ML20037B248

Safety Evaluation Supporting Amend 9 to License DPR-2

ML20037B248
Person / Time
Site:	Dresden
Issue date:	07/29/1974
From:	Silver R, Ziemann D US ATOMIC ENERGY COMMISSION (AEC)
To:
Shared Package
ML20037B245	List: ML20037B244 ML20037B247 ML20037B248 ML20037B251
References
NUDOCS 8009100719
Download: ML20037B248 (8)

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SAFETY kVALUATION BY THE DIRECIORATE OF LICENSING SUPPORTING AMENDMENT No. 9 TO LICENSE NO. DPR-2 (CHAEGE No. 29 IO APPENDIX A TECHNICAL SPECIFICATIONS) l COMMONWEALTH EDISON C0KPANY DOCKET NO. 50-10 f

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INTRODUCTION The previous Technical Specifications of Facility License No. DPR-2 for Dresden Unit 1 had been issued in 1962 and were largely descriptive i

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of the plant.

In addition, the specifications had been changed piece-i meal a number of times. The bases for the specifications which consisted of applications and supplemental information comprising approximately

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fifty documents were not always clear. This situation co= plicated j

licensing actions and determination of compliance. As a result, by i

Ictter of January 1972, we asked Commonwealth Edison (CE) to propose a complete revision to the Technical Specifications to clearly delineate

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limits, surveillance requirements, and bases.

By letter dated June 15, 1972, Comonwealth Edison Cocpany submitted a first proposed revision. Af ter considerable review by CE a.d the 4

l staff, comonwealth resubmitted a proposal by letter of May 17, 1973, l

which superseded the first proposal.

I The May 1973 submittal was evaluated by the staff to assure that all 4

I requirewnt's of the previous specifications significant to reactor i

safety are retained and to assure that new requirements were added, l

where necesscry, to clearly delineate what syste=s and co=ponents must be operable uncer various plant conditions, when the reactor cust be shut down or power limited, and the type and frequency of testing, calibration and checking of safety related equip.ent which l

must be acco=plished. Our evaluation was based on existing infor-l m:ation, including the Prelim:inary llazards Sum =ary Report, as amended, reports of operational experience, and the previous Technical Specif1-ca tions.

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. 1 The revised Technical Specifications were elmo written to conform as closely as possible to the format of the existing Technical Specifications for Dresden Units 2 and 3, and, wherever applicable, were changed to be identical to the specifications for Units 2 and 3.

The close con-formance is expected to ease utilization of the Technical Specifications for operations and regulation.

During the course of our review and through interaction with the applicant, we modified proposed specifications to include more definitive require-ments and, in some sections, more restrictive requirements than initially proposed by the applicant.

During the review we also determined that the format of the ratin body of the license was no longer current and was not consistent with the revised specifications. As a result we have modified the format to be consistent with present practice and to delete sections which would have been redundant with the Technical Specifications.

The revisions to the license are administrative in nature and have no effect on lit tations or other safety matters.

I EVALUATION The revised Technical Specifications set forth the requirements and limitations for safe reactor operation in the current format for power i

reactors and in conformanca with Part 50.36(c) of 10 CFR Part 50.

This format ideludes:

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definitions of key terms used in the specifications, i

2.

delineation of safety limits and limiting safety system 1

settings for those process variables important to reactor

safety, 3.

delineation of the limiting conditions for operation which define the lowest acceptable performance level for equipment, and the technical conditions necessary for continued operation, i

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requirements for surveillance of equipment which is essential to reactor safety, 1

5.

description of those facility features which cre it:portant to reactor safety, and 6.

administrative controls required for safe facility operation.

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3-f Our evaluation of the changes to each of these revised scetions of the Technical Specifications is discussed below:

i Section 1.0 - Definitions 1

j This section includes standard definitions of terms used in the Technical j

Specifications and terms mique to the Dresden 1 facility. The unique f.

definitions are related to the modas of operation and are consistent with previous Dresden 1 design and descriptions. The previous specifi-cations document did not have a section containing definitions of terms l

used.

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Sections 1.1 and 1.2 - Safety Limits The previous specifications did not include Safety Limits. These limits are listed in two categories, those related to the integrity of the fuel l

cladding and those related to the integrity of the reactor coolant system.

j Limits related to integrity of fuel cladding include those on allowable thermal power and, during shutdown, a lower limit on vessel water level.

The power limits are specified as a relationship between the observable parameters of reactor power, incore neutron detector readings and reactor pressure to assure that the minim== critical heat flux ratio l

1s greater than 1.0 in the operating range, including anticipated i

operational transients. The heat transfer correlations used are the

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same as those on which the existing specifications are based. The j

criteria for selection of the limit is the same as that presently set j

in other reactors; i.e., that a critical heat flux occurrence will not occur in any fuel rod in the core during normal plant operation, including l

anticipated transients.

i The safety limit related to reactor coolant system integrity is an upper Itmi t on reactor a>olant system pressure. The upper limit designated j

is in conformance with the ASME Boiler and Pressure Vessel Code approved I

for design. Yhe designation of reactor coolant system pressure as the j

safety limit related to reactor coolant syste= integrity is in conformance i

with our practice for other boiling water reactors.

