ML20042F433

Application for Amend to License NPF-29,clarifying Name Used to Describe Plant Location in Which Equipment Area Temp & Equipment Area Delta Temp Isolation Actuation Instrumentation Installed for RWCU

ML20042F433
Person / Time
Site:	Grand Gulf
Issue date:	05/04/1990
From:	Cottle W SYSTEM ENERGY RESOURCES, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20042F434	List: ML20042F433 ML20042F435
References
AECM-90-0040, AECM-90-40, NUDOCS 9005080314
Download: ML20042F433 (9)

Text

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Ensigy MnM2 * ,

William T. Cottle vice Pawe May 4, 1990 "" #""

U.S. Nuclear Regulatory Commission  !

Mail Station P1-137 '

Washington, D.C. 20555 Attention: Document Control Desk 1 Gentlemen:

SUBJECT:

Grand Gulf Nuclear Station Unit 1 Docket No. 50-416 I License No. NPF-29 RWCU System Isolation Actuation Instrumentation Proposed Amendment to the Operating License (PCOL-90/02)

AECM-90/0040 System Energy Resources, Inc. (SERI) is submitting by this letter a proposed amendment to the Granct Gulf Nuclear Station (GGNS) Operating License.

This proposed amendment requests clarification of the name used to describe the plant location in which equipment area temperature a.1d equipment area- t delta temperature isolation actuation instrumentation is installed for the

• Reactor Water Cleanup (RWCU) system. In particular, the RWCU system temperature isolation actuation instrumentation currently specified in the Technical Specifications (TS) as being in the "kWCU Valve Nest Room" is actually located in the "RWCU Heat Exchanger Room Valve Nest Area". I As discussed in AECM-90/0013 dated January 16, 1990,.SERI committed to pursue a TS change to clarify TS Table 3.3.2-2. Attachment 2 of this letter provides the discussion and justification for the proposed TS change described in the supplemental corrective actions section of AECM-90/0013.

In accordance with the provisions of 10CFR50.4, the signed original of' the requested amendment is enclosed. This amendment has been reviewed and accepted by both the Plant Safety Review Committee and the Safety Review Committee.

Based on the guidelines presented in *.0CFR50.92, SERI has concluded that this proposed amendment involves r.o..significant hazards considerations.

Yours truly, i

l WTC:mte "3 dh l Attachments: 1. Affirmation per 10CFR50.30

2. GGNS PCOL-90/02

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AECM-90/0040 Page 2 cc: Mr. D. C. Hintz (w/a)

Mr. T. H. Cloninger (w/a)

Mr. R. B. McGehee (w/a)

Mr. N. S. Reynolds (w/a)

Mr. H. L. Thomas (w/o)

Mr. H. O. Christensen (w/a)

Mr. Stewart D. Ebneter (w/a) [

Regional Administrator U.S. Nuclear Regulatory Commission [

(

Region 11 101 Marietta St., N.W., Suite 2900 Atlanta, Georgia 30323 I,

Mr. L. L. Kintree Project Manager (w/a)

Office of Nuclear Reactor Regulation [p U.S. Nuclear Regulatory Commission j Mail Stop 14B20 e Washington, D.C. 20555 Dr. Alton B. Cobb (w,'a)

State Health Officer State Board of Health P.O. Box 1700 f Jackson, Mississippi 39205 (

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1 BEFORE THE UNITED' STATES NUCLEAR REGULATORY = COMMISSION 1

' LICENSE-NO.;NPF-29

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DOCKET..N0;50416)

IN THE MATTER-OF MISSISSIPPI POWER & LIGHT COMPANY

" and SYSTEM ENERGY RESOURCES, INC.

and SOUTH MISSISSIPPI ELECTRIC POWER: ASSOCIATION ~

AFFIRMATION .

l I,' W. T. Cottle, .being duly sworn,- state -thai, 'I:am'- Vice > President, j

-Nuclear Operations'of System Energy Resources, Inc.;-thatton. behalf of System Energy Resources, 'Inc., and South Mississippi Electric Power -Association I- am . j authorized by System Energy Resources, Inc. to sign ~ and- file with the Nuclear t

1 Regulatory Commission, this' application for amendment of the Operating License-  ;

of the Grand Gulf Nuclear Station;' that:I' signed'this' application as' Vice  !

President, Nuclear Operations of System Energy Resources,LInc.';'and that the a" statements made and the matters set forth'there.in'are,true and correct to the best of my knowledge information and ' belief.

a w 3---  % ._ -

.W. T. Cottle-STATE OF MISSISSIPPI C0ilNTY OF CLAIBORNE

• o SUBSCRIBED AND SWORN TO before me, a Notary Public, in and for the.

