ML20248G153
| ML20248G153 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 06/02/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20248G150 | List: |
| References | |
| NUDOCS 9806050123 | |
| Download: ML20248G153 (6) | |
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UNITED STATES g
NUCLEAR REGULATORY COMMISSION 0,
WASHINGTON, D.C. 390964cM k * *'***
SAFETY EVALUATION BY THE OFFICE OF NUCI FAR REACTOR REGULATION RELATED TO AMENDMENT NO. 201 TO FACILITY OPERATING LICENSE NO. DPR-71 AND AMENDMENT NO. M1 TO FACILITY OPERATING LICENSE NO DPR-82 CAROLINA POWER & LIGHT COMPANY BRUNSWICK STEAM ELECTRIC PLANT. UNITS 1 AND 2 DOCKET NOS. 50-325 AND 50-324
1.0 INTRODUCTION
By letter dated April 30,1997, as supplemented October 28,1997, and May 15,1998, Carolina Power & Light Company (the licensee) requested amendments to the Surveillance Requirements (SRs) for the Technical Specifications (TS) at the Brunswick Steam Electric Plant (BSEP), Units 1 & 2. The proposed amendments would revise Surveillance Requirements 4.7.2.b.2 and 4.7.2.c to require testing of the control room emergency ventilation system's charcoal (at a temperature of 30*C and a relative humidity of 95%)in accordance with ASTM D3803-1989, " Standard Test Method for Nuclear-Grade Activated Carbon." The current testing demonstrates a filter efficiency of 95%. The proposed amendments would revise the acceptance criteria to allow a filter efficiency of 90%, consistent with the bounding calculations of control room doses. The October 28,1997, and May 15,1998, submittals contained supplementalinformation and did not expand the scope of the original Federal Reaister Notice or change the No Significant Hazards Consideration determination.
2.0 DISCUSSION AND EVALUATION Currently, SRs 4.7.2.b.2 and 4.7.2.c are conducted in accordance with the guidance of Regulatory Position C.6.a of Regulatory Guide 1.52, Revision 1,1976. The current testing assumes a relative humidity (RH) of 70% or less. The licensee discovered that with RH greater l
than 70%, TS testing under the current testing methodology does not assure a charcoal efficiency of 90% for iodine removal as assumed in the current control room dose analyses.
In accordance with the licensee's submittal, the proposed changes to Surveillance Requirements 4.7.2.b.2 and 4.7.2.c require that charcoal samples tested in accordance with the methodology of ASTM D3803-1989 meet the acceptance criteria of <5.0% penetration of methyl iodide. This corresponds to a filter efficiency of 90%, which is the filter efficiency assumed in the current bounding calculations of control room doses. In addition, the licensee DR D
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. states that the proposed acceptance criteria of <5% penetration of methyl lodide ensures that General Design Criterion (GDC) 19 dose limits for control room operators are not exceeded.
Current Requirements Surveillance Requirement 4.7.2.b.2 Verifying within 31 days after removal that a laboratory analysis of a representative carbon sample obtained in accordance with Regulatory Position C.6.b of Regulatory Guide 1.52, Revision 1, July 1976, meets the laboratory testing criteria of Regulatory Position C.6.a of Regulatory Guide 1.52, Revision 1,1976.
Surveillance Requirement 4.7.2.c After every 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of charcoal adsorber operation by verifying within 31 days after i
removal that a laboratory analysis of a representative carbon sample obtained in I
accordance with Regulatory Position C.6.b of Regulatory Guide 1.52, Revision 1, J uly 1976, meets the laboratory testing criteria of Regulatory Position C.6.a of Regulatory Guide 1.52, Revision 1, July 1976.
