ML20214E243

Proposed Tech Specs,Reevaluating Effect of Containment Purging Coincident W/Loca Using TID Source Terms Instead of Reactor Coolant Inventory Terms.Release of Radioactivity to Environ time-dependent,not Instantaneous

ML20214E243
Person / Time
Site:	Rancho Seco
Issue date:	05/14/1987
From:	SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:
Shared Package
ML20214E217	List: ML20214E216 ML20214E243
References
NUDOCS 8705220015
Download: ML20214E243 (13)

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- ATTAC K NT I-RANCHO SEC0lTECHNICAL SPECIFICATI'ONS

-(Pages affected by Proposed Amendment No. 111, Rev. 1) 8705220015 870514 'Q~

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P RANCHO SECO UNIT 1.'

nTECHNICAL'. SPECIFICATIONS-Limiting Conditions for 0peration.

' Table 316-1E

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CONTAINMENT ISOLATION VALVES NORMAL (1): MAXIMUM AUTO-

-OPERATING,(CLOSURE:

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VALVE NUMBER-DESCRIPTION

-ISOL.

POSITION

. TIME, sec.-

SFY-22009.

RC System Letdown AB Side-YES.

OPEN:

'25-I.

SFV-22023 RC. System Letdown, RB Side YES.

OPEN '

E SFV-24004'.

RC Pump Seal Return, RB Side YES OPEN 271-4 JSFV-24013

-RC Pump Seal Return, AB' Side-YESi OPEN-12 1 SFV 46014 RB. CCW' Supply, AB Side-NO OPEN 14.

L.

SFV-46203'

.RB CCW Return, RB Side' N0'

.OPEN.

14:

n SFV-46204 RB CCW Return, AB Side.

NO OPEN 18 SFV-46906 "CRD Cooling. Water. Supply, AB Side NO OPEN 13-SFV-46907 CRD Cooling Water Return,- RB Side

-N0l OPEN 14 SFV-46908 CRD Cooling Water Return, AB Side.

NO.

OPEN 11:

i.

SFV-53603 :

RB Press. Equalizer, RB Side YES CLOSED

25 SFV-53610

. RB Press. Equalizer, AB Side YES CLOSED.

25-SFV-53612

.RB Atm.' Purge Sample, AB Side-YES' OPEN 25 SFV-53613

'RB Atm. Rad. Sample, AB Side'

-YES OPEN 25

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SFY-53615 Reactor Building Hydrogen. Purge.

YES OPEN 25 SFY-53616-Reactor _ Building Hydrogen Purge YES OPEN

.25-3 SFV-60001' RC ~ System Vent Isol.,:RB Side YES OPEN 25-l SFV-60002 RC System Vent Isol., AB Side YES OPEN:

25 i

SFV-60003

- RC System Drain Isol., AB - Side YES:

OPEN'

.25-i SFV-60004 RC ' System Drain Isol., AB Side YES OPEN 25 SFV-66308

.RB Normal Sump Drain, AB Side -

YES:

OPEN 25 SFV-66309 RB Normal Sump Drain, AB Side-

.YES OPEN

^25 SFV-70001 Przr. Liquid Sample Isol., RB. Side YES

. CLOSED-

'25 SFY-70002 Przr. Liquid Sample Isol., AB Side YES -

CLOSED

.25 SFV-70003 Przr. Vapor Sample Isol., RB Side YES~

CLOSED 25-c SFV-72501 Przr. Gas Sample Isol., RB Side YES CLOSED 25 a

SFV-72502 Przr. Gas Sample.Isol., 'AB Side -

YES-

-CLOSED.

25 t

SFV-92520 Przr. Nitrogen Isol., AB Side YES' CLOSED 25 k

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(1) Valves without auto-isolation may be open provided the controls for. the

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respective valve is attended by an operator. Auto-isolation valves'may be in any position.

Proposed Amendment No.111, Rev.1 4

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-TECHNICAL SPECIFICATIONS Limiting Conditions-for 0peration 111>:

Table 3.6-1. (Continued) _

CONTAINMENT ISOLATION. VALVES-NORMAL (1) MAXIMUM' AUTO OPERATING - CLOSURE

' VALVE NUMBER-

~ DESCRIPTION-ISOL.

