ML20106G380

Safety Evaluation Supporting Amends 28 & 17 to Licenses NPF-10 & NPF-15,respectively

ML20106G380
Person / Time
Site:	San Onofre
Issue date:	12/19/1984
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20106G356	List: ML20106G353 ML20106G380
References
TAC-54872, TAC-54873, TAC-55999, TAC-56000, TAC-56001, TAC-56215, TAC-56220, NUDOCS 8502140360
Download: ML20106G380 (6)

Text

,

5, i1

>R RfC

/

o UNITED STATES g

8 NUCLEAR REGULATORY COMMISSION n

5 yg WASHINGTON. D. C. 20555

~s...../

i SAFETY EVALUATION AMENDMENT NO. 28 TO NPF-10 AMENDMENT NO.17 TO NPF15 SAN ONOFRE NUCLEAR GENERATING STATION, UNITS'2 & 3 DOCKET N05. 50-361 AND 50-362 INTRODUCTION Southern California Edison Company (SCE), on behalf of itself and the other.

licensees, San Diego Gas and Electric Company, the City of Riverside, California, and The City of Anaheim, California has submitted several applications for license amendments for San Onofre Nuclear Generating Station, Units 2 and 3.

The evaluations of four such requests are presented.below.

I.

By letter dated July 9,1984, SCE requested that the NRC revise San Onofre Unit 2 Technical Specification 3/4.5.2, ECCS Subsystems (PCN-126). Technical Specification 4.5.2.a specifies valve functions and positions required for emer-gency core cooling system operability.

The change is being made to conform the Unit 2 technical specifications to plant modifications required by the San Onofre 2 and 3 Safety Evaluation Report (SER) at the first refueling outage.

The amendment revises Technical Specification 3/4.5.2, ECCS Subsystems - Tavg Greater Than or Equal to 350 F.

Technical Specification 3/4.5.2 requires emer-gency core cooling system (ECCS) operability and specifies surveillance require-ments to verify such operability. Technical Specification 4.5.2.a specifies.

valve positions required for ECCS subsystem operability. The amendment revises Technical Specification 4.5.2.a to be consistent with modifications made to the

~

shutdown cooling system (SDCS) in accordance with NRC Branch Technical Position RSB 5-1.

The SDCS modifications provide remote valve alignment capability from the control room.

Previously, manual valve prealignment was required prior to SDCS operation, for Unit 2.

The Unit 3 Technical specifications already include this change.

II. By letters dated April 24, August 7, and September 12, 1984, SCE proposed to add a new specification, 3/4.7.10, Emergency Chilled Water System, to the San Onofre Unit 2 and-Unit 3 technical specifications (PCN-127).

The new Technical Specification 3/4.7.10 defines the operability requirements for the emergency chilled water system (ECWS), the surveillance requirements to verify operability, and the compensatory measures (Actions) to be taken when the ECWS is inoperable. Previously, operability _of the ECWS was not directly addressed by the technical specifications.

III. By letter dated August 27, 1984, SCE requested that the NRC revise San Onofre Units 2 and 3 Technical Specifications 3/4.1.1.2 and bases, as well as' Technical Specifications 3.1.2.2., 3.1.2.4, 3.1.2.6, 3.1.2.8, and 3/4.1 2 bases-3 (PCN-161). Supplemental information regarding this change was provided by SCE by letter dated October 1, 1984. These technical specifications define the 8502140360 841219 f

PDR ADOCK 05000361

, P PDR

M

+

t i

shutdown margin required when the core average moderator temperature.is less than or-equitl to 200*F (Mode 5).

The amendment increases the' required shutdown

' margin from 2.0% to.3.0% delta K/K, consistent with the safety analysis for _..

cycle 2 operation. 7n addition, a new surveillance requirement is added which tverifies that one ar~ only one charging pump is operable in Mode 5 when the:

. reactor coolant systu is drained below the hot leg centerline, as assumed in the' cycle.2 safety analysis.

IV. 'By letter dated August 21, 1984, SCE requested that the NRC staff revise

~ San Onofre. Unit 2 Technical Specifications-3.1.2.7, 3.1.2.8, and Bases 3/4.1.2 i

~(PCN-163). Technical Specifications 3.1.2.7 and 3.1.2.8 require borated water source operability and'specify volume, temperature and boron concentration r

requirements which assure that sufficient negative reactivity control'is avail-'-

1.

i able during each mode of facility operation. These technical specifications i

define the minimum boric acid storage tank water volume and temperature required E

.as'a' function of the boric acid concentration.- The amendment increases the t-boric acid storage tank, volume / concentration'and the minimum refueling water j

storage-tank water volume specified by Technical Specification 3.1.2.7, consist '

ent with the revised safety analysis associated with plant refueling and cyc h 2 I

operation.