County and State above named, this \.L. day of rns ,,1990, i - -

(SEAL) hME Mucchh

-Notary Public j

My commission expires: '

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Attachment 2 to AECM-90/0040-;

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A. SUBJECTL

1. NL-89/08 RWCU System Isolation Actuation Instrumentation -

2. Affected Technical Specification: Isolation Actuation Instrumentation.Setpoints, Table 3.3.2-2, page 3/4'3-17 -

B.- DISCUSSION 1, - GGNS Technical Specification (TS) 3/4.3.2. currently requires systemh

-isolation instrumentation for the " Reactor Water Cleanup (RWCU)

Heat Exchanger (Hx) Room", the "RWCU Pump Rooms," and the "RWCU Valve Nest Room" be: operable during Operational Conditions 1, 2, and 3.

2. A Quality Deficiency Report (QDR) identified and documented.on July 18, 1989 discrepancies _between RWCU pipe break' analyses assumptions and the actual plant inttrumentation'used to detect and: isolate

.RWCU pipe breaks. In.particular, the QDR identified that: ~ '

1) the RWCU line break analysis relied on an isolation 1 function-. time-consistent with the temperature. instrumentation design for breaks detectable only by the: flow instrumentation; and 2) the "RWCU Valver

. Nest Room"'(Room No. IA443) listed in TS Table 3.3.2-2!did not'-

contain equipment area temperature or equipment area. delta-temperature elements. The temperature elements referred to as the "RWCU Valve Nest Room" listed in TS Table 3.3.2-2 are actually located in the "RWCU.Hx Room Valve Nest Area". The."RWCU Hx Room Valve Nest Area" is part of' Room No.J1A414~("RWCU Hx Room").

3. A new pipe break analysis.was-performed for those portions:of the:

RWCU system which-are dependent on only'the delta flow- -

instrumentation for detecting and isolating the postulated line-break. The new analyses also evaluated piping failures in the -

"RWCU Valve Nest Room". In the new analysis for Room 1A443, credit-was taken only for the RWCU delta-flow isolation. A discussion of this analysis is provided in Section C.

4. The proposed change to the TS will; clarify the name used to describe the plant location in'which the-affected temperature-elements are actually located. The "RWCU Valve Nest Room" is revised to "RWCU Hx Room Valve Nest Area" (see the attached mark-up of TS Table 3.3.2-2).

5.

'The above described condition was submitted-in letter AECM-90/0013 dated January 16, 1990 to the NRC as a Licenses Event Report (LER).

SERI committed in that letter to pursue a TS change to clarify the current TS.

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Attachment-2lto.AECM-90/0d404

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e C. JUSTIFICATION

1. For postulated piping failures in:the RWCU system,;various diverse methods of leak detection.and system isolation are provided. The iplant areas containing-high energy RWCU piping and components are '

as follows. j a - Drywell,- .. . - . -

b. Main steam tunnel inside tht auxiliary building, l

c. ' RWCU pipe' chase inside the auxiliary building,

d. 'RWCU pipe chase inside the containment,-

e. Main' steam tunnel inside the co1tainment, -;

f. RWCU pump rooms A (1A209) and B (IA210),  ;

g. RWCU heat exchanger room (IA414), '

h. RWCU filter /demineralizer (F/D) rooms: A (1A516) and B-(IA517),

1. RWCU valve access area room (alsm termed the valve nest room,- a 1A443, located below the F/D roon's), 4

j. RWCU F/D valve room'(also termed the holding. pump room, 1A515)..

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2. The detection' of RWCU' leakage 'in' side t he drywell-is performed by the drywell unidentified leak: detection instrumentation. The .

remaining areas are monitored by'at least one of two methods: 1) high delta flow between the system inlet flow'. rate and the sum of 1

the system discharge flow rates; and 2) highLarea temperature and high area delta temperature:inside the RWCV. rooms containing " hot" process- fluid (i.e.,' above 200.*F). - The instrumentation ~ applicable "1 to these areas is safety related, redundant,:divisionally powered,  !

and provides control room alarms and a trip =of the Group 8 isolation valves.

3. The TS requirements for the RWCU isolatiod instrumentation-described in TS Table 3.3.2-2, Section 4 7ddress' leak detection instrumentation serving both " hot" process and " cold" process

! piping and components. The requirements oa the RWCU " hot"_ process ,

piping and components are both' delta flow s nstrumentation- and temperature (equipment area and' equipment area' delta)'

instrumentation. The requirement.on the RWOU_" cold" (i.e., less than 120*F) process piping and' components ir, delta flow instrumentation, only, i

'4. For rooms normally having RWCU piping with water at temperatures of j less than 120'F, the RWCU isolation circuit relies-on'the.high  ;

L delta flow isolation signals. The high area temperature and high area delta temperature isolation instrumentation for these areas ,

are generally not effective and were deleted from the TS in 1984 as '

part of TS Amendment 13 (see SER Supplement 6 dated August 1984).

