ML20205S120

Forwards Addl Info Re Proposed Revs to Tech Specs Concerning Emergency Ventilation/Exhaust Sys,Per NRC 881019 Request. Current Tech Specs Have Duplication of Requirements for Sys Flow Pressure Drop w/in-place Leakage & Bypass Testing

ML20205S120
Person / Time
Site:	Wolf Creek
Issue date:	10/31/1988
From:	Withers B WOLF CREEK NUCLEAR OPERATING CORP.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
WM-88-0288, WM-88-288, NUDOCS 8811100255
Download: ML20205S120 (9)

Text

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WQLF CREEK NUCLEAR OPERATING CORPORATION satt o. wws 0Ctober 31,1988 er aws and VM 88-0288 U. S. Nuclear Regulatory Commission ATTN Document Control Desk Mail Station Pl-137 l Washington, D. C. 20$35 References 1) WM 88-0056 dated February 26, 1988, from B. D. Withers, WCNOC to NRC

2) Letter dated October 19, 1988 f rom D. V. Picket t ,

NRC to B. D. Withers, WCNOC

Subject:

Additional Information Regarding the Droposed Revisions to the Emergency Ventilation / Exhaust System Technical Spec 1fications

, dentlement The purpose of this letter is to provide the additional information requestel by Re fe rence 2 to support the NRC Staff review of the propsoed '

revisions to the Welf Creek Generating scation Technical Specificatione concerning the Emergency Ventilation / Exhaust System. The proposed Technical Specification revisions were transmitted to the NRC by Reference 1.

The a t t a c'/.ta e n t to this letter provides Wolf Creek Nuclear Operating ,

Corporation's response to the Staf f questions transmitted by Reference 2.

The additional information requested by Mr. Douglas Pickett and Charles

.; Nichols of the NRC Staf f during telephone conference on October 27, 1988 has also been provided.

If you have any questions concerning this matter, please contact rue or ,

Hr. O. L. Maynard of my st a f f. t very truly yours, >

h rt D. Withers President and (

Chief Executive Officer BDW/jad i

Attachment cca G. W. Allen (NRC), w/a  !

5. L. Bartlett (NRC), w/a f D. D. Chamberlain (NRC), w/a J. Y. Le e ( N RC) , w/ a ,

1 R. D. Martin (NRC), w/a / l C. R. Nichols (NRC), w/a N D. V. Pickett (NRC), w/a (2) l bI g I P O. Son 411 I Burington MS 6(439 / Fiene. (316) 3644631 i i hbN F

.I$b$ $hMe FDC

^^ EM W"*v E"S*** *d"CVE' i

e STATE OP KANSAS )

) 33 COUNTY OF COPPHY )

Bart D. Withers, of lawful age, being first duly sworn upon oath says that he is President and Chief Executive Officer of Volf Creek Nuolear Operating Corporations that he has read the foregoing document and knows the content thereof that he hsa executed that same for and on behalf of said Corpo ration with full power ar.d authority to do son and thst the facts therein at2ted are true and correct to the best of his knowledge ,

infccmation and belief.

By Bart D. Withers President and Chief Executive Officer l

SUBSCRIBED and 6 worn to beft.,co me this $/ day of M , 1988.

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Attachment to WM 88-0288 Page 1 of 7 Additional Information Regarding the Proposed Revisions to the Emergency Wentilation/ Exhaust System Technic 11 Speelfications Question _l, Justify deleting the maintenance surveillance requirements under technical specifiction 3/4.7,6.c.1. This concerns the pressure differential verification across the filters for the flitration system and pressurization nystem.

E8_2 .f.*f I Technical Specifications 3/4.7.6.c.1 and 3/4.9.13.b.1 are intended to verl y that the in-place penetration and bypass leakage meet the requircJ acceptance criteria. These specifications were not intended to verify

! system flow rate requirements at a given pressure drop. System flow rate requirements at a given pressure drop are verified in specifications 3/4.7.6.c.3 and 3/4.9.13.b.3. The current Wolf Creek Generating Station (WCCS) Technical Specifications include the unnecessary and confusing duplication of the system flow pressure drop testing requirements in conjunction with in-plcce leakage and bypass testing.

The proposed technical specification changes separate unrelated testing requirements i ito individual paragraphs within the same technical specifications. The proposed changes to Technical Specifications 3/4.7.6.c.1 anI 3/4.9.13.b.1 are in accordance with the current reviston of the Westingho , Standard Technical Specifications (NUREC-0452) and meet the requirement s e t Gene ric 1.et te r 83-13.

9.ue a t,1,3n,2, ,

Justify deleting the dirty filter pressure differential verification ander technical speci fic at ion 4.9.13.b.l .

gayonne See Response t o Qve s t ion 1.

Question 3 Discuss why the exhaust fan flow rate must be changed from 9000 cfm to 6500 cfm in the fuel building.

