ML20237C236

Forwards Request for Addl Info Re Facility Modified Control Room Habitability Sys,Per 871109 Onsite Review.Sys Operability During All Modes of Operation Will Be Verified

ML20237C236
Person / Time
Site:	Rancho Seco
Issue date:	12/15/1987
From:	Kalman G Office of Nuclear Reactor Regulation
To:	Andognini G SACRAMENTO MUNICIPAL UTILITY DISTRICT
References
TAC-61413, NUDOCS 8712210177
Download: ML20237C236 (8)

Text

_ - _ - _ _ _ _ _ _ _ _ _

^

9 December 15, 1987 Docket No.: 50-312 Mr. G. Carl Andognini Chief Executive Of ficer, Nuclear Rancho Seco Nuclear Generating Station 14440 Twin Cities Road Herald, California 95638-9799

SUBJECT:

RANCHO SECO NUCLEAR GENERATING STATION - CONTROL ROOM HABITABILITY, REQUEST FOR ADDITIONAL INFORMATION (TAC N0. 61413)

During the week of Hovember 9, 1987, the staff performed an onsite review of the modified control room habitability systens in support of the Safety Evaluation Report related to the restart of the Rancho Seco Nuclear Generating Station. As a result of this review, and the subsequent review of docun:ents received at the site, the staff has identified areas where additional information is required.

Please provide the information requested in the attachment to this letter as soon as possible so that our review can be completed without impacting your restart schedule.

It should be noted that an additional site visit will be required to verify i

system operability during all n,cdes of operation.

Sincerely, l

, George Kalman, Project Manager l 8712210177 871215 Project Directorate V i PDR ADOCK 05000312 ,

Division of Reactor Projects - III, P IV, Y and Special Projects PDR  !

Office of Nuclear Reactor Regulation

Attachment:

As stated cc: See next page.

DISTRIBUTION.

Docket > File ? GKalman ACRS (10) GPA/PA NRC & Local'PDRs GKnighton TBarnhart(4) EJordan TMurley FMiraglia CRossi OGC-Bethesda PDV Reading JLee JPartlow i DMCrutchfield GMHolahan 0FC :DRSP/PDV :DRS DV :QP MPDV :0GC :ADR/DRSP :DRP/DRSP :ADP

,NAME :JLeef :GKsimen:CW :GP 'Jhton "r --- -wfiMHolahan :DCrutchfield FMiraglia :

lDATE:12f 7 :12// 3/87 :1/$/87 I :12/ /87C y(12 Q TF~iRT-i87 -:12/_/~87 0FC /:DONN , ' ~'

i  :  :  : O .,: /  :  :

iNAME :IMURLEL _

DATE :12/. /87 Q, fig ( % :.

0FFICIAL RECORD COPY

Pr. G. Carl Andognini Rancho Seco Nuclear Generating Chief Executive Officer, Nuclear Station Sacramento Municipal Utility District s cc:

Mr. David S. replan, Secretary Mr. John Bartus and General Counsel Ms. JoAnne Scott Sacramento Municipal Utility Federal Energy Regulatory Cacc41ssion i District 825 North Capitol Street, N. E. -

6201 S Street Washington, D.C. 20426 z P. O. Box 15830 l Sacramento, California 95813 l

l Thomas A. Baxter, Esq.

Shaw, Pittman, Potts & Trowbridge 2300 N Street, N.W.

Washington, D.C. 20037 Mr. John V. Vinguist  :

Acting Manager, Nuclear Licensing Sacramento Municipal Utility District Rancho Seco Nuclear Generating Station 14440 Twin Cities Road Herald, California 95638-9799 Mr. Robert B. Borsum Babcock & Wilcox Nuclear Power Generation Division 1700 Rockville Pike - Suite 525 kockville, Maryland 20852 Resident Inspector / Rancho Seco c/o U. S. N. R. C.

14440 Twin Cities Road Herald, California 95638 Regional Administrator, Region V U.S. Nuclear Regulatory Commission l 3450 Maria Lane, Suite 210 Walnut Creek, California 94596 Mr. Joseph 0. Ward, Chief Radiological Health Branch State Department of Health Services 714 P Street, Office Building #8 Sacramento, California 95814 Sacranento County Board of Supervisors 827 7th Street, Room 424 Sacramento, California 95814 Ms. Helen Hubbard P. O. Box 63 Sunol, California 94586

f, j i n, e , .