These rooms still have control room alarms on high area temperature and high area delta temperature (except 1A443 and the RWCU >1' containment pipe chase) but no automatic RWCV isolation based on-the temperature' parameters.

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Attachment--2 to;AECM-90/0040: 1 o, ,; p - '

. 5. In response to the QDR,Dthe. design analyses (e.g', the mass and' energy blowdown calculations).for'those postulated " cold" RWCV- *

. break locations which'are dependent on only the delta flow .

. instrumentation.for detection and automatic isolation were revised..  ;

The previous UFSAR analyses for the limiting' RWCU. piping failures- J were. based on leak detection and RWCV system isolation atino more .

than 60: seconds following the failure (see UFSAR Section 6.2). ~The 60: seconds blowdown time allowed only.2 seconds.for the: '

inst' amentation fun:: tion time (based on 'a trip on high area L temperature rather than.high delta flow). Since the actualisystem

isolation t' rip for piping failures in;the

" cold" RWCU piping occurs ,

using the delta flow instrumentation, ;the larger time delay associated with the delta flow trip. logic was not accounted foriin<  ;

the existing analyses. '

The: revised'line break analysis.was performed for the following r areas: '

a

a. RWCU pipe chase inside the containment, d 3

b. RWCV valve nest room (IA443), ,

c. RWCV holding. pump room, r'

d. RWCU F/D-rooms A and B.

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6. -From the results of the new RWCU line break analysis for the . ..

i identified areas, the new isolation function time based on cnly the  :

delta flow trip was determined to be acceptabie since the h.igher

.resulting blowdown parameters are still well within existing design

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o limits. This conclusion is based on an assessment of:the increased i blowdown parameters affecting systems, structures, and components needed to mitigate the postulated RWCU line breaks and perform the j required safe shutdown functions. :This assessment included the - '

dependent consequences (e.g., room. pressurization transients,.

environmental qualification profiles, etc.) for not' or.ly the' RWCU I areas immediately affected but also for the adjoining areas up to ,

and including the containment structure. The' relevant. parameters were calculated for the affected areas using appropriate. values'for 4 free volumes and heat sinks in the'subcompartment nodal analysis.

The impact of flooding from piping-failures in the RWCU-g subcompartments was found to be negligible. The offsite doses 5 resulting from the postulated RWCU piping failures-in the containment were also found to be' much less. than those already -

evaluated for the main' steam line break outside containment event.  :

Even though the radionuclide concentrations and activity levels in-the RWCU leakage are consistent with those of the~ main' steam line',

the total mass releases for the RWCU piping failures are.

significantly lower and the reduction of'the radioactivity levels o via the containment release pathway is much greater.

7. The reactor vessel water level response to the postulated RWCU  !

piping failures is a relatively mild. event in _ comparison to the  !

more limiting pipe breaks. Therefore, no specific reactor water level transient analysis was necessary for evaluating the existing RWCU line break scenarios. The new RWCU line break evaluation does '

not affect the design parameters applicable to reactor vessel water level protection.

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Attachment 2 to AECM-90/0040

8. The new RWCU line break analysis does not affect any of the associated TS instrument operability requirements or setpoint values nor are any new TS requirements being imposed for the delta flow or " hot pipe" temperature i'struments.

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9. SERI's evaluation has shown that the line break detection and isolation functions for piping failures in the "RWCU Valve Nest Room" are adequately performed by the delta flow instrumentation I and are consistent with other " cold" RWCU process component areas.

Therefore, additional TS requirements for temperature monitoring in the "RWCU Valve Nest Room" 1A443 are not necessary.

10. As described in the associated LER, the temperature elements specified in the TS as being in the "RWCU Valve Nest Room" are actually installed in the "RWCU Hx Room Valve Nest Area". Even though the actual location of the instruments was known and correctly shown in the design drawings, it was not recognized as a E. discrepancy prior to identification in the QOR. SERI's evaluation l j

determined that the discrepancy does not affect the analysis l performed for the "RWCU Hx Room" and that the temperature setpoints i listed in the TS are appropriate for the as-built configuration. )

Since the temperature elements associated with the "RWCU Hx Room  !

Valve Nest Area" are located in the area (and in the applicable HVAC ductwork) where required by analysis, only the location description specified in TS Table 3.3.2-2 is proposed to be changed to occurately reflect the physical location of the temperature t elements. l D. NO SIGNIFICANT HAZARDS CONSIDERA' IONS SERI is proposing with this amendment request a revision to TS Table 3.3.2-2, " Isolation Actuation Instrumentation Setpoints", which would clarify the location name of "RWCU Valve Nest Room" to "RWCU Hx Room Valve Nest Area" to accurately reflect the physical location of the equipment area temperature and equipment area delta temperature instrumentation. The proposed amendment is a result of a self identified deficiency in the RWCU pipe break analysis.

