ML20074A986

Safety Evaluation Supporting Amends 17 & 5 to Licenses NPF-10 & NPF-15,respectively

ML20074A986
Person / Time
Site:	San Onofre
Issue date:	04/29/1983
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20074A985	List: ML20074A984 ML20074A986 ML20074A987
References
TAC-51426, TAC-51427, TAC-51428, TAC-51429, NUDOCS 8305170234
Download: ML20074A986 (8)

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SAFETY EVALUATION AMENDMENTS 17 AND 5 TO NPF-10 AND -15.

SAN ONOFRE NUCLEAR GENERATING STATION, UNITS 2 & 3 i

DOCKET NOS.:

50-361 AND 50-362 Introduction By ~1etters dated February 24, March 4, April 14, sand April-19, 1983, SCE.

requested changes in the license conditions and Technical Specifications covering the Post Accident Sampling System'(PASS). The proposed changes

-would extend the date for PASS operability to September 1,1983. -Our evaluation,of'the proposed License Condition changes and the associated Technical Specification modifications is given below. Units 2 and 3 share a common Post Accident Sampling System.

Background

In Amendment No. 8 to Facility _ Operating License NPF-10, the NRC modified the San Onofre 2 license to change th'e date for PASS operability and post

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accident sampling program (PASP) implementation to January 1,1983.

In the San Onofre 3 license, NPF-15, the date for. PASS operability and PASP-l implementation is prior to exceeding 5% power (currently estimated to be mid-May, 1983).

ByLletter dated December 21, 1982, SCE informed the NRC staff that the PASS had beenLinstalled and modifications completed, and testing of individual components-had been completed. However, SCE stated that the planned system demonstration test had not been completed due to plant outages. The PASS was

' tested during January and February,1983, and as a _ result, SCE concluded that although most PASS functions had, at one time _-or another, been successfully carried out, the PASS was not reliable enough to be declare'd' operable in the near future. Also, additional time is required'during which both the PASS is functioning and one of the two units is 'at operating temperature and pressure j--

.(MODE 3 or higher). This additional time _ is required for training of plant operating personnel, and revision of procedures.

As a result, in its letter of February 24, 1983, SCE requested that the Unit 2 and 3 licenses'be amended to allow until September 1,1983 to make the PASS operable and to fully implement the PASP.

Following the February 24, 1983 request, the staff met with SCE on February 25 and March 2,1983, and at the staff's~ request SCE submitted-additional infomation by letter dated March 4, 1993. Subsequently, the staff visited the San Onofre site on April 4-8,.1983, to observe a demonstration test of the PASS and to discuss the PASS, the PSAP, and compensatory measures with SCE.

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Observations From the site visit and review of submitt,d documents, the staff concludes:

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SCE'has made a concerted effort to reeet the PASS requirements.

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2.. The-SONGS PASS status is at least equal, if not ahead of other licensees

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who have selected similar equipnent for meeting this requirement.

Implementation of this NUREG-0737-requirement has proven substantially 3.

more difficult than expected.

L4. The SONGS PASS, though installed and functioning, is~ not fully operable because:

. all the procedures have not been completed and many of 'the approved procedures have not been verified through use by plant personnel;

. the training of personnel to use the PASS has not been completed; and

. experience with the system is too. limited to provide high confidence in the results.

5. -While the. SONGS PASS has features that are -superior to other. PASS systems,'

~and which go beyond the requirements, it also has shortcomings such as:

. fit will not be used during normal operations so training, survie11ance, maintenance, etc.,'will all be'special efforts and personnel will11ack day-to-day f amiliarity with it;

. access -to the PASS is limited; 'and -

. it may be inherently incapable of meeting the 3-hour time limit for analysis results.;

i Evaluation The NRC staff has evaluated the SCE request fer. additional time to make the. PASS operable and fully implement the post accident sampling program, and has-concluded -

that the request is acceptable for-the reasons given below, subject ~to the additional conditions-discu'ssed below.

1.

PASS Capabilities. -- The Post Acciden't Sampling System is installed and has demonstrated. the capability to obtain informatien' relevant to post-

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accident condi.tions. The PASS has not yet-been declared operable because Lit has-not been-fully checked out and debugged. Successful operation of the PASS at this time frequent 1y ' requires more-than following procedures.