V i4' ,,

si, f( Y 'f '

,.i RANCHO SECO STARTUPc u CONTROL POOM HABITABILITY SYSTFM REQUEST F'OR ADDITIONAL INFORMATION ' '

O s PLANT SYSTEMS BRANCH

[

Eig y[,0 1. Ranctlc Seco's procedure'for' air balance of ventilation systems, M-111, "HVAC Maintenance Procedure'for Air Balance of Ventilation Systems,"

is relied on for providing'essurance that unfiltered air inleakage is within the bounds of the assumptions used in the dose calculations and 3 x - toxic cas analyses and tle system otherwise functions as designated.

Wj q Provide the following information:

3,> '

(' a) The prockdures and data sheets do not indicate that the +,yts it! 'any particular mcde of operatinn are made in a continuous runs,' The data

'*. sheets provided do not include the mode of operation of the train that is in service or the time of day the measurements were taken.

Previde assurance that test datn Jresented to the review team g represerts data recorded durinotthe operation of distinct.'centinuous y W test cycles for the HVAC system modes of operation, or provide  ;-

justification that data obtained in interrupted runs are acceptable.

,1 - .

b) Provide the data sheets associated with measurements (traverses on the A & B unit supplyind return) referrec' to in the remarks section.,of s the procedure dated April- 29, 1987 ~

c) Providethedatasheetassociatedwiththemeasurementbrhvarseon Utre A train outside air inia'te) referred to in the remarks section

~ "of the procedure dated April 29, 1987.

d) Provide justification for the validity of the readings recorded on the data sheet associated with the TSC return air data dated April 30, 1987. The remarks section of the procedure indicate that TSC return air.date were not taken on April 30, 1987 beceuse of a hole in the everhead grate. It should also be noted that since the

> overhead crea forms a common return air plenum, degraded grating ,

q could affect measurements on both the supply and return ducts. l e) Provide data sheets associated with traverse reedings taken on the control ro9m supply and return tm the filtration unit as referred to in remarks ' dated May 7,1987, asDH .h data sheets .for the several other meas'arements recorded in the remarks dated May 7,1987.

l f) Provideflowmeasurementdatasheetsforoutsideairmakeuptoboth of the HVAC trains for data taken on June 3, 1987 L ,

g) Provide the correct date associated with a flow measurement data sheet for the B train control room return. This data sheet was  ;

attached to the procedure, but did not include a test date.  !

k /

h) With regard to the balancing procedure, the current procedure shows f3s '

differential pressure readings for the control room to corridor and the TSC to the corridor, but does not provide differential pressure readings to other adjacent areas. Provide additional inforn tion to support the statement made in item 2.1.E of the most recent III.D.3.4 submittal dated July 22, 1987, that the system has been tested to verify that the control room TSC can be pressurized to at least 1/8 inch water gauge relative to all surrounding spaces.

A k

g n a

C,[

);

i) Procedure M-111 did not include any flow measurements in the ducts of the normal HVAC system or for any of the idle branches of the HVAC system. Further, the balaacing procedure did not measure '

exhaust air flow for fans located in the toilet, kitchen, and m

conference room areas of the control room. These measurements may show system inleakage or outleakage. *

.i ) Air balance. data for the air handling units taken on April 23,198h and September 30, 1987 irdicate.that the air inlet and the air outlet flows are exactly the same for both air handling unid.

In the staffs experience with testing of air handling unitsjar.d emergency filter trains at different plants, we have nev& observed any cases where the balancing (inlet to outlet air flowhtes) has agreed to the exact cfm.

The difference between inlet and outlet readings is most likely attributable to instrument error and variations in system flow. Provide additional information to support these data measurements.

k) Test data rded on June 3, 1987 for this procedure shows that~

more air is being returned from the control ronm envelope to the Essential HVAC system than is being' supplied t/ these units. Train A shows 297 cfm and Train B shows 601 cfm more, air returning to the essential units from the envelope than is being supplied. After reviewing Rancho Seco's system configuration, it appears that the nomal HVAC systen that continues to ron may be responsib4.for tMs additional flow. Therefore, provide assurance that inleakroe flow P through the isolation damper in the nomal supply duct fron AH-H-2 during operation in emergency modes is adeouately addressed by the assumptions of the dose calculations and toxic gas calculations and-is m(ot :rel lied s on for assuring adequate pressuri.Tation of the control- ' ronm envghpc. .

t t

2. R.G.1.52 Position 5.d provides that leak testiry of the carbon atorber section be conducted if the intentity of the afsorber is affected.