POSITION: cTIME, sec.

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HV-20593 LOTSG-A Sample Isol., AB Side NO-CLOSED

'12-

HV-20594_

-0TSG-B Sample Isol., AB -Side NO

. CLOSED 5l

-HV-20609

0TSG-A Blowdown Isol., RB Side NO

" CLOSED 115-14 HV-20610-OTSG-B Blowdown Isol;, RB Side NO-sCLOSED HV-20611' OSTGs Blowdown Isol., AB Side -

N0

> CLOSED 22 HV-53617 Reactor. Building. Hydrogen Purge N0~

CLOSED'

'25 HV-53618-

. Reactor Building Hydrogen Purge -

NO CLOSED 25~

HV-53620:

Hydrogen _ Recombiner NO CLOSED 25 HV-53621; Hydrogen Recombiner

~NO CLOSED 25 HV-53622 Hydrogen Recombiner N0

-CLOSED' 25 HV-53623 Hydrogen Recombiner N0 '

CLOSED 25' HV-70040.

Hydrogen Monitor Containment.

' Outlet Isol.-

N0

' CLOSED 25' HV-70041.

Hydrogen Monitor Containment Inlet Isol.-

NO CLOSED 25 HV-70042 Hydrogen Monitor Containment Inlet Isol..

N0' CLOSED.

25 HV-70043 Hydrogen Monitor Containment 25 Outlet Isol.

NO-

. CLOSED-HV-70044 Hydrogen Monitor Containment-Outlet Isol.

N0'-

' CLOSED 25 HV-70045 Hydrogen Monitor Containment Inlet Isol.

NO -

CLOSED 25' HV-70046 Hydrogen Monitor Containment

- Inl et ' I sol. -

NO CLOSED 25 HV-70047 Hydrogen Monitor-Containment

^

Outlet' Isol.

NO CLOSED 25 (1) - Valves without auto-isolation may be open provided the. controls for the respective valve is attended by. an operator. Auto-isolation valves may'be in :

any position.

Proposed Amendment No.111, Rev.1 3-40a I

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RANCHO SECO UNIT 1.

j tTECHNICAL-SPECIFICATIONS h.'.

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- 3.6.7-The Reactor Building Purge' Valves', SFV.53503, SFV 53504,'SFV 53604h and SFV 53605, shall be closed with their respective breakers;

. de-energized, except: during cold shutdown.or refueling. - Valves?.

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"SFV 53503 and SFV 53604 shall bei verified to be-in the above~ condition-at:1 east monthly... The breakers / disconnects ^on valves SFV 53504 and c:

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- SFV 53605-shall be' verified to be de-energized at least monthly.-

. 3.6.8-The Reactor Building Purge Valves shall sisolate on high ' containment-

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' radiation le' vel., See Table' 3.51-1 fcr? operability requirements. :

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Bases

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i' The reactor coolant system conditions of cold shutidown assure that no i

steam will-be formed and hence.no pressure buildup-in the contal.nment if' the reactor coolant system ruptures.

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P The-selected shutdown conditions are based on the ' type.of activities,that are being carried out and will preclude criticality in any occurrence.

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The Reactor Building is designed for an. internal l pressure of.59 psig and.

i an external pressure 2.0. psi greater than. the. internal pressure. The F

design external pressure corresponds to the differential pressure that could j

be developed if the building is! sealed with an internal temperature of

.120 F with a barometric pressure of 29.0_. inches of-Hg and -the building:

is_ subsequently cooled to an. internal temperature of 80 F with a concurrent -

j rise in barometricJpressure.to 31.0 inches of Hg.

When containment integrity is ~ established, the limits _ of 10 CFR 100 will' T

i not be exceeded should the maximum hypothetical accident. occur.