In addition, the amendment decreases the boric acid storage tank' water volume / concentration specified in Technical Specification 3.1.2.8, but-nevertheless maintains the reactivity control required for cycle 2 operation.,

j as'is demonstrated by the cycle 2 safety analysis.

EVALUATION I.

Revise San Onofre Unit 2 Technical Specification 3/4.5.2, ECC3 Subsystems (PCN-126).

1*

This change revises Technical Specification 4.5.2.a to include (1) the addition of two new SDCS bypass flow control valves (HV 8160 and HV 8161) 'and low pres-

+

sure safety injection (LPSI) pump miniflow isolation valves (HV 8162 and 4

HV 8163), (2) replacement of the existing SDCS flow control valve -(FV 0306 re-placed by HV 0396), and (3) deletion of the SDCS heat exchanger flow control y valve'and isolation valves (HV 9316, 14-78 and 14-80), SDCS bypass ~ flow control /-

isolation valve 14-153 and isolation valves 14-81 and 14-82.'

The changes require the plant operators to verify the correct' valve ~ alignment for ECCS sub--

system = operability including the recently-completed SDCS design modifications.C I

The new SDCS bypass flow control valves (HV 8160 and HV 8161) provide for redth-dant, remotely operable, Class'1E bypass flow control. HV 0396 and HV 8161 am

~

powered by the opposite train from HV 8160 in order to meet the single failure' criterion (specifically, if power.to.HV 8160'(normally used for flow control);

is lost, HV 8161-'will be closed and HV 0396 will be used to provide the required bypass flow control). HV 0396,~ HV 8160 and HV 8161 replace FV 0306 and 14-151~

to provide remote' operation capability, consistent with BTP RSB 5-1.

The pre" 4

viously-used,'non Class 1E powered SDCS heat exchanger flow control valve andt 4

associated isolation valves (HV 9316,-14-80) have been removed and the flow control function is now performed by new HV 8150 and HV 8151, which are redunf dant,. remotely operable and Class 1E powered.

s i

n

~

_~

,m.-

,m..,

.,r

..,e,_..e_._....,--

-., ~

_---~.,m m,.

e,.

~

~

3 j

' Motor-operated LPSI!miniflow isolation valves HV 8162 and HV,8163 have been -

added to provide ~ remote isolat;on capability consistent with BTP 5-1.

. Isolation of the miniflow lines is required to prevent transport of potentially contami-nated primary coolant to the refueling water storage tank (RWST). The valves are powered from the train not used to power the associated LPSI pump. This-I will prevent the loss of one train of emergency power from resulting in a

~

Lpotentially uncontrolled flow path-from the reactor coolant system to the RWST.

Isolation ~ valves 14-81 and 14-82 have been removed from Technical Specifica-

'tfon 4.5.2.a.

The closure of.14-81 and 14-82 [ isolation valves for-HV 0396 (normally closed)] has been previously analyzed for this configuration in the 4

~

FSAR failure modes ~and effects analysis of the Unit 3 safety injection system

~

-(FSAR Table 6.3-1 for Unit 3, Item 14). It was concluded that inadvertent-closure of these valves would have no effect on ECCS cperation, since HV 8160~

(open) and-HV 8161 (open) bypass 14-81 and 14-82 and provide the normal ECCS flowpath.

In addition, surveillance of these valves requires frequent-personnel entry into a confined contaminated area (14-81 and 14-32 are not egiipped with remote position indication)-with associated radiation exposure.

The SDCS design change has been reviewed and approved by the licensees and was

~

found not-to involve an unresolved. safety issue. A similar design change was j

implemented at Unit 3 prior to initial plant startup.

p i

The NRC staff has reviewed the SDCS changes and finds them acceptable because they provide the remote isolation capability recommended by Branch Technical Position RSB-5-1 (reference SRP section 5.4.7).

The staff has reviewed the.

associated technical specification changes and finds them to be acceptable-because they make the technical specifications consistent'with the modified plant design. The revised design and technical. specifications have previously been reviewed and found acceptable for use at San Onofre Unit 3.

II. Add Technical Specification 3/4.10.7, Emergency Chilled Water System, to the San Onofre 2 and 3. Technical Specifications'(PCN-127).

f The new technical specification is being added because the ECWS is a-support system which maintains acceptable environmental conditions for vario's safety u

systems in the event that the normal heating,' ventilating, and air conditioning 3

(HVAC) system becomes inoperable.

