ML20134D263

Forwards Updated Response to Draft SER Confirmatory Item 27 on Control Room Habitability (Originally Draft SER Open Item 53).Digital Radiation Monitoring Sys Design Modified to Ensure Adequate Operator Protection.Item Considered Closed

ML20134D263
Person / Time
Site:	Beaver Valley
Issue date:	08/14/1985
From:	Carey J DUQUESNE LIGHT CO.
To:	Knighton G Office of Nuclear Reactor Regulation
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-3.D.3.4, TASK-TM 2NRC-5-117, NUDOCS 8508190169
Download: ML20134D263 (4)

Text

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2NRC-5-117

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(412) 787-5141 Nuclear Construction Division (412)923-1960 Telecopy (412) 787-2629 Robinson Plaza. Building 2, Suite 210 Pittsburgh, PA 15205 August 14 , 1985 United States Nuclear Regulatory Commission Washington, DC 20555 ATTENTION: Mr. George W. Knighton, Chief Licensing Branch 3 Of fice of Nuclear Reactor Regulation

SUBJECT:

Beaver Valley Power Station - Unit No. 2 Docket No. 50-412 Response to Draf t SER Confirmatory Item on Control Room Habitability REFERENCES : (a) DLC Letter 2NRC-4-124, dated August 13, 1984 (b) DLC letter 2NRC-4-158, dated October 3,1984 Gentlemen:

Attached is the updated res ponse to the NRC Accident Evaluation Branch's (AEB) Draft SER confirmatory item on Control Room Habitability.

This item was originally Draf t SER Open Item No. 53, and is currently listed as Confirmatory Item No. 27 in Table 1.4 of the Final Draft SER.

In Reference (a), DLC provided the response to Parts 2 and 3 of this item. The res pons e to Part 2 was accepted by the AEB reviewer, Mr. K.

Dempsey, in a telephone conference on October 19 , 1984, and is repeated in this submittal for info rmat ion only. The attached response to Part 3 is revised, as requested by Mr. Dempsey in a telephone conference on October 22, 1984, to indicate that the rad ioact ive release points shown on FSAR Figure 6.4-5 are normal effluent release point s and not post-accident release points. It is Duquesne Light Company's (DLC) understanding that, with this added clarification, the response to Part 3 is also acceptable.

In Reference (b), DLC provided the response to Part 1. In this part the AEB requested that DLC demonstrate that the control room habitability systems provide adequate operator prot ect ion , in accordance with GDC 19, in the event of high airborne radiation levels resulting from design basis accidents occurring out s ide the containment. The res ponse to Part 1, as provided in Reference (b), stated that DLC was in the process of performing the appropriate analyses to determine the adequacy of the con r room habitability systems. The res ponse further stated that any neces ary plant design changes would be made to ensure compliance with GDC 19 , if the analyses indicated that such design ch anges are required. Baded on this response, the status of this item was changed from open to conf *fmatory.

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F United Stctos Nuclesr Regul4ttory Commission Mr. George W. Knighton, Chief Response to Draft SER Confirmatory Item on Control Room Habitability Page 2 As stated in the attached revised response to Part 1, DLC is modify-ing the design of the Digital Radiation Monitoring System (DRMS). The implementation of this design modification, as described in the attached res po nse , will ensure that the BVPS control room habitability systems will provide adequate operator protection, in accordance with GDC 19, in the event of any design basis accident. The re fo re , DLC considers this issue to be closed unless further notification indicating otherwise is received from the NRC.

The appropriate FSAR revisions to reflect the modified design of the DRMS will be incorporated into a future FSAR amendment.

DUQUESNE LIGHT COMPANY By J, __gCarey /

Vi e President JDO/wjs Attachment cc: Mr. K. Dempsey, NRC AEB (w/a)

Mr. B. K. Singh, Project Manager (w/a)

Mr. G. Walton, NRC Resident Inspector (w/a)

COMMONWEALTH OF PENNSYLVANIA )

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COUNTY OF BEAVER )

On this / I day of ///j4 , k6 , before me, a Notary Public in and for said Commopwealth and County, personally appeared J. J. Carey, who being duly sworn, deposed and said that (1) he is Vice Pres ident of Duquesne Light, (2) he is duly authorized to execute and file the foregoing Submittal on behalf of said Company, and (3) the statements set forth in the Submittal are true and correct to the best of his knowledge.

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Notary Public

$NillA N. FATTORE. NOTARY PU0 llc SMIPPINGPORT sono. BEAvta COUNTY MY COMMISSION EXPlH5 SEPT.16.1945 Member Pennsylvanie Assesisties of Noterier

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L Draf t SER Confirmatory Item on Control Room Habitability (Formerly Draf t SER Open Ites No. 53):

The staf f review of the Beaver Valley control room emergency HVAC system indicates there are several additional open items, not previously identi-fled, that relate to control room operator thyroid doses. The following three areas will have . to be. addressed by ~ the applicant:

-?. Automatic control room pressurization on detection of radiation in the outside air intake is not addressed in the applicable FSAR sect ions . Radiation detectors in the out side air intakes may. be necessary to initiate the control room emergency systems (and main-tain control room dose to within GDC 19 guidelines) in the event of design basis accidents occurring outside the containment, such as steamline break, fuel handling accident and small line break outside containment.

2. Flow rates of the bottled air pressurization system, which pressur-izes the control room to 1/8 inch w.g. or greater for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> follow-ing a design basis accident, are needed. If they are greater or much less than the post-accident air makeup rate of 1,400 CFM (Table 6.4-1 ~

of FSAR), an explanation would have to be submitted by the applicant.

3. ~ Radioactive gases release point E, shown on Figure 6.4-5 of the FSAR appears to be less than 10 0 feet from the nearest control room air intake. Because of the close proximity of this release po int , an evaluation .of control room operator doses is needed from the appli-cant for those design basis accidents that result in radiation to be released from point E.

Until these matters are resolved, control room habitability remains an open item.

Based upon the fo regoing , the applicant has not demons trated that the control- room habitability systems will adequately protect the control room operators in accordance with the requirements of NUREG-0737, Item III.D.3.4, and 10CFR Part 50, Appendix A, GDC 19.

Response

1. A containment Phase B isolation (CIB) signal from either BVPS-1 or BVPS-2 will automatically isolate both the BVPS-1 and BVPS-2 sides of the common control room and automatically initiate the control room emergency pressurization systems.

In order to ensure that the control room habitability systems provide adequate operator protection, in accordance with GDC 19, in the event of high airborne radiation levels resulting from design basis acci-dents occurring outside containment, DLC is modifying the design of the Digital Radiation Monitoring System (DRMS). The upgraded design provides Category I, redundant, area radiation monitors on both the BVPS-1 and BVPS-2 sides of the control room (four mnitors to t al) .

On detection of a high radiation level in the control room, any one

-of these four monitors will alarm locally, automatically initiate isolation of both the BVPS-1 and BVPS-2 sides of the common control

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room, and simultaneously initiate the control roora emergency pressur-ization systems. The implementation of this design mdification will ensure that the BVPS control room habitability systems will provide adequate operator protection, in accordance with GDC 19, in the event of any design basis accident.

In addition to the above, the airborne radiation level in the BVPE-2 portion of the control room is monitored by a non-1E, Category II airborne ~ radiation' monitor which samples air from the control room ventilation system as described in FSAR Section 12.3.4.2.

The DRMS modifications described above will be installed and tested prior to BVPS-2 fuel loading.

2. In orde r to maintain a minimum pressure of 1/8 inch water gauge in the control row following a design basis accide nt , an air makeup rate of 800 cfm is required. The BVPS control room emergency bottled air pressurization system can provide a total of 1000 cfm through the five supply lines which carry 200 cfm each. Current design changes being considered for the BVPS-1 emergency pressurization fans may increase . the post-accident air makeup rate of these fans from the current 400 cfm to as high as 1000 c fm. This combined BVPS-1 and BVPS-2 air makeup rate of 2000 cfm would present no problems as far as overpressurization of the control room is concerned.

3. The radioactive gaseous release points shown on FSAR Figure 6.4-5 are normal effluent release point s and are not post-accident release points. : Point E is monitored by a BVPS-1 radiation monitor. If a high radiation signal is received, the outflow from Point E is trans-ferred to the BVPS-1 Supplementary Leak Collection and Release System.- The flow then passes through a train of HEPA filters before being released to the atmosphere through BVPS-1 elevated release

- Point D which is located at the top of the BVPS-1 reactor contaimnent building. The refo re , the control room operators are adequately protected against any potential radioactive releases from Point E.

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