I The OPERABILITY of the containment' isolation ensures' that the containment.

atmosphere will be, isolated from the outside environment'in-the event' of' l _

a release of radioactive material to the containment atmosphere by-pres-L surization of the containment. Containment isolation within the time 161><11mits specified for valves which receive an automatic isolation. signal ensures 5

that the release of, radioactive material to the environment will;be consistent ~

3 161> with the assumptions'used in the analyses for ~LOCA. ' Valve's ~which are permitted

' to be open 'during plant operation are either;part.of closed systems which would not'cause. releases to the environment, or are administratively controlled to

{1 1614-ensure their rapid closure in the event of: an ' accident..

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Specifications 3.6.7 and 3.6.8. are in response to NUREG 0737 item II.E.4.2.

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.(1) FSAR, section 5 f

Proposed Amendment No. 111, Rev. 1 111><

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FACILITY CRANGE SAFETY ANALYSIS:

PAGE 1 0F 7

-PROPOSED AMENDMENT NO. 111, REV. 1L

' DESCRIPTION:'

'The following' changes are being proposed as Amendment. Number 111~, Rev. 1 to

'the Ranche.Seco Nuclear Generating Station Technica1' Specifications:-

1.

Table 3.6-1, page 3-40: Delete Reactor. Building. Purge < Valves HV-53503, HV-53504, HV-53604 and HV-53605.

2. -Table 3.6-1, page 3-40: Increase maximum closure time to'25 seconds for-valves SFV-53612, SFV-53613,-SFV-60003,~SFV-66308,'SFV-92520, SFV-53610, SFV-60002, SFV-60004, SFV-66309,- SFV-70002, SFV-72502, SFV-53603, SFV-60001, SFV-70001, SFV-70003, SFV-72501, SFV-22023, and SFV-22009.

3.

Table 3.6-1, page 3-40'& 3-40s: -Reformat table to' include columns for-

" Auto Close" and " Normal' Operating Position."

4.

Table 3.6-1, page 3-40 & 3-40s: Change footnote to read:

(1) Valves without auto-isolation may be open provided the controls for the respective valve is attended by an operator. Auto-isolation may be in any

. position.

5.

Table 3.6-1, page 3-40: Change title from." Safety Features Containment.

Isolation Valves" to " Containment Isolation Valves."

6.

Table 3.6-1 page 3-40 and page 3-40s: Add containment isolation. valves which were installed in 1983 (SFV-53615 & 53616,~HV-53617 & 53618,-

HV-53620 through HV-53623, HV-70040 through HV-70047).

7.

Change existing page 3-40a to 3-40b.

REASON FOR CHANGE:

Purpose Proposed Amendment No. 111, Rev. 1 consists of a renumbered page,.a title change for. table 3.6-1 of the' Rancho Seco Technical Specifications, and five.-

general changes'to Table 3.6-1.

The deletion of four Reactor Building Purge Isolation valves (#1,' above) from Table 3.6-1 of Technical Specifications is proposed to remove an unnecessary

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requirement for closure of valves which, procedurally,:are' closed during operation, and verified monthly.

P The reason for proposing that the maximum closure time of ~certain of the safety features containment' isolation valves be increased to 25 seconds (#2, i :

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above) is to maintain the closure time in accord with the implementing

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- :ll ATTACIDEENT II (Cont.)-

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FACILITY CHANGE SAFETY ANALYSIS:

PAGE'2 0F 7 LPROPOSED AMENDMENT NO. 111, REY. 1

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Purpose-(Cont.)'

analysis which supports compliance'with the requirements of-10 CFRL100, and

.not necessarily remain based on the overly conservative capability of the valves. -It is to be unted that 10 CFR 100 in itself is:sufficiently-4

~ conservative forJassuring that unacceptable releases of tradioactive material to the environment are prevented.

j Table 3.6-1 was reformatted (#3, above) to provide additional'information on.

the SFAS. condition of the valves. The list of valves was reordered to group

}l the safety features designated valves (SFVs) and hand-operated valves (HVs).

1 Additionally, two new columns were included in Table 3.6-1...One column states whether the valves isolate automatically upon: receipt of an;SFAS signal. The other column lists each valve's normal operating position.

i A change is proposed to the existing footnote on table 3.6-1 (#4, above) to 4

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state that the valves may be operated as necessary (for. sampling, surveillance, etc.) under adainistrative control but when valves without auto-isolation are open, the controls are attended by'an operator. The valve positions shown on Table 3.6-1 are only the valve's " Normal" positions.