The new Technical Specification 3.7.10 states as the limiting condition for plant operation that two independent emergency chilled water systems must be.

operable. For a situation in which one ECWS becomes inoperable,.the action L

statement requires that the inoperable ECWS must be restored to operable status i

within seven days and that the operability of'the following systems must be verified within the specified time period: -(1) the portion of the normal HVAC system which maintains environmental conditions in rooms associated with vital power distribution to safety systems, within one hour; (2) the safety-related l

shutdown systems'which do not depend on the inoperable ECWS, within eight hours; l'

and'(3)-the required systems which depend'on the operable ECWS, within twenty-l~

four hours. Technical: Specification 4.7.10 requires that the operability.of i

the emergency chilled water systems'and specific safety-related equipment be demonstrated-periodically. The surveillance requirements of Technical Specifi-c,ation 3/4.7.10 provide specific tests for verifying ECWS.. operability.-

1 l

.~.._

.-,-,r,

..~

n e

~ ~,

o-

+,,,

n..

4 W

4

The'NRC staff has reviewed'the propose'd-technical specification and finds it to-

~

E be acceptable, because it provides additional: assurance that '.he ECWS will. be available if.needed.

i h

.III. Revise Technical Specifications 3/4.1.1.2 and bases, and T.S. 3.1.2.2,

~

~

e3.1.2.4, 3.1.2.6,L3.1.2.8,.and 3/4.1.2 bases (PCN-161).

~

Technical Specificction:3.1.1.2 specfies the shutdown margin required in~ Mode.5.

1 The change in this specification. increases the Mode 5 requirement from 2.0% to

. 3.0%' delta k/k. - Technical Specifications 3.1.2.2,.3.1.2.4,.3.1.2.6, 3.1;2.8, B 3/4.1.1 and 8_3/4.1.2~have been revised accordingly, to assure compliance with_.

the revised Mode 5 shutdown margin requirement.

In addition, a new surveillance requirement is-implemented for Technical Specification 4.1.1.2, to assure.that l'

one and only'one charging pump ~is operable in Mode 5 when the RCS is drained) below the hot -leg 1 centerline, in order to be con;istent with.the cycle 2 safety -

analysis.

The requirement for a limiting condition for operation governing the shutdown margin is based on 10 CFR Part 50, Appendix A, General Design Criterion 26 --

"ReactivityLControl System Redundancy and' Capability".(GDC-26), which requires

[

reliable control of reactivity changes to assure that the fuel design limits

'are not exceeded during design basis accidents and anticipated operational occurrences. This is accomplished, in part, by providing adequate shutdown

- margin. Specific criteria necessary to meet the relevant requirements-of F

GDC-26 are given in NUREG-0800, the Standard Review Plan (SRP) Section 15.4.6 -

i(

" Chemical and Volume Control. System Malfunction that Results in a Decrease in Boron Concentration in the Reactor Coolant." The criteria of SRP 15.4.6 are used'in evaluating the safety analysis of the. inadvertent boron dilution event.

Analysis.results are used to establish the Mode 5 shutdown margin.

This approach is consistent with 10 CFR 50.36, which states that the technical-specifications are to be derived from the safety analyses and evaluations' included in the safety analysis report.

t.

Core performance analyses of the cycle'2 reactor fuel management design show-that the critical. boron concentrations have increased due to the change in core F

performance characteristics from-cycle 1.

As a consequence, the minimum Mode 5 l

shutdown margin required during cycle 2 has increased. Also, constraints on the_. operability.of the charging pumps are required to' assure that~ assumptions L

used in the safety analysis are valid. The-cycle 1' inadvertent boron dilution analyses showed that greater than 60 minutes were available between the initia-tion of an unplanned moderator' dilution event and the time of: loss of shutdown l

. margin. 'The cycle 2 analyses, incorporating the proposed changes. discussed i

above,'also show that greater than'60 minutes remain available between initia--

tion of an unplanned moderator dilution event and the time of loss of shutdown p

margin.

In both cycles, the operator will be alerted to this eveat with a minimum of 15 minutes' remaining before criticality, by the alarm on the startup channel nuclear instrumentation, as required by SRP 15.4.6.

Thus,'the cycle 2-analyses show no significant increase in the probability or consequences of.any accident previously evaluated, nor is there'any significant reduction in a mar-l-

gin of safety.

i-i O

m,--w

+,-,,-e w

-y w.,

ym..-

.-i-,e.,.-.-,---.ym.,

-,,r,r

,awo

.,,....-,-.e,...

~

n.,

.-w m,%

5 To clarify the usage of borated water from various sources during plant shutdown operation, the' licensee stated that for Cycle 1 operation, the boric acid makeup tank (BAMT) contained sufficient borated water to provide the required shutdown margin and makeup requirement to the RCS to compensate for reactor coolant volume contraction. For Cycle 2 operation, the required shutdown margin will be provided by. injecting borated water to the RCS from the BAMT. The BAMT will-also provide portiors of the makeup requirement to the RCS. The remaining por-tion of the required RCS shrinkage makeup will be provided through-the refueling water storage tank (RWST).