The Commission has provided standards for determining whether a no i significant hazards consideration exists as stated in 10CFR50.92(c). A )

proposed amendment to an operating license involves no significant I hazards consideration if operation of the facility in accordance with the proposed amendment would not: (1) involve a significant increase in the probability or consequences of an accident previously evaluated; or I (2) create the possibility of a new or different kind of accident from {

any accident previously evaluated; or (3) involve a significant l reduction in a margin of safety.

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SERILhas evaluated the 'no= significant hazards considerations in its , .

request.for a-license amendment. In accordance'with 10CFR50.91(a), SERI  :!

is providing the analysis of'the proposed amendment.~against the three standards in 10CFR50.92: i 1

1. No significant increase in.the probability or. consequences of an -i

< accident previously evaluated results from.this change,

a. Although the proposed' change results in an' increase in the RWCU l' isolation time.in mitigating a~ postulated RWCU line break-(due to.the 45.second delay timer in the 'delta' flow:

~. instrumentation), this:increasedsisolation time has-been  !

' demonstrated to have 'no = adverse- effects onl systems,c structures, 3 or components.necessary to mitigate postulated RWCU line breaks

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and safely-shut down the plant.,'In' addition, this change clearly has-no potential tc. increase the likelihood.'of any11ine break. Therefore,!this change will not increase the.

4 probability of occurrence of a.previously evaluated ~ accident.- i

b. -The large break' temperature and pressure transients for'~the applicable RWCU areas have been reanalyzed. The newsanalysis incorporates inputs based'on a more accurate estimate of ,

forward flow blowdown enthalpy'and mass flow rate, mass "

inventory available.for reverse flow,.and additional heat' sinks inside the containment. The'results'of this' analysis have-shown that:the new parameter.~ values are; enveloped.by the  :

existing design. As previously described, the; increased v' temperature profiles in the affected compartments have been evaluated and still remain. within theitested: temperature. limits ,

of affected environmentally qualified equipment. .The:

o' subcompartment pressure profiles also: remain-within'the' <

structural design limits. The bounding containment l negative }

pressure transient is' based on a break-in the RWCV-system

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L followed by an inadvertent actuation of containment spray. The resulting net pressure differential.across the containment is-l- still much less~than_the design negative 1 pressure of_3.0 psid. a L The limiting suppression pool vent velocities.and thus the 1 L reverse pool swell drag and impact loads resulting from the containment negative pressure transient were not.affected by  ;

(- this change. . In addition,.the offsite doses resulting'from the  :

postulated RWCU piping ' failures were ~found- to be much less than -

those already evaluated for other events (e.g., the' main. steam '

line break outside containment). Since the new analysis has demonstrated that the required design functions- are_ met and the-temperature elements are.actually located where required, th_e consecuences of previously evaluated accidents are'not-

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increased,

c. Therefore, the -probability or consequences of previously analyzed accidents are not increased.

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s Attachmerit 2 to AECM-90/0040

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2. . -The change would not :reate the possibility of.'a.new or.different kind of accident from any previously' analyzed..  :

a. This. change involves an increase in isolation time in the. event of an.RWCU' pipe break. There is no' adverse rimpact-on systems,

-structures, and components-necessary to mitigate a postulatedL

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RWCU-line break or safely shut down:the plant. There are no" new event precursors created by'this change. Tho'TS are  ;

changed to. reflect the actual location of the temperature i elements as required by analysis.

- b. No.new' mode of operation .is introduced by th_is' change. 'l

c. Therefore . this cha'nge does. not create the possibility' of a new- ,

or different kind of accident from any'previously; evaluated. t j

3. Thischangewouldnotinvolvea'significantreduction$inithe~margilni -

of safety..

a. The clarification of.th'e TS requirements for- RWCU.systemb -

isolation: based'on lack-of temperature; elements in;the "RWCU.

Nalve Nest Room" is based on a reanalysis of RWCU breaki scenarios:taking credit for only the existing. delta flows '

j isolation instrumentation.- The analytical limits and the bases m 3

for the existing delta flow isolation'act'uationfinstrumentati.oni '

trip setpoints:are'not affected by this. change. "The new ,

analysis:is based on the existing safety limits and TS values,  !

for-valve stroke > times, instrumentation responseitimes,-and- l accuracy allowances.- The reanalysis 1 demonstrated that,0for the'  !

_ postulated RWCU breaks, there are no adverse effects on . '

i -systems, structures, or components required to mitigate the pipe break or to safely shut down'.the plant. The proposed-

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r change will result in the. actual location of the temperat'ure ,

elements being properly described. ~

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b. Therefore, this change will not involve a significant reduction in the margin of safety.

Therefore, based on the above evaluation, operation in accordance with the proposed amendment involves no significant. hazards. considerations.-

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