Sixteen containment isolation valves from the hydrogen monitor system, hydrogen recombiner and hydrogen purge system are added to Table 3.6-1 (#6,

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above). This incorporates valves which were added to the' system in 1983.

1 The remaining changes (#5 and #7, above) are administrative in nature and do y

not affect reactor safety.

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i EVALUATION AND BASIS FOR SAFETY FINDINGS i

Systems, Subsystems, Components Affected 1

Table 3.6-1 of the Rancho Seco Technical Specifications lists the " Safety.

Feature Containment Isolation Valves." The valves listed in Table 3.6-1 are part of various plant systems. Additionally, the affected valves are part of 4

the Reactor. Building isolation system. The specific valves which are affected by the proposed amendment are' discussed in the remaining sections. The t-Reactor Building isolation system"is addressed in USAR Section 5.2.4 (Reactor.

i Building Isolation System) and Technical Specification.Section 3.6, (Reactor j.

Building).

p Safety Functions of Affected Systems / Components i-i The Reactor Building isolation system is designed to minimize the leakage of,

j radioactive materials through the pipes penetrating the Reactor Building ~ walls in the event of a loss of coolant accident. Double barrier protection is-4 4

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k ATTACHHBff'II (Cont'.)

- FACILITY CHANGE SAFEFY ANALYSIS PAGE 3 0F'7" i

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. PROPOSED AMENDMENT NO. 111, REY. 1

. Safety Functions'of Affected Systems / Components (Cont.)

provided to ensure that no single ~,' credible. failure or, malfunction.of an active component will result in a loss of isolation. The installed' double barriers take the form of closed piping systems, both 'inside: and outside. the

. Reactor Building, and various ty' pes of isolation valves (USAR section'5.2.4.1,1

- Design Basis).

t Effects on Safety Functions:

l Four reactor building inlet and outlet Reactor Building Purge Isolation valves (SFV-53503, 53504, 53604, and 53605) will be deleted from Table 3.6-1 (#1, above). The four. valves are administrative 1y closed.(by Technical Specification Section 3.6.7) for all plant conditions above cold shutdown, and these are judged as not requiring maximum closure times shown on Table 3.6-1.

Since the valves are closed during plant operation, this Lehange-has no effect on safety functions.

This proposed amendment increases the maximum closure time of selected containment isolation valves to 25 seconds (#2, above),. which, by analysis has been determined to result in a release which remains within-10 CFR 100.11 requirements, even in the event of a LOCA. Since-the requirements of the CFR are met, there is no effect on ' safety functions.

Certain valves in Table 3.6-1 are currently identified with a single asterisk to designate them as having no automatic initiation. Some of the so designated valves have SFV valve identifiers which would normally indicate SFV actua tion. diange #3 clarifies this situation by reformatting the table and '

stating which of the valves have no automatic initiation, regardless of their SFV identifier.

The existing footnote discussed in the previous paragraph has been changed to allow-operation of the valves under administrative control (#4, above). 'The Normal Operating Position column on the revised table is added for information only; the valves may be operated in accord with the appropriate approved.

procedures. However, when valves that do not auto-isolate are open, the control for the respective valve is attended by an operator. The safety consequences of. manipulating the valves during Lpower operation have been -

previously established in-the preparation and~ issuance of the procedures. The

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designation of~these valves in Table 3.6-1 as being under' administrative control is an administrative change that has no involvement with plant safety.

Containment isolation valves for Post Accident Sampling System (hydrogen monitor isolation valves HV-70040 through HV-70047), Hydrogen Recombiner (HV-53620 through HV-53623), and Reactor' Building Hydrogen Purge (HV-53617:&-

HV-53618) were installed in 1983. These are normally-closed valves,~ operated from panel'H4PBA &.H4PBB, per Procedures A.11.A,. Reactor Sampling System and~

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' FACILITY CHANGE. SAFETY ANALYSIS PAGE 4 0F 72 I

l PROPOSED AMNDMENT NO.111, REY.21;

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' Effects on Safety Functions (Cont.)