Restonse The emergency exhaust system for the fuel building and auxiliary building is se rv ic ed by the same fans (CGCO2A and CCCO2B). Since a flow reduction is required for the auxiliary building the satae flow change must be made for the fuel building flow rates.

d Attachment to VM 88-0288 Page 2 of 7 Quantion 4 Justify with the bases that the accident releases are adequately controlled during postulated accident conditions at the new negative pressure levels it the auxiliary building and fuel building. c R,,gs p,o,,n s e The negative pressurn level limits in the auxiliary building and fuel ballding are not af fected by the proposed technical specification changes.

The- negative pressure requirement of -0.25 inches W.C. ensures the exfiltration from the buildings does not occur. During accident conditions effluents form these buildings are processed throagh safety-related filter /adsorber units prior to release via the unit vent.

Question _5_

What is the thickness of the charcoal beds for each filtet and their assigned iodine removal ef ficiencies? Verify with bases that at the revised '

flow rates the system complies with Regulatory Culde (RC) 1.52 Postion 31 (at least .25 sec/2 inch of admorbent bed).

Response

Each of the filter charcoal beds is composed of multiple charcoal sections each of which is two inches thick. Although these charcoal beds have iodine removat efficiencies of up to 99.9 percent for elemental lodine, a conservative removal ef ficiency of 90 percent has been assigned for use in accident analyses. The approximate quantity of activated charcoal in each filtration unit is presented in Updated Safety Analysis Report Table 9.4-4.

W?CS continues to comply with Position 31 of Re gula t ory Cu'de (R.C.)l .52.

For the Emergency Exhaust System the proposed reduction in flow will result in an increase in the "residence time" of effluent in the charcoal bed (0.25 sec/2 in minimum).

The Control Room r ressurisation System was designed to meet the R.C. 1.52 minimum "residence tiwe" at a flow rate of 1000 cfm. Therefore, although j

the proposed increase in pressurization flow from 500 cfm to 750 cfm will decrease the "residence time" from its current value, any flow rate equal to or less than 1000 cfm ensures a "residence riae" of at least 0.25 see/2 in.

in accordance with R.C. 1.52.

Attachment to WM 88-0288 Page 3 of 7 g_uestion,6 Provide unfiltered in-leakage flow rates due to the ingress and egress, per SRP 6.4.111.3.d.3, for use in dose calculations.

R, e a p,o,,n,s e, The control room dose calculations pe r f o rmed for Wolf Creek Generating Station (WCCS) assume no unfiltered in leakage as a result of control room ingress and egress.

As noted in NUREG 0800, Standard Keview Plan; Section 6.4.III.3.d.(3), 10 cfm infiltration is normally assumed for conservatism, however, this flow could be reduced or eliminated if assurance that backflow (primarily as a result of ingress and egress) will not occur. The WCCS control room design provides this assurance by utillaing a two-door vestibule configuration.

CQER,0L ROOM RABITAR,I_L,I'Qf As discussed in Updated Safety Analysis Report (USAR) Section 9.4, Cont rol Building HVAC and 6.4, Habitability Systems, the design basis for the Control Room Emergency Ventilation system is to ensure that the Control Roma remains habitable throughout the duration of any of the postulated Design Base Accidents (DB As) discussed in USAR Chapter 15.

An evaluation of the radiological consequences associated with the Accident l Analyses presented in USAR Chapter 15 is provided in Appendix 15A of the

• USAR. In rega rd s to the radiological consequences associated with the Control Room, only the radiation doses to the Control Room due to a postuisted Loss of Coolant Accident ( LOCA) are addressed. The reason for addressing only the LOCA condition is that a study of all the radiological consequences in the Control Room, due to the various postulated accidents, resulted in the LOCA as being the limiting case.

The radiological consequences of the postulated LOCA doses in the Control Room are identified in USAR Section 15A.3. A Control Room Ventilation Isolation Signal (CRVIS) starts both trains of the Control Room Pressurination and the Control Room Filtra: ion systems. The USAR indicates that, in determining the dose to the Control Room personnel, the worst case single failure has been ascertained to be the failure of the filtration fan in one of the two filtration systeis trains. During this condition, a potential pathway exists allowing air f rom the Control Building to er .er the Control Room, bypassing the Control Room filtration filte ,. In l consideration of the above single failure, the accident analy,is assumes

! that operator action will occur in 30 minutes to isolate the train with the l failed filtration fan. At the same tire, one train of the Control Room l pressurization system will also be isolated. After isolation, one Control l Room Pressurization f au and one Control Room Filtration fan are assumed to operate for the duration of the accideut.

L

Attachment'to WM 88-0288 Page 4 of 7 The parameters utilized in the Accident Analysis are presented in USAR Table 15A-1. The filtered intake to the Control Building is assumed to be 1000 cfm prior to operator action and is reduced to 500 cfm after 30 minutes.