That is, system repair.or procedure alteration.may be required in order -

to cope with problems that arise. In particular,: the three-hour time.-

limit for obt.a.ining thb' required information may not be met. Thus, at this time the. licensee doe's" not consider the PASS operable. However, the NRC staff ~has r'eviewed the syste'm.and witnessed successful demonstration

' tests'-on April (5,'1983,'and believes that ' hen manned by qualified personnel, w

the PASS'is capable of providing. additional' in' formation for evaluating

. post-accident reactor conditions, although not necessarily within the time const'raints identified ~ in NUREG-0737.

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Availability of Qualified PASS Operators - At this time, only a. few people at San Onofre are qualified to operate the PASS.

By letters dated April 14, and April. 19, 1983, SCE has committed to take action that provides reasonable C

assurance that qualified operators will be'available when needed.. In the April _19, 1983 letter, SCE stated that it is their intent to normally have sufficient qualified PASS operators on site.

In the April 14, 1983 letter, SCE stated that their PASS operator training program provides, in the short term, a suf ficie'nt number of qualified SCE personnel to assure that at least two could be called to report in a timely manner following an accident.

3. ' Development and Modification of Procedures - In its letters of March 4, and April 14, 1983, the licensee defined the status of all PASS procedures and defined the schedule for completion of all procedures except the one for core damage assessment.- Many of the procedures are complete now, and all except the core damage assessment procedure are scheduled to be complete

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by May 1, 1983. We will condition the San Onofre 2 and 3 licenses to require that all PASS procedures be substantially complete by June 1,1983.

During our1 site visit on April 4-8, 1983, the NRC staff reviewed a number

.of the existing PASS procedures and observed the procedures being used during a PASS demonstration tes.t. While all, the procedures are not yet in their final form, ' reviewed and approved by the licensee, they appear to be 'sufficiently developed.that they can be used by the present operators to operate the PASS.

4.

Compensatory Measures - The availability of backup measures reduces the significance of possible unavailability of portions of the PASS. These compensatory measures 'were identified in the SCE letters of March 4, and April 14,1983. Surveillance and maintenance of these compensatory measures is required by a license condition.

The requirements of NUREG-0737 did not classify the PASS as safety related, and therefore, it'is not required to meet redundancy requirements. During system checkout, moreover, the PASS will be even less ' reliable. Thus, the backup provisions become more important and their availability has contributed to the staff conclusion that reactor operation during PASS checkout prior to the PASS being declared operable is acceptable.

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m, 4 The primary purpose of 'the PASS is to assist in assessing conditions after

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a severe accident; it is expected to provide additional information that may be useful. This information is to be obtained from radiological and chemical analysis of the reactor coolant, the containment atmosphere and the containment sump fluid. As discussed in. the following paragraphs, alternative sources of data exist for each measurement.

4 The determination 'of hydrogen in the containment atmosphere can be made '

with the in-containment hydrogen monitors. These instruments are seismic-Category I, Quality Class II, and IE powered and, thus, are reliable. As a further backup, estimates of containment hydrogen are available from core temperature measurements.

If both the PASS and the in-containment hydrogen monitors are inoperable, the recombiner can.be energized as a precautionary. measure if core temperatures ever exceed levels that would

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support metal-water reactions.

Radioactivity in containment atmosphere can be determined from the high range area -radiation monitors inside containment. These monitors measure dose rate but.do not provide gamma spectra data.~ The staff has concluded that reasonable estimates of the radioactivity in the containment atmosphere can be made, based on the high range area monitor readings, using the analyses and methods developed by SCE. These instruments are qualified to function in a post-accident environment and are considered to be reliable.

Other available backup approaches to determine radioactivity in containment

~ utiliza (1) the normal sampling system, and (2) the high range effluent j

Thus, even without the PASS there will be capability for monitoring system, determining the level of radioactivity in the containment atmosphere, f

Dilute samples of the containment atmosphere are not explicitly required but.

would be provided by the PASS. A diluted sample is needed to facilitate the analysis called for~ in NUREG-0737 because of the potentially high radiation level s' - A single ml (stp)'of containment atmosphere could produce radiation levels of 0.4 R/hr at a distance of one foot, three hours after the accident.