(),

Procedures STP 1063A, " Control Room /TSC Essentini Filtration Unit C' Air / Aerosol Mixing Uniformity Test Train A" artIW1063B, Control g' Room /TSC Essential Filtration Unit Air / Aerosol Mixing Unifomity Test '

Train B", require the removal of carbon filter, trays to perform the test.

.- ~

The procedures do not require 'a Freon in-puce test after the carbon filter trays are reinstalled.

j Provide additicnal information which 1 essures that the carbon trays hyve been properly reinstalled (thereb limiting bypass flow) without performance of this type of test, or '

modify the test procedure or otherwise provide [ assurance that the ,

adsorber section will be leak tested. .

3 i \

c l i

i l,

f, I l

i i ,

l

- - s

s

3. With regard to procedure I.044, " Calibration Procedure for Chlorine Analyses Probes AE-54701 and AE-5470?"" and I.045, " Calibration

b. Procedure for Chlorine Analyses AIT-54701 and AIT-54702", provide the following infomation:

a) Verification that the detectors are capable of detecting a chlorine concentration of 5 ppm per Position C.d.d(1) of Regulatory Guide 1.95.

b) Frequency of the calibration. (Neither procedure included this

)g infomation) . Position c.4.d(6) of R.G.1.95 requires calibration c'.v's once every six months.

q. 7 c) Verification that routine operational checks are conducted at one week intervals per Position c.4.d(6) of R.G.1.95 or justification for any deviation. (No procedures or checklist was provided to 1 the review team that indicated that a weekly operational check is being perfomed on the chlorine detectors).

,, d) R.G.1.95 states that the control room should be isolated in 10

/ seconds for a type V control room after a chlorine concentration

,1' of 5 ppm reaches the detectors. It is not evident that either l procedure 1.044 or 1.045 verifies that this response time is l being met for the detectors. Provide justification for this l apparent deviation.

l .t l 4. Af ter reviewing the licensee's control room envelope configuration, it l appears that a door in the shift supervisor's office opens directly to the outside. Provide additional information to support the apparent i deviation from R.G.1.95 Position 4.b.(3) that a control rom exit leading

,, directly to the outside of the building should have two interlocking low-leakage doors in series.

5. The SPUD letter dated June 30, 1987, addressing the NPC's concern regarding deviation from the RG 1.52 position on the use of silicone sealants in FSF filter systens., addressed only the radiation resistance of the sealant.

Provide rational adcressing other potentially significant effects on sealant

.furctions with age in service. Where test results are relied on or where tests 1

are proposed, describe how the conditions represent (and limitations) the as-installed condition of~the sealant over the life of the plant considering the aterials in contact with the sealant, the characteristics of the inter-f ace b'etween the sealant and these materials, the so lent temperature, the effect of mass transfer between the sealant and the surroundings, and variable stresses due to vibration and pressure cycling.

Describe the measured parameters and hw they provide assurances that the sealant is perfoming the function to adequataly limit air inleakage.

Otha-wise, provide means for verifying over the life of the plant the in-leakage rates assumed in the dose calculations, e.g., periodic testing of the function of the sealant.

l s.

& . . . . _ _ _ . . _ - _ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ------ - ' - - - - - - - ^ - - - '- - - - - - - ^ - ^ ~ - - - ^ ' ~ ^

- _ - _ _ - _ _ _ _ _ _ - - _ - _ - _ _ = _ _ - _ _ - _ _ _ _ _ _ - - _

'4 6.

The CR/TSC Essential A'ir Conditioning System Status Report, Rev.1, addresses each problem.45 licensee identified problems and plans for resolution of Licensee-identified concerns / questions are also addressed in the document " Expanded Augmented System Review and Test Program, Evalu-etion of the CP/TSC Essential HVAC System."

Additional releted licensee identified problems and plans for resolution exist (e.g. Diesel Exhaust Fumes in CP/TSC Atmosphere 1 Provide a description (including results) of evaluations, analyses, measurements, changes, training, revisions, verifications, corrections, tests performed or planned (provide schedule) to resolve Justify each of the related licensee-identified problems and concerns.

thesr: cases where you do not plan resolution prior to restart.