Prooosed Revision Surveillance Requirement 4.7.2.b.2 Verifying within 31 days after removal that a laboratory analysis of a representative carbon sample obtained in accordance with Regulatory Position C.6.b of Regulatory Guide 1.52, Revision 1, July 1976, and tested in accordance with the methodology provided by ASTM D3803-1989, at a temperature of 30*C' and a relative humidity of 95%', meets the acceptance criteria of <5.0% penetration of methyllodide.
Surveillance Requirement 4.7.2.c After every 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of charcoal adsorber operation by verifying within 31 days after removal that a laboratory analysis of a representative carbon sample obtained in j
accordance with Regulatory Position C.6.b of Regulatory Guide 1.52, Revision 1, July i
1976, and tested in accordance with the methodology provided by ASTM D3803-1989, at a temperature of 30*C ', and a relative humidity of 95%', meets the acceptance criteria of <5.0% penetration of methyllodide.
Current TS 4.7.2.b.2 and 4.7.2.c require that laboratory analyses of the carbon samples use the test procedures of and meet the acceptance criteria of Regulatory Position C.6.a of RG 1.52, Revision 1. Regulatory Position C.6.a refers to Table 3 of RG 1.52, Revision 1. Table 3 I
2 Laboratory testing within the temperature and humidity tolerances provided in Table 1 of ASTM D3803-1989 constitutes compliance with Surveillance Requirements 4.7.2.b.2 and 4.7.2.c.
l
. references test Sb in table 2 of RG 1.52, Revision 1. Test 5.b references the test method from paragraph 4.5.3 of Military Specification RDT M 16-1T," Gas Phase Adsorbents for Trapping Radioactive lodine and lodine Components," October 1973, but specifies that the test is to be conducted at 80*C and 95 % RH with preloading and postloading sweep at 25'C. This test is referred to as the "25-80-25 test." The essential elements of this test are as follows:
e 70-percent RH for air filtration systems designed to control the RH to 70 percent, 5-hour pre-equilibration (pre-sweep) time, with air at 25'C and 70 percent RH, e
2-hour challenge, with gas at 80'C and 70 percent RH, and I
e A 2-hour elution (post-sweep) time, with air at 25'C and 70 percent RH.
i Note that the proposed SRs also require that samples be obtained as described in Regulatory Posi'hn C.6.b of RG 1.52, Revision 1, but specify that the samples be tested in accordance with ASTM D3803-1989, "Stanc'ard Test Method for Nuclear-Grade Activated Carbon
- at 30*C and 95 percent RH. ASTM D3803-1989 is updated guidance based on an NRC verification and validation effort on ASTM D3803-1979, which is updated guidance based on RDT M16-1T. The essential elements of the proposed SR change for testing per ASTM D3803-1989 are:
e 95-percent RH 2-hour thermal stabilization, at 30*C, e
16-hour pre-equilibration (pre-sweep) time, with air at 30'C and 95 percent RH, e
2-hour equilibration time, with air at 30'C and 95 percent RH, e
1-hour challenge, with gas at 30'C and 95 preent RH, and e
1-hour elution (post-sweep) time, with air at 30'C and 95 percent RH.
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4 The major differences between the current and proposed SR requirements for carbon testing are:
MAJOR DIFFERENCES Proposed TS Current TS Pre-Equilibration 30*C 25'C (Pro-Sweep) Temperature
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Challenge Temperature 30;C 80'C l
Elution (Post-Sweep) 30'C 25*C Temperature l
Total Pre-Test Equilibration 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> 5 hours Relative Humidity S5%
70%
Tolerances of Test Smaller.
Larger Parameters l
The discussion below demonstrates that these differences make the proposed SRs more conservative than the present requirements.
ASTM D3803-1989 challenges the representative charcoal s.mples at 3C nher than at
' 80*C. The quantity of water retained by charcoal is dependent on tempe moro, with less water being retained as the temperature rises. The water retained by the charcoal decreases its efficiency in adsorbing other contaminants. Because most charcoalis anticipated to be challenged at a temperature closer to 30'C rather than 80*C, the lower temperature test condition of ASTM D3803-1989 will yield more realistic results than a test performed at 80*C.
