ML100840083

Preliminary RAIs - Watts Bar Unit 2 FSAR Chapter 12

ML100840083
Person / Time
Site:	Watts Bar
Issue date:	03/25/2010
From:	Joel Wiebe Watts Bar Special Projects Branch
To:	Arent G, Stockton R Tennessee Valley Authority
Wiebe, Joel NRR/DORL/WBSP, 415-6606
References
Download: ML100840083 (4)

Text

From: Wiebe, Joel Sent: Thursday, March 25, 2010 8:24 AM To: 'Gordon Arent'; 'Ricky Stockton'

Subject:

Preliminary RAIs - FSAR Chapter 12

1. Amendment 95 revised FSAR Section 12.2.1.3 to include incore instrumentation thimble assemblies as important radioactive sources during refueling operations and deleted the incore detectors from this list. Provide an analysis of the impact of the dose rates to areas of the plant with the thimbles stored in the BMI guide tubes, as described.

Describe the plant design features that minimize radiation exposure to plant individuals from this radiation source.

2. Amendment 95 revised the estimated airborne radioactivity concentrations listed in Tables 12.2-19 and 12.2-22. Provide a description of what changed in the Watts Bar design that resulted in the revised values of airborne contamination?

3. Amendment 97 revised the last paragraph of page 12.3-1 to read, Typically, cleaner areas are exhausted to areas of higher potential airborne radioactivity [emphasis added]. List those areas of the plant where this is not the case and describe compensatory measures to minimize the spread of contamination from high to lower airborne areas.

4. As required by 10 CFR 20.1406, describe the Watts Bar Unit 2 design features and operating procedures that will minimize, to the extent practicable, contamination of the facility and the environment to facilitate decommissioning.

5. Amendment 97, in Section 12.3.1 revised the discussion of the radiation source terms used in the facility design.

a. NUREG-0800, Standard Review Plan, identifies that 0.25% fuel cladding defects is considered an acceptable source term. NUREG-0847, Safety Evaluation Report related to the operation of Watts Bar Nuclear Plant, Units 1 and 2, Supplement 14, Section 12.3 states that the descriptions of radioactive sources conform to the acceptance criteria of the Standard Review Plan and therefore are acceptable to the staff. The revised text refers to 1/8% failed fuel. Verify that the source term used for the design (normal operation) of the radiation shielding and ventilations system continues to be based on 0.25% fuel cladding defects, consistent with the acceptance criteria of the Standard Review Plan (NUREG 0800) and NUREG-0847, or provide information demonstrating the acceptability of the use of 1/8% failed fuel as the source term.

b. The last sentence of the revised text indicates that the radiation accident levels are based on the Oak Ridge National Laboratory ORIGEN computer code. The ORIGEN code calculates the inventory of radionuclides in the reactor core, it does not determine the types and quantities of radioactive materials released into plant systems during the accident. Verify that the accident source term used in the design of the Watts Bar 2 radiation protection design features is consistent with the guidance in TID-14844 and NRREG 0737, Action Item II.B.2.

6. Provide plant lay out drawings that indicate the radiation zoning for accident conditions in each of the vital areas (listed on pages 12.3-13 and 12.3-14 of the FSAR) and the planned access/egress routes to these vital areas.

7. The text at the top of page 12.3-3 indicates that the layout drawings provided show the controlled access areas, decontamination areas, onsite laboratories and counting rooms. However, Amendment 97 deleted FSAR Figures 12.3-18 and 19 that contained the drawings of these design features. Provide drawings that indicate the location and arrangement of these radiation protection features.

8. Amendment 97 revised the frequency of the radiation monitor channel operability tests.

Describe the criteria used in the Technical Specifications, ODCM, and plant procedures to determine the frequency of these tests. Provide a basis for concluding that the operability tests will be performed at a frequency sufficient to detect operability issues with the monitors in a timely manner.

9. Provide a description of the radiation monitoring in areas where reactor fuel is handled or stored sufficient to demonstrate compliance with the requirements of 10 CFR 70.24 or 10 CFR 50.68.

10. Amendment 97 revised the description of the airborne monitoring channels on page 12.3-21 of the FSAR to replace the seven (7) channels of airborne monitors previously indicated for the Auxiliary Building with four (4) portable airborne monitors.

a. Verify that these portable monitors will detect a 10 DAC-hour change in airborne levels in the areas monitored.

b. Describe the controls in place to ensure these portable monitors will not be inadvertently relocated from their intended monitoring areas.

c. Are these monitors different than the CAMs used to monitor the sample rooms, and waste packing areas?

d. Verify that the Containment upper and lower monitors are able to detect a 10 DAC-hour change in airborne levels in the areas they monitor.

e. Verify that these monitors alarm locally on high airborne conditions as well as instrument malfunction and high radiation.

11. Provide a basis for deleting the radiation monitors (listed on table 12.3-4) from the Unit 1 and 2 post accident sample rooms.

12. Amendment 95 revised FSAR Section 12.4, Dose Assessment. This revised assessment is of insufficient detail to meet the guidance in Regulatory Guide (RG) 8.19.

In addition, the 120 person-rem/outage dose estimate in the revised assessment is not consistent with Watts Bar Unit 1 operating history. Provide a revised assessment that meets the criteria in RG 8.19 and describe what measures will be employed in the Unit 2 operations to improve on the annual collective dose experienced in operating Unit 1.

13. The first sentence at the top of page 12.5-2 states that the minimum qualification requirements for the Radiation Protection Manager are stated in Section 13.1.3 of the

FSAR. Section 13.1.3 refers to Regulatory Guide 1.8 with the alternatives identified in NUCLEAR QUALITY ASSURANCE PLAN, TVA-NQA-PLN89-A. Clarify which alternatives in TVA-NQA-PLN89A could be applied to the Radiation Protection Manager, if any.

14. The discussion of High Radiation Area controls at the top of page 12.5-5 indicates that High Radiation Areas with dose rates greater than 1.0 rem/hour, but less than 500 rads/hour, will be posted as a Locked High Radiation Area, but does not indicate that they will actually be maintained locked. Clarify the proposed controls for these areas.

Typographical Errors

1. The header to page 12.2-35 of the FSAR indicates that it was revised by Amendment 95; however, it appears no change was made to this page.

2. On page 12.3-2, fourth paragraph, ANSI/ANS 18.1 Revision 0 of was dated 1976 not 1984, as stated.

3. On Page 12.5.6, in the middle of the page, ectering should read entering.

E-mail Properties Mail Envelope Properties (F371D08C516DE74F81193E6D891DC4AF304B3F30BF)

Subject:

Preliminary RAIs - FSAR Chapter 12 Sent Date: 3/25/2010 8:23:45 AM Received Date: 3/25/2010 8:23:00 AM From: Wiebe, Joel Created By: Joel.Wiebe@nrc.gov Recipients:

GArent@tva.gov ('Gordon Arent')

Tracking Status: None RAStockton@tva.gov ('Ricky Stockton')

Tracking Status: None WBN2HearingFile.Resource@nrc.gov (WBN2HearingFile Resource)

Tracking Status: None Post Office:

HQCLSTR02.nrc.gov

Files Size Date & Time MESSAGE 18196 3/25/2010 Options Expiration Date:

Priority: olImportanceNormal ReplyRequested: False Return Notification: False Sensitivity: olNormal Recipients received: