ML20137Y872

Forwards List of Discussion Items for Plant to Review in Preparation for 970428 Meeting

ML20137Y872
Person / Time
Site:	Point Beach
Issue date:	04/18/1997
From:	Anthony Huffert NRC
To:	NRC
Shared Package
ML20137Y857	List: ML20137Y852 ML20137Y872
References
NUDOCS 9704230265
Download: ML20137Y872 (7)

Text

L .

From: Anthony Huffert To: WNP3.LLG Date: 4/18/97 3:58pm

Subject:

Point Beach Discussion Items As we agreed this morning during our meeti q, attached is a list of discussion items for Point Beach to review in preparation for the 4/28/97 meeting. PERB does not consider the list of items a request for additional information - perhaps those types of question will be generated after the 4/28/97 meeting. i PERB realizes that some of the questions were answered during our meeting today.

However, the licensee should be prepared to discuss those questions with the staff if they arise on 4/28/97.

Although the attached list does not contain questions on control room operator occupancy factors or the ECCS leak rate calculations (which were discussed during our meeting this morning), Point Beach should be prepared to discuss those items also.

Regarding the onsite meteorology issue, PERB would like to hold a telephone conference with Point Beach next Tuesday or Wednesday in preparation for the 4/28/97 meeting.

I Thank you again for the briefing this morning -

Tony Huffert 415-1081 4

ENCLOSURE 1 9704230265 970421 PDR ADOCK 05000266 p PDR

Discussion Items on Point Beach Amendment Requests Control Room

1. The 1984 III.D.3.4 analysis described 4 modes of operation for the control room. The licensee's III.D.3.4 analysis presented dose consequence I assessments for 2 modes of operation in their LOCA dose calculation: mode 3 (isclation and filtered recirculation) and mode 4 (filtered makeup and i unfiltered recirculation). It appears that mode 3 was originally the system l default for high radiation signals in the control room, but now mode 4 is the  !

system default for that signal. It is noted that recent licensee analyses do not take into account mode 3 operation.

a. Based on current tech specs and emergency operating procedures, what control room ventilation systen, alignments and what system initiation signals (e.g., control room high radiation, containment isolation, etc.) are used to actuate changes in the control room HVAC system for each cf the following design basis accidents: LOCA, steam generator tube rupture, control rod ejection, main steamline break and locker

rotor?

b. What signals and default system configurations were used for these accidents in the III.D.3.4 submittal?

c. What changes has the licensee made to their modes of operation since 1 the III.D.3.4 submittal? What changes were made to make certain modes j

. of operation unavailable (e.g., mode 3) to mitigate the consequences of these accidents?

d. What regulatory mechanism was used to review such changes? Were dose calculations made to support the licensee's changes?

2. Attachment 3 of the April 2, 1997 letter from the licensee states that a 1994 modification to the control room established a new flow-path from discharge of the control room recirculation fans to a mechanical room that houses HVAC equipment. This flow-path diverts about 700 cfm from the contro's room recirculation flow into the room. The licensee stated that this modification affects mode 2 operation sufficiently that previous analyses for mode 2 should be disregarded,

a. What is the basis for the new inleakage value of 765.2 cfm for mode 2 operation? How did the licensee arrive at this new inleakage value?

Was it based on the supply of control room air into the mechanical room?

b. What plant changes were made in 1994? How did the plant changes impact the calculated iodine protection factor (IPF) for mode 2?

c. Was the mechanical room previously considered part of the control room envelope? If it was not, should it be considered part of the control room envelope, based on the 1994 changes to the system?

d. What regulatory reviews were performed of these changes? Were dose calculations included to support the licensee's changes?

, 1 i

Discussion Items on Point Beach Amendment Requests (continued)

3. The April 2, .1997 letter from the licensee states the IPF for mode 4 is  ;

approximately 10.5. . q j

a. What should the current IPFs be for each of the four modes of i operation? l

b. How have the IPFs changed since the III.D.3.4 submittal?

4. . .The III.D.3.4 analysis' assumed a 95% iodine removal efficiency for the charcoal filters, but the recent analysis assumed only a 90% efficiency.

a. What should be assumed for charcoal adsorber efficiency based on the tech spec acceptance criteria, actual test protocol, and protocol conditions of temperature and relative humidity?

b. Did the licensee take into account the system flowrate tolerances (plus or minus 10%) and in-place penetration and bypass leakage when calculating the IPF for each mode?

3 3

5. The control room volume increased from 55,195 ft to 65,243 ft since the l III.D.3.4 analysis was submitted. The increased volume may be due to changes '

made in the HVAC system in 1994, which "added" rooms to the control room j envelope. ],

a. Was the change to the control room envelope volume analyzed by the licensee?

b. Was this change to the control room reviewed by the NRC? If so, did NRC staff. take into account the additional heat load of the  ;

computer room when considering mode 3 for long-term (30 days) i accident mitigation purposes? Did the licensee provide a heat load analysis to NRC for review?

]

c. By what regulatory mechanism was this change reviewed? 'Were dose  !

calculations included. in the licensee's analysis?

6. It's PERB's understanding that the licensee upgraded the supply of bottled air for the control room in the early 1990s. PERB/DRPM/NRR needs additional information about this system if credit for use of SCBAs is to be a consideration for dose reduction purposes.

a. Is the system safety-grade?

b. What is the source of fresh air?

c. - How will and air bottles for SCBAs be refilled during an accident and who will perform this task?

7. Is the control room rad monitor on the outlet side of the main inlet fans capable of detecting radioactivity for accident mitigation purposes when the HVAC system operates in the recirculation or pressurization modes?

Discussion Items on Point Beach Amendment Requests (continued)

Auxiliary Buildina

1. The III.D.3.4 submittal credits the use of the auxiliary building HVAC for

. reducing the calculated doses from the LOCA ECCS pathway. The original submittal assumed a charcoal adsorber efficiency of 95%, but the recent submittal does not take credit for filtered releases.

a. Is the system safety grade and can it be relied upon for accident mitigation purposes?

b. Similar to question 4a above, what should be assumed for charcoal adsorber efficiency for this system?

c. 45 the system capable of operating with an assumed loss of offsite power?

2. The licensee recently requested a change in the operation of the effluent radiation monitor for the auxiliary building, which may also serves to actuate the filtration system. How does the licensee's request affect the ability of the system to respond for accident mitigation purposes?

l l

1 l

Control Room HVAC [ heating, ventilation, and air conditioning] Design Mode 1 is the normal HVAC mode, in which 5% of the air flow (1000 cfm) is outside air and 95% (18,800 cfm) is recirculated air. Either fan W1381 and W13B2 supply flow of 19,800 cfm.

Mode 2, which originally consisted of 100% recirculated unfiltered air within the control room, is initiated either by a containment isolation signal or manually from the control room. This design changed when a supply vent was added, during a modification installed in 1994, that allows air from the i control room envelope to exhaust to the room housing the control room HVAC  !

equipment. It also introduced a pathway for unfiltered inleakage from the computer room (which is connected to turbine building via ductwork) or I meci.anical equipment room.

Mode 3, manually initiated from the control room, allows filtered recirculated airflow via fans W14A or W14B.

Mode 4, initiated either by a control room radioactivity signal or by manual initiation, supplies 25% of the available flow (4,950 cfm 110%) with filtered <

outside air while the remaining 75% air flow is unfiltered recirculation '

(14,850 cfm).

Control Room Area Radiation Monitor RE-101 (located on the yest wall of control room indicates dose rates) has a range of 0.1 to 10 mr/hr. This monitor initiates a switch to Mode 4. RE-235 is a noble gas monitor and  !

RE-234 is the control room iodine monitor (RE-234B control room iodine and noble gas sample system background monitor). Only monitor RE-235 initiates a switch to Mode 4.

Electrical supply per FSAR [ Final Safety Analysis Report] Table 8.2-2 accident unit and common loads include the control room filter fan and control room recirculation fan and an instrument air compressor. The auxiliary building i fans are not part of the EDG [ emergency diesel generator] loads.

Filterina Capability Filter banks 2-inch beds removal efficiencies are Elemental Iodine 90%

Methyl Iodine 90%

Particulate 99%

TS [ technical specification) testing requirements for the control room emergency filtration:

HEPA [high efficiency particulate air] filters and charcoal adsorbers shall be tested and analyzed at least once per year, or after 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of operation since the previous test, and following significant painting, fire or chemical release in the control room during filtration operation.

ENCLOSURE 2

4

. i e

\

i Cold D0P testing of the HEPA filter bank shall be performed after each l

! complete or partial replacement of HEPA filters, or after any structural j maintenance on the filter housing. D0P shall be at design velocity

20%.

! Per TS 15.3.12 Operability of the control room emergency filtration during j power operation and refueling operation, except as specified in 15.3.12.3 a below, the control room emergency filtration system shall be operable at all

]

times during power operation and refueling operation of either unit.

The results of in-place cold DOP and halogenated hydrocarbon tests, j conducted in accordance with Spec 15.4.11 on HEPA filter and charcoal adsorber banks shall show a minimum of 99% DOP removal and 99%

i halogenated hydrocarbon removal.

The results of laboratory charcoal adsorbent tests shall show a minimum of 90% removal of methyl iodide. If laboratory analysis results for in-place charcoal indicate less than 90% methyl iodide removal, this specification may

, be met by replacement with charcoal adsorbent which has been verified to 2

achieve 90% minimum removal and which has been stored in sealed containers, and retesting the charcoal adsorber bank for halogenated hydrocarbon removal.

! The results of fan testing, conducted in accordance with specification j 15.4.11, shall show operation within 10% of design flow.

i From the date that the control room emergency filtration is made or

. found to be inoperable, reactor operation or refueling operation of

{ either unit may be continued only during the succeeding 7 days, unless the 1

, system is sooner made operable. l

If the conditions in the paragraph above cannot be met, the operating i reactor (s) shall be brought to cold shutdown conditions within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> j and refueling operations shall be terminated as soon as practicable.

t j Basis: The control room emergency filtration is designed to filter control i room atmosphere and makeup air during control room isolation conditions. HEPA i filters are installed before the charcoal adsorbers to prevent clogging and to

remove essentially all particulate material. Charcoal adsorbers are installed to reduce the potential intake of radioactive iodine to the control room

- during accident conditions. If the system is found to be inoperable, there is 3 no immediate threat to the cor. trol room and operation may continue for a

limited period of time.

As presented in January 16, 1997, letter, "If the methyl iodide efficiency i falls below 95%, the charcoal adsorbers will be replaced with fresh ones and j be' retested in accordance with applicable TS. DOP and Freon tests must show j >99% DOP and Freon removal.

I Based on a control room volume of 65,243 cubic feet, the inleakage as

specified in the April 2,1997, submittal as 65.2 cfm for Mode I and 10.0 cfm

for Mode 4. The licensee assumed 1065.2 cfm for unfiltered inleakage and makeup during Mode I which is greater than the 765.2 cfm that could be assumed in Mode 2.

i

~

)

Iodine Protection Factor (Attachment 3 to April 2, 1997, submittal) for Mode 4 ,

is 10.5 as modeled by the TITAN % computer code. This is less than the factor l 2

of 20 allowed in Murphy-Campe paper for a control room model that only includes filtered intake without any filtered recirculation. J i

l Modification Request (MR)85-025 replaced the original humidifiers to increase I the maximum water flow rate from the demineralized water system to 32.4 lbs/hr l to the control room and 8.3 lbs/ hour to the computer room. Highest humidity I

' was determined to be 55%. Reduced Mode 1 outside air makeup flow from 4950 cfm 1

to 1000 cfm. This did not affect Mode 4 flow of 4950 cfm. '

MR M-620 installed a stand-alone smoke and heat removal subsystem with a dedicated fan (W-13C) to remove heat and smoke from the cable spreading room, }

control room, or computer room. Damper controls exhaust air from one zone at  !

a time. l MR 86-015 changed fire dampers from 1.5-hour rated to 3-hour rated dampers.

MR 87-003 installed gauge to monitor the control room to turbine hall dP. )

MR 87-168 changed the automatic water suppression system for the charcoal filter from a fusible link design to a manual actuation system using approved components.

l MR 93-041 installed in 1994 changed the following:

Changed the CR-HVAC system pneumatic controls to permit operation of control room chiller HX-38B, fail heating temperature control valves to bypass heat exchanger (HX-100A/B) and fail system dampers to Mode 4, following a loss of instrument air. To allow uninterrupted control of system modes, the modification also provided non-interruptible power to control panel C-67. The modification changed the original system configuration aligned to Mode 3 on receipt of a control room high radiation signal to align to Mode 4 to reduce the quantity of negative pressure ductwork subject to unfiltered inleakage, added the computer room to the control room zone, and supplied the mechanical equipment room with filtered air. Installed redundant, diesel-backed power to the control room supply and emergency filtration fans to increase system reliability and keep the operators from having to don air masks in a 4 potentially high temperature environment. )

MR E-237 revised the circuitry such that the CR-HVAC system would remain in Mode 2 when a containment isolation signal was reset.

MR IC-261 added noble gas monitors.

MR 90-103 removed ceiling tiles in control room to increase effective room volumes to address heat up resulting from station blackout.