsistent HUREG-0123 guidance (72-hours).

However, based on diesel generator reliability information provided by the licensee in response to the staff's previous Generic Letter 84 15 diesel generator reliability review effort, there is insufficient basis for upgrading to the requirements of current policy (72. hour A0T and staggered test intervals) as a condition for acceptance of the i

proposed changes.

The licensee's proposed changes are acceptable.

Section 4.9.B.3.a. Page 201, would also be revised.

This section presently specifies:

Each diesel generator shall be manually started and loaded once every month to demonstrate operational readiness. The test shall continue until both the diesel engine and the generator are at equilibrium conditions of temperature while full load output is maintained.

This would be replaced by:

Each diesel generator shall be manually started, loaded and operated at approximately rated load for at least 60 minutes once every month to demonstrate operational readiness.

Changing the monthly operability test duration from the period of time its tokes for conditions to stabilize to 60 minutes is consistent with NUREG 0123 guidance, provides an adequate time period for conditions to stabilize and will provide a more clearly defined test termination criterion.

This change is therefore acceptable, pire pumps:

The licensee's application requests changes to Section 3.13.B.

Fages 225 and 226.

The proposed changes would eliminate the requirement for daily testing of the remaining two fire suppression pumps, when one of the pumps is determined to be inoperable.

This is acceptable based on the previously stated position that normal surveillanwe test intervals provide a high level of confidence in systems operability, and that additional testing has the potential to degrade equipment performance.

Table of Contents and Bases: The licensee's application includes proposed changes to (a) the Table of Contents and (b) Bases included in the Technical

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Specifications. These reflect the " Limiting Conditions for Operation" and

" Surveillance Requirements" changes proposed above and are acceptable.

Additional Staff Comment:

In conducting its review of the above proposed changes, the staff has used NUREG-0123 extensively as guidance.

This is consistent with Section 16.0 of the Standard Review Plan. Where Monticello has unusual design features that would invalidate the use of NUREG 0123 for evaluating proposed changes to its Technical Specifications the differences have been noted and evaluated accordingly.

3.0 ' ENVIRONMENTAL CONSIDERATION This amendment involves a change in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 or changes an inspection or surveillance requirement.

We have determined that the 1

amendment involves no significant increase in the amounts, and no significant

- change in the types, of any effluents that may_ be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.

The Commission has previously published a proposed finding that this amendment involves no significant hazards consideration and there has been no oublic comment on such finding. Accordingly, this amendment meets the eligibility-criteria for. categorical exclusion set forth in 10 CFR 51.22(c)(9).

Pursuant'to10CFR51.22(b),noenvironmentalim)actstatementorenvironmental 4

assessment need be prepared in connection with tie issuance of this amendment.

4.0 B CLUSION We have concluded basedon'theconsiderationsdiscussedabove,that(1)there

-is reasonable assu,rance that the health and safety of the pub 1_ic will not be endangered by operation in ti. proposed manner;s regu(2) such activities will and be conducted in compliance with the Commission lations, and the issuance of this' amendment will not be inimical to the common defense and security or-to-the health and safety of the public.-

i Principal Contributor:

W. Long

,Date: February 15,-1991 4

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