Text

Application for Amends to Licenses NPF-76 & NPF-80,revising Min Vol Requirement for Tech Spec 3.7.1.3, Auxiliary Feedwater Storage Tank, from 518,000 to 485,000 Gallons
	ML20082M534
Person / Time
Site:	South Texas
Issue date:	08/26/1991
From:	Kinsey W; HOUSTON LIGHTING & POWER CO.
To:	; NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20082M537	List: ML20082M550; ST-HL-AE-3861, Application for Amends to Licenses NPF-76 & NPF-80,revising Min Vol Requirement for Tech Spec 3.7.1.3, Auxiliary Feedwater Storage Tank, from 518,000 to 485,000 Gallons;
References
	ST-HL-AE-3861, NUDOCS 9109050242
	Download: ML20082M534 (12)
	v • d • e

-

'The Light cllouston o mLighting p a n& Power y 8"'h Tynas l'ndn t l}nipy penyyating steign j';p no 28{ yad ong.ynni7fyy _

August 26, 1991 ST ilL AE-3861 File No.: G9.06 10CFR50.90 U. S. Nuclear Regulatory Commission Attention: Docunent Control Desk Washington, DC 20555 South Texas Project Electric Generating Station Units 1 6 2 Docket Nos. STN 50 498, STN-50 499 Proposed Amendment to the Unit I and Unit 2 Technical Soecifications The purpose of this submittal is to propose a change to the requirements of Technical Specification 3.7.1.3, Auxiliary Feedwater Storage Tank. This proposed change will revise the minimum volume requirement for this tank from 518,000 to 485,000 gallons.

HIAP has reviewed the attached proposed amendment pursuant to 10CFR50.92 and determined that it does not involve a significant hazards consideration.

The basis for this determination is provided in the Attachments. In addition, based on the information contained in this submittal and the NRC Final Environmental Assessment for STPEGS Units 1 and 2, IllAP has concluded that, l pursuant to 100FR51, there are no significant radiological or non radiological impacts associated with the proposed action and the proposed license amendment will not have a significant effect on the quality of the environment.

The STPEGS Nuclear Safety Review Board has reviewed and approved the proposed changes.

In accordar.co with 10CFR50.91(b), liiAP is providing the State of Texas with a copy of this proposed amendment.

b d b > '(( l

'0 0f A1/OH.NL9 A Subsidiary of Ilouston Industries incorporated VI I 9109050242 910826 (

PDR ADOCK 05000498 L

P PDR

, liouston Lighting & Power Company South Texas Project Elcetric Generating Station ST llL- AE-3861 File Fo.: l9.06 Page 2 If the NRC should have any questions concerning this matter, please contact Mr. A. W liarrison at (512) 972 7298.

Warren H. Kinsey Vice President, Nuclear Generation CCS/ amp Attachments: 1. Significant Hazards Evaluation for a Proposed Change to the Auxiliary Feedwater Storage Tank Minimum Volume Requirement

2. Summary of the Analysis Performed for the Auxiliary Feedwater Storage Tank Minimum Volume

3. Question 440.30N 4 Proposed Change to Technical Specification 3.7.1.3 l

A1/027.NL9

- - - . - - - _ . - ~ ~ . - . - ~ . - - - - . - - - . . - . - - - - -

f*.

ST llL AE'3861 llouston Lighting & Power Cornpany File No,;G9,06 4

South Texas Pndat Electric Generating Station Page3 t ec:

L I I

Regional Administrator, Region IV Rufus S. Scott

Nuclear Regulatory Commission Associate General Counsel 1 611 Ryan Plaza Drive, Suite 1000 llouston Lighting & Power Company Arlington, TX- 76011 P. O. Box 61867 Houston, TX 77208 i George Dick, Project Manager U.S. Nuclear kegulatory Commission INPO i Washington, DC 20555 Records Centor j 1100 Circle;75 Parkway J. I. Tapia Atlanta, GA 30339 3064-

Senior Resident Inspector

{ c/o U. S.-Nuclear Regulatory Dr. Joseph M. llendrie j _ Commission 50 Be11 port Lane

! .P. O. Box 910 Be11 port, NY 11713

Bay City, TX 77414 j

i. D. E. Lacker- J l' J. R.-Newman, Esquire Bureau of Radiation Control (

[ Newman & iloitzinger, P.C. Texas Department of Health _ ;

i 1615 L Street, N.W. 1100 West 49th Street Washington, DC 20036 Austin, TX 78756-3189 1

D. E. Ward /T. M. Puckett Central Power and Light Company i P. O. Box 2121 l- Corpus Christi, TX 78403 i

{ J . C. Lanier/M. B. Lee l City of Austin

! Electric' Utility Department i P.O. Box 1088 l Austin, TX 78767 i- R. R.'Fiedler/M. T. liardt 4

City.Public Service Board P. 0.. Box 1771 San Antonio, TX 78296 L

t' Revised 07/09/91 L4/NRC/

i

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter )

)

Houston Lighting & Fower ) Docket Nos. 50 499 Company, et al., ) 50 499

)

South Texas Project )

Units 1 and 2 )

AFFIDAVIT Warren 11. Kinsey being duly sworn, hereby deposes and says that he is Vice President, Nuclear Generation, of Houston Lighting & Power Company; that he is duly authorized to sign and file with the Nuclear Regulatory Corurission the attached proposed changes to the South Texas Project Electric Generating Station Technical Specifications relative to the Auxiliary Feedwater Storage Tank Technical Specification 3.7.1.3; is familiar with the content thereof; and that the matters set forth therein are true and correct to the best of his knowledge and belief.

k m Warren H. Kinsey IL)'

Vice President, Nuclear Genecation

, STATE OF TEXAS )

l }

}

Subscribed and sworn to before me, a Notary Public in and for The State of Texas this 2(#4ay of 6p4 , 1991.