A.52, Hydrogen Purge System. :These valves _ meet the criteria of Standard

. Review. Plan 6.2.4.II.6.r,-Containment: Isolation. System Acceptance Criteria,

and as such,'they-meet;the= requirements of criterion 66 of;10CFR50, Appendix-

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Additionally, Reactor Building Hydrogen Purge valves SFV-53615 and 53616 I

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- are added to the. table. These are normally-open isolation' valves, operated from pane 1~H2 SPA and H2SFB per1 Procedure A.52, Hydrogen Purge. System.c These

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-valves automatically close upon receipt of a-safety features signal. The t

inclusion of these sixteen valves into Table 3.6-l'(#6, above).is required.

since these are containment isolation valves.

1 The title of Table'3.6-1 will be changed from " Safety Features. Containment Isolation Valves" to " Containment Isolation-Valves" since the listed valves

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are not exclusively safety features actuated' (#5, above). This title change is

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. considered purely administrative, and is judged to have no ' involvement with plant safety. Similarly, the renumbered page (#7, above), resulting fros' j

additions to Table 3.6-1, is an administrative change and also judged as j

having no involvement with plant.' safety.

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Analysis of Effect on Safety Functions i

As' discussed in the previous section, four isolation-valves (SFV-53503, 53504, 53604,-and 53605) will be deleted from Technical Specification Table 3.6-1.

These four valves are administrative 1y closed.for all plant conditions above cold shutdown, and thus are judged'as not requiring maximum closure times to be shown on Table 3.6-1.

The deletion of these purge valves from Table 3.6-1.

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is judged to have no. involvement with plant-safety.' This is-because:

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i-The four reactor building purge valves are administrative 1y locked closed for all plant conditions above cold shutdown (Operating' Procedure A.14, i.10), and their position is verified monthly (Surveillance

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-Procedure.SP 205.07, as required by Section 3.6.7).

Operability, closure j

on failure, and acceptable closure time per ASME Subsection IWV-of Section XI are tested at cold shutdown (Surveillance Procedure 214.01), and seat.'

I leakage-is checked at-each refueling'-outage. Since the' operability of.the j

purge system is required in Technical Specification Section 3.8.10, surveillance on the valves will' continue to be performed in surveillance-procedure 205.07C.

o The'above cited administrative. controls assure isolability of the reactor a

building purge valves for all conditions 'of plant operation, and their -

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deletion from Table 3.6-1 is judged as:

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a.

Not involving a significant increase in the' probability of an accident or malfunction which has been previously evaluated. <The r

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ATTACHMENT II (Cont.)

_ L FACILITY CHANGE SAFETT ANALYSIS.

PAGE 5 0F 7' PROPOSED AMENDMENT NO. 111, REY. 1

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Analysis of Effect on Safety Functions 1(Cont.)_

deletion of the purge valves from Table 3.6-1 in no.way. increases the

probability of a previously analyzed accident condition as-

. administrative controls assure their' safe (closed). position.

b.

Not creating the' possibility of.a new or different kind of accident from any accident.previously evaluated..TheLdeletion of the purge.

. valves from Table 3.6-1 in no way introduces a new or.different accident condition as administrative controls (Technical Specification Section 3.6.7) assure their safe -(closed) position.

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Not involving a significant reduction in a margin of safety.

Deletion of the four reactor building purge valves fron' Table 3.6-1 in no way affects the operation of valves'which, by_ administrative controls, ensures that safety margins 'are not affected.

The increase in closure time to 25 seconds of selected isolation valves has, by analysis, been determined to result in offsite doses which remain within-10 CFR 100.11 limits. It was determined that at a maximus' closure time of-25 seconds, these selected containment isolation valves would not allow a radiation release to the Exclusion Area Boundary.(EAB) or Low Population Zone (LPZ) during the worst accident condition (LOCA) that would exceed the limits of 10 CFR 100.11. In fact,'a significant margin exists between the calculated values and those of 10 CFR 100.11.