Without the PASS, there are no provisions for taking a diluted sample, e,o the specified analysis could not be performed. The backup provision is a measurement of direct radiation from the normal sampling system. While this would not provide the desire accuracy, it could provide information j

' essential.to coping with an emergency.

l In addition -to analysis of the containment atmosphere, provisions are

. required 'for analyses of reactor coolant for radionuclides, boron, chloride, i-l and dissolved gases (or hy.drogen).

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' i Radioactivity,in the -reactor coolant can be estimated, without-the PASS, using the area radiation monitors.in containment in all cases where a substantial quality of coolant is released to containment. -While this would not provide the specified radionuclide data, it would provide a i

basis.for. estimating core damage utilizing the methods developed by SCE.

'Dir'ect radiation m'easurements from normal sample lines would provide some infonnationlin the improbable event of serious core damage without coolant

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~ release to containment.

Determining the choride content of the primary coolant is difficult without the PASS available.to provide a diluted sample. The chloride determination, 4

Thus, there is time to take however, can-safely-be delayed several hours.

the necessary action to rsturn the PASE to service even if it were not operational at the ' start of' the accident'. Consequently, there is reasonable assurance that this information can be obtained if needed.

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The boron. determination is neede'd to provide assurance that cooldown and xenor decay will not cause nuclear. criticality. The need exists because i

the control rods do notjprovide enough negative reactivity to compensate for complete loss of boron. The PASS.is not designed to provide information for use during an accident transient'so initially reliance must be placed on.Other instrumentation, primarily the excore neutron detectors backed-up by the incore neutron instruments. 'These same instruments will provide timely information if the' reactor returns to a critical state after being shutdown.

The PASS measurement of boron would only confirm these measurements and

.possibly provide some advance warning of a possible return to criticality.

As a further backup measure, SCE had' developed a procedure for calculating l

boron concentration based;.on known pre-accident concentrations and on tank 1evel measurements.

Reactor The dissolved gas-measurement is itself a backup measurement.

I If the coolant normally will contain a limited amount of excess hydrogen.

coolant' contair.s an abnormally large amount of gas, it suggests that Direct-inadequate core ~ cooling may have resul_ted.in a metal-water reaction.

measurements of coolant temperature and pressure, however, provided a When available, i

better and more reliable measure of inadequate core cooling.

l the PASS provides measurements of ' dissolved oxygen and hydrogen but these '

are not required. The. oxygen measurement supports the chloride' measurement to provide information about corrosion. The hydrogen measurement would i

l provide further assurance that the inadequate core cooling' determination I

The PASS is expected to he capable of providing this information was correct.

but initially, at least, the 3-hour-time criterion may not be met. Thus, the staff. concludes' that the dissolved ' gas information will be available l

l to meet emergency'needs.

In summary, as discussed 'above, the staff concludes that' adequate compensatory provisions exist for. obtaining the information needed for coping with

'an emergency, if one should occur, when the PASS is not operable.

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Time Requirement,- The SONGS PASS performs many analyses on-line, thus,

- once the. system is in operation, measurements can be repeated easily and the measurements can be reasonably reliable. However, there is a startup probl em. SCE estimates that 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> may be needed to assemble trained personnel, provide them with health physics equipment, verify a safe atmosphere, conduct a health physic _s survey, send the people to the PASS area, energize and verify the system and select the sample points.

If these preliminaries.are complete before a decision is made to take a sample, the 3-hour time limit can be met.

If the " clock starts" before initiation of the preliminaries, the time to obtain results may approach 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />.

The staff has reviewed this. issue and concluded that the system is acceptable, at least on 'an interim basis.. Principle c.onsiderations are the lack of a direct impact on public health and safety,0f the failure to obtain PASS results, and the determination that PASS result.s would most-probably be 4

useful only.seve'ral hours' after.the. initiation of an accident. However

' SCE has comitted to ' exert best' ef. forts to reduce the time requirement to th'ree hours' prior to or d0 ring the'first refueling outage.

6.

0perability 'D' ate - We will condition the San Onofre 2 and 3 licenses to require that the PASS sbe. operable aifd the post accident sampling program be fully. implemented by September 1,1983, the date requested in the SCE

. letter of: February,.24', 1983.