ASTM D3803-1989 specifies a test temperature of 30*C for both the pre-and post-test sweep rather than 25'C. There is little difference in the adsorption behavior of charcoal between these two temperatures. A temperature of 25'C is more conservative; however, the increase from' 25'C to 30'C does not represent a significant variation in the test results.
ASTM D3803-1989 provides results which are reproducible compared to RDT M16-1T because it has smaller tolerances on various test parameters, and it requires that the charcoal cam:>le be pre-equilibrated for a much longer period. The longer pre-equilibration time is more conservative because it will completely saturate the representative charcoal sample until it is in the condition to which the subject charcoal adsorbers are expected to be exposed during design-basis accident conditions. During the pre-equilibration, the charcoalis exposed to a flow of air controlled at the test temperature and RH before the challenge gas is fed through the charcoal. The purpose of the pre-equilibration phase of the test is to ensure that the charcoal has stabilized at the specified test temperature and RH.for a period of time which results in the
- charcoal adsorbing all the available moisture before the charcoal is challenged with methyl iodide. Hence~, the proposed testing in accordance with ASTM D-3803-1989 standard would result in a more realistic' prediction of the capability of the charcoal.
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Performing the laboratory test of the charcoal samples at 70% RH is based on the system being designed to maintain the RH of the air stream entering the charcoal to s70% under worst-case design basis conditions. The licensee discovered that the system could not maintain the RH to s70%. Therefore, the licensee has proposed to test at an RH of 95% instead of 70% to ensure that the charcoal can perform its function under worst-case design basis conditions.
This is consistent with the requirements of ASTM D3803-1989 and is acceptable.
Proposed SRs 4.7.2.b.2 and 4.7.2.c require that the laboratory testing of charcoal samples shows a methyl iodide penetration of 55%. In the licensee's dose analysis, the control room emergency ventilation system charcoal beds are credited with a filter efficiency of 90%. The licensee's proposed acceptance criteria of s5% methyl iodide penetration for the control room emergency ventilation system includes 'a safety factor of two which provides the staff with a degree of assurance that, at the end of the operating cycle, the charcoal will be capable of performing at a level at least as good as that assumed in the licensee's dose analysis. This factor of safety is acceptable based on the accuracy of test results obtained using the ASTM D3803-1989 standard.
The testing criteria of ASTM D3803-1989 are more stringent than those provided by the guidance of Regulatory Position C.6.a of Regulatory Guide 1.52, Revision 1,1976. For example, the testing temperature required by ASTM D3803-1989 is 30*0.2'C whereas the testing temperature of Regulatory Guide 1.52 is 8012*C. ASTM D3803-1989 requires an RH of 95% versus 70% for Regulatory Guide 1.52. Because of these parameters, testing in accordance with the requirements of ASTM D3803-1989 is more conservative than testing in accordance with the criteria of Regulatory Position C.6.a of Regulatory Guide 1.52, Revision 1, 1976.
The NRC staff reviewed the proposed changes to SRs 4.7.2.b.2 and 4.7.2.c and concluded that the proposed changes to the SRs will revise the control room emergency ventilation system charcoal filter testing program for BSEP such that these changes will correct the existing flawed test methodology.- The staff also concluded that the proposed changes will adequately demonstrate the operability of the sh am, and therefore, are acceptable.
3.0 STATE CONSULTATION
in accordance with the Commission's regulations, the State of North Carolina official was notified of the proposed issuance of the amendments. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
These amendments involve a change in the installation or use of a facility component located 7
within the restricted area, as defined in 10 CFR Part 20, and change surveillance requirements.
The NRC staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any efflue sts that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (62 FR 40846). Accordingly, the amendments meet the eligibility criteria for categorical
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o.
) impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.'
5.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor. H. Walker, NRR/DSSA Date:
June 2,1998 l
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