Variations in the ambient air temperature periodically require' the 12" reactor building pressure equalization valves' to be opened. In addition, other containment isolation valves listed in' Table 3.6-1 offer direct flow paths from the. containment building atmosphere to the environment. 'During the maximum hypothetical accident (hHA),.the. flow through these valves, as containment integrity is being established,:can produce an additional source of fission product leakage.

The equalization valves have a maximum closing timefof 25 seconds.. If loss of off-site power is-assumed, an' additional 10_~ seconds _is required ~for the diesels'to accept the power' loads for the valves. Therefore, it is.

conservatively assumed that the equalization valves are open for the first I

34.9 seconds af ter the MHA, and are completely closed:st 35 seconds (0.1' second valve closure). The other containment isolation valves which provide a.

direct flow path from the containment atmosphere to the environment associated with these penetrations have closurn times less than or equal'to the closure time of the equalization valves and therefore are conservatively assured to -

perform similar to the equalization-valves (i.e., remain open for 34.9 seconds and close in 0.1 seconds).

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s ATTACHMENT II- (Cont.)

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' FACILITY CHANGE SAFETY ANALYSIS

-PAGE 6 0F:7 PROPOSED ' AMENDMENT NO. lil, REY.1 i

Analysis of.Effect on Safety Functions (Cont.)-

r As discussed in USAR section 14.2.2.7, Maximum Hypothetical' Accident, no-mechanism was postulated wherein a gross-release of fission products would

. occur since a multitude of failures would be required'in safety features which

'are provided to prevent.such an occurrence.. USAR section'14.2.2.5, Loss-of-Coolant Accident (LOCA),. discusses.a mechanistic evaluation of a-LOCA.- Table 14.2-13. lists peak clad temperature and the time of~ occurrence for an 8.55-sq.-ft. DE break at. pump discharge for four and three pump operation. Peak clad' temperatures (which are well-below fuel melt temperatures as discussed in section 14.2.2.5.4.F., Examination of Core.

Component Structural integrity) occur at 61.5 seconds post-accident-or. longer.

1-Based on the discussion in the previous paragraph, it:is conservatively I

assumed that containment integrity is achieved at T=35 seconds. Since peak clad temperature occurs af ter T=35 seconds it is not credible to assume that-i core melt can occur before this time. Therefore it is assumed that the total i

RCS coolant activity (see USAR Table 14D-2) including a pre-existing iodine i

spike of 60 uci/cc dose equivalent. I-131, is available for release via the containment isolation valve pathways. This method of developing-the' source i

terms used for the radiological calculations of the MHA dose contribution:

j during the establishment'of containment integrity is consistent with Branch i

l Technical Position CSB 6-4, section B.5.a.

j Calculational results of the doses to the Low Population Zone (LPZ) and Exclusion Area ' Boundary (EAB) due 'to the MHA are provided in Enclosure I.

The

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incremental dose to the control room due to leakage prior to the establishment of containment integrity is negligible.

Although the maximum closure times for the listed valves will be increased'to 25 seconds, the current " reference time" for valve closure (based on t

manufacturer's design stroke time) will be retained in surveillance procedure l

SP 205.07C. Comparison of stroke times, as observed during surveillance,'with l

this original " reference time" will ensure against degradation of valve i

function.

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i The change does not involve an increase in the probability of an accident; l

previously evaluated but does slightly increase the radiological releases above the values from the previous analysis. The radiation releases to the i

EAB and LPZ under the worst accident conditions result in radiation expceures j

that are well below the guideline values allowed by 10 CFR 100.11. Acceptable performance of the containment isolation valves is ' assured at all times by the periodic testing of all these valves in accord with the acceptance l

. requirements 'of ASME Section XI, Subsection IW.

1 The change does not create the possibility of a new or'different kind of I

accident from what had been previously evaluated. The increase 'of maximum I'

closure _ times' of the specified containment isolation valves does not in'troduce t

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ATTACEMENT II (Cont.).