=ces w m m 0 2 % @ m,,

I ROSE MARY PEREZ Nowy rvoc.suta or ian Notary Public in dnd for tl Mr Comnwon Capu 624 95 State of Texas l

l A1/02/,RL9

e d.

ATTACHMENT 1 SIGNIFICANT HAZARDS EVALUATION FOR A PROPOSED CHANGE TO THE AUXILIARY FiEDWATER STORAGE TANK HINIMUM VOLUME REQUIREMENTS A1/027.NL9

=- . . . - _ _ . - _ _ _ _ _ . _ - - . . . . . _ .

Attachment 1-ST IIL AE 3861 Page 1 of 4 SIGNIFICANT llAZARDS EVALUATION FOR A PROPOSED CllAN9E TO TiiE AUXILIARY TEEDWATER STORAGE TANK (AFST) MINIMUM VOLUMb REQUIREMENT Hackground The Auxiliary Feedwater (APW) system provides an independent means to supply feedwater to the steam generstors whenever the main feedwater system is not available. The AFW System also functions as an Engineered Safety Features Actuation-System component and is designed to function during a main feedwater line break (HFLB), main steam line break (MSLS), loss of offsite power (LOOP),

and loss of coolane accident (LDCA).

Under the above accident conditions, the APW system is designed to permit operation at hot standby for at least four hours, followed by a cooldown to RilR cut-in conditions. The RilR system continues the cooldown to cold shutdown conditions.

During the development of Draft Technical Specifications for STPEGS, a calculation.was performed assuming 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months at hot standby with a 10 hour1.157407e-4 days 0.00278 hours 1.653439e-5 weeks 3.805e-6 months natural circulation cooldown. This was followed by an 8 hour9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months soak period which prevented the formation of a steam bubble in the reactor vessel head. The calculation required 360,000 gallons for 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months at hot standby and 10 hours1.157407e-4 days 0.00278 hours 1.653439e-5 weeks 3.805e-6 months of cooldown. The 8 hour9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months soak time required 85,000 gallons and the volume of water spilled from a postulated faulted steam generator was 20,250 gallons Volumes were also derived to prevent vortex formation (13,100 gallons), the volume required for seal Icakage (16,800 gallons) and to account for an instrument.

-error of 24 (12,500 gallons). The unusable volume (10,400 gallons) of the AFST along with the above requirements resulted in-a total calculated Technical Specification volume of 518,050 gallons. This calculated volume for the AFST was used in Draft Technical Specification 3.7.1.3 and is the basis for the current Technical Specification 3.7.1.3 minimum required volume for the AFST, This calculation was overly conservative. The 8 hour9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months soak period is not required to prevent a steam bubble in the reactor vessel head, In NUREG 0781 Supplement No. 3, Section 5.4,7 the NRC staff accepted the position that a 8 hour9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months soak time is not required. The reactor vessel head vent can be operated during the cooldown to' promote upper head cooling which in conjunction with a

- 25"F/hr cooldown will eliminate the need for upper head soak. Qualified

-instrumentation (upper head thermocouples) is used to determins when the head vent should be operated.

A1/027,NL9

1 Attachment 1 ST HL AE 3861 Page 2 of 4 froblem Description The Auxiliary Feedwater Storage Tank (AFST) has a high alarm level of 516 inches of water. The current low alarm is set just above the Technical )

Specification limit of 518,000 gallons t.t 504 inches of water. This provides 12 '

inches of water for an operating range which requiros' manual level control instead of automatic level control. Manual filling of the tank has caused the AFST to overflow. This overflow violates water quality discharge Ilmits and requires an Exceedence Notification to be filed with the State of Texas and the Envirotunental Protection Agency.

This narrow operating range does not provide advance warning to thi '

operator that a Technical Specification limit is being approached. When the AFST in at a low level (518,000 gallons) the plant is placed in the Action Statement for Technical Specification 3.7.1.3. This results in entry into a Limiting Condition for Operation Action Statement. As a result of this problem, HL&P re evaluat1d the AFST minimum volume requirement.

AFST Minimum Vplume Reouirement Safety Evaluation A series of calculations vere performed to evaluate the possibility of a-reduction f.n~the required minimum level in the AFST. These calculations would ;

determinu the maximum amount of AFW required to cool the RCS to RHP. cut in conditions. The calculations determined that the AFST Technical Specification can he reduced to 485,000 gallons and permit operation at hot shutdown for 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months followed by cooldown to the RHR cut in temperat .a. This can be performed from the control room using only safety grade equipment and assuming the worst case single active failure. The calculations evaluated four cases which are summarized in Attachment 2.

EKpoosed Shgggg e

HL&P proposes to change the minimum AFST water volume, as specified in Technical Specification 3.7.1.3 from $18,000 gallons to 485,000 gallcns. A mark up of Technical Specification 3.7.1.3 is in Attachment 4.

l A1/027.KLB u, _ _ . _ _ _ _ . . . - , . _ _ _ _ _ _ _ . _ _ , . - _ _ _ _ _ _

. . i t

. i Attachment 1 l ST llL.AE 3861 !

Page 3 of 4 j Etterminstian of Significant Hazardg !

An analysis of the proposed change has been perforued in accordance with l 10CFR50.91 regarding no significant hazards consideration using the criteria -

established in 10CFR50.92. This analysis has determined that: f f

1. The proposed change does not involve a significant increase in the j probability or consequences of an accident previously evaluated. The t

proposed change cannot increase the probability of a previously j evaluated accident because the AFST has no accident initiation l potential. The proposed change has been evaluated by analysis and the I bounding events have been chosen to assure that the AFST has an !

adequate volume of water prior to RilR cut in. No AFW performance !

parameters are affected; therefore, the consequences of a previously i evaluated accident do not increase. ;

i

2. The proposed change does not create the possibility of a new or ;

different kind of accident from any previously evaluated. The purpose i of the AFST is to mitigate an accident and the proposed level change j can not create the possibility of a new or different accident. The [

limiting reenaries were analyzed and the proposed Technical ;

Specification value was chosen to ensure that adequate AFST volume is i available for previously evaluated accidents. [

3. The proposed change does not involve a significant reduction in the l margin of safety. The originel analysis utilized overly conservative l assumptions in the calculation of the AFST required volume which [

resulted in a Technical Specification minimum required AFST volume of ;

518,000 gallons. l i

The current analysis determines the water requirements for various [

accident scenarios which are combined with water losses for the range ;

of aingle failures postulated. This results in a litriting case of l 471,000 gallons. The current analysis is more accurate while [

remaining conservative and conforms with the regulatory requirements. ,

i Margin of safety can be defined as the difference between the ultimate -

failure and the NRC acceptance criteria. Since the currenc analysis !

stays within the NRC acceptance criteria (SRP 10.4.9) the proposed !

change does not involve a significant reduction in the margin of ,

safety. [

i I,

1 l

i i

l A1/027.NL9 b

_ _ . . _ _ _ _ _ . _ . . . _ . _ . _ _ _ _ _ _ _ . _ . _ ~ . _ _ _ . _ _ . _ . _ . . _ . . _ . . . _

Attactument 1 ST ilL AE 3861 Page 4 of 4 Irwiementation This proposed Technical Specification change can be iteptemented when the change is approved by the NRC.

Conclusion lil4P has performed an analysis to determine the ininimwn required volume

~for the ATST. IllAP proposes that the proposed change be approved.

Y 3

s l

l l

A1/027.NL9

.. .~ . _. . . . . . . _ . _ . _ . _ . . . . . ~ _ . - _ . , , _ _ . . . . . . . . . . _ . . . . _ _ . . _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

ATTACllMENT 2

SUMMARY

OF ANALYSIS PERFORMED FOR Tile AUXILI ARY FEEDWATER STOR/.GE TANK HINIMUM VOLUME Al/027.NL9

i. ~ .

6 i ATTAClEiENT 2 SLN.Y OF ANALYSIS PERFORMED FOR THE AUXILIARY FEEDWATER STORAGE TANK MINIMLM VOLUME CASE 1 CASE 2 CASE 3 CASE 4 MFLB w/ Failure MFLB w/Faihre Loop w/ Failure Imop v Failure i of' AFW Flow Cont. of Train "A* Power of AP.C* Valve of Train "A" Power 3

Total Time to l RHR cut-in < 21 hrs 21 hrs 14 hrs 19 hrs i conditions l AFW needed.

I' for decay heat:

i removal and < 376,000 376,000 < 305,600 315,000 cool-down (Cal.)

i Miscellaneous i losses (Cal.) 95,000 81,000 < 165,000 78,000 i

I 1

j TOTAL REQUIREL

, (Gal.) <.471,000 457,000 < 470,600 393,000 i

automatic recirculation control

_ 3 u te r _

C m [hI i mt.:

b$

%ms-i % -<

h i

i l

i

' . . , - , , _ _ . , , _ . . ._ . _ _ - - . . _ . . - . . - _ ._s . . - . . _ . . . _ -.-

l

. 4

)

1 bi i

l l

l i

i i

ATTACIMENT 3 QUESTION 440.30N t

I i

l l

l' l

t i

l

(; ;

A1/027.NL9

. _ .

ST-HL-AE-3861, Application for Amends to Licenses NPF-76 & NPF-80,revising Min Vol Requirement for Tech Spec 3.7.1.3, Auxiliary Feedwater Storage Tank, from 518,000 to 485,000 Gallons

Text

SUMMARY

Navigation menu

Search