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j Sectiono 2.1 and 2.2 - Limiting Safety Systen Settings

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Liniting safety system settings are being specified to provide assurance j

that the Safety Limits will not be exceeded. The requirencnts related to fuel rod integrity include specified scram settings for the incore l

and out-of-core neutron flux monitoring systems, and scram settings l

related to turbine stop and bypass valve closure and scrat from primary I

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j steam isolation valve closure. The designated scrams were required by previous Tech =4=1 Specifications but are being stated in revised format i

and with bases to make clear the importance and purpose of the settings.

i The requirements related to reactor coolant system integrity include s

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specified scram setting for reactor coolant high pressure and set

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points for each of the primary system safety valves. The high coolant system pressure scram was required by previous Technical Spec 1fications.

l Mari zum safety valve pressure settings were in previous Technical j

Spe<1fications. The revised specification lists the setting for each L

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i Sections 3 and 4 - T 4=4 ting Conditions of Operation and Surveillance _

i Recuirements i

I The limiting conditions of operations and surveillance requirements in the revised Technical Specifications are based on the Preliminary

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Hazards Sunnaary Report, as amended, 'prdvidus-Technical Specifications j

requirements, operating experience, guidance provided by Regulatory Guides, where applicable, and regulations. The most significant modifi-cations from previous specifications are clear delineations of actions h

to be taken in the event certain conditions cannot be met, testing and F

j calibration requirements for equipment important to safety, and bases I

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axplaining the requirements.

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Sections.3.1 and 4.1 - Reactor Protection System (L

Lin:iting conditiens of operations include operability requirements for I -

the incore neutron monitoring systesa and minimum number of operable r

f instrument channels and trip level setting for each scram trip system.

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'Ibese limiting enditions are the same as in the previous' specifications.

j Requirements on type and frequency of tests on scram instrirnantation were not specified in the previous specifications and have been added to l

the revised specifications. The minimum test frequencies are similar E

to those specified for Dresden Unita 2 and 3.

Past experience at

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D Dresden station indicates that these frequencies should provide acceptable j

j assurance of operability.

Sections 3.2 and 4.2 - Protective Instrumentation

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Lir.iting conditions of operation and surveillance include requirements on the core and containment cooling systems initiation and control, the steam jet air ejector off-gas system and post-accident monitoring i

instrumentation. The operability and surveillance requirements for the j

cooling systems were in previous Technical Specifications in another format. Operability and surveillance requirements for the stenn jet air l

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.: 5-h ejector off-gas system and post-accident monitoring system are new y

specifications for existing equipment. The trip settings of the off-Ic l

gas monitors are set to provide assurance that off-gas limits are not exesuled. Post-accident monitoring is specified to provide capability for post-accident evaluation of conditions within containment.

Sections 3.3 and 4.3 - Raactivity Control his section includes requirements on shutdown reactivity, control rod 4

operability, and control rod worth. A requirement has been added to limit the==1r4=== worth of any in-sequence control rod to less than 1.5% delta k.

De acceptability of a 1.5% delta k in-nequance rod j

worth had been previously evaluated by the staff but the limit had not i

been incorporated into the Technical Specifications.

Sections 3.4 and 4.4 - Standby Liquid Control System j

his section contains the requiresAnts for the liquid " poison" system which provides a ma===

independant of the control rods to shut down the reactor. The new requirements include periodic testing specifi-i cations and requirements on sodium pentaborate sodium concentration and temperature. The new requirements are similar to those found acceptable for Droaden Units 2 and 3.

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sections 3.5 and 4.5 - Core and containment cooling Systems i_ ~

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The limiting conditions of operation and surveillance requirenents for j

these systems were specified by Change No.17 to the existing specifi-cations. he revised specifications are primarily a change in format.

Sections 3.6 and 4.6 - Primary System Boundary This section includes requirements concerning thermal limitations, pressurization temperature, coolant chemistry, coolant leakage, safety valves, and structural integrity.

The pressurization temperature specifications are based mainly on analyses submitted by Commonwealth Edison by J etter of August 3,1972, j

and approved by the staff. The coolant chemistry requirementa are based on previous analyses for the three Dresden Station reactors and on Regulatory Guide 1.56.