7.

Provide assurance that there will be no unfiltered inleekage, while operatinn in any emergency mode, through the return ducts around the essential filtration units. Describe the safety significerce of establishing steady flow through the essential filtration unit prior to opening the outside air intake dampers after receipt of a radiological emergency signal. Provide assurance that this sequence will occur in radiological emergencies.

8. Provide assurance that filter by-pass and other potential air flow through drains will not adversely affect operation of the control room habitability system.

9.

Provide assurance that the reliance on the installed " semi-remote" chlorine detectors and the absence of ammonia detectors is in compliance with SRP 6.4 and meets the intent of RGs 1.78 and 1.95, considering:

(a) shipments of chlorine and ammonia to the site, (b) meteorological conditions, including building wake effects, that would transport released chlorine or ammonia to the control room but not be detected in time. to adequately protect the control room operators, (c) pntential improvements to safety afforded by reliance on chlorine detectors and ammonia detectors located at the points of potential release and administrative controls durirg deliveries of these materials to the site, (d) exhausts from operation of the emergency diesels.

10. Provide ,1vstification for the deviation from the RG 1.78 regarding provision of readout of the toxic gas monitors in the control room.

H. Regarding RG 1.57, provide ,4 justification for the discrepancy between

the charcoal efficiency used in the dose calculations, and the f laboratory testing acceptance criterie used.

\

l 1

12. Provide an evaluation of all potential release points that have not been previously analyzed in conjunction with the operator dose calculations (e.g., radiation waste exhaust vent on the auxiliary building level).

)

13.

Provide on evaluation of accident doses to the operators involving all potentiallouvered building pathways other than from the outside through the auxiliary door.

14 Provide dose calculations to include the tine during which both trains of the energency filtration system would be running and the time required for flow stabilization after system initiation. Provide assurance that -

the system will be operated within the bounds of the dose calculations (i.e. limit times for both trains running and for flow stabili7ation). i

15. Provide additional infomation which confirms that control room operators are adequately trained regarding HVAC equipment potential failures (single failures, etc.) to be able to promptly identify failures and take the necessary corrective actions.

16. Provide additional information to demonstrate adequate detailed operator training in use of the self-contained breathing apparatus in the control room.

17. Provide justification for the significant reliance on the non-safety related IDADS computer systen for HVAC equipment status information during emergencies as opposed to reliance on the safety-related instrumentation display and readout on the control room panels (especially regarding identifying single failures of the HVAC system).

18. Provide additienal information which justifies that the IDADS computer's flow response time in displaying changing HVAC system flow rates will not impact the ability to operate the system properly.

19. Provide additional information to explain the staff's observation of flow measurement readout in the IDADS output when the particular train of the system was considered shutdown and inoperable.

20. Provide additional information that justifies that the control roon boundary doors will be properly maintained closed in order to ensure control room integrity during emergencies. Specifically consider maintenance of seals and provision of administrative controls to ensure closure.

21. Provide additional information that confims that current surveillance procedures adequately provide for the surveillance of hardcast tape in-stallations or provide specific identification of hardcast tape installation locations alona with the procedure.

O

22. In addition, the staff will request that the system be operated and maintenance / surveillance testing be conducted in accordance with approved station procedures and observed by the staff as follows:

(a) Each train, independently, would be operated sequentially in the r.ormal, toxic gas, normal and radiation modes. The staff would observe characteristics of system operation at the controls (control room), IDADS system data output (technical support center) and other indications (HVAC equipment location on the roof). The staff would also verify the initiation of the toxic gas and radiation modes for each. train upon receipt of appropriate initiating signals (manual, toxic gas detection, radiation detection). During operation in the radiological modes, the staff also would observe measurements made by the licensee of the differential pressure of various areas of the control room envelope with respect to important adjacent areas.

(b) During operation in the radiation mode, the staff would observe licensee testing of appropriate system flow rates to verify that unfiltered inleakage air flow rates through isolation dampers in the rormal HVAC supply duct (AH-H-2), or through another path deemed appropriate, because of potential significance through prior discussions with the staff, are within the levels assumed i'n the dose calculations and toxic gas analyses.

l i

l L _. _ --_--.__----- _--_- _