In the staff's opinion, this allows sufficient time, from. June 1 to September 1,1983, for the licensee to finalize all PASS' procedures, train a full complement of operators, and resolve all

' har'dware and hardware. reliatiility problems associated with the PASS.

7.

Surveillancedriteria. In their April-14, 1983 le'tter, SCE proposed

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surveillance criteria.for: the PASS measurements. The staff finds these criteria acceptable except-that for the' " gross gamma activity spectrum",

the range should be-from 1.0 Ci/ml to.10.0'Ci/ml.

Furthermore the dtaff(recomends that S'CE endeavor to improve the accuracy of the-reactor coolant' hydrogen. monitor in the. low concentration range.

This instrument might be u' sed.to dete'rmine the probability of oxygen in the l

coolant aft.er a LOCA.. For;this ' purpose,:it is necessary to measure below normal concentrations.~ of hydrogen.' -

8. ' Operability Definition - In.their April 14, 1983 letter, SCE proposed a definition of foperability for the~ PASS for use in evaluating compliance with the relevant license. conditions. The. staff agrees that a special definition

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for this system is appropriate 'for' SONGS. Further, the staff has reviewed the definition proposed by:SCE; an.d has. concluded that it is acceptable 1

if, modified'to read:

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_ The PASS is considered operable if:

1.

Routine surveillances described in Survaillance Procedure (50123-111-8.1) are conducted at the prescribed intervals when plant conditions permit and any necessary _ actions are taken expeditiously to make the system meet the approved acceptance criteria.

2.

In the event of a PASS component' malfunction, the specific alternate

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method of sampling listed in.the " Alternate Methods of Post-Accident Parameter Sampling" procedure (S0123-III-8.8) is available and measures are being taken to effect repairs to the component that has

' mal functioned.

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3.~ Calibration of PASS Instruments is current.

9.

Progress Reports - To' allow the NRC staff to monitor SCE's progress in moving toward PASS operability and full implementation of the post accident sampling program, the San Onofre 2 and.3 licenses will be conditioned to require monthly progress reports, from the present time until September 1, 1983.

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10. In addition to the above, the' asterisks in Specification 6.8.4.b, In-Plant Radiation Monitoring, in the Technical Specifications for San Onofre Unit 2, NPF-10, are removed. The asterisks ~ were inadvertantly not removed in Amendment No. 8 'to NPF-10. dated September 17,1982,- as they should have been..The In-Plant Radiation Monitoring program required in ' Specification 6.8.4.b is implemented and the asterisked statement."not required to be

. implemented until September 1,1983" is not applicable to this program.

The asterisks in Specification:6.8.4.b, Ih-Plant Radiation Monitoring, have, therefore,~been. removed.

In light of the ability to use..the PASS to perform a number of its intended functions, the present availability of a number of qualified operators and procedures,.and the existence of desireable compensatory measures, we find accep. table the proposal.to extend the date for _ operability of the PASS to September.1,-1983 and for finalization of procedures to June 1,1983.

Environmental Consideration The NRC staff h'as determined that these amendments do not authorize a change

'in effluent types or total amount nor an increase in power level and will l

not result in any significant environmental impact. Having made this deter-minatio'n, we have further concluded that these amendments involve actions which are insignificant from the standpoint of environmental impact and pursuant to 10 CFR Section 51.5(d)(4), that an environmental impact statment l

or. negative declaration and environmsntal impact appraisal need not be prepared in connection with the issuance of these amendments.

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Conclusion Based ~ upon our evaluation of the proposed changes to the San Onofre, Unit 2 and 3 Operating License and Technical Specifications, we have concluded that:

(1) because these amendments do'not involve a significant. increase in the

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probability or c'onsequences of accidents previously considered, do not create

. the possibility of an accident of a type. different from any evaluated previously, and do not involva a ' ignificant decrease in a safety margin, these amendments s

do not involve a significant safety hazards consideration; (2) there is reasonable assurance that the health and safety.of the public will not be endangered by operation in the proposed manner, and _(3) such activiti.es will be conducted in compliance with the Commission's regulations and the issuance of these amendments 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 accep. table.

Dated: APR 2 91983 t

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