Coolant leakage and lenk detection system specifications are new requirements specified for existing 1

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'l equipment. These specifications include minimum operability require-ments, minimum surveillmace requirements, and action levels to assure

-that small leaks are detected and that appropriate action is taken j

in a timely manner. The requirements are based partly on operating experience which has demonstrated that the leak detection systems h.

j operated in the manner specified, pr' ovide warning of the presence of a small crack in sufficient time to take appropriate action in a deliberate manner. The noudastructive inspection program specified to assure structural integrity was approved in our letter to Commonwealth Edison dated September 13, 1973.

i Section 3.7 and 4.7 - Contain==nt Systems i

l The containent systems specifications, including limiting conditions j

of operation, surveillanca requirements, and bases, were previously 1

reviewed and approved by Ciange No. 28 dated November 9,1973.

Sections 3.8 and 4.8 - ladioactive Materials I

i I-l These spaci fications ine1"Aa requirements concerning airborne affluents,

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-h==ical vacine pump isolation, liquid affluents, radioactive waste storage, and general requira==nts, including an environmental monitoring j

program and radioactive affluent monitoring availability. Tne limiting f

j conditions for operation for elrborne effluents are essentially the same as those specified in Change No. 21 dated Jtale 13, 1972.

Isolation i

I revised specifications to provide assurance that release of activity

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l requiramants for the mechanical vacuum pump have been included in the i -

from the==4n condenser following an accident would be limited. Liquid l

affluent requirements have been revised to provide common site limitations, f.

j Radioactive liquid waste storage limitations have been added to assure that even if the worst possible failure were combined with the historic I

low river flow, the river concentration would be such that no single L

intake of river water by an individual would exceed one-third the l

yearly intake allowabin by 10 CFR 20 for identified radioisotopes.

i The general requirements, including the environmental ronitoring program, are cc:=on to the station. Therefore, the require =ents are identicci l

to those in the Dresden 2 and 3 licenses. Radioactive effluent conitoring l

availability requirements have been added to assure maximum benefit i

from existing instrumentation and to assure that effluent vill bc l

nonitored.

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Sections 3.9 and 4.9 - Auxiliary Electrical Ffstems This section includes limiting conditions cf operation and surveillance a.:

1 requirements for offeite and onsite auxiliary electrical power, sur-veillance requirements for onsira auxiliary power systems, and bases j

for the requirements. The requirements are essentially as issued in Change No.17 dated Jun 5,1972, with revised format and some changes for clarity.

I Sections 3.10 and 4.10 - Refueling This section ineludes requirements during refueling on interlocks, enre monitoring, fuel storage pool water level, control rod and control rod drive maintenance, and extended core maintenance. The purpose of these j

specifications is to limit the probability of inadvertent criticalf ty,

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to assure adequate monitoring during core operations, and to assure adequate shielding and cooling of the irradiated fuel.

The specifi-j cations are based on existing requirements and practice at Dresden station.

t Section 5.0 - Design Features _

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The site features section contains significant design information in

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j the following subject areas: site, reactor, reactor vessel, containment, j

fuel storage, and seismic design. The subject areas are selected in accordance with 10 CFR Part 50.36(c)(4) and contain only those design 4

features which if altered or modified would have a significant effect on safety and are not covered by other sections of technical specifi-cations. Therefore, much of the descriptive material in the previous

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Technical Specifications, which is not in the category of information specified in paragraph 36(c)(4) has been omitted from the revised Technical Specifications.

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Section 6.0 - A M nistrative Controls _

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'Ibe Mministrat1ve Controls section of Technical Specifications had been 1

previously revised by Change No. 27 to the license to conform with present format. The only difference between revised and previour, cpecifications is reporting requirements. Section 6.6, Reporting Requirements, is being revised in its entirety to conform with the reporting requiremente of i

Regulatory Guide 1.21, 4.1 and with one exception,1.16.

Subnission of FSAR chanEes as stated in Regulatory Guide 1.16 is not being required at this time pending further review of our requirements. In addition to the reports required by the Regulatory Guides, requirements for special reports presently in the specifications will be retained.

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t t-s CO !CLUSION We have determined that the revised Technical Specifications, as modified, include those safety limits, operating restrictions, and ad:::inistrative requircr.cnts that are important to safety. Uc hcve concluded that; (1) i because the change does not involve a significant incrence in the probchility or. consequences of accidents previously considered and does not involve a si:::nificant decrease in a safety margin, the change does not involve a significant hazards consideration; mid (2) there is reasonabic assurance that the health and scfety of the public vill not be endan3cred by operacion in accordance with the amendment, including the revision of the licenso and l

the technical specifications in their eatirety. Uc hsve also concluded that the issuance of the an-ndrent will not be ininicc1 to the connon defense j

and nec,urity.

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Richard D. Silver l

Operattag Reactors "rnach U2 l

Directorate of Licensing F

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l Dennis L. Zienann, Chief j

Opercting Reactors tranc') !

Directorate of Licencing

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