The filtered and unfiltered flows from the control building are each assumed to be 400 cfm. A revised LOCA dose analysis has been performed. In the revised analysis, the assumed, filtered Control Building intake flow increased to 2000 cfm prior to operator action and 1000 cfm following o pe ra t o r action, and the filtered and unfiltered flow from the Control Building to the Control Room each increased from 400 cfm to 440 cim. All other assumed parameters remain unchanged. The resultant Control Room thyroid dose to the operators would be less than those presently identified in USAR Table 15.6-8, while the associated Whole-Body and Beta skin dose vould increase slightly. Ilowever, all Contro; Room doses remain well below General Design Criteria-19 limits. The Conttol Room doses are provided in the attached markup to USAR Table 15.6-8.

The proposed Technical Specification change im reases the Control Building flow to 750 cfm, not the 1000 cfm assumed in t'ie analysis. The re f ore , che proposed changes reflected in the attached USAR Tables 15.A-1 and 15.h-d provide a bounding case.

1 i

l k .

' Attachment to WH 88-0288 v Page S Of 7

• WOLF CREEK i .

TABLE 15.6-8 RADIOIDGICAL CONSEQUENCES OF A I4SS-OF-COOLANT-ACCIDENT Doser (ren)

I. Exclusion Area Sv;ddacy (0-2 hr)

a. Containment 'Aeakage (0-2 hr)

Thyroid 65 Whole body 2.2

b. ECCS recire. leakage (0.47 hr-2 hr)

Thyroid On whole body 0.061

11. Iow Population Zone Outer Boundary (0-30 day)

a. Containment leaxage (0-30 day) ,

42 Thyroid Whole body '-* 0.78

b. ECCS recirc. leakage (0.47 hr-30 day)

Thyroid 45 Whole body 0.045 III. Control Room (0-30 day)

a. Containment leakago (0-30 day)

-it- 9,16 Thyroid Whole bcd.y -ern- 0.3G Beta-skin 4rs- 6.29

b. ECCS recirc. leakago (0.47 hr-30 day)

Thyroid -ht- 1.33 Whole body 4.cE 5.0E-S

-Gv-a r,-+ 4.4 E-4 Dota-ckin Rev. O

.-

• Attachment to WM 88-0288 Page 6 of 7 WOLF CREEK TABLE 15A-1 PARAMETERS USED IN ACCIDENT ANALYSIS I. General

1. Coro power level, Hwt 3565

2. Full-power operation, days 1000

3. Number of fuel assemblies in the core 193

4. Maximum radial peaking factor 1.65

5. Parcontage of failed fuel 1.0

6. Steam generator tube leak, lb/hr 500 II. Sources

1. Coro inventories, ci Table 15A"3

2. Gap inventories, ci ~

Table 15A-3

3. Primary coolant specific activities,

.. /* C1/gm Tablo 11.1-5

4. Primary coolant activity, technical specification limit for iodines - I-131 done equivalent, /ACi/gm 1.0

5. Secondary coolant activity technical specification limit for iodines - I-131 dose equivalent,p Ci/gm 0.1

, III. Activity Release Parameters ,

3 6

1. Free volume of containment, ft 2.5 x 10 2

2. Containment leak rate

i. 0-24 hours, % per day 0.2 . . .

ii. after 24 hrs, % per day 0.1 IV. Control Room Dose Analysis (for IDCA)

1. Control building

1. Mixing volume, cf 150,000

11. Filtered intake, cfa Prior to operator action (0-30 minutes) -looe- 2000 After operator action (30 minuten -

720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br />) -soo- 1000 111. Unfiltered inloahago, cfm 3 0 iv. Filter officiency (all forms of iodine), t 90 Rev, o

\

• Attachment to kN 88-0288 Page 7 of 7 WOLF CREEK TABLE 15A-1 (Shoot 2)

2. Control room

1. Volumo, cf 100,000 li. Filtered flow from control building, cfm ao& 440 111. Unfiltered flow from control building, cfm Prior to operator action (0-30 minutos) 400- 440 After operator action (30 minutos -

720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br />) 0 iv. Filtered recirculation, cfm -1400- 1560

v. Filter officiency (all forms of iodino), % 90

v. Miscollaneous

1. Atmospheric dispersion factors, %/Q soc /m 3 Table 15A-2

2. Dono conversion factors

1. total body and bota skin, rom-motor /

3

/

[

Ci-soc Table 15A-4 i

11. thyroli, rom /Ci Tablo 15A-4 3

Dreathing rates, motor /sec 3.

i. control room at all times 3.47 x 10

~4

)

/'

11. offsite ~

d' 0-8 hra 3.47 x 10 '4

~

8-24 hrs 1.75 x 10 ~4 24-720 hrs 2.32 x 10

4. Control room occupancy fractions 0-24 hrs 1.0 24-96 hrs 0.6 96-720 hra 0.4 Rev. 0 Y

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