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p FACILITY CHANGE SAFErY ANALYSIS:

PAGE'7 OF 7

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PROPOSED AMENDMENT NO. 111, REY. 1-i Analysis'of-Effact'on Safety Functions (Coat;)

a design or operational change which could result in i new or:different-raccident-potential.which is worse than the LOCA already considered.1 1-The change does not involve a-significant; reduction in' a' margin of safety. -

' Although increasing the maximum closure times of the containment isolation valves from the presently specified range-_of from 3 to 21' seconds, to 25 i

seconds does' represent'an increase in exposure -calculations confira that, __.

there remains an adequate margin to the guideline' exposures established in 10-1 CFR 100.11.1 For these reasons,-the increase in.the maximum closure time for t

the s'pecified containment isolation valves has no adverse effect on plant' safety.

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Summary l

Proposed Amendment No. 111, Rev..I consists of five general changes to Table 3.6-1 of the Rancho Seco Technical Specifications,' as well as two:

administrative changes.- The general changes include the deletion and addition 4

of valves to Table 3.6-1, as well as increasing the maximum closure time for 18 containment isolation valves.

l The proposed amendment is not a change to the facility as described in the i

USAR. However, USAR Table 14.3-1, Summary of Maximum Integrated Doses in Rees -

(attached) will be amended to incorporate the information contained in Enclosure I.

As discussed in the previous section, as a result'of this j.

amendment to the Technical Specifications, the probability of' occurrence or-the consequences of an accident previously evaluated will not be increased, i

the possibility of an accident of'a different type than previously evaluated l_

will not be created, and the margin of safety _as defined in the Technical I

Specifications is not reduced. The slight increase in off-site doses is well within acceptable limits. An Unreviewed Safety Question is not, involved.

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ATTACHMENT III "NO SIGNIFICANT HAZARDS" CONSIDERATIONS PAGE 1 OF 2 Proposed Amendment No. 111, Rev. 1 consists of four (4) general changes to Table 3.6-1 of the Rancho Seco Technical Specifications, and a resulting renumbering of one page of the technical specifications.

The District has evaluated the proposed changes against each of the criteria of 10 CFR 50.92, and concluded that plant operation with the proposed changes incorporated in the Rancho Seco Technical Specifications would not result in any significant hazards.

The proposed changes and the evaluation of them against 10 CFR 50.92 criteria are addressed below:

1.

The four (4) reactor building purge valves are being deleted from Table 3.6-1.

These valves, through administrative controls, are locked closed during power operation and thus need not have their maximum closure time specified in the technical specifications.

The reactor building purge valves are only open during cold shutdown, and in the event of high airborne radio-activity, the radiation monitoring system automatically closes the valves.

The function of those valves is in accord with USAR Chapter 14, and their deletion from Table 3.6-1 does not result in any new failure mode.

Thus, deletion of the four (4) Reactor Building Purge Valves is judged to cause no new or previously evaluated accident potential or have any effect on margins of safety.

2.

Containment Isolation Valves which are not in direct flow paths from the containment atmosphere to the environment presently are specififed in Table 3.6-1 to have maximum closure times of 3 to 21 seconds depending on their in-situ closure times when initially installed.

This proposed amendment increases the maximum closure time of these valves to 25 seconds which, by analysis has been determined to remain within 10 CFR 100.11 requirements even in the worst accident condition, i.e.,

LOCA.

Since the function of these valves remain in accord with the requirements of 10 CFR 100.11, their increase to higher maximum closure times is judged to cause no new or previously evaluated accident potential or have any significant effect on any margin of safety.

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.The following. proposed' changes are administrative in nature and therefore are evaluated together:

a.

The title of Table 3.6-1 is changed from " Safety Features Containment. Isolation Valves" to "Contain-ment Isolation Valves" because the listed valves are not exclusively Safety. Features Actuated valves.

b..

The additions to Table 3.6-1 of the containment isolation valves installed during the 1983 refueling outage necessitate changing page 3-40a of the Rancho Seco Technical Specifications to page 3-40b.

4 These two changes, being purely administrative, are judged as causing no new or previously evaluated accident potential or having any effect on margins of safety.

On the basis of the above evaluation, the proposed changes are not foreseen as being a significant hazard to the public.

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