The licensee indicates that boron mixing under natural circulation is rather rapid, and meets the criteria specified in BTP RSB 5-1.

The mixing mechanism is mainly influenced by the system configuration and is independent of the charging fluid temperature. Since the boron delivery path configuration beyond the charging pump discharge remain unchanged during all modes of plant operation for San;0nofre Unit 2, the results of adcquate boron mixing-in the RCS and nuclear vessel during the natural circulation test performed at the San Onofre Nuclear Station, Unit 2 should not be affected by the proposed TS change.

Based on the above, the staff finds that this change is consistent with GDC-26, SRP 15.4.6, and BTP RSB 5-1 (SRP 5.4.7) and is acceptable.

IV.

Revise San Onofre Unit 2 Technical Specifications 3.1.2.7, 3.1.2.8, and Bases 3/4.1.2 (PCN-163).

The borated water source required by these technical specifications is part of the boron injection system which assures that negative reactivity control is available during each mode of facility operation. This system is required to satisfy 10 CFR Part 50, Appendix A, General Design Criterion.26, " Reactivity j

Control System Redundancy and Capability." GDC-26 states that a nuclear power plant must contain two independent reactivity control systems, one of which is capable of holding the reactor core subcritical under shutdown conditions.

1 Core performance analyses of the cycle 2 reactor fuel management design show that the boron concentration re: quired to (1) maintain the required shutdown margin after xenon decay and cooldown to 200*F, and (2) satisfy GDC-26, has increased due to the differences in core design and core performance charac-teristics from cycle 1.

As a consequence, the minimum borated water volume in the refueling water storage tanks and the minimum boric acid makeup tank water volume must be revised for cycle 2 operation in order to meet the limiting con-ditions for operation on shutdown margin. The minimum water volume required in the boric acid makeup tank and refueling water storage tank in Modes 5 and 6 has been increased due to the increased Mode 5 shutdown margin required for cycle 2 operation.

In addition, the Modes 1 through'4 boric ac.id makeup tank water volume requirement has been decreased in order to facilitate plant opera-tion while nevertheless providing the required shutdown margin. For cycle 1

[

operation, borated water from the boric acid storage tank was used during plant shutdown to provide makeup for reactor coolant system (RCS) shrinkage. Makeup l

i for RCS shrinkage during cycle 2 will be provided from the refueling water storage tank.

f 6

Therefore, the proposed Technical-Specifications 3.1.2.8 and B3/4.1.2 would specify the' boric acid storage tank' water volume / concentration and the refueling water. storage tank' volume required for negative reactivity control consistent

)

with the requirements of cycle 2 operation.

On this basis, the NRC' staff finds l

the proposed change to be-acceptable.

l CONTACT.WITH STATE OFFICIAL The NRC staff has advised the chief of the Radiological Health Branch, State Department of Health Services, State of California, of the proposed determina-tions of no significant hazards consideration.

No comments were received.

ENVIRONMENTAL CONSIDERATION These amendments involve changes in the installation or use of facility compo-nents located within the restricted area. -The staff has determined that the amendments involve no significant increase in the anfounts of any effluents that-may be released offsite and that there is no significant increase in individual or cumulative occupation radiation exposure.

The Commission has previously issued proposed findings that the amendments involve no significant hazards consideration, and there has been no public comment on such findings.

Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR Sec.

51.22(c)(9).

Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of these amendments.

CONCLUSION Based upon our evaluation of the proposed changes to the San Onofre Units 2 and 3 Technical Specifications, we have concluded that there is' reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and such activities will be conducted in compliance with the Commission's regulations 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.

We, therefore, conclude that the proposed changes are acceptable.

Dated: December 19, 1984 l

l l

DL IB#3 DL:

,,ghton i

HRood 12/\\\\/84 12/g/84

v.

,e;

= t, December 19, 1984

' ISSUANCE OF AMENDMENT NO. 28 TO FACILITY OPERATING LICENSE NPF.AND AMENDMENT NO.-17 TO FACILITY OPERATING LICENSE NPF-15 SAN ONOFRE NUCLEAR GENERATING STATION, UNITS 2 AND 3

-DISTRIBUTION RM:FtW$$$$$?E3 ^

NRC PDR Local PDR NSIC PRC System LB#3 Reading JLee LBf3 Reading JLee (15)

HRood TMNovak JSaltzman, SAB-LChandler, OELD Chiles.

HDenton/ECase JRutberg Atoalston WMiller, LFMB NGrace EJordan LHarmon DBrinkman, SSPB TBarnhart(8)

IBailey

(

<